To see the other types of publications on this topic, follow the link: Retinal nerve fiber layer.
Dissertations / Theses on the topic 'Retinal nerve fiber layer'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 49 dissertations / theses for your research on the topic 'Retinal nerve fiber layer.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Hayashi, Celina. "Vitamin D and Retinal Nerve Fiber Layer Thickness in Patients with Multiple Sclerosis." Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/scripps_theses/325.
Full textAbstract:
Multiple Sclerosis (MS) is a neurological autoimmune disease characterized by demyelination of central nervous system tissue and one way this is presented is in the demyelination of the retinal nerve, causing vision disturbance and loss (Munger et al., 2006). The thinning of the retinal nerve fiber layer (RNFL) can be measured and visualized using a noninvasive technique called Optical Coherence Tomography (OCT), which is also used to measure relative MS severity (Petzold et al., 2010). One environmental factor that has been found to have a relationship with MS is vitamin D; research findings suggest that sufficient levels of vitamin D may reduce the risk of developing MS, decrease MS severity, and may slow its progression (Ascherio et al., 2010; Munger et al., 2006; Muris et al., 2013). The mechanism by which vitamin D affects certain symptoms requires deeper investigation.
This research examines the relationship between serum concentrations of 25-hydroxyvitamin D and retinal nerve fiber layer thicknesses in patients with MS. It was hypothesized that patients with sufficient vitamin D levels would have less demyelination of the retinal nerve caused by MS, and therefore would have a thicker RNFL in both eyes based on the proposed immunomodulatory role of vitamin D found in other studies. Blood samples were assayed to measure the concentration of 25-hydroxyvitamin D and OCT was used to measure RNFL thicknesses in patients with MS at the Harbor-UCLA Medical Center Neurology Clinic. Patients with sufficient levels of 25-hydroxyvitamin D had a greater mean global RNFL thickness in both eyes than in patients with insufficient levels of 25-hydroxyvitamin D; however the differences were not significant. Further research is necessary in order to determine whether or not there is a correlation between vitamin D and RNFL thickness and what role vitamin D plays in MS presentation.
2
Häntzschel, Janek, Naim Terai, Olga Furashova, Karin Pillunat, and Lutz E. Pillunat. "Comparison of Normal- and High-Tension Glaucoma: Nerve Fiber Layer and Optic Nerve Head Damage." Karger, 2014. https://tud.qucosa.de/id/qucosa%3A70550.
Full textAbstract:
Purpose: The aim of this study was to investigate differences in the nerve fiber layer and glaucoma-induced structural optic nerve head (ONH) damage in patients with normal- (NTG) and high-tension (HTG) glaucoma. Methods: In this retrospective pair-matched comparative study, 22 NTG and 22 HTG eyes were matched according to the same glaucomatous damage based on rim volume, rim area and disk size, as measured by Heidelberg retinal tomography (HRT III). Visual fields (VF) were assessed by Humphrey perimetry, and nerve fiber layer thickness was determined both by scanning laser polarimetry (GDxVCC) and spectral-domain optical coherence tomography (SD-OCT). Comparisons of all measured parameters were made between NTG and HTG groups. Results: Based on HRT results, both NTG and HTG eyes displayed comparable structural damage to the ONH (NTG/HTG, mean: disk area, 2.30/2.31 mm 2 , p = 0.942; rim area, 1.02/0.86 mm 2 , p = 0.082; rim volume, 0.19/0.17 mm 3 , p = 0.398). NTG eyes had significantly less VF damage than HTG eyes (NTG/HTG, mean deviation: –4.23/–12.12 dB, p = 0.002; pattern standard deviation: 5.39/8.23 dB, p = 0.022). The inferior nerve fiber layer of NTG patients was significantly thicker than that of HTG patients (NTG/HTG, mean: GDx inferior: 53.5/46.3 μm, p = 0.046). SD-OCT revealed a significantly thicker nerve fiber in NTG compared with HTG patients in all quadrants (NTG/HTG, total mean: 72.72/58.45 μm, p = 0.002). Conclusion: At comparable glaucomatous stages, nerve fiber loss was more advanced in HTG patients compared with NTG patients.
3
Nukada, Masayuki. "Detection of localized retinal nerve fiber layer defects in glaucoma using enhanced spectral-domain optical coherence tomography." Kyoto University, 2013. http://hdl.handle.net/2433/174800.
Full text
4
Nevalainen, J. (Jukka). "Utilisation of the structure of the retinal nerve fiber layer and test strategy in visual field examination." Doctoral thesis, University of Oulu, 2010. http://urn.fi/urn:isbn:9789514262012.
Full textAbstract:
Abstract
The aim of this study was to create a mathematical model of the retinal nerve fiber layer and of the entire hill of vision, and to compare different perimetric methods and test grids in the detection of visual field loss in glaucoma and optic neuritis.
A mathematical model of the retinal nerve fiber layer was developed, based on traced nerve fiber bundle trajectories extracted from 55 fundus photographs of 55 human subjects. The model resembled the typical retinal nerve fiber layer course within 20° eccentricity from the foveola. The standard deviation of the calculated corresponding angular location at the optic nerve head circumference ranged from less than 1° up to 18° (mean 8.8°).
A smooth mathematical model of the hill of vision was created, based on 81 ophthalmologically healthy subjects. The model fit R2 was 0.72.
Applying individually condensed test grids in 41 glaucomatous eyes of 41 patients enhanced remarkably the detection of progression. Seven out of 11 (64%) of the progressive scotomata detected by spatially condensed grids would have been missed by the conventional 6° × 6° grid.
In 20 eyes of 20 patients with advanced glaucoma, the comparability of visual field areas obtained with semi-automated kinetic perimetry and automated static perimetry was satisfactory and within the range of the test-retest reliability of automated static perimetry.
Using a standardized grid of 191 static targets within the central 30° visual field, the most common finding in 100 eyes of 99 patients with acute optic neuritis were central scotomas, accounting for 41% of all visual field defects in affected eyes.
In conclusion, a model of the retinal nerve fiber layer was developed, which provided a detailed location specific estimate of the magnitude of the variability on the courses of retinal nerve fiber bundle trajectories in the human retina. A smooth mathematical model of the hill of vision with a satisfactory model fit was described for the 80° visual field. Individually condensed grids enabled the detection of a glaucomatous visual field progression more frequently and also earlier than conventional grids. Semi-automated kinetic perimetry was found to be a valuable alternative to automated static perimetry in monitoring advanced glaucomatous visual field loss. Using a grid with a higher spatial resolution may enhance the detection of small central visual field loss in optic neuritis.
5
Clayton, L. M. "Peripapillary retinal nerve fibre layer thickness in individuals with epilepsy exposed to vigabatrin." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1331875/.
Full textAbstract:
Background: The antiepileptic drug vigabatrin (VGB) is associated with the development of visual field loss in around 50% of exposed individuals. The mechanisms of VGB retinotoxicity are unknown, and there is continued debate as to the best methods of assessing visual function in VGB-exposed individuals, particularly in those unable to perform perimetry. Methods: 204 VGB-exposed individuals, 90 non-exposed individuals with epilepsy and 90 healthy controls participated. Individuals underwent visual field testing using Goldmann kinetic perimetry and peripapillary retinal nerve fibre layer (ppRNFL) imaging using optical coherence tomography (OCT). Results: A retrospective analysis of the evolution of vigabatrin associated visual field loss (VAVFL) in individuals continuing VGB showed progression of VAVFL in all individuals over a ten-year period. More VGB-exposed individuals were able to perform OCT compared to perimetry. Measures of ppRNFL thickness were found to be highly repeatable in this population. There was a strong correlation between ppRNFL thickness and visual field size suggesting that irreversible VAVFL may be related to loss of retinal ganglion cells (RGCs). Duration of VGB exposure, maximum daily VGB dose, male gender and the presence of a homonymous visual field defect were associated with ppRNFL thinning. The pattern of ppRNFL thinning suggested that ppRNFL loss progresses with increasing VGB exposure. Subtle ppRNFL thinning may occur in discrete areas after exposure to small amounts of VGB, whilst other ppRNFL areas appear to be resistant to large cumulative VGB exposure. The ppRNFL was significantly thinner in non-exposed individuals with epilepsy compared to healthy controls. Factors that may be associated with ppRNFL thinning included the presence of learning disability, MTLE with HS and longer duration of epilepsy. Conclusions: ppRNFL imaging using OCT provides a useful tool to assess VGB-exposed individuals, and can provide an accurate estimate of the extent of VAVFL in the absence of a reliable direct measure of the visual field. Understanding patterns of ppRNFL thinning associated with cumulative VGB-exposure may aid in the early detection of VGB toxicity. Pathophysiological mechanisms of VAVFL are unknown; however, pathology of RGC apparatus is evidently implicated.
6
Saarela, V. (Ville). "Stereometric parameters of the Heidelberg Retina Tomograph in the follow-up of glaucoma." Doctoral thesis, University of Oulu, 2010. http://urn.fi/urn:isbn:9789514263286.
Full textAbstract:
Abstract
Glaucoma is a progressive neuropathy of the optic nerve. It causes degeneration of ganglion cell axons resulting in defects in the retinal nerve fibre layer (RNFL) and characteristic changes in the optic nerve head (ONH). The Heidelberg Retina Tomograph (HRT) is a confocal scanning laser imaging device, which measures the topography of the ONH and the adjacent RNFL. To quantify the measurements of the ONH topography, various stereometric parameters are calculated.
The change in the stereometric parameters of the HRT was studied in 34 eyes with glaucomatous progression in RNFL photographs and 34 eyes without progression. The change in only one stereometric parameter, the cup shape measure, showed a statistically significant correlation with the progression of the RNFL defect. An optimised change in the best three-parameter combination had 77% sensitivity and 79% specificity for progression.
The change in the stereometric parameters was compared in 51 eyes with glaucomatous progression in stereoscopic ONH photographs and 425 eyes without progression. The parameters having the best correlation with progression include cup:disc area ratio, vertical cup:disc ratio, cup volume and rim area. The parameter with the largest area under the receiver operating characteristics curve (0.726) was the vertical cup:disc ratio. A change of 0.007 in the vertical cup:disc ratio had a sensitivity of 80% and a specificity of 65% for progression.
The factors having the most significant effect on the sensitivity and specificity of the stereometric parameters for progression were the reference height difference and the mean topography standard deviation, indicating image quality. The change in image quality and age also showed a consistent, but variably significant influence on all parameters tested.
Exercise was associated with an increase in variance in 17 of the 18 stereometric parameters.
In conclusion, the change in the stereometric parameters provides useful information on ONH topography, especially when image quality is excellent. However, the evaluation of glaucomatous progression should not rely solely on the stereometric parameters of the HRT.
7
Mok, Kwok-hei, and 莫國熙. "The characterization of retinal nerve fiber layer thickness in normal,high-tension and normal-tension glaucoma using optical coherencetomography." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B31381005.
Full text
8
Mok, Kwok-hei. "The characterization of retinal nerve fiber layer thickness in normal, high-tension and normal-tension glaucoma using optical coherence tomography." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31381005.
Full text
9
Siik, S. (Seppo). "Lens autofluorescence:in aging and cataractous human lenses. Clinical applicability." Doctoral thesis, University of Oulu, 1999. http://urn.fi/urn:isbn:9514252675.
Full textAbstract:
Abstract
This study was carried out to investigate in vivo the changes
of the human lens autofluorescence (AF) with aging and cataractogenesis.
Measurements were performed in the blue-green AF range (495 nm/520
nm) using a fluorometer designed, built and now clinically tested
in our department.
43 random eyes of 43 healthy volunteers aged 6-86 years, five
of each decade, were studied for effects of aging and 84 eyes of
84 patients with cortical, nuclear, posterior subcapsular or mixed
lens opacities were studied for differences of various cataract
types. The results were compared with the back light scatter values
obtained by the commercially available Interzeag Lens Opacity Meter
701. Also AF and back light scatter of the lens were measured from
122 smoking males aged 57 to 76 years who participated in a cancer
prevention study. The results were compared with the widely used
subjective lens opacities classification system, LOCS III. In addition
data was collected from 30 randomly chosen eyes of as many subjects
with varying degrees of yellow-brown lens coloration in an otherwise
healthy eye. We studied the influence of lens yellowing expressed
by means of lens AF on visibility of retinal nerve fiber layer
in black-and-white images.
Lens AF profile consists of anterior and posterior peaks and
a central plateau. The height of the anterior peak was used as
a measure of the maximum AF value. The square root of the ratio
between the posterior and the anterior AF peaks was used for estimating
the lens transmission. Our technique was highly reproducible. The
coefficient of variation was 3.9% for maximum AF and 2.9% for
the lens transmission index.
Both the maximum AF and light scatter were exponentially increased
with age (r = 0.95 and 0.94, respectively; p < 0.0001).
According to the regression line of AF begins to increase in early
childhood. It appears by extrapolation to be absent at birth. In
contrast light scatter in the lens was present even in young children.
The lens transmission for blue-green light, determined from the
lens AF curve, was almost unchanging with age up to 60 years. Thereafter
it decreased rapidly and the interindividual variation increased.In
cataractous lenses the mean AF and scatter values differed statistically
significantly from those of age matched healthy controls. The highest
AF values were measured in nuclear cataracts where AF was also
related to visual acuity and an increasing yellow-brown colour
of the nucleus. About half of the total variation of the transmission
index values could be accounted for by changes in nuclear colour
as assessed by the LOCS III grading system. The transmission index
provided a more precise prediction about nuclear colour and opalescence
than age or light scatter did.
In cortical cataracts the AF curve was low and flattened and
the maximum AF value was significantly lower than in the age matched
control eyes. The highest light scatter values were measured from
cortical cataracts, but the correlation between LOCS III cortical
grades and light scatter values was rather weak.
Posterior subcapsular cataracts cannot be quantified either
with AF or with light scatter measurements. Lens yellowing, expressed
as lens AF, had an actual effect on retinal nerve fiber layer visibility.
AF measurements provided a better prediction about the visibility
score than age or visual acuity did.
The results of the present study indicate that the lens autofluorescence
measurement may be a useful additional tool together with a subjective
grading system in the follow-up of optical changes occurring in
the nuclear region of the lens.
10
Tatham, Andrew John. "The clinical relevance of structural changes of the optic nerve head and retinal nerve fibre layer in glaucomatous optic neuropathy." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10046134/.
Full textAbstract:
BACKGROUND: Imaging is widely used to quantify glaucomatous structural changes. Although previous studies have examined the relationship between structure and function, measured using standard automated perimetry (SAP), the true relevance of structural changes remains poorly understood. AIM: The aim of this body of work was to explore the structure-function relationship and to ascertain the point at which structural changes become associated with impaired ability to perform vision-dependent tasks. PLAN OF RESEARCH: After critically appraising previously described structurefunction models, an investigation was conducted progressively evaluating the relationship between glaucomatous structural changes and 1) estimated loss of retinal ganglion cells (RGCs), 2) an objective measure of visual function (the pupil response), and 3) a vision-related task relevant to quality of life (driving). RESULTS: Localised RNFL defects visible on photographs, a common manifestation of glaucoma, were associated with large estimated RGC losses. However, problems were identified with the published method of RGC estimation. Asymmetric RNFL thinning was also found to be associated with asymmetry of the pupil response, and the magnitude of asymmetry required for a clinically detectable relative afferent pupillary defect (RAPD) was calculated. Finally, loss of RNFL was associated with worse ability to perform a simulated driving task, providing additional information to SAP alone. SIGNIFICANCE: Glaucomatous structural defects may be associated with significant functional impairment. Incorporating information from both structure and function may improve our ability to predict patients at risk of developing problems with vision-related tasks of daily living.
11
Md, Din N. B. "Elevated intraocular pressure in uveitis : effects on the retinal nerve fiber layer, clinical course and surgical outcome in adults and children." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1457525/.
Full textAbstract:
Intraocular Pressure (IOP) elevation is a pertinent risk factor for glaucoma in uveitis. Macula oedema and disc swelling may mask glaucoma assessment making glaucoma detection challenging. This thesis aimed to evaluate whether peripapillary retinal nerve fiber layer (RNFL) measurement with the spectral-domain optical coherence tomography (SD-OCT) can be a conjunctive method. We reviewed records of 309 patients with uveitis and analysed the SD-OCT results. Mean RNFL was thicker in uveitic compared to normal eyes. RNFL thinning was seen in all except the temporal quadrant of glaucomatous but only in the inferior quadrant of hypertensive uveitic eyes. RNFL defect was detected in approximately 20% of hypertensive eyes without clinical signs of glaucoma. Older age, higher maximum IOP and uveitis-induced IOP elevation were risk factors for RNFL defect and glaucoma. Reduced RNFL thickness correlated with worsening Humphrey visual field (VF) mean deviation. A chart review of 103 children with non-Juvenile Idiopathic Arthritis-related uveitis revealed IOP elevation occurred in approximately 40% of children, steroid-induced in 35% of eyes with nearly 70% of them being high responders. Chronic uveitis was a strong risk factor for IOP elevation and glaucoma. The RNFL was thicker in uveitic compared to normal eyes. We found no RNFL thinning in hypertensive but significant thinning only in the inferior quadrant of glaucomatous uveitic eyes. The outcome of the second compared to the first eyes of 30 patients with bilateral uveitis and raised IOP who underwent bilateral glaucoma surgery was assessed. We postulated the second eyes would suffer more from oral acetazolamide omission following early phases of surgery. The surgical success rates were comparable with no significant visual acuity progression. Although the survival rate of the cup-to-disc ratio progression was worse in the second eye within the first 5 postoperative years, no significant difference was detected in the Humphrey VF progression.
12
Takayama, Kohei. "High-Resolution Imaging of Retinal Nerve Fiber Bundles in Glaucoma Using Adaptive Optics Scanning Laser Ophthalmoscopy." Kyoto University, 2013. http://hdl.handle.net/2433/180344.
Full text
13
Bruce, Alison. "Structural Integrity of Eyes Diagnosed with Amblyopia. The measurement of retinal structure in amblyopia using Optical Coherence Tomography." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4894.
Full textAbstract:
Amblyopia is the leading cause of monocular visual impairment in children. Therapy for amblyopia is extremely beneficial in some children but ineffective in others. It is critical that the reasons for this discrepancy are understood. Emerging evidence indicates that current clinical protocols for the diagnosis of amblyopia may not be sufficiently sensitive in identifying individuals who, on more detailed examination, exhibit subtle structural defects of the eye. Presently, the magnitude of this problem is unknown. The aim of this study was to establish the prevalence of subtle retinal/optic nerve head defects in eyes diagnosed with amblyopia, to distinguish between possible explanations for the origin of such defects and to investigate the relationship between quantitative measures of retinal structure, retinal nerve fibre layer thickness and optic nerve head dimensions. Using the imaging technique of Optical Coherence Tomography (OCT) retinal structure has been investigated in detail, following the visual pathway across the retina from the fovea, via the paramacular bundle to the optic disc, where peripapillary retinal nerve fibre thickness has been imaged and subjected to detailed measures along with optic disc size and shape. The study formed two phases, the first imaging the eyes of visually normal adults and children, comparing them to amblyopes, both adults and children who had completed their treatment. The second phase, a longitudinal study, investigated retinal structure of amblyopic children undertaking occlusion therapy for the first time. By relating pre-therapy quantitative measures to the visual outcome the second phase of the study aimed to examine whether OCT imaging could identify children achieving a poor final outcome. The results show a clear picture of inter-ocular symmetry structure in all individuals, visually normal and amblyopic. Optic disc characteristics revealed no structural abnormalities in amblyopes, in any of the measured parameters, nor was there any association between the level of visual acuity and the measured structure. At the fovea differences were shown to occur in the presence of amblyopia, with thickening of the fovea and reduction of the foveal pit depth. The structural changes were found to be both bilateral and symmetrical with the fellow eye also affected. In the longitudinal phase of the study these changes were demonstrated to a greater extent in children who 'failed' to respond to treatment. This bilateral, symmetrical structural change found at the fovea, which has not been previously reported, cannot therefore be the primary cause of the visual loss which has been diagnosed as amblyopia.
14
Vihanninjoki, K. (Kyösti). "The Heidelberg Retina Tomograph in the diagnosis of glaucoma." Doctoral thesis, Oulun yliopisto, 2017. http://urn.fi/urn:isbn:9789526216737.
Full textAbstract:
Abstract Glaucoma is a group of eye diseases characterized by a chronic, progressive optic neuropathy. During the disease process, the axon damage of the retinal ganglion cells leads to changes in the retinal nerve fiber layer, causing optic nerve head, and visual field defects typical of glaucoma. The Heidelberg Retina Tomograph (HRT) is a confocal scanning laser imaging device acquiring and analysing three-dimensional data of the ocular fundus wit good accuracy and reproducibility. Conventional planimetric measurements were compared to those taken with the HRT in a pilot study of 12 eyes with early glaucomatous optic disc, retinal nerve fiber layer and/or visual field abnormalities. The neuroretinal rim area measurements and cup-to-disc area ratio did not differ statistically from each other when using these two different methods. The effect of four different reference levels on the HRT parameter measurement values was tested in two separate studies. In the first study there were 67 eyes, 40 of the eyes were healthy and 27 eyes had glaucoma of different stages. Then, 279 eyes, 180 of which were non-glaucomatous and 99 glaucoma eyes, were included in another study. The flexible reference level gave the most reliable HRT parameter measurement values in both non-glaucomatous and glaucomatous eyes. The ability of the HRT parameters to separate between non-glaucomatous and glaucomatous eyes was tested in 77 eyes, 40 of the eyes were non-glaucomatous, 10 ocular hypertensives and 27 eyes had different stages of glaucoma. The reference level dependent HRT parameters cup-to-disc area ratio, vertical linear cup-to-disc ratio, mean retinal nerve fiber layer thickness (RNFLt) and rim volume as well as the reference level non-dependent HRT parameter, cup shape measure (CSM), separated best between the clinical groups. The best combination of the HRT and other structural and functional parameters in separating between non-glaucomatous and glaucomatous eyes was studied in 55 eyes. There were 32 non-glaucomatous eyes and 23 eyes with ocular hypertension or glaucoma. CSM, RNFLt, together with age- and lens coloration-corrected mean deviation of the B/Y perimetry showed good discrimination (ROC area 0.91) between non-glaucomatous and glaucomatous eyesTiivistelmä Glaukooma koostuu joukosta hitaasti eteneviä näköhermon rappeumasairauksia. Sairausprosessin aikana verkkokalvon gangliosolujen aksonivaurio johtaa muutoksiin verkkokalvon hermosäiekerroksessa ja näköhermon päässä aiheuttaen glaukoomalle tyypillisiä näkökenttämuutoksia. The Heidelberg Retina Tomograph (HRT) on konfokaali laserskanneritekniikkaan perustuva kuvantamislaite, joka tuottaa ja analysoi silmänpohjasta saatua kolmiulotteista mittaustietoa tarkasti ja toistettavasti. Tavanomaisen planimetrian antamia mittaustuloksia verrattiin HRT:n antamiin tuloksiin 12:ssa silmässä, joissa oli todettu varhaisia glaukoomamuutoksia. Näköhermon pään hermoreunan (rim) pinta-ala ja keskuskuopan suhde papillan läpimittaan eivät poikenneet tilastollisesti toisistaan näitä kahta menetelmää käytettäessä. Neljän eri referenssitason vaikutusta HRT-parametrien mittausarvoihin testattiin kahdessa eri tutkimuksessa. Ensimmäisen tutkimusaineisto koostui yhteensä 67:stä silmästä, joista 40 oli terveitä ja 27:ssä eriasteisia glaukoomamuutoksia. Toisessa tutkimuksessa oli yhteensä 279 silmää, joista 180 oli terveitä ja 99:llä oli glaukooma. Papillomakulaarisäikeisiin tukeutuva, fleksiibeli referenssitaso antoi luotettavimmat HRT-parametrien mittaustulokset sekä terveissä että glaukoomasilmissä. HRT-parametrien kykyä erottaa terveet silmät glaukomatoottisista testattiin yhteensä 77:ssä silmässä, joista 40 oli terveitä, 10 oli korkeapaineisia ilman glaukoomamuutoksia, ja 27:ssä oli glaukoomamuutoksia. Referenssitasosta riippuvaiset HRT-parametrit, keskuskuopan suhde papillan läpimittaan, vertikaali-lineaarinen keskuskuopan suhde papillan läpimittaan, keskimääräinen verkkokalvon hermosäiekerroksen paksuus (RNFLt) ja `rim´:in tilavuus samoin kuin referenssitasosta riippumaton keskuskuopan ´vinous´-mitta (CSM) erottelivat parhaiten nämä kliiniset ryhmät toisistaan. Terveitä ja glaukoomasilmiä erottelevaa HRT:n ja muiden rakenteellisten ja toiminnallisten parametrien kombinaatiota etsittiin 55:n silmän aineistosta. Silmistä 32 oli terveitä ja 23 korkeapaineisia ja/tai glaukoomavaurioisia. CSM ja RNFLt, yhdessä iän ja mykiövärjäytymisen suhteen korjatun sinikeltaperimetrian keskipoikkeaman kanssa osoittivat hyvää erottelukykyä (ROC area 0.91) terveiden ja glaukoomasilmien välillä
15
Lai, Wing-ki, and 黎穎琪. "Off anti-glaucoma medication study: changes in visual field, retinal nerve fiber layer thickness and riskestimation of glaucoma onset in 1 year follow up." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48333967.
Full textAbstract:
Objective: To examine the changes of visual field and retinal nerve fiber layer (RNFL) measurements and the risk of glaucoma progression before and after taking off intraocular pressure (IOP) lowering medication in Chinese patients with ocular hypertension.
Design: Prospective study.
Participants: 106 ocular hypertension patients (4 were excluded because there was no 1 year follow up examination).
Method: All patients underwent visual field testing by Humphrey Field Analyser and Retinal Nerve Fiber Layer (RNFL) thickness measurement by a spectral-domain optical coherence tomography. Eyes without glaucomatous visual field defect and had an IOP ?30mmHg were instructed to stop taking IOP lowering medication and measurements of IOP, visual field and RNFL measurements were taken. Changes in the visual field mean deviation, average, superior and inferior RNFL thickness and the risk of developing glaucoma between the baseline and follow-up examinations were compared between the groups with and without stopping IOP lowering medications. Logistic regression was used to analyze the association between corneal hysteresis, ocular pulse amplitude and the onset of glaucoma.
Results: There were 73 patients with IOP lowering medications taken off and 29 with continued medications. No significant differences were found in the changes of visual field mean deviation, average RNFL thickness and the risk of glaucoma progression (P=0.92, P=0.81, P=0.35, respectively) between the groups. Ocular pulse amplitude was a significant predictor of glaucoma development by functional (-0.61, P=0.047) and structural criteria (-0.74, P=0.024).
Conclusion: There were no functional and structural changes in patients with ocular hypertension after stopping IOP lowering medications in one year. Low ocular pulse amplitude could be a predictive factor for the conversion from ocular hypertension to glaucoma. Clinicians should not prescribe IOP-lowering medication simply base on high IOP.published_or_final_version
Medicine
Master
Master of Medical Sciences
16
Liu, Yingna. "Old and New Methods of Glaucoma Diagnosis Using Spectral-Domain Optical Coherence Tomography: Testing Limitations of Older Retinal Nerve Fiber Layer Thickness Measurements and Diagnostic Potential of Newer Retinal Volume Measurements." Thesis, Harvard University, 2017. http://nrs.harvard.edu/urn-3:HUL.InstRepos:32676131.
Full textAbstract:
Purpose:
Optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness measurements are a reproducible and quantitative diagnostic modality widely used for glaucoma evaluations, but a high rate of testing artifacts limits its clinical utility. In Part I of this thesis, we aimed to characterize artifact types and assess artifact rates in two-dimensional (2D) RNFL thickness measurements obtained by the Spectralis OCT machine (Heidelberg Engineering, Heidelberg, Germany), as well as to determine patient factors and eye conditions associated with a higher artifact prevalence. In Part II of this thesis, we aimed to compare a new parameter, peripapillary retinal volume (RV), with the traditional 2D RNFL thickness parameter for diagnostic capability and artifact rates.
Methods:
Part I: The prevalence of 12 artifact types were described in this retrospective, cross sectional review of 2313 eye scans from 1188 patients who underwent a complete eye examination with Spectralis OCT scanning during the period of September 2009 to July 2013. Generalized estimating equations model was used to analyze associations between increased artifact prevalence and 10 patient characteristics, including age, sex, race, visual acuity, refractive error, astigmatism, cataract status, glaucoma staging, visual field reliability, and glaucoma diagnosis.
Part II: This is a retrospective, cross-sectional review. A total of 180 subjects [113 open angle glaucoma (OAG) and 67 normal participants] had spectral domain optical coherence tomography (OCT) volume scans and RNFL thickness measurements (Spectralis, Heidelberg Engineering, Heidelberg, Germany). Peripapillary RV values were calculated using a custom-designed program with 4 different sized circumpapillary annuli (CA): CA1 had circle diameters of 2.5 and 3.5 mm; CA2, 3 and 4 mm; CA3, 3.5 and 4.5 mm; and CA4, 4 and 5 mm. Area under the receiver operating characteristic (AUROC) curves, sensitivity, and specificity were calculated for global, quadrant, and octant regions for RV (CA1 – CA4) and RNFL thickness. Pair-wise comparisons were conducted between RV and RNFL measurements. Artifacts rates were determined.
Results:
Part I: A total of 1070 or 46.3% of the 2313 2D eye scans had at least one artifact. De-centration error was the most common artifact (27.8%), followed by posterior vitreous detachment artifacts (14.4%). Visual acuity of less than 20/40 (p<0.0001), presence of moderate to severe cataracts (p<0.0001), advanced stage of glaucoma (p<0.0001), and a diagnosis of open angle glaucoma (p=0.0003) were associated with increased prevalence of artifacts.
Part II: Of the 180 study subjects who had 3D eye scans, mean age was 62.6 ± 15.4 years and 41.7% were male. Among RV measurements, best diagnostic performances were for the smallest two annuli for inferior RV (CA1 0.964, CA2 0.955). Of the 4 annuli, the smallest CA1 had the highest diagnostic performance. Of specific regions, the inferior RV quadrant had the highest performance across CA1 to CA4. Peripapillary RV had similar diagnostic capability compared to RNFL thickness (p > 0.05). The artifact rate per B-scan for RV was 6.0%, and for 2D RNFL thickness scans was 32.2%.
Conclusions:
Clinicians should first assess scans for artifacts and pay attention to patient characteristics associated with a higher prevalence of artifacts before making therapeutic decisions based on RNFL thickness measurements. Meanwhile, the diagnostic capability of RV could be equal to that of RNFL thickness for diagnosing perimetric OAG, with fewer artifacts. RV may be a useful novel parameter in the evaluation of perimetric glaucoma.
17
Cremasco, Fernanda 1979. "Variability of peripapillary retinal nerve fiber layer measurements with spectral domain OCT = Variabilidade de medidas de espessura da camada de fibras nervosas peripapilar utilizando spectral domain OCT." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/312259.
Full textAbstract:
Orientador: Vital Paulino CostaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
Made available in DSpace on 2018-08-23T06:08:01Z (GMT). No. of bitstreams: 1 Cremasco_Fernanda_D.pdf: 5564009 bytes, checksum: bb04dfbdd0809568c204a7076f6df39f (MD5) Previous issue date: 2013
Resumo: Esta pesquisa teve por finalidade avaliar a variabilidade intrasessão, intersessão e interexaminador das medidas de espessura da camada de fibras nervosas da retina peripapilar (CFNRP) com a Tomografia de Coerência Óptica de Domínio Espectral (TCO-DE). Foi incluído no estudo apenas um olho de 32 indivíduos saudáveis e de 34 pacientes com glaucoma. As medidas da CFNRP foram obtidas com o Cirrus HD-OCT 4000 (Carl Zeiss Meditec, Dublin, Califórnia, EUA) cinco vezes no mesmo dia, por um único examinador, para avaliação da variabilidade intrasessão. O mesmo examinador realizou medidas de espessura da CFNRP nos mesmos sujeitos em cinco dias diferentes, para avaliação da variabilidade intersessão. Um segundo examinador realizou medidas da espessura da CFNRP nos mesmos pacientes para avaliação da variabilidade interexaminador. O coeficiente de variação (CDV) e o coeficiente de correlação intraclasse (CCI) foram obtidos para os seguintes parâmetros: espessura média, espessura nos quadrantes e espessuras setoriais. Em relação à variabilidade intrasessão, em pacientes com glaucoma, os CDVs variaram de 4,51% a 11,84% e os CCIs variaram de 0,74 a 0,99; em indivíduos saudáveis, os CDVs variaram de 2,92% a 6,99% e os CCIs variaram de 0,89 a 0,98. Na análise da variabilidade intersessão observou-se que, em pacientes com glaucoma, os CDVs variaram de 3,68% a 10,50% e os CCIs variaram de 0,82 a 0,99; em indivíduos saudáveis, os CDVs variaram de 3,13% a 6,92% e os CCIs variaram de 0,87 a 0,99. Em relação à variabilidade interexaminador, em pacientes com glaucoma, os CDVs variaram de 2,62% a 14,94% e os CCIs variaram de 0,55 a 0,98; em indivíduos saudáveis, os CDVs variaram de 2,04% a 7,31% e os CCIs variaram de 0,86 a 0,98. Estes resultados indicam que as medidas de espessura da CFNRP com a TCO-DE apresentam reprodutibilidade excelente, com baixa variabilidade intrasessão, intersessão e interexaminador
Abstract: The purpose of this study was to evaluate the intrasession, intersession and interexaminer variabilities of peripapillary retinal nerve fiber layer (PRNFL) thickness measurements with Spectral Domain Optical Coherence Tomography. One eye of 32 healthy individuals and 34 patients with glaucoma were included in the study. The PRNFL measurements were obtained with the Cirrus HD-OCT Model 4000 (Carl Zeiss Meditec, Dublin, Califórnia, USA) five times during the same sitting by one examiner to assess intrasession variability. The same examiner performed PRNFL measurements in the same patients in five different days to assess intersession variability. A second examiner performed PRNFL measurements in the same patients to assess interexaminer variability. The coefficient of variation (COV) and the intraclass correlation coefficient (ICC) were obtained for the following parameters: average thickness, quadrant thickness and clock-hour thickness measurements. The analysis of the intrasession variability, in glaucoma patients, showed that COVs ranged from 4.51% to 11.84% and ICCs varied from 0.74 to 0.99, whereas in healthy individuals, COVs ranged from 2.92% to 6.99% and ICCs varied from 0.89 to 0.98. Regarding the intersession variability, in glaucoma patients COVs ranged from 3.68% to 10.50% and ICCs varied from 0.82 to 0.99; whereas in healthy individuals, COVs ranged from 3.13% to 6.92% and ICCs varied from 0.87 to 0.99. In interexaminer variability, between glaucoma patients, COVs ranged from 2.62% to 14.94% and ICCs varied from 0.55 to 0.98, whereas in healthy individuals, COVs ranged from 2.04% to 7.31% and ICCs varied from 0.86 to 0.98. These findings indicate that PRNFL measurements with Spectral Domain Optical Coherence Tomography display excellent reproducibility, with low intrasession, intersession and interexaminer variabilities
Doutorado
Oftalmologia
Doutor em Ciências Médicas
18
Urbánek, Dušan. "Detekce nervových vláken v oftalmologických obrazech metodami texturní analýzy." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217218.
Full textAbstract:
This thesis deals with detection of the retinal nerve fiber layer in gray level retinal images taken by fundus camera. The first part describes a physiology of human eye and glaucoma disease. Then, the use of wavelet transform and algorithm of texture analysis applied for texture analysis. Next chapters describe theory of texture analysis named „Gray level run length matrices“ and its application for detection of the nerve fiber layer. Applications of this method are described for three types of retinal tissues and for whole image. The last chapter describes gray levels around optic disc and results obtained from parameters from GLRL matrices.
19
Rossman, Ian. "OPTICAL COHERENCE TOMOGRAPHY TO MEASURE EFFECTS OF AUTOLOGOUS MESENCHYMAL STEM CELL TRANSPLANT IN MULTIPLE SCLEROSIS PATIENTS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1486132609814919.
Full text
20
Odstrčilík, Jan. "Analýza obrazových dat sítnice pro podporu diagnostiky glaukomu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-233628.
Full textAbstract:
Fundus kamera je široce dostupné zobrazovací zařízení, které umožňuje relativně rychlé a nenákladné vyšetření zadního segmentu oka – sítnice. Z těchto důvodů se mnoho výzkumných pracovišť zaměřuje právě na vývoj automatických metod diagnostiky nemocí sítnice s využitím fundus fotografií. Tato dizertační práce analyzuje současný stav vědeckého poznání v oblasti diagnostiky glaukomu s využitím fundus kamery a navrhuje novou metodiku hodnocení vrstvy nervových vláken (VNV) na sítnici pomocí texturní analýzy. Spolu s touto metodikou je navržena metoda segmentace cévního řečiště sítnice, jakožto další hodnotný příspěvek k současnému stavu řešené problematiky. Segmentace cévního řečiště rovněž slouží jako nezbytný krok předcházející analýzu VNV. Vedle toho práce publikuje novou volně dostupnou databázi snímků sítnice se zlatými standardy pro účely hodnocení automatických metod segmentace cévního řečiště.
21
Novotný, Adam. "Texturní analýza vrstvy nervových vláken na snímcích sítnice." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218649.
Full textAbstract:
This work describes completely new approach to detection of retinal nerve fibre layer (RNFL) loss in colour fundus images. Such RNFL losses indicate eye glaucoma illness and an early diagnosis of RNFL changes is very important for successful treatment. Method is presented with the purpose of supporting glaucoma diagnosis in ophthalmology. The proposed textural analysis method utilizes local binary patterns (LBP). This approach is characterized especially by computational simplicity and insensitivity to monotonic changes of illumination. Image histograms of LBP distributions are used to gain several textural features aimed to classify healthy or glaucomatous tissue of the retina. The method was experimentally tested using fundus images of glaucomatous patients with focal RNFL loss. The results show that the proposed method can be used in order to supporting diagnosis of glaucoma with satisfactory efficiency.
22
Cunha, Luciana Virginia Ferreira Costa. "Correlação entre as espessuras da mácula e da camada de fibras nervosas da retina, medidas pelas tomografias de coerência óptica de dominio Fourier e de domínio do tempo, e a perimetria automatizada na atrofia em banda do nervo óptico." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/5/5149/tde-21072011-134114/.
Full textAbstract:
OBJETIVO: Investigar a correlação entre as espessuras da mácula e da camada de fibras nervosas da retina (CFNR), medidas pelas tomografias de coerência óptica de domínio Fourier (FD - OCT) e de domínio do tempo (TD - OCT) e a perda de sensibilidade no campo visual (CV) em pacientes com atrofia em banda do nervo óptico. Comparar a habilidade diagnóstica dos dois instrumentos. MÉTODOS: 36 olhos de 36 pacientes com perda de CV permanente por compressão do quiasma óptico e 36 controles normais foram submetidos ao exame de CV pela perimetria automatizada padrão (Humphrey Field Analyzer TM; Carl Zeiss Meditec, Dublin, CA), ao FD - OCT (3 D OCT-1000TM Topcon Corp., Tokyo, Japan) e ao TD - OCT (StratusTM ;Carl Zeiss Meditec Inc, Dublin, California, USA). Foram comparados os protocolos análogos de ambos os equipamentos para avaliação da espessura macular.Foi realizado a divisão macular em quatro quadrantes e em metades, sendo calculado a média da espessura macular global, a média da espessura dos quadrantes e a média da espessura das metades maculares. A média global e setorial da medida da espessura da CFNR peripapilar também foi analisada. A perda de sensibilidade no CV foi inicialmente avaliada pelo defeito temporal médio. O CV foi ainda dividido em 6 setores de acordo com a distribuição da CFNR e em 16 pontos centrais para a realização da correlação estrutura-função entre os parâmetros medidos pelo FD - OCT e a perda de sensibilidade no CV em decibéis e 1/Lambert. Foi calculado o coeficiente de correlação de Sperman e a análise de regressão linear. As áreas sobre a curva ROC e valores fixos de sensibilidade e especificidade foram calculados para cada parâmetro estudado. RESULTADOS: As medidas da espessura macular e da CFNR pelo FD - OCT e TD - OCT foram capazes de discriminar olhos com atrofia em banda do nervo óptico dos controles normais. A espessura global e setorial dos parâmetros maculares e da CFNR mostraram diferenças significativas (p<0,001) entre os doentes e os controles e os dois aparelhos tiveram desempenho semelhante na discriminação entre pacientes e controles. Em ambos existiram correlações significativas entre a perda de sensibilidade do CV e as medidas da espessura macular e da CFNR. As medidas de espessura nos quadrantes e nas metades nasais da macula, avaliadas pelo FD - OCT tiveram os melhores desempenhos nas correlações com os defeitos de CV, sendo o parâmetro com a melhor correlação, a medida do quadrante infero-nasal da mácula e a perda de sensibilidade do CV central do quadrante temporal superior central (r = 0.78, R2 = 61%, p<0,001). CONCLUSÕES: A espessura macular e a espessura da CFNR medidas pelo FD - OCT e pelo TD - OCT se correlacionaram topograficamente com a perda de sensibilidade no CV de pacientes com hemianopsia temporal por compressäo quiasmática. A correlação entre os quadrantes maculares e a perda de sensibilidade no CV, foram melhores do que aquelas entre o CV e as medidas da CFNR, principalmente nas medidas realizadas pelo FD - OCT. Este estudo demonstrou a importância clínica das medidas maculares na correlação estrutura-função e na quantificaçäo do dano neural em pacientes com compressão quiasmática, podendo ser útil na monitorização destes pacientesPURPOSE: To investigate the relationship between fourier-domain optical coherence tomography (FD - OCT) measured macular and retinal nerve fiber layer thickness (RNFL) and visual field sensitivity loss on standard automated perimetry in eyes with permanent temporal hemianopia from chiasmal compression and compare the ability of FD - OCT and time-domain optical coherence tomography (TD - OCT) to detect axonal loss in eyes with band atrophy of the optic nerve. METHODS: One eye of each of 36 patients with permanent temporal visual field defects and 36 age- and sex-matched healthy subjects. Subjects underwent standard automated perimetry and macular and RNFL thickness measurements with FD - OCT (3 D OCT-1000® Topcon Corp., Tokyo, Japan) and TD - OCT (Stratus; Carl Zeiss Meditec Inc, Dublin, California, USA). Macular thickness measurements as a global average, divided in four quadrants and in two halves as well as average and sectoral RNFL thickness around the optic disc were calculated. Visual field sensitivity loss was evaluated by the temporal mean defect; as deviations from normal in six sectors of the visual field and in 16 central visual field test points. Relationship between visual field sensitivity loss in decibel and 1/Lambert units and optical coherence tomography measurements were evaluated using Spearman correlation coefficients and by linear regression analysis. Receiver operating characteristic curves and sensitivities at fixed specificities were calculated for each parameter. RESULTS: Global and sectoral macular and RNFL thickness parameters showed a significant difference in eyes with band atrophy compared with controls. The strongest correlations were seen between visual field sensitivity loss and quadrantic or hemianopic nasal macular thickness measurements than with sectoral retinal nerve fiber layer thickness measurements. The highest correlation was observed between the inferonasal quadrant macular thickness and the visual field sensitivity loss in the superior temporal central visual field quadrant (r = 0.78, R2 = 61%, p <0.001). CONCLUSION: Both RNFL thickness and macular thickness FD - OCT and TD - OCT measurements were related topographically with visual field sensitivity loss in patients with temporal hemianopia from chiasmal compression and there is a stronger relationship in quadrantic macular compared to RNFL thickness measurements with FD - OCT. Macular thickness measurements could potentially be used to quantify neuronal loss in patients with chiasmal compression and could prove clinically useful for detection of damage and for monitoring these patients
23
Vodáková, Martina. "Analýza vrstvy nervových vláken pro účely diagnostiky glaukomu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220012.
Full textAbstract:
The master thesis is focused on creating a methodology for quantification of the nerve fiber layer on photographs of the retina. The introductory part of the text presents a medical motivation of the thesis and mentions several studies dealing with this issue. Furthermore, the work describes available textural features and compares their ability to quantify the thickness of the nerve fiber layer. Based on the described knowledge, the methodology to make different regression models enabling prediction of the retinal nerve fiber layer thickness was developed. Then, the methodology was tested on the available image dataset. The results showed, that the outputs of regression models achieve a high correlation between the predicted output and the retinal nerve fiber layer thickness measured by optical coherence tomography. The conclusion discusses an usability of the applied solution.
24
Peter, Roman. "Obrazový databázový systém pro podporu diagnostiky glaukomu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217228.
Full textAbstract:
Tato práce popisuje přehled standardních a pokročilých metod používaných k diagnose glaukomu v ranném stádiu. Na základě teoretických poznatků je implementován internetově orientovaný informační systém pro oční lékaře, který má tři hlavní cíle. Prvním cílem je možnost sdílení osobních dat konkrétního pacienta bez nutnosti posílat tato data internetem. Druhým cílem je vytvořit účet pacienta založený na kompletním očním vyšetření. Posledním cílem je aplikovat algoritmus pro registraci intenzitního a barevného fundus obrazu a na jeho základě vytvořit internetově orientovanou tři-dimenzionální vizualizaci optického disku. Tato práce je součásti DAAD spolupráce mezi Ústavem Biomedicínského Inženýrství, Vysokého Učení Technického v Brně, Oční klinikou v Erlangenu a Ústavem Informačních Technologií, Friedrich-Alexander University, Erlangen-Nurnberg.
25
Magula, Filip. "Software pro zpracování retinálních snímků." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218653.
Full textAbstract:
This thesis deals with practical solutions of software for retinal images digital processing. The theoretic part describes human eye and retinal anatomy and also glaucoma disease. It is also focused on description of method for retinal nerve fiber layer enhancement and analysis. These enhancement are then used for designing of automated image processing. One chapter is devoted to detection and analysis of retinal nerve fibers layer. The practical part includes the user manual for application Image Blockz, which was established within this thesis. Further practical part contains the programmer's manual describing the basic structure of the program and its possible extensions.
26
Václavek, Martin. "Automatická detekce výpadku ve vrstvě nervových vláken." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218724.
Full textAbstract:
This work is focused on detection of loss in nerve fibre layer on colour pictures of retina, witch are makes by fundus camera. It describe every simple objects of retina, optic nerve head, macula lutea and vascular bed. It detect optic nerve head and his near area, witch is general for detection of breakdownds. It use several metodes of picture adjusting for picture elaboration and objects detection (segmentation, thresholding, enhancement, hough transformation ). The detection of loss in nerve fibre layer is based on comparing of statistic parameters ( average, standart deviation, skewness coefficient and kurtosis coefficient histogram, entropy ) in choosed areas with and withou destruction of nerve layers. Vascular bed have badwatsh on results, cause of this we using hand choosing of essay.
27
Lin, Roger Chin. "Optical Coherence Tomography for the Screening of Donor Corneas and Examination of the Retinal Nerve Fiber Directional Reflectance." online version, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1144703489.
Full text
28
Chiu, Yee-hang Thomas. "Intraocular pressure, optic nerve fiber layer thickness and visual field in normotensive eyes with narrow drainage angle /." View the Table of Contents & Abstract, 2006. http://sunzi.lib.hku.hk/hkuto/record/B37207994.
Full text
29
Chiu, Yee-hang Thomas, and 趙懿行. "Intraocular pressure, optic nerve fiber layer thickness and visual field in normotensive eyes with narrow drainage angle." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B45011102.
Full text
30
Avelino, Rodrigo Rezende Gomes. "Influencia da redução medicamentosa da pressão intra-ocular na medida da espessura da camada de fibras nervosas da retina de olhos hipertensos e glaucomatosos pela polarimetria de varredura a laser." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/312262.
Full textAbstract:
Orientador: Vital Paulino CostaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
Made available in DSpace on 2018-08-09T04:54:16Z (GMT). No. of bitstreams: 1 Avelino_RodrigoRezendeGomes_M.pdf: 2930957 bytes, checksum: c66d1b04f0e830ee3e2b0a2e3897981b (MD5) Previous issue date: 2007
Resumo: Objetivo: Avaliar o efeito da redução da pressão intra-ocular (PIO) obtido com o uso de terapia medicamentosa na espessura da camada de fibras nervosas da retina medida pela Polarimetria de Varredura a Laser (PVL) em pacientes glaucomatosos ou hipertensos oculares. Métodos: Trinta e sete olhos de 37 pacientes foram prospectivamente incluídos no estudo e avaliados com a PVL sem uso de medicação ocular hipotensora e num período entre 15 e 30 dias após a instituição de medicação ocular hipotensora, que resultou em redução da PIO de pelo menos 25%. Os parâmetros medidos pela PVL antes e após a redução da PIO foram comparados com o teste t de Student pareado. Resultados: A PIO média dos 37 pacientes diminuiu significativamente de 26,57 ± 4,23 mmHg para 16,54 ± 2,92 mmHg (p<0,05) após terapia medicamentosa. Não houve diferença estatisticamente significativa entre os valores dos 10 parâmetros do PVL medidos antes e após a administração de medicação ocular hipotensora (p>0,05). Conclusão: A redução da PIO com o uso de medicação ocular hipotensora não altera a medida da espessura da camada de fibras nervosas da retina pela PVL em pacientes com glaucoma ou hipertensão ocular
Abstract: Purpose: To evaluate changes in retinal nerve fiber layer thickness as measured by scanning laser polarimetry (SLP) after the use of medication to reduce intraocular pressure (IOP) in glaucomatous or ocular hypertensive patients. Methods: The authors prospectively enrolled 37 eyes of 37 patients in whom IOP was reduced by more than 25% after the use of medication. The images were obtained before and 15 to 30 days after the introduction of medication. The SLP parameters measured before and after the use of medication were compared using paired Student¿s t Test. Results: The mean IOP was significantly reduced from 26.57 ± 4.23 mmHg to 16.54 ± 2.92 mmHg after the use of medication (p<0.05). None of the 10 SLP analyzed parameters was significantly affected by the reduction of IOP with medication (p>0.05). Conclusion: The retinal nerve fiber layer thickness, as measured by SLP, is not affected by the reduction of IOP with medication in patients with glaucoma or ocular hypertension
Mestrado
Oftalmologia
Mestre em Ciências Médicas
31
Sedláček, Miloš. "Matematický model trajektorie svazku nervových vláken pro účely diagnostiky glaukomu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219503.
Full textAbstract:
This work deals with mathematical description of nerve fiber bundle trajectories for the diagnosis of glaucoma. Also gives a brief explanation in the principle of fundus camera and glaucoma. Its aim is to implement the model into MATLAB software, to project a~methodics of its use and also to realize it.
32
Kunc, Martin. "Detekce nervových vláken v barevných obrazech sítnice." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217969.
Full textAbstract:
This thesis is deals with the nerve fibre layer in the colour ophthalmology images of retina. The thesis describes how can we use finding of nerve fibre layer and how was it solved in the past. In the thesis are proposed the methods that are based on processing and scoring frequency spectrums of individual sample of retina. At first here are described the methods of detection on the artificial generated samples that just simulate the nerve fibre layer. Then the thesis concentrates on processing of real images of retina. Because of the bloodstream, that depreciates processing at real images, are all surveyed samples are chosen manually. Except detection the nerve fibre layer itself, the thesis also deals with determination of direction their dissemination.
33
Medeiros, Felipe de Araujo Andrade. "Comparação de métodos de imagem do disco óptico e da camada de fibras nervosas da retina para o diagnóstico do glaucoma." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/5/5149/tde-14102014-163044/.
Full textAbstract:
Alterações no aspecto do disco óptico e da camada de fibras nervosas da retina (CFN) freqüentemente precedem o aparecimento de defeitos de campo visual no glaucoma, o que faz com que a avaliação destas estruturas seja essencial para o diagnóstico precoce e prevenção da perda visual nesta doença. A polarimetria de varredura a laser (GDx VCC), a oftalmoscopia confocal de varredura a laser (HRT II [Heidelberg Retina Tomograph]) e a tomografia de coerência óptica (Stratus OCT) são tecnologias que permitem a avaliação objetiva e quantitativa do disco óptico e da CFN. No presente estudo, estas tecnologias foram comparadas em sua habilidade para diferenciar pacientes glaucomatosos de indivíduos normais. Pacientes com glaucoma foram selecionados com base na presença de defeitos reprodutíveis de campo visual na perimetria acromática automatizada (glaucoma perimétrico), ou com base na evidência documentada de progressão do dano glaucomatoso ao disco óptico, sem presença de defeitos de campo visual (glaucoma pré-perimétrico). Indivíduos normais apresentaram campos visuais e exame clínico dentro da normalidade. Todos os indivíduos foram submetidos a exames com o GDx VCC, HRT II, Stratus OCT e campo visual dentro de um período de três meses. Diversas medidas foram utilizadas para avaliação da acurácia diagnóstica, incluindo áreas sob as curvas receiver operating characteristic (AROC), sensibilidades para especificidades fixas, e razões de probabilidade. Modelos estatísticos foram utilizados para avaliação da influência da severidade do glaucoma e tamanho do disco óptico na performance diagnóstica dos diferentes instrumentos. Um olho de cada indivíduo foi utilizado para análise. Dos 258 sujeitos inicialmente avaliados, 33 (13%) foram posteriormente excluídos por apresentarem imagens de baixa qualidade em pelo menos um dos aparelhos, restando 225 indivíduos (133 glaucomatosos e 92 normais) para análise. Na comparação entre os parâmetros de cada instrumento com maiores valores de AROC, o parâmetro do GDx VCC, Nerve Fiber Indicator (NFI; AROC = 0,91), e o parâmetro do Stratus OCT, Espessura Média (AROC = 0,90), apresentaram áreas sob as curvas ROC significativamente superiores à do parâmetro do HRT II, função discriminante de Bathija (AROC = 0,84). A severidade do defeito de campo visual exerceu influência significativa sob a acurácia diagnóstica dos três instrumentos, com melhora no poder diagnóstico em casos mais avançados da doença. Para o GDx VCC e Stratus OCT, o aumento no tamanho do disco óptico foi associado à diminuição na sensibilidade para detecção do glaucoma; enquanto que, para o HRT II, diminuição no tamanho do disco óptico foi associada à diminuição na sensibilidade. Razões de probabilidade para resultados anormais nas xxv classificações finais de cada instrumento foram associadas a grandes efeitos de mudança na probabilidade pós-teste em relação à probabilidade préteste, sugerindo que o encontro de um resultado anormal em qualquer um destes testes, durante a avaliação de um paciente com suspeita de glaucoma, tem impacto significativo em aumentar a probabilidade de que a doença esteja presente. Além disso, os resultados obtidos na avaliação de pacientes com glaucoma pré-perimétrico sugerem que todos os três instrumentos sejam capazes de detectar alterações estruturais precoces no glaucoma, antes do aparecimento de defeitos de campo visual na perimetria acromáticaChanges in the structural appearance of the optic nerve head (ONH) and retinal nerve fiber layer (RNFL) have been reported to precede the development of visual field loss in glaucoma. Detection of ONH and RNFL damage is therefore crucial for early diagnosis of glaucoma and prevention of functional loss from the disease. Scanning laser polarimetry (GDx VCC), confocal scanning laser ophthalmoscopy (HRT II [Heidelberg Retina Tomograph]) and optical coherence tomography (Stratus OCT) are different technologies capable of providing objective and quantitative information related to these structures. The purpose of the present study was to compare, in a single population, the diagnostic abilities of these technologies in the discrimination of glaucomatous patients from healthy subjects. Glaucoma patients were selected based on the presence of repeatable visual field defects, as identified by standard automated perimetry (perimetric glaucoma), or documented evidence of progressive damage to the optic disc, in the absence of detectable visual field loss (preperimetric glaucoma). Normal subjects had normal visual fields and normal clinical examination. All subjects underwent imaging with the GDx VCC, HRT II and Stratus OCT within a 3-month period. Several measures were used for evaluation of diagnostic accuracy, including the area under the receiver operating characteristic curve (AROC), sensitivities at fixed specifities, and likelihood ratios. Statistical models were used to evaluate the influence of glaucoma severity and optic disc size on the diagnostic performance of the different instruments. One eye of each individual was randomly selected for statistical analysis. From an initial group of 258 eligible subjects, 33 (13%) had images of unacceptable quality, leaving 133 glaucoma patients and 92 healthy subjects for further analysis. In the comparison of the parameters with highest values of AROC from each instrument, the GDx VCC Nerve Fiber Indicator (AROC = 0.91) and the Stratus OCT Average Thickness (AROC = 0.90) perfomed significanlty better than the HRT II Bathija discriminant function (AROC = 0.84). For all instruments, the diagnostic accuracy increased with increasing severity of visual field defects. For the GDx VCC and Stratus OCT parameters, an increase in the size of the optic disc was related to a decrease in the sensitivity for glaucoma detection. An opposite effect was observed with the HRT II: a decrease in the size of the optic disc was related to a decrease in the sensitivity for glaucoma diagnosis. Abnormal results for each of the instruments were associated with strong positive likelihood ratios, indicating a large change from prestest to posttest probability of glaucoma. These results suggest that the finding of an abnormal result in any of these tests, when assessing a patient suspect of having glaucoma, would substantially raise the probability of disease. Results of the evaluation of patients with preperimetric glaucoma also suggest that all three instruments are able to detect early glaucomatous structural damage in the absence of visual field loss
34
Staša, Josef. "Texturní analýza snímků sítnice se zaměřením na směrovost vrstvy nervových vláken." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219648.
Full textAbstract:
Hlavním cílem této diplomové práce byla texturní analýzou fundus snímku se zaměřením na směrovost vrstvy nervových vláken. Úvodní část popisuje fyziologii lidského oka a glaukomové onemocnění. Jedná se tedy o literární rešerši. Hlavní část této práce je pak zaměřena na metody texturní analýzy za účelem zobrazení směrovosti nervových vláken. Metody byly realizovány a otestovány v programovém prostředí Matlab R2009b.
35
"Detection of retinal nerve fiber layer progression in glaucoma." 2013. http://library.cuhk.edu.hk/record=b5884385.
Full textAbstract:
Yu, Chak Yan Marco.Thesis (Ph.D.)--Chinese University of Hong Kong, 2013.
Includes bibliographical references (leaves 153-178).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
36
"Evaluation of retinal nerve fiber layer measurement with spectral-domain optical coherence tomography in glaucoma." 2012. http://library.cuhk.edu.hk/record=b5549471.
Full textAbstract:
青光眼作為一種慢性進展性視神經病變，已經成為世界眼科病變中導致不可逆盲的首要原因。青光眼的早期診斷和治療對於降低疾病進展的風險至關重要。光學相干斷層掃描（OCT）可以提供在體視網膜橫斷面的視圖，從而實現了對視網膜神經纖維層（RNFL）改變的客觀測量，這些改變已經被證明了與青光眼引起的視神經損害相關，並已成為診斷青光眼的重要參考依據。頻域OCT是最新一代的光學相干斷層掃描，它具有比時域OCT更快的掃描速度和更高的圖像解析度，因此，頻域OCT可以提供更可靠的RNFL厚度測量和RNFL缺損評估。本文的研究目的在於評估頻域OCT對RNFL厚度的重測再現性，以及探討影響RNFL厚度測量的因素，這些因素包括（1）影像平均法的應用，（2）RNFL分層錯誤，和（3）視網膜血管的影響。此外，由於RNFL攝影是一個評估青光眼RNFL缺損的臨床參考標準，我們還將其對RNFL缺損的測量與頻域OCT的RNFL厚度偏差圖所作出的測量進行了比較。
首先，為了評估頻域OCT對RNFL厚度測量的重測再現性，15名正常人和15名青光眼患者連續四周每週均接受一次OCT掃描。正常組和青光眼組的RNFL厚度再現性係數分別為4.77-12.65微米和4.53-16.66微米，由於組內相關性係數均大於0.773，說明頻域OCT所作出的RNFL厚度測量是具備可重複性的。
其次，通過分析54隻眼（25名正常志願者和29名青光眼患者）的RNFL厚度測量值，本文對圖像平均法的應用是否會影響RNFL厚度的測量這一問題進行了探討。分析中，每一隻眼均接受了3次OCT掃描，3次掃描的圖像分別使用2、8、和16張連續的圖像進行影像平均。結果顯示，除了青光眼組的鼻下象限RNFL厚度測量值之外（P=0.036），不同的圖像幀數並不會對兩組的總體和其它各象限的RNFL厚度測量值產生顯著的影響（P≥0.055）。雖然圖像平均法的應用對RNFL厚度測量的影響並不顯著，但是視網膜血管和RNFL分層錯誤對青光眼,尤其是對RNFL非常薄的晚期青光眼患者的RNFL厚度測量有影響。結論來自對60個正常人，66個輕至中度青光眼（MD≥-6 dB）患者和54個嚴重青光眼（MD<-6 dB）患者的共180張OCT圖像的分析。視網膜血管相對於平均RNFL厚度的比例均值在正常組，輕至中度青光眼組，和嚴重青光眼組分別為11.2±2.3，12.6±2.5，和16.6±3.9。在人為調整了RNFL界限以糾正RNFL分層錯誤的前後，總體RNFL厚度的差異範圍在正常組為-3.0-2.5微米，輕至中度青光眼組為-2.5-5.0微米，嚴重青光眼組為-11.0-9.5微米組。
最後，通過對41名青光眼患者的51隻眼的RNFL缺損面積，位置，和覆蓋角度進行測量，本文將頻域OCT作出的測量結果和共焦鐳射掃描檢眼鏡（CSLO）RNFL反射影像圖的測量結果進行了比較，結果顯示：OCT不但可以檢測到所有出現在CSLO的RNFL反射影像圖上的RNFL缺損，更重要的是，OCT還可以檢測出額外的並未在RNFL反射影像圖上出現的RNFL缺損。
總之，頻域OCT是一種可提供高再現性RNFL厚度測量的影像方法。對青光眼,尤其是晚期青光眼的RNFL厚度測量值的詮釋，應當考慮到視網膜血管和RNFL分層錯誤的影響。OCT具備對RNFL缺損進行多維度量化（包括厚度，面積，位置，和覆蓋角度）的能力，在青光眼RNFL改變的檢測和監測方面，相對于傳統的RNFL攝影，OCT無疑是更有效的選擇。
Glaucoma, a chronic progressive optic neuropathy, is the leading cause of irreversible blindness in the world. An early diagnosis and treatment of glaucoma is vital to reduce the risk of disease progression. Providing a cross-sectional view of the retina in vivo, optical coherence tomography (OCT) can objectively measure the changes of retinal nerve fiber layer (RNFL), which has been shown to be of relevance and importance in detecting glaucomatous damage of the optic nerve.
The latest generation of OCT, the spectral-domain OCT, has a faster scan speed and a higher image resolution compared to the time-domain OCT. It is expected that the spectral-domain OCT would allow a more reliable measurement of the RNFL thickness and assessment of RNFL defects. The objectives of this research project were to examine the test-retest reproducibility of spectral-domain OCT RNFL measurement and investigate factors including (1) image averaging, (2) segmentation failure, and (3) contribution of retinal blood vessels that might affect the measurement of RNFL thickness. As RNFL photography is a reference standard to evaluate RNFL defects in glaucoma, we also evaluated whether RNFL defects measured in the spectral-domain OCT RNFL thickness map would be comparable to those detected in RNFL photographs.
To evaluate the test-retest reproducibility of RNFL measurements obtained by the spectral-domain OCT, 15 normal individuals and 15 glaucoma patients were followed and imaged weekly for 4 consecutively weeks. The reproducibility coefficients of RNFL thicknesses ranged between 4.53 and 16.66 μm for the normal group, and 4.77 and 12.65 μm for the glaucoma group. The intraclass correlation coefficients were all above 0.773, indicating RNFL measurement with spectral-domain OCT was reproducible.
We then investigated if multiple-image averaging would influence the measurement of RNFL thickness. A total of 54 eyes from 25 normal volunteers and 29 glaucoma patients with RNFL images captured and averaged with 2, 8, and 16 consecutive image frames were analyzed. For both groups, there were no significant differences in global or sectoral RNFL thicknesses among the image series averaged with different number of image frames (all with P≥0.055) except for the inferonasal sector in the glaucoma group (P=0.036). Although the impact of image averaging on RNFL measurement was insignificant, the presence of retinal blood vessels and segmentation errors were influential on the measurement, particularly in advanced glaucoma patients when the RNFL was thin. Analyzing a total of 180 eyes from 60 normal individuals, 66 mild to moderate (MD≥-6 dB) and 54 advanced (MD<-6 dB) glaucoma patients, the mean proportion of retinal blood vessels relative to the average RNFL thickness was 11.2±2.3%, 12.6±2.5% and 16.6±3.9%, respectively. After correcting the segmentation errors by manually refining the RNFL boundaries, the differences in average RNFL thickness ranged from -3.0 to 2.5 m in the normal, -2.5 to 5.0 m in the mild to moderate glaucoma and -11.0 to 9.5 m in the advanced glaucoma groups.
Finally, we compared the area, the angular location, and the angular width of RNFL defects from 51 eyes of 41 glaucoma patients measured with the spectral-domain OCT and RNFL reflectance images obtained by a confocal scanning laser ophthalmoscope (CSLO). OCT was able to detect areas of RNFL abnormalities in all eyes with RNFL defects which were evident in the CSLO RNFL reflectance images. More important, OCT could identify additional RNFL thinning not apparent in RNFL reflectance images.
In summary, spectral-domain OCT could offer an effective approach in measuring RNFL with high reproducibility. Interpretation of RNFL measurement should take the contribution of the retinal blood vessels and segmentation errors into consideration, particularly in advanced glaucoma when the RNFL is thin. With the ability to quantify multiple dimensions of RNFL defects (thickness, area, angular location, and angular width), OCT could provide a useful alternative to detect and monitor RNFL changes in glaucoma.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Ye, Cong.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2012.
Includes bibliographical references (leaves 117-130).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
ABSTRACT --- p.i
摘要 (ABSTRACT IN CHINESE) --- p.v
DEDICATION --- p.viii
ACKNOWLEDGEMENT --- p.ix
TABLE OF CONTENTS --- p.x
PUBLICATIONS --- p.xiv
ABBREVIATIONS --- p.xvi
Chapter CHAPTER 1: --- INTRODUCTION --- p.1
Chapter 1.1 --- Glaucoma --- p.2
Definition of Glaucoma --- p.2
Epidemiology of Glaucoma --- p.3
Pathogenesis of Glaucoma --- p.4
Diagnosis of Glaucoma --- p.7
Chapter 1.2 --- Retinal Nerve Fiber Layer --- p.13
Anatomy of Retinal Nerve Fiber Layer --- p.13
Visualization of Retinal Nerve Fiber Layer --- p.14
Retinal Nerve Fiber Layer Defect in Glaucoma --- p.16
Significance of Detecting Retinal Nerve Fiber Layer Defect in Glaucoma --- p.18
Chapter 1.3 --- Optical Coherence Tomography --- p.20
Principle of Optical Coherence Tomography --- p.20
Retinal Nerve Fiber Layer Imaging with OCT --- p.21
Optic Nerve Head Imaging with OCT --- p.27
Advantages and Disadvantages of Optical Coherence Tomography --- p.29
Chapter 1.4 --- Research Objectives --- p.30
Chapter CHAPTER 2: --- GENERAL MATERIALS AND METHODS --- p.32
Chapter 2.1 --- Subject Enrollments --- p.33
Chapter 2.2 --- Clinical Ophthalmic Examination --- p.34
Chapter 2.3 --- Visual Field Examination --- p.35
Definition of Normal and Glaucoma Groups --- p.35
Chapter 2.4 --- Optical Coherence Tomography Imaging --- p.37
Cirrus HD-OCT Imaging --- p.37
Spectralis OCT Imaging --- p.37
Chapter 2.5 --- Statistical Analysis --- p.39
Chapter CHAPTER 3: --- RETINAL NERVE FIBER LAYER IMAGING WITH SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY --- p.40
Chapter 3.1 --- Reproducibility and Agreement of Retinal Nerve Fiber Layer Measurement --- p.41
Introduction and Study Objectives --- p.41
Methods --- p.42
Results --- p.45
Discussion --- p.47
Tables and Figures --- p.51
Chapter 3.2 --- Effect of Multiple B-scans Averaging on Retinal Nerve Fiber Layer Measurement --- p.58
Introduction and Study Objectives --- p.58
Methods --- p.59
Results --- p.61
Discussion --- p.62
Tables and Figures --- p.67
Chapter 3.3 --- Impact of Blood Vessels and Segmentation Failure on Retinal Nerve Fiber Layer Measurement --- p.73
Introduction and Study Objectives --- p.73
Methods --- p.75
Results --- p.78
Discussion --- p.80
Tables and Figures --- p.84
Chapter 3.4 --- Agreement of Localized Retinal Nerve Fiber Layer Defect Assessment with Confocal Scanning Laser Ophthalmoscopy --- p.95
Introduction and Study Objectives --- p.95
Methods --- p.97
Results --- p.101
Discussion --- p.103
Tables and Figures --- p.108
Chapter CHAPTER 4: --- GENERAL CONCLUSIONS --- p.115
REFERENCES --- p.117
37
Liu, Shuang active 2012. "Thickness, phase retardation, birefringence, and reflectance of the retinal nerve fiber layer : implications for glaucoma diagnosis." 2012. http://hdl.handle.net/2152/22238.
Full textAbstract:
Glaucoma is the second leading cause of blindness worldwide after cataract. Retinal nerve fiber layer thickness (RNFLT), phase retardation, and birefringence measured by Polarization Sensitive Optical Coherence Tomography (PS-OCT) have been used for glaucoma diagnosis. We first investigated two different image registration algorithms, a mutual information (MI) based algorithm and a log-polar transform cross-correlation (LPCC) based algorithm, on both human and non-human primate models. We evaluated the effects of image registration on longitudinal analysis of RNFLT in non-human primates using PS-OCT. Then, we investigated thickness, phase retardation, birefringence, and reflectance of the retinal nerve fiber layer as measured by PS-OCT in normal and glaucomatous non-human primates in a longitudinal study. We defined a new Reflectance Index (RI) and demonstrated that it might be an earlier indicator of glaucoma onset than RNFLT, phase retardation, or birefringence. Finally, we validated this finding on cross-sectional clinical study on human eyes measured by PS-OCT and RTVue OCT. For the data measured by PS-OCT, we showed that for distinguishing between glaucomatous and healthy eyes, as well as for distinguishing between glaucoma suspect and healthy eyes, our new normalized RNFL reflectance index (NRRI) performs significantly better than phase retardation and birefringence. The performances of NRRI and RNFL thickness in both conditions were statistically indistinguishable in this study, which is likely due to the limited sample size. For the data measured by RTVue OCT, the performances of NRRI and RNFL thickness were statistically indistinguishable for distinguishing between glaucomatous and healthy eyes. NRRI performs significantly better than RNFL thickness for distinguishing between glaucoma suspect and healthy eyes. NRRI also performs significantly better than temporal, superior, nasal, inferior and temporal (TSNIT) average and nerve fiber indicator (NFI) from GDx VCC for distinguishing between glaucoma suspect and healthy eyes. NRRI is a promising parameter for distinguishing glaucoma suspect and healthy eyes and may indicate disease in the pre-perimetric stage.text
38
Yin, Biwei. "Optical coherence tomography for retinal diagnostics." Thesis, 2013. http://hdl.handle.net/2152/26614.
Full textAbstract:
Optical Coherence Tomography (OCT) is a non-invasive three-dimensional imaging technique. OCT synthesizes a cross-sectional image from a series of lateral adjacent depth scans, and with a two-dimensional scanning scheme, three-dimensional intensity image of sample can be constructed. Due to its non-invasive capability, OCT has been widely applied in ophthalmology, cardiology and dermatology; and in addition to three-dimensional intensity image construction, various functional OCT imaging techniques have been developed for clinical application. My research is focused on developing functional OCT systems for application in ophthalmology, including polarization-sensitive optical coherence tomography (PS-OCT) for retinal nerve fiber layer (RNFL) birefringence measurement and dual-wavelength photothermal optical coherence tomography (DWP-OCT) for microvasculature blood oxygen saturation (SO2) measurement. In the study, a single-mode-fiber based polarization-sensitive swept-source OCT (PS-SS-OCT) with polarization modulator, polarization-sensitive bulk-optics balanced detection module is constructed and polarization processing methods based on Stokes vectors are applied to determine birefringence. PS-OCT is able to provide human subject's RNFL thickness, phase retardation, and birefringence information. Degradation in the degree of polarization (DOP) along depth is investigated and its difference between four quadrants of RNFL (superior, temporal, inferior and nasal) indicates the structural property difference. DWP-OCT is a novel functional OCT system consisting of a phase-sensitive optical coherence tomography system (PhS-OCT) and two photothermal excitation lasers. PhS-OCT is based on a swept-source laser operating in the 1060 nm wavelength range; the two photothermal excitation lasers with wavelength 770 nm and 800 nm are intensity modulated at different frequencies. PhS-OCT probe beam and two photothermal excitation beams are combined and incident on the sample, optical pathlength (op) change on the sample introduced by two photothermal excitation beams are measured and used for blood SO2 estimation. A polarization microscope is proposed for future study. The polarization microscope is an imaging technique providing molecular structure and orientation based on probe light's polarization state information. The polarization microscope uses a wavelength tunable light source, and can achieve any incident polarization state by a retarder-rotator combination. Specimen's birefringence can be determined based on the changing of detected light amplitude.text
39
Cheloni, Riccardo, and Jonathan Denniss. "Depth-resolved variations in visibility of retinal nerve fibre bundles across the retina in enface OCT images of healthy eyes." 2020. http://hdl.handle.net/10454/18175.
Full textAbstract:
YesRecent developments in optical coherence tomography (OCT) technology enable direct enface visualisation of retinal nerve fibre bundle (RNFB) loss in glaucoma. However, the optimum depth at which to visualise RNFBs across the retina is unknown. We aimed to evaluate the range of depths and optimum depth at which RNFBs can be visualised across the retina in healthy eyes. The central ± 25° retina of 10 healthy eyes from 10 people aged 57–75 years (median 68.5 years) were imaged with spectral domain OCT. Slab images of maximum axial resolution (4 μm) containing depth‐resolved attenuation coefficients were extracted from 0 to 193.5 μm below the inner limiting membrane (ILM). Bundle visibility within 10 regions of a superimposed grid was assessed subjectively by trained optometrists (n = 8), according to written instructions. Anterior and posterior limits of RNFB visibility and depth of best visibility were identified for each grid sector. Effects of retinal location and individual eye on RNFB visibility were explored using linear mixed modelling with likelihood ratio tests. Intraclass correlation coefficient (ICC) was used to measure overall agreement and repeatability of grading. Spearman’s correlation was used to measure correlation between depth range of visible RNFBs and retinal nerve fibre layer thickness (RNFLT). Retinal location and individual eye affected anterior limit of visibility (χ2(9) = 58.6 and 60.5, both p < 0.0001), but none of the differences exceeded instrument resolution, making anterior limit consistent across the retina and different eyes. Greater differences were observed in the posterior limit of visibility across retinal areas (χ2(9) = 1671.1, p < 0.0001) and different eyes (χ2(9) = 88.7, p < 0.0001). Optimal depth for visualisation of RNFBs was around 20 µm below the ILM in most regions. It varied slightly with retinal location (χ2(9) = 58.8, p < 0.0001), but it was not affected by individual eye (χ2(9) = 10.7, p = 0.29). RNFB visibility showed good agreement between graders (ICC 0.89, 95%CI 0.87–0.91), and excellent repeatability (ICC 0.96–0.99). Depth range of visible RNFBs was highly correlated with RNFLT (ρ = 0.9, 95%CI: 0.86–0.95). The range of depths with visible RNFBs varies markedly across the healthy retina, consistently with RNFLT. To extract all RNFB information consistently across the retina, slab properties should account for differences across retinal locations and between individual eyes.
This work was supported by a College of Optometrists Research Fellowship (JD).
The full-text of this article will be released for public view at the end of the publisher embargo on 5th Nov 2021.
40
Bachir, Vanessa. "The relationship between retinal nerve fiber layer, visual function and vision-specific quality of life in multiple sclerosis." Thesis, 2019. http://hdl.handle.net/1866/23985.
Full textAbstract:
La sclérose en plaques est une maladie dégénérative qui peut affecter la vision ainsi que différentes structures du système visuel afférent. La partie de l'oeil plus souvent affectée par la sclérose en plaques est le nerf optique, sous forme de névrite optique. Une technologie, nommée TCO (tomographie par cohérence optique), permet de prendre une image du nerf optique et de ses fibres nerveuses qui s'étendent sur la rétine. Dans cette thèse, la TCO a permis d’obtenir une épaisseur des fibres nerveuses autour du nerf optique, ainsi qu’une épaisseur totale de la macula et de la couche de cellules ganglionnaires chez les patients atteints de sclérose en plaques, avec et sans histoire de nérite optique, et chez un groupe de patients contrôle. Les résultats démontrent que seule l’épaisseur de la couche de cellules ganglionnaires permet de différentier les patients avec sclérose en plaques sans histoire de névrite optique des patients contrôle. Une deuxième étude a évalué la qualité visuelle en mesurant la sensibilité aux contrastes ainsi que la qualité de vie reliée à la vision avec un questionnaire de qualité de vie. Les résultats démontrent qu’une nouvelle charte de sensibilité aux contrastes, plus facile à administrer en clinique, permet aussi de différentier les patients sans névrite optique du groupe contrôle. De plus, la qualité de vie des patients ayant eu un épisode de névrite optique semble significativement affectée, même si le pronostic est considéré très favorable et que l’acuité visuelle est « bonne » suite à une névrite optique. En conclusion, l’utilisation de l’OCT en plus de mesures sensibles de fonction visuelle, telle la sensibilité aux contrastes, et de qualité de vié peuvent contribuer à mieux détecter des dysfonctions oculo-visuelles subtiles, mais importantes chez les patients atteints de sclérose en plaques.Multiple sclerosis (MS) is the most common neurological condition causing disability in working-age adults. The hallmark of MS related disability is axonal loss. Through new technologies, such as optical coherence tomography (OCT), the retinal nerve fibre layer (RNFL), composed of ganglion cell axons, can be visualized and studied non-invasively in cross-section. Furthermore, recent OCT advances allow precise retinal layer segmentation and macular imaging of the ganglion cell layer. In this thesis, these different OCT parameters were measured to see which layers would be most affected in MS patients without previous optic neuritis. Results show that macular ganglion cell layer thickness is the only OCT parameter that can differentiate this sub-group of patients from healthy controls. Visual function was then assessed using a newly available, easy to use contrast sensitivity chart that can be self-administered by patients. Results show that this chart is also capable of differentiating MS patients without optic neuritis from controls, but usually gives better contrast sensitivity scores than the Mars chart. Lastly, vision-specific quality of life was assessed and proved to be reduced in MS patients with prior optic neuritis, despite supposed favorable recovery and good visual acuity in patients with this diagnosis. In sum, the use of OCT imaging, as well as sensitive visual function and quality of life measures, could help detect subtle, yet important structural or functional visual changes in patients with MS. This could ultimately help better screen, manage and counsel this subset of patients.
41
Paranjape, Amit Shrikant. "Application of polarization sensitive optical coherence tomography (PS-OCT) and phase sensitive optical coherence tomography (PhS-OCT) for retinal diagnostics." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-05-2660.
Full textAbstract:
An Enhanced Polarization-Sensitive Swept Source Optical Coherence Tomography (EPS-SS-OCT) instrument for high sensitivity cross-sectional imaging of Retinal Nerve Fiber Layer (RNFL) has been designed, constructed, and verified. The instrument is capable of measuring the thickness and birefringence of the RNFL. Birefringence change of the RNFL could serve as an early indicator of glaucoma.
The associated image processing methods for completely automated, time efficient algorithm to segment the RNFL in images of the human retina recorded by the EPS-SS-OCT. Detected RNFL boundaries are used to compute peripapillary thickness maps. Numerical algorithms to compute the birefringence of the detected RNFL layer are presented along with the associated phase retardation and birefringence peripapillary maps. Glaucoma affects the vitality of retinal ganglion cell axons in the retinal nerve fiber layer (RNFL) and may be clinically detected through a change in RNFL birefringence. Comprehensive peripapillary maps of healthy and glaucoma suspect human RNFL birefringence were constructed using EPS-SS-OCT.
Presence of macrophages is a hallmark of several retinal diseases such as drusen and age related macular degeneration. Application of photothermal Optical Coherence Tomography (OCT) to detect macrophages in ex vivo arteries which have engulfed nanoclusters of gold coated iron oxide (nanorose) is reported. Nanorose engulfed by macrophages in arteries absorb incident laser (800nm) energy and cause optical pathlength (OP) variation which is measured using photothermal OCT. OP variation in polydimethyl siloxane tissue phantoms containing varying concentrations of nanorose match values predicted from nanoparticle and material properties.
Measurement of OP variation in arteries in response to laser excitation provides an estimate of nanorose concentration in arteries 2.5x109 particles/ml. OP variation in nanoparticle containing artery sections and tissue phantoms taking up nanorose has a different magnitude and profile from that observed in control aorta and phantoms without macrophages and is consistent with macrophage presence as identified with RAM-11 histology staining. Our results suggest that tissue regions with macrophages taking up nanorose can be detected using photothermal OCT.text
42
Elmaanaoui, Badr. "Swept Source Polarization Sensitive Optical Coherence Tomography for retinal imaging at 1 micron." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-05-1361.
Full textAbstract:
Glaucoma is the second leading cause of blindness in the world. The disease is characterized by irreversible damage to retinal ganglion cells. Once glaucoma is
detected, further vision loss can be prevented by pharmacological or surgical treatment. However, current diagnostic methods lack the necessary sensitivity and up to 40% of vision maybe irreversibly lost before detection occurs.
A Swept Source Polarization-Sensitive Optical Coherence Tomography (SS-PSOCT) instrument for high sensitivity cross-sectional imaging of optical anisotropy in turbid media has been designed, constructed, and verified. A multiple-state nonlinear fitting algorithm was used to measure birefringence of the retinal nerve fiber layer with
less than 1%± average uncertainty.
To perform eye imaging efficiently a slit-lamp based interface for the SS-PSOCT instrument with a Line Scanning Laser Ophthalmoscope (LSLO) was used. This interface allowed for repeatable, stable, and registered measurements of the retina. A fixation target was used to stabilize the volunteer’s eye and image desired areas of the
retina. The LSLO allowed for an optimization of the location of OCT scans on the retina and provided a fundus blood vessel signature for registration between different imaging sessions.
The SS-PSOCT system was used to measure depth-resolved thickness,
birefringence, phase retardation and optic axis orientation of the retinal nerve fiber layer in normal volunteers. The peripapillary area around the optic nerve head (ONH) is most sensitive to glaucoma changes and hence data was acquired as concentric ring scans about the ONH with increasing diameters from 2mm to 5mm. Imaging of normal
patients showed that higher values of phase retardation occurred superior and inferior to the optic nerve head especially next to blood vessels and thicker parts of the retinal nerve fiber layer.text
43
Deschênes, Micheline Céline. "Effect of hormone replacement therapy on retinal and optic nerve head blood flow and topography in postmenopausal women, and retinal tissue perfusion in ovariectomized rats." Thèse, 2007. http://hdl.handle.net/1866/6502.
Full text
44
Asokan, Nitin. "Design and implementation of a miniaturized swept source spectral domain polarization sensitive optical coherence tomographic imaging system to diagnose glaucoma." 2010. http://hdl.handle.net/2152/9015.
Full textAbstract:
Glaucoma is an ophthalmic pathology that is the second leading cause of blindness. The laboratory design of a Polarization Sensitive Spectral Domain Optical Coherence Tomographic System aims to detect early glaucoma symptoms and prevent vision loss that occurs due to late or no glaucoma diagnosis. In order to perform human clinical trials at partner hospitals across the country, a miniaturized and portable version of the laboratory system was developed. The system facilitates easy transportation and clinical testing of the otherwise voluminous laboratory system across different eye centers. Significant consideration was given for performance optimization, cost reduction, design improvements and providing a friendly user-patient interface.text
45
Ganeshrao, S. B., A. M. McKendrick, Jonathan Denniss, and A. Turpin. "A Perimetric Test Procedure That Uses Structural Information." 2015. http://hdl.handle.net/10454/11090.
Full textAbstract:
noPurpose: To develop a perimetric test strategy, Structure Estimation of Minimum Uncertainty (SEMU), that uses structural information to drive stimulus choices. Methods: Structure Estimation of Minimum Uncertainty uses retinal nerve fiber layer (RNFL) thickness data as measured by optical coherence tomography to predict perimetric sensitivity. This prediction is used to set suprathreshold levels that then alter a prior probability distribution of the final test output. Using computer simulation, we studied SEMU’s performance under three different patient error response conditions: No Error, Typical False Positive errors, and Extremely Unreliable patients. In experiment 1, SEMU was compared with an existing suprathreshold cum thresholding combination test procedure, Estimation of Minimum Uncertainty (EMU), on single visual field locations. We used these results to finalize SEMU parameters. In experiment 2, SEMU was compared with full threshold (FT) on 163 glaucomatous visual fields. Results: On individual locations, SEMU has similar accuracy to EMU, but is, on average, one presentation faster than EMU. For the typical false-positive error condition, SEMU has significantly lower error compared with FT (SEMU average 0.33 dB lower; p < 0.001) and the 90% measured sensitivity range for SEMU is also smaller than that for FT. For unreliable patients, however, FT has lower mean and SD of error. Structure Estimation of Minimum Uncertainty makes significantly fewer presentations than FT (1.08 presentation on average fewer in a typical false-positive condition; p < 0.001). Assuming that a location in the field is marked abnormal if it falls below the 5th percentile of normal, SEMU has a false-positive rate of less than 10% for all error conditions compared with FT’s rate of 20% or more. Conclusions: On average, simulations show that using RNFL information to guide stimulus placement in a perimetric test procedure maintains accuracy, improves precision, and decreases test duration for patients with less than 15% false-positive rates.
46
Al-Bourini, Omar. "Retrospektive Evaluation retinaler Nervenfaserschichtdicke mit der cerebralen T2w-Läsionslast im MRT sowie dem Expanded Disability Status Scale (EDSS) bei pädiatrischen Patienten mit Multipler Sklerose." Doctoral thesis, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E405-A.
Full text
47
Kasl, Zdeněk. "Měření vrstvy nervových vláken sítnice u pacientů s Alzheimerovou chorobou." Doctoral thesis, 2017. http://www.nusl.cz/ntk/nusl-357212.
Full textAbstract:
Retinal nerve fiber layer measurement in patients with Alzheimer's disease The current ophthalmologist's possibilities in diagnostics of Alzheimer's disease Alzheimer disease (AD) is the most common cause of dementia syndrome and mild cognitive impairment. To enroll the disease most securely there are used so called biomarkers using evidence of changed brain metabolism by pozitron emission tomography (PET) and in cerebrospinal fluid or the brain's structure magnetic resonance imaging (MRI). These methods are expensive, organisationally and temporally challenging and burdening for the patients. According to that reasons we are still seeking for alternative attitudes suitable for early diagnosis. The evaluation of thickness of retinal nerve fiber layer (RNFL) which is well accessible to examination through optical aparatus of the eye could be one of the options. The aim of our work was to present current knowledges about Alzheimer's disease targeting relations of Alzheimer's disease and an ophthalmological finding. In the next part of this paper we introduce the retinal nerve fiber layer measurement by optical coherence tomography (OCT) as a potential diagnostics method by screening of patients with Alzheimer's disease and to present our results measured in our cohort of patients. The studied cohort...
48
Nurieva, Olga. "Prospektivní studie dlouhodobých zrakových následků akutních intoxikací metanolem." Doctoral thesis, 2019. http://www.nusl.cz/ntk/nusl-395906.
Full textAbstract:
Background: Methanol poisoning is a life-threatening condition which induces acute toxic optic neuropathy with possible long-term visual sequelae in survivors. Aim: To study the prevalence, character, dynamics, and key determinants of chronic morphological and functional visual pathway changes during 4 years after methanol-induced optic neuropathy. Methods: A total of 55 patients with confirmed methanol poisoning with mean age 46.7 ± 3.6 years (46 males and 9 females), and 41 controls were included in this prospective longitudinal cohort study. The patients were examined 4.9 ± 0.6, 25.0 ± 0.6, and 49.9 ± 0.5 months after discharge. The following tests were performed: visual evoked potential (VEP), optical coherence tomography with retinal nerve fiber layer (RNFL) measurement, brain magnetic resonance imaging (MRI), complete ocular examination, biochemical tests, and apolipoprotein E (ApoE) genotyping. Results: Of 42/55 patients with all three consecutive examinations, abnormal RNFL thickness was registered in 13 (31%) and chronic axonal loss during the observation period was found in 10 (24%) patients. The risk estimate of chronic global RNFL loss for arterial blood pH<7.3 at admission was: 11.65 (1.91-71.12; 95% CI) after adjusting for age and sex. The patients with chronic axonal degeneration demonstrated...
49
Denniss, Jonathan, A. Turpin, F. Tanabe, C. Matsumoto, and A. M. McKendrick. "Structure–Function Mapping: Variability and Conviction in Tracing Retinal Nerve Fiber Bundles and Comparison to a Computational Model." 2014. http://hdl.handle.net/10454/11088.
Full textAbstract:
yesPurpose: We evaluated variability and conviction in tracing paths of retinal nerve fiber bundles (RNFBs) in retinal images, and compared traced paths to a computational model that produces anatomically-customized structure–function maps. Methods: Ten retinal images were overlaid with 24-2 visual field locations. Eight clinicians and 6 naïve observers traced RNFBs from each location to the optic nerve head (ONH), recording their best estimate and certain range of insertion. Three clinicians and 2 naïve observers traced RNFBs in 3 images, 3 times, 7 to 19 days apart. The model predicted 10° ONH sectors relating to each location. Variability and repeatability in best estimates, certain range width, and differences between best estimates and model-predictions were evaluated. Results: Median between-observer variability in best estimates was 27° (interquartile range [IQR] 20°–38°) for clinicians and 33° (IQR 22°–50°) for naïve observers. Median certain range width was 30° (IQR 14°–45°) for clinicians and 75° (IQR 45°–180°) for naïve observers. Median repeatability was 10° (IQR 5°–20°) for clinicians and 15° (IQR 10°–29°) for naïve observers. All measures were worse further from the ONH. Systematic differences between model predictions and best estimates were negligible; median absolute differences were 17° (IQR 9°–30°) for clinicians and 20° (IQR 10°–36°) for naïve observers. Larger departures from the model coincided with greater variability in tracing. Conclusions: Concordance between the model and RNFB tracing was good, and greatest where tracing variability was lowest. When RNFB tracing is used for structure–function mapping, variability should be considered.