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Dissertations / Theses on the topic 'Scleral'
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1
Tang, Junhua. "Ultrasonic Characterization of Corneal and Scleral Biomechanics." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354678642.
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Malik, Nageena S. "Ageing of the human corneal and scleral collagen." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336205.
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Maswadi, Saher. "Investigation of scleral buckling by CO2 by laser." Thesis, University of Hull, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396085.
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Backhouse, Simon. "Induced myopia in the guinea pig: scleral myofibroblasts and biomechanics." Thesis, University of Auckland, 2009. http://hdl.handle.net/2292/3377.
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Aims: To determine the effect of induced myopia on the in vivo scleral biomechanical properties and scleral cell populations in the guinea pig. Methods: One week old guinea pigs were monocularly deprived of form vision (MD) for 14 days. Cycloplegic refractive error was measured with an IR Optometer, and the results analysed using power vectors and linear mixed modelling. The in vivo ocular biomechanical response was investigated by raising the IOP to 50 mmHg for one hour in anaesthetised animals. A-scan ultrasound measures of axial length were taken every 10 minutes with raised IOP, and after returning IOP to 15 mmHg. The total cell population (DAPI antibody) and myofibroblast population (α-SMA antibody) was determined in transverse scleral sections from the posterior 100 degrees of each eye. Results: The average relative myopic refractive error induced was -4.06 ± 0.35 D, which was mainly the result of vitreous chamber depth (VCD) elongation. This was confirmed by a negative correlation between mean sphere and VCD (R2 = 0.4295). On increasing the IOP the deprived and control eyes showed rapid viscoelastic expansion of the VCD that normal eyes did not show. When the increased IOP was maintained the deprived and control eyes showed lower creep rates than normal eyes. Myofibroblasts were shown to be present in guinea pig sclera, as previously observed in human and tree shrew sclera. On average, approximately 64% of the scleral cells were myofibroblasts. The induction of myopia had minimal effect on the cell populations, except for a decrease in total cell numbers in the 10° region equivalent to the location of scleral crescent formation in myopic human eyes. Conclusions: Ahigh proportion of scleral cells show contractile potential in the guinea pig. Form deprivation appears to minimally affect cell numbers, except in the region equivalent to scleral crescent formation in myopic human eyes. However, the in vivo viscoelastic response of the VCD in deprived eyes differs from that in normal eyes, suggesting some factor(s) other than cell number alone has a role in axial length control.
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Tomlinson, David Robert. "Torsional calibration of scleral coil measurements of the human eye." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/83675.
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Nixon, Alex D. "Visual Performance of Scleral and Soft Contact Lenses in Normal Eyes." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397498763.
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Tamimi, Ehab A., Jeffrey D. Pyne, Dominic K. Muli, Katelyn F. Axman, Stephen J. Howerton, Matthew R. Davis, Christopher A. Girkin, and Geest Jonathan P. Vande. "Racioethnic Differences in Human Posterior Scleral and Optic Nerve Stump Deformation." ASSOC RESEARCH VISION OPHTHALMOLOGY INC, 2017. http://hdl.handle.net/10150/626003.
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PURPOSE. The purpose of this study was to quantify the biomechanical response of human posterior ocular tissues from donors of various racioethnic groups to better understand how differences in these properties may play a role in the racioethnic health disparities known to exist in glaucoma. METHODS. Sequential digital image correlation (S-DIC) was used to measure the pressure-induced surface deformations of 23 normal human posterior poles from three racioethnic groups: African descent (AD), European descent (ED), and Hispanic ethnicity (HIS). Regional in-plane principal strains were compared across three zones: the optic nerve stump (ONS), the peripapillary (PP) sclera, and non-PP sclera. RESULTS. The PP scleral tensile strains were found to be lower for ED eyes compared with AD and HIS eyes at 15 mm Hg (P = 0.024 and 0.039, respectively). The mean compressive strains were significantly higher for AD eyes compared with ED eyes at 15 mm Hg (P = 0.018). We also found that the relationship between tensile strain and pressure was significant for those of ED and HIS eyes (P < 0.001 and P = 0.004, respectively), whereas it was not significant for those of AD (P = 0.392). CONCLUSIONS. Our results suggest that, assuming glaucomatous nerve loss is caused by mechanical strains in the vicinity of the optic nerve head, the mechanism of increased glaucoma prevalence may be different in those of AD versus HIS. Our ONS strain analysis also suggested that it may be important to account for ONS geometry and material properties in future scleral biomechanical analysis.
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Muzakare, Lea. "Tissue engineering a human conjunctiva-scleral model for in vitro testing." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26725.
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My objective was to tissue engineer a human conjunctiva-scleral equivalent with very basic inflammatory components, using a combinatorial approach. The complete model would comprise an innervated, vascularised stroma, overlaid by a stratified epithelium within a bio-synthetic matrix. Matrices fabricated from fibrin and either poly (N-isopropylacrylamide) or poly (N-isopropylacrylamide)-co-acrylic acid, supported differentiation of a human vascular endothelial cell line I immortalized into vessel-like structures. Human neutrophils and a granulocytic cell line, HL60 were able to migrate through these matrices and produce matrix metalloproteinases, in response to chemotactic stimuli. Innervation was introduced by embedding dorsal root ganglia as nerve sources within the matrices, while epithelial cells were seeded on top of the matrix. Contributions of this thesis include: (1) methodology for tissue engineering a conjunctiva-scleral tissue substitute, and (2) demonstrating basic functionality. This model may be further developed for use as an alternative to animals for in vitro toxicology testing.
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Fyfe, D. M. "An analysis of the development of the scleral ossicle system in the chick embryo." Thesis, University of Aberdeen, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379211.
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Shelton, Setareh Lillian. "Characterization of mechanisms regulating scleral extracellular matrix remodeling to promote myopia development." Oklahoma City : [s.n.], 2009.
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Länsman, S. (Satu). "Evaluation of bioabsorbable poly-L/D-lactide implant for scleral buckling:an experimental study." Doctoral thesis, University of Oulu, 2009. http://urn.fi/urn:isbn:9789514260742.
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Abstract
Bioabsorbable materials enable temporary implantation without the need for subsequent implant removal. The aim of the present experimental study was to evaluate the suitability of a fibrous bioabsorbable implant made of poly-L/D-lactide (PLDLA) 96/4 fibres as an episcleral implant.
The general tissue reactions were evaluated in subcutaneous tissues in rats in follow-up periods ranging from 3 days to 48 weeks. The episcleral tissue reactions were studied in rabbits with follow-up periods of one, three, five and 48 weeks. A silicone sponge implant was used as a control material and operations were performed using similar technique with both implants. Tissue reactions were located just around the implant area and consisted of an acute inflammatory reaction in the early follow-up periods, continuing as a foreign body inflammatory reaction. With episcleral implants there were no inflammatory cells seen within the sclera or in the retinal layers, and the structure of the retina and the cornea was also normal. The biocompatibility was good in the 48 week follow-up despite the relatively high surface area of the fibrous implant. The material had not degraded by 48 weeks.
The indentation effect by the PLDLA implant (diameter of 3–3.5mm) was lower than that achieved with the silicone sponge implant (diameter 4mm). The depth of indentation decreased over time in both groups with comparable rates over the follow-up period of 5 months. The duration of the indentation effect was sufficient to be used for scleral buckling in retinal detachment surgery.
In conclusion, the biocompatibility of a fibrous implant made of PLDLA 96/4 placed subcutaneously and episclerally was good in the follow-up lasting 48 weeks despite the relatively high surface area of the implant. The fibrous implant made of PLDLA 96/4 seemed to be well-tolerated by ocular tissues and the indentation effect was sufficiently long.
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Law, Glenn W. (Glenn Woodrow). "Measurements of ocular counterrolling during linear accelerations using an electromagnetic scleral search coil system." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/43236.
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Robinson, Christa Lee. "Evaluation of efficacy and biocompatibility of indirect intraocular pressure monitoring using a telemetric scleral sensor." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274142444.
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Barron, Martin John. "Mitochondria and the eye : ageing and disease." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369753.
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Huffman, Ryan Issac. "Cataract Formation After Retinal Procedures." Yale University, 2007. http://ymtdl.med.yale.edu/theses/available/etd-06282006-095623/.
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The purpose of this project is to study the risk of cataract development in patients who had undergone pars plana vitrectomy, scleral buckle, or both. A retrospective study was performed of phakic patients who underwent pars plana vitrectomy, scleral buckle, or both at Yale University Eye Center from 1998 to 2005. Mild postoperative cataract, defined as a change in severity of 1+, developed in 32 of 53 (60%) eyes following vitrectomy, 2 of 19 (11%) post scleral buckle, and 14 of 16 (88%) after both. Moderate postoperative cataract, defined as a change in severity of 2+, developed in 14 of 53 (26%) eyes post vitrectomy, 1 of 19 (5%) post scleral buckle, and 11 of 16 (69%) after both procedures. In eyes that underwent vitrectomy, a lens change of at least 2+ occurred in 8% at 3 months, 15% at 6 months, 21% at 12 months, and 26% at 36 months. In eyes status post scleral buckle surgery, one eye (5%) experienced a 2+ change at 36 months. In eyes that underwent both vitrectomy and scleral buckle, a lens change of at least 2+ occurred in 44% at 3 months, 50% at 6 months, 63% at 12 months, and 69% at 36 months. Cataract extraction surgery was performed in 15% of eyes post vitrectomy, 0% post scleral buckling, and 50% after both. The most common type of cataract to develop was nuclear sclerotic, which accounted for 61% of cataracts after vitrectomy, 50% after scleral buckling, and 50% after combined vitrectomy and scleral buckling. Scleral buckling surgery is associated with a low risk of cataract formation. Pars plana vitrectomy and combined vitrectomy and buckle have a higher risk of cataract development.
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Liu, Fang. "The comparison of long-term visual recovery between acute and sub-acute macula-off retinal detachment after scleral buckling surgery." [S.l.] : [s.n.], 2005. http://archiv.ub.uni-marburg.de/diss/z2005/0335/.
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Wallman, Andrew. "Safety and Visual Outcomes of Novel Abexterno Akreos® Single Pass Method of Transscleral Sutured Posterior Chamber IOL Implantation for Scleral Fixation of IOL." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/606216.
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A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine.We present the safety and efficacy of a novel transscleral sutured posterior chamber intraocular lens (TSSPCIOL) implantation approach utilizing 25 gauge vitrectomy and a foldable posterior chamber intraocular lens implant (AKREOS AO60, Bausch & Lomb). 80 consecutive eyes that underwent single surgeon TSSPCIOL implantation between October 2008 and July 2012 at a referral‐based retina institution were analyzed for best spectacle‐corrected visual acuity (BCVA) and safety indicators. Postoperative complications included retinal detachment in 2 eyes (2.5%), Irvine‐Gass cystoid macular edema in 3 eyes (3.75%), with 2 of those cases occurring late, persistent postoperative corneal edema in 1 eye (1.25%), hyphema in 2 eyes (2.5%) and 1 case of postoperative vitreous hemorrhage with spontaneous clearing. The modified external approach with AKREOS® TSSPCIOL placement with 25 gauge vitrectomy has relatively few complications, improves visual acuity in patients requiring TSSPCIOL, and offers several advantages over traditional anterior chamber or conventional scleral sutured techniques.
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Bausili, Portabella Maria Montserrat. "Supervivencia a largo plazo de las lentes intraoculares de cámara posterior suturadas a esclera." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/668328.
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asulcus y los factores de riesgo asociados a la rotura de la sutura. A pesar de ser una técnica ampliamente utilizada por los cirujanos de segmento anterior y posterior en aquellos casos donde no hay suficiente soport ecapsular, ésta no está exenta de posibles complicaciones, entre ellas la rotura de la sutura y luxación o subluxación de la lente.
OBJETIVO: El propósito de este estudio es el de evaluar a largo plazo la supervivencia y seguridad de la LIO y analizar las posibles causas que conducirían a la rotura de la sutura.
METODO: Se ha realizado un estudio retrospectivo de una serie de casos consecutivos. Se han incluido todos aquellos pacientes mayores de 18años y con un período de seguimiento de 10 años. Se ha analizado varios factores:
- Preoperatorio: edad, sexo, lateralidad del ojo, longitud axial.
- Intraoperatorio: características de la técnica quirúrgica, tipo de lente, tipo sutura, características del colgajo escleral, complicaciones intraoperatorias.
- Postoperatorio: complicaciones.
- Agudeza visual pre y postoperatoria.
- Presión Intraocular pre y postoperatoria.
- Función de Supervivencia.
RESULTADOS: Se analizaron 345 casos consecutivos de pacientes con sutura escleral de LIO. Veinticinco ojos requirieron una segunda intervención debido ala rotura de una o dos suturas. De estos 25, tres requirieron una tercera intervención. El grupo de adultos jóvenes, uso de una combinación de suturas (Prolene y Mersilene) o la sutura de una solo flap fueron factores de riesgo asociados a la rotura de la sutura tras 10 años de seguimiento. La probabilidad de supervivencia de la sutura tras 10 años se seguimiento fue de 0.79. Tanto la agudeza visual como la presión intraocular se mantuvieron estables tras 10 años de seguimiento.
CONCLUSIÓN: La sutura escleral de la LIO en ojos con falta de soporte capsular es una técnica efectiva y segura con un porcentaje bajo de complicaciones y resultados visuales estables a largo plazo.INTRODUCTION: This study shows the survival function of sclera-sutured intraocular lens (IOL) and the in those cases without capsular support, it is not exempted of possible complications, such as suture breakage and luxation or subluxation of the IOL. PURPOSE: The purpose of this study was to evaluate the long-term stability of scleral-sutured IOL and analyze possible causes of suture breakage. METHODS: This is a retrospective study of consecutive cases. We included all patients that underwent a scleral-sutured IOL with a follow-up longer than 6 months and patients over 18 years of age. Preoperative data (best-corrected visual acuity testing (BCVA), Intraocular pressure (IOP), axial length, and slit-lamp examination), intraoperative data (characteristics of the scleral flaps, suture material and scleral-sutured IOL) and postoperative data (BCVA, IOP, slit-lamp examination and complications) through 10 years were collected for analysis. RESULTS: Three hundred and forty-five consecutive cases of scleral-sutured IOL were included. Twenty-five eyes underwent a second operation after a prior sutured IOL due to suture breakage and three of them needed a third surgery. Younger adults, use a combination of Prolene and Mersilene sutures to perform the surgery and suturing only one flap were found to have higher risk of suture breakage after a follow up of 10 years. The probability of surviving of the scleral-sutured IOL at 10 years after surgery was 0.79. Visual acuity and intraocular pressure were stable all over the years. CONCLUSION:Scleral-sutured posterior chamber IOL in eyes with lack of capsular support is a safe and effective procedure with a low rate of complication and stable visual acuity. Further studies with special focus on younger adults or myopic eyes are required to demonstrate long-term safety in those special cases.
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Jarboui, Ahmed. "Etude de l'oxygénation de la cornée en présence d'un dispositif oculaire par des approches couplées de modélisation et d'expérimentations." Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTG038.
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Ce travail de thèse présente une étude de l'oxygénation de la cornée en présence d'un dispositif oculaire (sensor). Ce dispositif vise à permettre la mesure en continu de la pression intraoculaire de façon à mieux anticiper l’apparition du glaucome. L’étude de l'oxygénation a été réalisée via des approches couplées de modélisation et d'expérimentations. L’outil expérimental développé dans ce travail, basé sur une méthode chrono-ampérométrique, a permis de mesurer la perméabilité à l’oxygène des matériaux de fabrication du sensor ainsi que la perméabilité globale du dispositif. Des mesures expérimentales de la variation de l’épaisseur cornéenne par OCT ont permis de montrer que le gonflement cornéen, provoqué principalement par un manque d’oxygénation, varie localement à la cornée. Pour expliquer cette hétérogénéité spatiale, un modèle mathématique de l’oxygénation de la cornée a été développé en géométrie 2D. Le modèle intègre la description des phénomènes de transfert de matière (transfert et diffusion de l’oxygène) et des réactions biochimiques au sein de la cornée par voies aérobie et anaérobie. Le modèle apermis d’identifier les points limitants de l’oxygénation de la cornée dans différentes conditions de port du sensor, en intégrant un décentrage potentiel, et pour différents designs du dispositif. En tant qu’outil prédictif, le modèle a également permis d’identifier des stratégies d’amélioration telle que la diminution de la surface du circuit, l’implémentation des canaux d’oxygénation ou l’augmentation de la perméabilité des matériaux de fabricationThis work presents a study of the cornea oxygenation in the presence of an ocular device (sensor). This device aims to allow continuous measurement of intraocular pressure in order to better anticipate the onset of glaucoma. The oxygenation study was carried out using coupled modeling and experimental approaches. The experimental apparatus developed in this work, based on a chronoamperometric method, enabled to measure the oxygen permeability of the materials used to manufacture the sensor as well as the overall device permeability. Experimental OCT measurements concerning the change in corneal thickness have shown that corneal swelling, caused mainly by a lack of oxygenation, varies locally at the cornea. To explain this spatial heterogeneity, a mathematical model of corneal oxygenation has been developed in 2D geometry. The model involves the description of mass transfer phenomena (oxygen transfer and diffusion) and biochemical reactions within the cornea by aerobic and anaerobic pathways. The model enabled to identify the limiting phenomena of cornea oxygenation under different conditions of sensor wearing, by integrating a potential decentering, and for different designs of the device. As a predictive tool, the model also identified improvement strategies such as reducing the surface area of the circuit, implementing oxygen channels or increasing the permeability of manufacturing materials
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Chen, Anthia Yenshiu. "The hydrodynamic permeability of sclera." Thesis, Massachusetts Institute of Technology, 1991. https://hdl.handle.net/1721.1/129505.
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Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1991.Includes bibliographical references (leaves 30-31).
by Anthia Yenshiu Chen.
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1991.
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Alkassar, Sinan Husam Mahdi. "Advancing the technology of sclera recognition." Thesis, University of Newcastle upon Tyne, 2018. http://hdl.handle.net/10443/3979.
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Emerging biometric traits have been suggested recently to overcome some challenges and issues related to utilising traditional human biometric traits such as the face, iris, and fingerprint. In particu- lar, iris recognition has achieved high accuracy rates under Near- InfraRed (NIR) spectrum and it is employed in many applications for security and identification purposes. However, as modern imaging devices operate in the visible spectrum capturing colour images, iris recognition has faced challenges when applied to coloured images especially with eye images which have a dark pigmentation. Other issues with iris recognition under NIR spectrum are the constraints on the capturing process resulting in failure-to-enrol, and degradation in system accuracy and performance. As a result, the research commu- nity investigated using other traits to support the iris biometric in the visible spectrum such as the sclera. The sclera which is commonly known as the white part of the eye includes a complex network of blood vessels and veins surrounding the eye. The vascular pattern within the sclera has different formations and layers providing powerful features for human identification. In addition, these blood vessels can be acquired in the visible spectrum and thus can be applied using ubiquitous camera-based devices. As a consequence, recent research has focused on developing sclera recog- nition. However, sclera recognition as any biometric system has issues and challenges which need to be addressed. These issues are mainly related to sclera segmentation, blood vessel enhancement, feature ex- traction, template registration, matching and decision methods. In addition, employing the sclera biometric in the wild where relaxed imaging constraints are utilised has introduced more challenges such as illumination variation, specular reflections, non-cooperative user capturing, sclera blocked region due to glasses and eyelashes, variation in capturing distance, multiple gaze directions, and eye rotation. The aim of this thesis is to address such sclera biometric challenges and highlight the potential of this trait. This also might inspire further research on tackling sclera recognition system issues. To overcome the vii above-mentioned issues and challenges, three major contributions are made which can be summarised as 1) designing an efficient sclera recognition system under constrained imaging conditions which in- clude new sclera segmentation, blood vessel enhancement, vascular binary network mapping and feature extraction, and template registra- tion techniques; 2) introducing a novel sclera recognition system under relaxed imaging constraints which exploits novel sclera segmentation, sclera template rotation alignment and distance scaling methods, and complex sclera features; 3) presenting solutions to tackle issues related to applying sclera recognition in a real-time application such as eye localisation, eye corner and gaze detection, together with a novel image quality metric. The evaluation of the proposed contributions is achieved using five databases having different properties representing various challenges and issues. These databases are the UBIRIS.v1, UBIRIS.v2, UTIRIS, MICHE, and an in-house database. The results in terms of segmen- tation accuracy, Equal Error Rate (EER), and processing time show significant improvement in the proposed systems compared to state-of-the-art methods.
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Fullwood, Nigel James. "Ultrastructural studies of cornea and sclera." Thesis, Open University, 1992. http://oro.open.ac.uk/57389/.
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The work of Goodfellow et al., (J. Mol. BioI. 119: 231. 1918) and Sayers et al., (J. Mol. BioI. 160: 593. 1982), was repeated using fresh, equilibrated cornea, confirming their finding that the plot of interfibrillar spacing against liydration is a linear relationship. Intermolecular spacing in cornea, sclera and rat-tail tendon was shown to increase rapidly over the hydration range H=O to H::1, then tan off (physiological hydration is at H=3.2). Intermolecular and interfibrillar spacings rise in unison over the hydration range H=O to H~1, after which virtually all of the water goes between the fibrils. It was found that freezing corneas to 40oC and then thawing had no effect on normally hydrated or dehydrated corneas, but caused damage to swollen corneas. Freezing to ·180°C and thawing resulted in permanent damage to normally hydrated corneas . The changes in intermolecular spacing, D-period spacing, fibril diameter and fibril packing as a result of processing for TEM and SEM have been described. Low temperature embedding in Lowicryl K4M resin produced least disruption in the cornea. The fibril diameter in cornea at normal hydration was established to be 37.4nm±1.4. X-ray data modelling indicates that fibril packing in the cornea is liquid-like, as proposed by Worthington and Inoyue (Int. J. Macromol. 7: 2. 1985). It was shown that the water in the corneal stroma is evenly distributed around the fibrils over the hydration range H=O to H=4. Above H=4 more water is entering the stroma than can be "accounted for if its distribution is uniform. The transmittance of light through the bovine cornea (excluding interference effects), was calculated as T ==::12%. Thus, most of ~he transparency of the cornea must be due to constructive interference as first proposed by Maurice (J. Physiol. 136: 263. 1951). Examination of keratoconus corneas by the the SEM and TEM and showed abnormal epithelial cells, disrupted lamellae, and abnormally arranged proteoglycans. Analysis of X-ray data proved that stromal thinning in keratoconus was not due to closer fibril packing. Also that keratoconus corneas had increased intermolecular spacing, and an abnormal arrangement of proteoglycans along the fibrils. No differences were found between the corneal stroma of normal and myopic chicks. Myopic chick sclera was shown to have more aggrecan proteoglycan which was associated with larger empty spaces, than normal sclera. The fibril attachment sites of the proteoglycans was the same in normal and myopic sclera.
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Periketi, Prashanth Rao. "GAZE ESTIMATION USING SCLERA AND IRIS EXTRACTION." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_theses/145.
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Tracking gaze of an individual provides important information in understanding the behavior of that person. Gaze tracking has been widely used in a variety of applications from tracking consumers gaze fixation on advertisements, controlling human-computer devices, to understanding behaviors of patients with various types of visual and/or neurological disorders such as autism. Gaze pattern can be identified using different methods but most of them require the use of specialized equipments which can be prohibitively expensive for some applications. In this dissertation, we investigate the possibility of using sclera and iris regions captured in a webcam sequence to estimate gaze pattern. The sclera and iris regions in the video frame are first extracted by using an adaptive thresholding technique. The gaze pattern is then determined based on areas of different sclera and iris regions and distances between tracked points along the irises. The technique is novel as sclera regions are often ignored in eye tracking literature while we have demonstrated that they can be easily extracted from images captured by low-cost camera and are useful in determining the gaze pattern. The accuracy and computational efficiency of the proposed technique is demonstrated by experiments with human subjects.
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Träisk, Frank. "Evaluation of the infrared reflection method for saccadic eye movement velocity analysis /." Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-609-3/.
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Hoss, Kátia Arenhart. "Anatomia foliar de espécies do gênero Scleria (Cyperaceae)." reponame:Repositório Institucional da UFSC, 2013. https://repositorio.ufsc.br/handle/123456789/107015.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Biologia Vegetal, Florianópolis, 2013.Made available in DSpace on 2013-12-05T22:59:03Z (GMT). No. of bitstreams: 1 319866.pdf: 1900163 bytes, checksum: 74cfcfa13bafa26f0e34402492a7d2c7 (MD5) Previous issue date: 2013
O gênero Scleria, pertence à família Cyperaceae e suas espécies caracterizam-se por serem ervas perenes e cespitosas, que ocupam preferencialmente ambientes úmidos, podendo ser encontrados também em outros locais, como campos e matas. A delimitação do gênero Scleria tem sido muito controversa, pois assim como a maioria das espécies de Cyperaceae, a morfologia externa de seus órgãos vegetativos é muito similar, as flores são muito reduzidas e a inflorescência é difícil de interpretar. Em função disso, foi analisada a anatomia foliar de Scleria distans, S. gaertneri, S. latifolia, S. leptostachya, S. panicoides, S. plusiophylla, S. secans, S. sellowiana, S. uleana e S. variegata, coletadas no estado de Santa Catarina, com o objetivo de verificar a ocorrência de características anatômicas que possam distinguir as espécies. E ainda foi analisada a origem dos feixes invertidos que ocorrem nas folhas da espécie de S. plusiophylla. O material coletado foi processado de acordo com técnicas usuais em estudos de anatomia e ontogenia. Os caracteres anatômicos comuns às espécies são: formato de W invertido da lâmina foliar em secção transversal, epiderme unisseriada, células epidérmicas geralmente maiores na face adaxial em relação à abaxial, células buliformes presentes na face adaxial da nervura central e costelas laterais, presença de tricomas escabrosos no bordo foliar, esclerênquima associado ao feixe em ambas as faces da folha e estômatos presentes na face abaxial. Os caracteres que permitiram separar as espécies foram: presença de células buliformes distribuídas de forma contínua ou dispersas ao longo da face adaxial da lâmina foliar, tipo de mesofilo, feixe vascular da nervura central deslocado, ocorrência de células secretoras de mucilagem, tricomas tectores presentes apenas na face abaxial ou adaxial da epiderme, esclerênquima associado aos feixes vasculares apenas na epiderme abaxial e esclerênquima do bordo foliar ligeiramente voltado para a epiderme adaxial. Através do estudo ontogenético conclui-se que o bordo da lâmina foliar de S. plusiophylla é a extensão da ala da bainha que permanece na lâmina foliar, apresenta epiderme abaxial em ambas as faces e os feixes vasculares invertidos apresentam origem de cordões procâmbiais independentes os quais seguem a organização da bainha e ficam invertidos em relação à lâmina foliar.
Abstract : The genus Scleria, belongs to the family Cyperaceae, and its species are characterized by perennial herbs and tussock, occupying preferably moist environments, can also be found in other places, such as fields and forests. The delimitation of the genus Scleria has been much controversy, as well as most species of Cyperaceae, the external morphology of their vegetative organs are very similar, the flowers are very small and the inflorescence is difficult to interpret. Because of that, were analyzed the leaf anatomy of Scleria distans, S. gaertneri, S. latifolia, S. leptostachya, S. panicoides, S. plusiophylla, S. secans, S. sellowiana, S. uleana and S. variegata, collected in the state of Santa Catarina, with the objective of verify the occurrence of anatomical features that can distinguish the species. Also examining the origin of the inverted vascular bundle occurring in the leaves of the species S. plusiophylla. The material was processed according to standard techniques in studies of anatomy and ontogeny. The anatomical characters common in species are: W format inverted leaf blade in cross section, uniseriate epidermis, epidermal cells on the adaxial side generally larger in relationship to abaxial, bulliform cells present in the adaxial midrib and lateral ribs, prickles on the leaf margins, sclerenchyma associated with the vascular bundle on both faces of the leaf epidermis. The characters were allowed the separation species: presence of bulliform cells distributed continuously or scattered along the upper side of the leaf blade, type of mesophyll, vascular bundle of the midrib shifted, occurrence of mucilage secretory cells, trichomes present only on the abaxial and adaxial epidermis, sclerenchyma associated with vascular bundles only in the lower epidermis and sclerenchyma maple leaf slightly toward the adaxial epidermis. Through ontogenetic study concludes that the edge of the leaf S. plusiophylla is the length of the side of the sheath that remains in the leaf blade has abaxial on both sides and have reversed the vascular bundles of strands procambial independent source which follows the organization of the sheath and are inverted in relation to the leaf blade.
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Jiang, Ninghao. "Ocular drug delivery using microneedles." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/19796.
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Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2007.Committee Chair: Prausnitz, Mark R.; Committee Member: Allen, Mark; Committee Member: Edelhauser, Henry; Committee Member: Geroski, Dayle; Committee Member: Nickerson, John; Committee Member: Sambanis, Athanassios.
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Wen, He. "Characterization of Human Sclera Barrier Properties and Development of Episcleral Implant for Transscleral Delivery." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1396454281.
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Mayhew, Jessica A. "Attention cues in apes and their role in social play behavior of western lowland gorillas (Gorilla gorilla gorilla)." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3368.
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The research aims of this thesis are to investigate the attention cues available to and used by apes, especially gorillas (Gorilla gorilla), to ascertain the direction of conspecific attention during social interactions with a special reference to social play. Minimal research has been conducted on the role of attention cues - eye gaze, head, and body orientation - to regulate natural social interactions, such as social play, in non-human primates. This thesis begins with an investigation of the "cooperative eye hypothesis", which poses that humans have evolved a unique white sclera adaptation for advertising and detecting gaze direction. Chapter 2 reports the existence of a natural white sclera variation in a proportion of gorilla eyes - contradicting the widely held assumption that white sclera is an exclusively human characteristic - and analyzes the presence of white sclera in relation to other morphological changes in the human eye. The study concludes that the morphological elongation of the eye might be a more important and unique change than the white sclera coloration. Chapter 3 experimentally explores the contribution of white sclera in both great ape and human eye gaze to the perception of gaze direction detection by human observers. This chapter concludes that although white sclera contributes to the accuracy and speed of gaze direction detection (an assumption that this thesis has put to experimental test for the first time), this merely adds to the already efficient gaze cues available in the eye areas of the ape face. Chapter 4 investigates the role of eye gaze, head, and body orientations during gorilla social play behavior, and more specifically, introduces a novel analysis of "vigilance periods" (VPs), in which gorillas may use the interaction between attention cues to gauge the attention and intentions of play partners to successfully navigate play. The final study (Chapter 5) complements Chapter 4 and investigates the role of gorilla postures, behaviors, and movements during changes in attentional cue orientations. This chapter concludes that gorillas often engage in physical rest during VPs but maintain attentional engagement and can assemble and impart socially relevant information based on the behaviors, movements, and attention orientations of their partner. Together, these studies suggest that attention orientation is conveyed and assessed by gorillas through a variety of interacting cues to navigate and modify social play interactions.
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Ayyalasomayajula, Avinash. "A Computational Framework to Determine the Mechanical Properties of Ocular Tissues and a Parametric Study on their Effects on the Biomechanical Response of Lamina Cribrosa." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/594913.
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As is the case with many ocular neuropathies, primary open-angle glaucoma (POAG) leads to an irreversible damage to the visual field. Loss of visual field first occurs in the peripheral vision and slowly propagates towards the middle. Although there are differences in its rate of incidence, glaucoma is projected to be the leading cause of blindness, second only to cataract, affecting significant percentage of populations across different age, race/ethnic groups. A hallmark of POAG is the dysfunction of retinal ganglion cells (RGCs) which connect to the axons which, in turn, relay the visual information from the eye to the brain. Previous research has shown that axonal density in the optic nerve head (ONH) is greatly reduced due to chronically elevated intraocular pressure (IOP). IOP-lowering treatment has been shown to reduce the visual field loss, and continues to be the dominant treatment methodology for glaucoma. Previous research has shown that the biomechanics of the lamina cribrosa (LC) - a highly porous tissue through which the axons carrying the visual information exit the eye, is important in influencing the viability of the RGCs. In a normal eye, the LC is primarily made up of collagen of types I, III, and IV which encompass (specifically, arranged circularly) the axon shafts and the blood vessels (1). In addition to elevated IOP, changes in the material properties of ocular tissues in and around the ONH region, which include peripapillary sclera and LC, could affect its biomechanics, which could be a result of changing microstructure and morphology of these tissues, and may contribute to POAG. The current work is aimed at creating computational models to incorporate the complex nature of ocular tissues, and develop computational techniques to characterize the variation in the material properties of ocular tissues (which include the tissue moduli, fiber orientation, permeability etc.), and study the effects they have on the biomechanical response of the LC region.
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Pino, Monica. "Apatite deposition on NaOH-treated HDPE, PEEK and UHMWPE films for sclera materials in artificial cornea implants." Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/1896/.
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Corneal disease is the second most common cause of blindness in the word. It is estimated that 45 million people worldwide are bilaterally blind and 10 million are affected by corneal blindness. Corneal blindness mostly affects the population in the equatorial zone, due to the high exposure to UV light. Corneal grafting presents complications such as rejections and the lack of donor material and resources. Conventional cornea grafting (keratoplasty) is not advised for patients with bilateral corneal blindness or for those who suffer from a range of clinical problems including tear deficiency, chemical burns and uncontrollable intraocular pressure. At present, an artificial cornea, i.e. a keratoprosthesis (KRPO), is the only alternative to keratoplasty (corneal donor transplantation). Cornea implants consist of a clear optic part and a surrounding ring known as the skirt, which needs to integrate with the sclera of the eye. Currently used skirt materials lead to poor tissue integration, a major failure of cornea implants. Better integration may be achieved when using a bioactive skirt material, which adapts to the metabolic activity of the cornea. For this purpose, high density polyethylene (HDPE), polyether ether ketone (PEEK) and ultra-high molecular weight polyethylene (UHMWPE) films provide interesting possible alternatives, if they can be rendered bioactive. This study investigated the potential of using surface modified polymer films to fabricate the skirt. To improve bioactivity of the materials a two-step treatment using chemical surface modification (immersion in NaOH) and formation of apatite layers from Simulated Body Fluid (SBF) was applied. The effectiveness of the different molarity of the NaOH on the formation of the bioactive layer was investigated. Results showed that with an increase in NaOH concentration the wettability improved but also some changes to the topography (increase/decrease of roughness) of the polymers were observed. Moreover, 10M NaOH treatments resulted in more rapid formation of the apatite layer when compared with a non-treated and lower molarity solution. As immersion time in SBF increased, further nucleation and growth produced a thicker apatite layer which can be expected to be highly bioactive. Interestingly, the apatite growth is dependent on both the concentration of NaOH solution and the structure of the polymer surface. It was concluded that hydroxyapatite layers were formed on HDPE, PEEK and UHMWPE films after they were incubated in 1.5 SBF, which promises to render such thin-film structures bioactive – a necessity if they are to be integrated into artificial cornea. The Ca/P molar ratio of the apatite deposited on the polymers increases with NaOH strength and SBF incubation time. The favourable effect of NaOH on apatite formation may at least partly be attributed to an increased wettability of the polymer films after such treatment, as well as to the modified topography. The apatite layer contained phosphate and carbonates ions, providing potentially good in vitro bioactivity on polymeric films. The inorganic layers are chemically stable as the calcium deposited on the films did not dissolve fully when immersed in water for one week. This demonstrates that polymer films can be rendered bioactive, using the described approach, hence providing potential materials suitable for artificial cornea implants.
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Kawabata, Simone Cristina. ""Avaliação da estabilidade de cor da esclera em prótese ocular"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/23/23144/tde-08082006-094243/.
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Baseados no fato de que o corpo escleral sofre alterações progressivas de sua cor no decorrer do tempo, e também pela ausência na literatura específica de trabalhos experimentais relacionados com estas alterações, o presente trabalho tem por objetivo, verificar o desempenho de resinas para esclera e de três tipos de pigmentos neste processo. Os pigmentos utilizados para este fim foram: lápis aquarelável, acrílico termo-polimerizante colorido e pigmento cerâmico; nas cores azul, amarelo e vermelho. Para a realização do experimento, foram confeccionados 100 corpos de prova, sendo 50 de resina para esclera no1e os outros 50 de resina para esclera no2. Cada grupo foi subdividido em 10 subgrupos, com 5 unidades cada, separados em quatro categorias: A, B ,C e E. O grupo A foi caracterizado com lápis aquarelável, o B com resina termo-polimerizável colorida, o C com pigmento cerâmico e o E não recebeu caracterização. Todos os grupos foram recobertos por uma camada de resina incolor. Inicialmente, todos os corpos de prova foram submetidos à análise em um espectrofotômetro acoplado a um sistema de colorimetria. A leitura inicial foi considerada como padrão, sendo as demais, efetuadas a cada 24 horas, até um total de 144 horas intercaladas com ensaios de envelhecimento acelerado por radiação UVA. Os dados colorimétricos, obtidos através das curvas de reflexão de cada amostra, foram utilizados para o cálculo das diferenças de cor. Após o tratamento estatístico dos dados obtidos, foi possível concluir que o lápis aquarelável, nas cores amarela e vermelha e o pigmento cerâmico vermelho, apresentaram uma estabilidade de cor clinicamente aceitável durante todo o tempo experimental. Das duas resinas para esclera avaliadas, a de no2 apresentou melhor estabilidade de cor.Based on the fact that the sclera of ocular prosthesis presents progressive color alterations with time and due to lack of experimental studies on this topic, the purpose of this study was to evaluate the performance of two types of resins combined with three different kinds of pigments. The pigments used herein were: watercolour pencils, heat-polymerized acrylic resin and ceramic pigment on the colors blue, yellow and red. A total of one-hundred specimens were prepared, among which 50 were made by resin no 1 and the remaining 50 were made by resin no 2. Each group of 50 samples were divided in 10 subgroups containing 5 specimens each, and were separated in four categories: A, B, C and E. Group A was colored with watercolour pencils, while in group B it was used heat-polymerized acrylic resin and in group C, it was used ceramic pigment. Group E was not pigmented. After pigmentation, all specimens received a transparent heat-cured resin layer. At time point zero, all specimens were assessed by a spectrophotometer connected to a colorimeter system, and the initial data were used as the standard value. Immediately after the initial assessment, all samples were kept in a UVA irradiation chamber. The following data were taken after every 24 hours until completion of 144 hours. All colorimetric data were obtained by the reflection curves of each sample and used to calculate the color difference rate. After statistical analysis, it was concluded that the samples colored with watercolour pencil in yellow and red as well as the ceramic pigment in red showed color stability clinically acceptable during the whole experimental period. Between the two types of resin used herein, the resin no 2 showed better color stability.
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Bisplinghoff, Jill Aliza. "Biomechanical Response of the Human Eye to Dynamic Loading." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/31880.
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Blindness due to ocular trauma is a significant problem in the United States considering that each year approximately 500,000 years of eyesight are lost. The most likely sources of eye injuries include sports related impacts, automobile accidents, consumer products, and military combat. Out of the 1.9 million total eye injuries in the country, more than 600,000 sports injuries occur each year and 40,000 of them require emergency care. In 2007, approximately 66,000 people suffered from vehicle related eye injuries in the United States. Of the vehicle occupants sustaining an eye injury during a crash, as many as 15% to 25% sustained severe eye injuries and it was shown that within these severe eye injuries as many as 45% resulted in globe rupture.
The purpose of this thesis is to characterize the biomechanical response of the human eye to dynamic loading. A number of test series were conducted with different loading conditions to gather data. A drop tower pressurization system was used to dynamically increase intraocular pressure until rupture. Results for rupture pressure, stress and strain were reported. Water streams that varied in diameter and velocity were developed using a customized pressure system to impact eyes. Intraocular pressure, normalized energy and eye injury risk were reported. A Facial and Ocular Countermeasure Safety (FOCUS) headform was used to measure the force applied to a synthetic eye during each hit from projectile shooting toys. The risk of eye injury for each impact was reported. These data provide new and significant research to the field of eye injury biomechanics to further the understanding of eye injury thresholds.
Master of Science
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Affonso, Regina Celis Lopes. "Diversidade e aspectos nomenclaturais em Scleria P. J. Bergius (Cyperaceae) de Santa Catarina, Brasil." Florianópolis, 2012. http://repositorio.ufsc.br/xmlui/handle/123456789/99285.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas. Programa de Pós-Graduação em Biologia VegetalMade available in DSpace on 2013-03-04T18:35:55Z (GMT). No. of bitstreams: 0Bitstream added on 2013-07-16T20:52:24Z : No. of bitstreams: 1 308036.pdf: 3454443 bytes, checksum: 5917ff7a3a3d901c0cae67d4a2c22873 (MD5)
O gênero Scleria apresenta distribuição pantropical sendo seu centro de diversidade o continente americano. No Brasil, o gênero distribui-se em todas as regiões. O presente estudo foi elaborado com base em coleções de herbários, estudo das populações no campo e consulta à literatura especializada. O gênero distribui-se por todo o Estado e está representado nas diferentes formações vegetais, incluindo restinga, campos litorâneos, campos de altitude e floresta atlântica. Foi confirmada a ocorrência de 13 espécies: Scleria distans Poir., S. filiculmis Boeck., S. gaertneri Raddi, S. georgiana Core, S. latifolia Sw., S. leptostachya Kunth, S. microcarpa Nees ex Kunth, S. panicoides Kunth, S. plusiophylla Steud., S. secans (L.) Urb., S. sellowiana Kunth, S. uleana Boeck. e S. variegata (Nees) Steud. A maioria das espécies apresenta distribuição ampla estendendo-se em diferentes países das Américas e algumas com registro também para a África. Scleria uleana e S. variegata apresentam distribuição restrita ao sul e sudeste do Brasil e S. filiculmis registro apenas para o sul do país (SC e PR). São fornecidos chave de identificação taxonômica para as espécies, descrições morfológicas acompanhadas de dados de distribuição geográfica, habitat, aspectos fenológicos, comentários taxonômicos e ilustrações. São propostos lectótipos para quatro nomes: Scleria filiculmis Boeckeler, Scleria catharinensis Boeckeler, Scleria microcarpa Nees ex Kunth and Scleria panicoides Kunth.
The genus Scleria has pantropical distribution, with higher diversity in the American continent. In Brazil, this genus is distributed all over the regions. The present study was carried out based on herbarium collections, on natural population and on the specialized literature. This genus is distributed throughout the state of Santa Catarina and is present in different plants compositions, including sandbanks, seacoast fields, highlands and the Atlantic forest. The occurrence of Scleria distans Poir., S. filiculmis Boeck., S. gaertneri Raddi, S. georgiana Core, S. latifolia Sw., S. leptostachya Kunth, S. microcarpa Nees ex Kunth, S. panicoides Kunth, S. plusiophylla Steud., S. secans (L.) Urb., S. sellowiana Kunth, S. uleana Boeck., and S. variegata (Nees) Steud has been confirmed. Most species are widely distributed throughout different countries in the Americas, and some of them are also present in Africa. The distribution of Scleria uleana and S. variegata is restricted to Brazil's south and southeast regions, and S. filiculmis is present only in south region(SC and PR). Taxonomic identification keys for the species, morphological descriptions along with geographic distribution data, habitat, phenological aspects, taxonomic notes, and illustrations are provided. Lectotypes are proposed for four names: Scleria filiculmis Boeckeler, Scleria catharinensis Boeckeler, Scleria microcarpa Nees ex Kunth and Scleria panicoides Kunth.
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Metzler, Kimberly M. "The Influence of IOP, Corneal Stiffness, and Sclera on Corneal Deformation Response to an Air Puff Using the CorVis ST." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1418479307.
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Candioto, Cinthia Graziela [UNESP]. "Histomorfometria do bulbo do olho de peneireiro-de-dorso-malhado (Falco tinnunculus – LINNAEUS, 1758)." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/95942.
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O bulbo do olho é uma parte do organismo pouco estudada e que carece de mais valores fisiológicos nas diversas espécies de animais. Neste sentido, o objetivo deste trabalho foi avaliar os cortes histológicos dos olhos de Falco tinnunculus (peneireiro-de-dorso-malhado), por meio da morfometria da córnea, retina, coróide e esclera. As aves eram adultas e de vida livre. Os resultados obtidos foram comparados entre machos e fêmeas e entre os olhos direito e esquerdo. Após enucleação dos olhos, os mesmos foram fixados em solução tamponada de formaldeído por 48 horas e posteriormente, descalcificados. Os olhos direitos foram cortados verticalmente (dorsoventral), e os esquerdos horizontalmente (temporonasal). Após inclusão em parafina, foram confeccionados cortes de 5m de espessura e corados pelas técnicas rotineiras de hematoxilina e eosina. Para a análise dos cortes, foram definidos e medidos, seis pontos (1 a 6) na retina, coróide e esclera, e três pontos referentes na córnea (A, B e C). Com um software de análise de imagens, avaliou-se a espessura em micrômetros da córnea total, e suas camadas (epitelial, “camada média”, endotelial), além da retina, coróide e esclera nos seus respectivos pontos pré-determinados. Na córnea as maiores espessuras foram na periferia (ponto A e C) e as menores na área central (ponto B). As comparações entre as médias foram feitas pelo teste de Tukey (p<0,05). Nas fêmeas a retina foi mais espessa que nos machos. O dados descritos no trabalho complementam os conhecimentos básicos da histomorfologia do olho de Falco tinnunculus necessários para avaliação de cortes histopatológicos
The bulb of the eye is not a well-studied part of the body and needs more physiological values for various animal species. In this manner, the objective of the study was to evaluate the histological eye Falco tinnunculus (commom kestrel), through measurements of the cornea, retina, choroid and sclera. The birds were adults from wild life. The results were compared between males and females and between the right and left eyes. After enucleation of the eyes, they were fixed in buffered formaldehyde for 48 hours and subsequently decalcified. The right eyes were cut vertically (dorsoventral), and left horizontally (temporonasal). After paraffin embedding, sections were prepared from 5m thick and stained using routine hematoxylin and eosin. For the analysis of the cuts, six points (1-6) in the retina, choroid and sclera, and three points on the cornea (A, B and C) have been defined and measured. With an image analyzing software, the corneal thickness and its layers (epithelium, middle layer, endothelial), were evaluated in total microns, as well as the retina, choroid and sclera in their respective pre-determined points. Corneal thickness was greater in the periphery (A and C) and lower in the central area (B). Comparisons between means were made using the Tukey test (p <0.05). In females retina was thicker than the males. The data described in the paper complement the basic knowledge of histomorphology eye Falco tinnunculus for the assessment of histopathology
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CODET, JEAN-MARC. "Tumeurs du limbe sclero-corneen : reflexions cliniques et therapeutiques a partir de 23 observations." Limoges, 1989. http://www.theses.fr/1989LIMO0148.
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N'Guyen, Mailfer Christine. "La genodermatose sclero-atrophiante et keratodermique des extremites (sclerotylosis) : etude clinique, ultrastructurale, genetique et therapeutique." Lille 2, 1989. http://www.theses.fr/1989LIL2M029.
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Nguyen, Boihoan Audrey. "The Role of the Sclera and Orbital Tissues in the Biomechanical Deformation Response of the Cornea and Whole Eye Under Loading by Dynamic Scheimpflug Analyzer." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1563535029748361.
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Hubert, Isabelle Berrod Jean-Paul. "Vitrectomie sans indentation sclérale dans le traitement de première intention du décollement de rétine à propos de 175 cas /." [S.l] : [s.n.], 2002. http://www.scd.uhp-nancy.fr/docnum/SCDMED_T_2002_HUBERT_ISABELLE.pdf.
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Candioto, Cinthia Graziela. "Histomorfometria do bulbo do olho de peneireiro-de-dorso-malhado (Falco tinnunculus - LINNAEUS, 1758) /." Jaboticabal : [s.n.], 2011. http://hdl.handle.net/11449/95942.
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Orientador: Karin WertherBanca: Fabiano Montiani-Ferreira
Banca: Rosimeri de Oliveira Vasconcelos
Resumo: O bulbo do olho é uma parte do organismo pouco estudada e que carece de mais valores fisiológicos nas diversas espécies de animais. Neste sentido, o objetivo deste trabalho foi avaliar os cortes histológicos dos olhos de Falco tinnunculus (peneireiro-de-dorso-malhado), por meio da morfometria da córnea, retina, coróide e esclera. As aves eram adultas e de vida livre. Os resultados obtidos foram comparados entre machos e fêmeas e entre os olhos direito e esquerdo. Após enucleação dos olhos, os mesmos foram fixados em solução tamponada de formaldeído por 48 horas e posteriormente, descalcificados. Os olhos direitos foram cortados verticalmente (dorsoventral), e os esquerdos horizontalmente (temporonasal). Após inclusão em parafina, foram confeccionados cortes de 5m de espessura e corados pelas técnicas rotineiras de hematoxilina e eosina. Para a análise dos cortes, foram definidos e medidos, seis pontos (1 a 6) na retina, coróide e esclera, e três pontos referentes na córnea (A, B e C). Com um software de análise de imagens, avaliou-se a espessura em micrômetros da córnea total, e suas camadas (epitelial, "camada média", endotelial), além da retina, coróide e esclera nos seus respectivos pontos pré-determinados. Na córnea as maiores espessuras foram na periferia (ponto A e C) e as menores na área central (ponto B). As comparações entre as médias foram feitas pelo teste de Tukey (p<0,05). Nas fêmeas a retina foi mais espessa que nos machos. O dados descritos no trabalho complementam os conhecimentos básicos da histomorfologia do olho de Falco tinnunculus necessários para avaliação de cortes histopatológicos
Abstract: The bulb of the eye is not a well-studied part of the body and needs more physiological values for various animal species. In this manner, the objective of the study was to evaluate the histological eye Falco tinnunculus (commom kestrel), through measurements of the cornea, retina, choroid and sclera. The birds were adults from wild life. The results were compared between males and females and between the right and left eyes. After enucleation of the eyes, they were fixed in buffered formaldehyde for 48 hours and subsequently decalcified. The right eyes were cut vertically (dorsoventral), and left horizontally (temporonasal). After paraffin embedding, sections were prepared from 5m thick and stained using routine hematoxylin and eosin. For the analysis of the cuts, six points (1-6) in the retina, choroid and sclera, and three points on the cornea (A, B and C) have been defined and measured. With an image analyzing software, the corneal thickness and its layers (epithelium, "middle layer", endothelial), were evaluated in total microns, as well as the retina, choroid and sclera in their respective pre-determined points. Corneal thickness was greater in the periphery (A and C) and lower in the central area (B). Comparisons between means were made using the Tukey test (p <0.05). In females retina was thicker than the males. The data described in the paper complement the basic knowledge of histomorphology eye Falco tinnunculus for the assessment of histopathology
Mestre
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Körber, Nicole. "Ein neuer therapeutischer Ansatz zur vorbeugenden Behandlung der pathologischen Myopie - Einfluss des skleralen Riboflavin/Blaulicht Cross-Linkings auf das Augenwachstum junger Kaninchen." Doctoral thesis, Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-220353.
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Die Arbeit umreißt das Krankheitsbild der Myopie (Kurzsichtigkeit) und deren unterschiedliche Ausprägungen, im Speziellen der progressiven und pathologischen Myopie. Hierbei wird ein Einblick in die Symptomatik, die anatomischen Ursachen und die heutigen medizinischen Interventionen gegeben. Hierdurch wird die Problematik einer zu „weichen“ Sklera (Lederhaut des Auges) und des damit einhergehenden fortschreitenden Augenwachstums deutlich. Im Zentrum der Arbeit steht ein neuer therapeutischer Ansatz zur vorbeugenden Behandlung der pathologischen Myopie; das Riboflavin/Blaulicht Cross-Linking der Sklera des Kaninchenauges.
Dessen Wirkungsweise ermöglicht die biomechanische Versteifung von kollagenem Gewebe. Aus diesem Sachverhalt ergibt sich die Fragestellung der Arbeit: Ist das sklerale Riboflavin/Blaulicht Cross Linking geeignet das Augenwachstum im Tiermodell (junge Kaninchen) verträglich zu hemmen?
Operationsbeeinflussende Parameter wie die Riboflavin-Durchdringungsdauer der Sklera und die sklerale Lichtdurchlässigkeit werden untersucht und für die Optimierung der Operationsmethode herangezogen und diskutiert. Zur Einschätzung des Versuchsansatzes werden die im Methodikteil dargelegten Anwendungen an adulten und jungen Kaninchen/Kaninchenaugen durchgeführt. In Tierversuchen wird die Schadensschwelle in Abhängigkeit der Blaulichtintensität, des Alters und der Pigmentierung untersucht, wobei histologische, immunhistochemische und elektronenmikroskopische Verfahren angewendet werden. Der inhibitorische Einfluss des Riboflavin/Blaulicht Cross-Linkings auf das Augenwachstum kann im Jungtiermodell durch verschiedene metrische Verfahren und MRT-Untersuchungen belegt werden.
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BAUTE, BERNARD. "Complications du traitement conservateur des melanomes malins de la choroide par applicateurs scleraux de ruthenium et d'iridium : a propos de 84 cas." Lyon 1, 1988. http://www.theses.fr/1988LYO1M203.
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Saeed, Kilani Mohammad Ali. "L'utilisation des agents d'embolisation liquides dans les vaisseaux périphériques : mise au point, défis et futures perspectives : preuves de concept d'un nouvel agent sclero-embolique : Alconyx." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM5052/document.
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Les agents d'embolisation liquides utilisés dans le traitement endovasculaire ont de nombreuses limitations. Des polymères, tels que l’Onyx et les cyanoacrylates sont disponibles. L’alcool est un agent puissant, mais non radio-opaque. Les cyanoacrylates entrainent une réaction inflammatoire significative. Leur polymérisation rapide est responsable d’un comportement mal prévisible.Il existe une possibilité de traitement incomplet.L’Onyx est efficace pour le traitement des MAV.Une pénétration plus distale est obtenue avec l’alcool, mais associée à un risque de migration systémique. Nous avons évalué les propriétés d'un nouvel agent embolique (Alconyx) composé d'un mélange d'alcool et d'Onyx. Cet agent devrait cumuler les avantages respectifs de l'alcool et de l'onyx avec une visualisation adéquate sous fluoroscopie, une meilleure pénétration distale que l'Onyx seul et moins de toxicité systémique liée à la réduction de quantité d’alcool injecté. Divers mélanges ont été testés avec différentes concentrations d'Onyx 18 et d’alcool absolu. Alconyx 25 (75% Onyx 18; 25% d'éthanol) est la formulation la plus prometteuse. Nous avons démontré sa facilité d'injection in vivo, sa nature cohésive sans fragmentation ainsi que sa bonne visualisation sous fluoroscopie. En raison de sa moindre viscosité démontrée in vitro, Alconyx a été capable de pénétrer profondément dans le lit artériel.. L'occlusion proximale par Alconyx 25 devrait permettre d'améliorer le contact entre l'éthanol et la paroi vasculaire et donc augmenter son pouvoir sclérosant et limiter son passage systémique. Les propriétés occlusives d’Alconyx 25 sont similaires à celle de l’Onyx 18 sous haute pression in vitroCommercially available liquid embolization agents used in endovascular treatment have many limitations. Polymeric agents as Onyx and cyanoacrylate are available. Ethanol also is a potent sclero-embolic agent. Cyanoacrylates are effective liquid embolic agents, however, their rapid polymerization makes their behaviour unpredictable with possibility of incomplete treatment. These properties render their use challenging.Onyx is easy to use. However, in very small arterial niduses, Onyx, is unable to penetrate deeply. Deep penetration is obtained with ethanol, associated with risk of systemic migration.Poor visualization of ethanol under fluoroscopy is major drawback. Mixing Onyx with ethanol had never been described in the literature till now. In this work, various mixtures have been tested with different concentrations of Onyx 18 and absolute ethanol. Alconyx 25 (75% Onyx 18; 25% ethanol) seems to be a promising product. We proved its ease of injection in vivo and in vitro, its cohesive nature showing no fragmentation or interruption of the injected column as well as its good visualization under fluoroscopy. It was able to penetrate deeply in the arterial bed. The occlusive properties of Alconyx 25 were rated as good as Onyx 18 under high pressure in vitro. Further investigation is needed to better understand the behavior of ethanol in the suspension and its effect on tissues compared to Onyx diluted simply with an equivalent amount of DMSO. Studies on other commercially available concentrations of Onyx would certainly be interesting
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Torres, Rogil José de Almeida [UNIFESP]. "Avaliação das anormalidades precoces esclerocoriorretinianas observadas em coelhos hipercolesterolemicos tratados com Rosiglitazona." Universidade Federal de São Paulo (UNIFESP), 2010. http://repositorio.unifesp.br/handle/11600/9053.
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Previous issue date: 2010-04-28O objetivo deste trabalho é avaliar as anormalidades da esclera, coroide e retina de coelhos induzidas pela dieta hipercolesterolêmica, além da possibilidade de prevenção dessas anormalidades com administração sistêmica de rosiglitazona. Para isto, 54 coelhos new zealand foram distribuídos em quatro grupos: grupo-controle (GC) recebeu dieta normal; grupo 1 recebeu dieta hipercolesterolêmica; grupo 2 recebeu dieta hipercolesterolêmica associada à administração diária de 3 mg de rosiglitazona a partir do 14º dia do início do experimento; e grupo 3 recebeu dieta hipercolesterolêmica associada à administração diária de 3 mg de rosiglitazona desde o início do experimento. Os coelhos foram pesados e submetidos à dosagem sérica de colesterol total, triglicerídeos, high density lipoprotein (HDL) colesterol e glicemia de jejum no início do experimento, no 14º dia e no momento da eutanásia (42º dia). A esclera e coroide foram submetidas à análise histológica e histomorfométrica. A retina foi submetida à análise imuno-histoquímica com o anticorpo monoclonal anticalretinina (CR) e anticorpo anti-glial fibrillary acidic protein (GFAP). Quando positivo para o marcador anticalretinina, duas análises quantitativas foram realizadas. Na primeira, foram contadas todas as células ganglionares imunorreativas. Na segunda, todas as células e elementos celulares imunorreativos foram avaliados pelo exame de morfometria de cores. Os dados foram analisados pelo teste nãoparamétrico de Kruskal-Wallis e teste de Shapiro-Wilks-Testand. Valores abaixo de 0,05 foram considerados estatisticamente significantes. Os resultados referentes ao peso demonstraram significativo aumento nos grupos 1 e 3 em relação ao GC no 14º dia (p<0,009), enquanto no 42º dia os grupos 1, 2 e 3 apresentaram representativamente mais peso que o GC (p<0,023). Quanto às variáveis laboratoriais, destacaram-se o aumento significativo da glicose e colesterol total de G1 em relação ao controle (p<0,001), assim como o acentuado aumento da HDL no G3 em relação aos demais grupos (p<0,001), no 14º dia. A HDL manteve-se expressivamente elevada no G3 em relação aos demais grupos no momento da eutanásia (p<0,001). À análise histomorfométrica da esclera e coroide obteve-se normalidade do GC. Por outro lado, o G1 mostrou marcante aumento da espessura da esclera e coroide em relação ao GC (p=0,008), enquanto que no G3 houve espessamento de esclera e coroide menor que no G1 (p=0,048). Elevado número de histiócitos foi observado na parede escleral do grupo submetido à dieta hipercolesterolêmica (G1), seguido de forma decrescente por G2, G3 e GC. A análise imuno-histoquímica da retina com o anticorpo monoclonal anticalretinina ressaltou número mais alto de células ganglionares imunorreativas no G1 que no G3 (p=0,002). O exame de morfometria de cores revelou significativa imunorreatividade das células e elementos celulares do G1 em relação aos outros grupos (p<0,001). Nesta análise evidenciou-se também acentuada imunorreatividade das células e elementos celulares de G2 e G3 em relação ao GC (p≤0,002). GFAP foi negativo em todos os grupos. Neste modelo, os achados permitem concluir que a hipercolesterolemia provoca anormalidades precoces histomorfométricas e imuno-histoquímicas do complexo esclerocoriorretiniano; e a ativação dos receptores do PPAR gama-ocular, a partir da dieta oral de rosiglitazona, foi efetiva em atenuar tais anormalidades nessas estruturas.
The purpose of this study is to evaluate scleral, choroid and retinal abnormalities in rabbits induced by a hypercholesterolemic diet and the prevention of these abnormalities after oral administration of rosiglitazone in rabbits. Fifty-four new zealand rabbits were divided into four groups: the control group (CG) was fed a normal diet; group 1 G1), a hypercholesterolemic diet; group 2 (G2) a hypercholesterolemic diet associated with daily administration of 3 mg of rosiglitazone from day 14 after the beginning of the diet; and group 3 G3), a hypercholesterolemic diet associated with daily administration of 3 mg of rosiglitazone since the beginning of the experiment. The rabbits were weighed and underwent the following examinations: seric dosages of total cholesterol, triglycerides, cholesterol HDL, and fasting glycemia at the beginning of the experiment, on the 14th day and on the 42nd, the euthanasia day. The sclera and choroid underwent histologic and histomorphometric analyses and the retina underwent immunohistochemical analysis with anti-calretinin (CR) and anti-glial fibrillary acidic protein (GFAP) antibody. When positive for the anti-calretinin marker, two quantitative analyses were performed. In the first analysis, all immunoreactive ganglion cells were counted. In the second analysis, all immunoreactive cells and cell elements were studied with the color morphometry method. The data were evaluated using the nonparametric Kruskal-Wallis and the Shapiro – Wilk tests. Values of p<0.05 were considered statistically significant. The results obtained showed a significant weight increase in Groups 1 and 3 in relation to CG on Day 14 (p<0.009). Additionally, a significant weight increase was observed in G1, G2 and G3 in relation to CG on Day 42 (p<0.023). The lab results showed a significant increase in glucose and total cholesterol in G1 in relation to CG (p<0.001) on Day 14, as well as a significant HDL increase in G3, when compared with the other groups (p<0.001) on Day 14. HDL in G3 was significantly high when compared to the other groups, on the euthanasia day (p<0.001). The results obtained regarding weight showed a significant increase in Groups 1, 2 and 3 in relation to CG on Day 14 (p<0.01) and Day 42 (p<0.02). The lab results showed a significant increase in glucose and total cholesterol in Groups 1, 2 and 3 in relation to CG (p<0.01) on Day 14, as well as a significant increase in HDL in G3 when compared with the other groups, on euthanasia day (p<0.01). The histomorphometric analysis of CG sclera and choroid presented normal results. Conversely, G1 showed a significant increase in sclera and choroid thickness in relation to CG (p= 0,008), whereas G3 showed thickness lower than in G1 (p=0,048). A larger number of histiocytes were observed on the scleral wall of the group that was fed the hypercholesterolemic diet (G1), followed, in a descending order, by groups 2 and 3, and the control group. The immunohistochemical analysis of the retina with the anti-calretinin monoclonal antibody showed that G1 presented a larger number of immunoreactive ganglion cells than G3 (p = 0.002). The color morphometry showed significant immunoreactivity of G1 cells and cell elements when compared with the other groups (p<0.001). A significant immunoreactivity of G2 and G3 cells and cell elements in relation to CG was also observed (p<0.002). GFAP results were negative in all groups. The findings of this proposed study model suggest that hypercholesterolemia induces early histomorphometric and immunohistochemical abnormalities in the sclerochorioretinal complex and that the activation of PPAR gamma in ocular cells attenuated these abnormalities with the administration of the oral rosiglitazone diet.
TEDE
BV UNIFESP: Teses e dissertações
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LaiI, Kuan Yu, and 賴冠宇. "Cyclodextrin modified nanoemulsion for scleral lutein delivery." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/72563533303303461022.
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碩士長庚大學
化工與材料工程學系
101
Lutein is a lipophilic biomolecule which is difficult to dissolve in water and has low bioavailability. Lutein plays an important role in maintaining retina normal function. Lutein can prevent photoreceptor cells by reducing short-wavelength light damage, apoptosis and the formation of free radicals. Most of epidemiological studies and clinical trials support the notion that lutein has a potential role in the prevention and treatment of certain eye diseases such as age-related macular degeneration, cataract and retinitis pigmentosa. Since lutein cannot be synthesized in the human body, oral supplementation of lutein is the main strategy to prevent the related eye diseases. Recently, some papers showed that oral lutein delivery may have limited bioavailability in the retina. How to improve the efficiency of lutein delivery is a major challenge. Nanocarriers include nanoemulsion and nano lipid carrier. These nano-scaled lipid droplets can absorb on the tissue surface, increase the contact area and delivery rate, and enhance the bioavailability of the active ingredient. The aim of this study is to investigate the preparation, characterization and lutein delivery of cyclodextrin (CD) modified nanoemulsion (NE). We use the ultrasonic method to optimize the formulation of surfactant in order to achieve nanoparticles. Further in vitro measurements were performed to study the partition and permeation of lutein in retinal tissues. Our results indicated that lutein loaded in the 2% hydroxyethyl-β-CD modified NE has more scleral accumulation in a time-dependent manner. From the simulated tear diffusion experiments, the lutein release kinetics of hydroxyethyl-β-CD modified NE was non-Fickian release. Additionally, the modification of NE+2% hydroxyethyl-β-CD on NE surface could increase viability of retinal ganglion cells and corneal endothelial cells at 1% (v/v) addition.
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Liao, Chao-Wei, and 廖朝葳. "Research and Development of Biodegradable Antibiotic/Steroid Scleral Plug." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/58738549897935131613.
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碩士長庚大學
醫療機電工程研究所
95
Endophthalmitis is a serious complication of intraocular surgery. The purpose of this report was to develop novel solvent-free biodegradable scleral plugs for vancomycin, amikacin and dexamethasone delivery. To fabricate a biodegradable plug, polylactide-polyglycolide copolymers were pre-mixed with the drugs. The mixture was then compression molded and sintered to form a scleral plug of 1.4mm in diameter. An elution method was utilized to characterize the in-vitro release characteristics of the antibiotics and the steroid over a 14-day period. The HPLC analysis and the bacterial inhibition test showed that biodegradable scleral plugs released a high concentration and significant activity of vancomycin and amikacin (well above the minimum inhibition concentrations) and dexamethasone vitro, for the period of time needed to treat intraocular infection. By adopting this novel technique, we will be able to fabricate biodegradable plugs of various types of pharmaceuticals for long-term drug deliveries.
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"Scleral biomechanics in the normal, glaucomatous and aging eye." Tulane University, 2008.
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Glaucoma is the second leading cause of blindness worldwide and is characterized by an irreversible damage to the retinal ganglion cell axons within the optic nerve head (ONH). Once thought to only occur at elevated levels of intraocular pressure (IOP), glaucoma can develop at normal levels without distinct etiology. Since IOP alone cannot explain the development and progression of the disease, we have theorized that the biomechanics of the ONH plays a central role in driving several pathologic mechanisms that can lead to the neuropathy The ONH is embedded within the posterior scleral shell - the white outer coat of the eye. From a biomechanical perspective, the sclera directly transmits IOP-induced stress and strain to the ONH, and we therefore hypothesize that the biomechanical behavior of the sclera contributes to the development and progression of glaucoma Our objective is to use state-of-the-art experimental and computational tools to characterize scleral biomechanics in normal and glaucomatous monkey eyes. Because the prevalence of glaucoma increases exponentially with age, we additionally characterize scleral biomechanics in the aging monkey eye to investigate the underlying mechanisms for the age-related increased susceptibility to glaucoma We introduce a constitutive model for the posterior sclera that includes stretch-induced stiffening and multi-directionality of the collagen fibers. Application of this model to an idealized eye geometry shows that scleral collagen fibers have a strong impact on ONH deformations. By experimentally measuring IOP-induced 3-D scleral deformations, and regional variations in scleral topography and thickness, we characterize the mechanical properties of individual scleral shells using an inverse finite element (FE) method. We show that monkey posterior sclera (1) is a nonlinear, anisotropic, inhomogeneous tissue, (2) stiffens with age, (3) is biomechanically altered in some, but not all, glaucomatous eyes. In normal eyes, we suggest that the sclera shields the ONH from biomechanical insult by resisting large deformations (nonlinearity), and scleral canal expansion (anisotropy). We suggest that age-related scleral stiffening could dramatically impact the homeostasis of the ONH. Finally, we suggest that scleral remodeling occurs in glaucomatous eyes to prevent further increase in ONH deformations and thus inhibits progression of the diseaseacase@tulane.edu
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Wen, Chin Wei, and 溫慶偉. "Research and Development of Biodegradable Scleral Plug for CMV Retinitis." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/84611882922082225101.
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碩士長庚大學
醫療機電工程研究所
97
Cytomegalovirus (CMV) retinitis is a frequent opportunistic ocular infection in immune-compromised patients, especially in AIDS patients. Before the widely use of highly active antiretroviral therapy (HAART), lifelong anti-CMV therapy was demanded for such patients. In the HAART era, cessation of specific anti-CMV therapy may be possible if immune recovery is achieved after introduction of HAART. Ganciclovir was widely used as the first line therapy for the CMV retinitis for a long time. But CMV retinitis that is resistant to ganciclovir mono-therapy is frequently encountered. Combined therapy with ganciclovir and foscarnet has been reported with good response in resistant cases. Although the anti-CMV therapy may be discontinued after a period of immune recovery, the maintenance of intraocular pharmaceutical level of anti-CMV drugs for a certain period was still required at acute infection stage. Previously, repeated intravitreal injections, usually twice a week, were commonly performed, but repeated injections contributed to the potential risk of secondary intraocular infection and rhegmatogenous retinal detachment. A ganciclovir device implantation is another alternative, which provides prolong release of ganciclovir monothearpy. But the implantation procedure needs large sclerotomy incision and makes possible of related complications. We develop a sintering process which incorporating both ganciclovir and foscarnet with polylactide-polyglycolide at low temperature into a biodegradable scleral plug. The plug provides sustained release of both ganciclovir and foscarnet for an extended period both in vitro and in vivo, besides, the biodegradable nature prevents the necessity of secondary explantation. The biocompatibility of the plugs was further evaluated by histopathology study and electroretinogram (ERG) in an experimental rabbit animal model. In conclusion, this study aims at development of biodegradable scleral plugs which provide sustained release of combination therapy for CMV retintis. The biocompatibility and release profile of the plug were thoroughly evaluated. Keyword: Cytomegalovirus(CMV) retintis, biodegradable scleral plug, polylactide-polyglycolide, ganciclovir, foscarnet, in vitro, in vivo, biocompatibility, histopathology, electroretinogram (ERG)
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Araújo, Rute Juliana Ferreira Macedo de. "Clinical performance and biological interactions during scleral contact lens wear." Doctoral thesis, 2019. http://hdl.handle.net/1822/65748.
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PhD Thesis in Optometry and Vision SciencesScleral lenses are among one of the best visual correction options nowadays. Despite the great augment on the peer-review literature related to scleral lenses in last few years, the impact of these lenses on the anterior ocular surface, as well as the comfort and visual enhancements over the long-term lacks to be addressed in both irregular and regular corneal surfaces. The main goal of the present work was to investigate the short-, medium- and long-term interactions of scleral lenses with the ocular surface and quantify the optical enhancement in patients with diseased and non-diseased corneas. We also aimed to evaluate the success rate and the Learning Curve of scleral lens fitting and to develop new measurements to aid during the fitting process and on-eye scleral lens fitting through time. Ninety-five patients were primarily recruited and divided into two groups, according to their corneal condition: irregular cornea or regular cornea. Patients were fitted with scleral lenses from Procornea (Eerbeek, The Netherlands) and were prospectively evaluated over several appoints through a 1-year follow-up time. Clinical measures were obtained at Clinical and Experimental Optometry Research Lab (CEORLab, University of Minho, Portugal). The results showed that scleral lenses are already adopted as potential devices for visual correction by a significant number of Portuguese and Brazilian specialty contact lens prescribers. Also, that a novel practitioner can reduce significantly the mean number of trial lenses and reorders after the first fittings. We suggested new approaches that could aid the practitioners during the fitting process and evaluation: first we conclude that scleral topography devices are able to quantify sclero-conjunctival changes after scleral lens wear and therefore aid in the selection of the best landing zone geometry for each eye; second, although the scleral lenses do not touch the corneal surface, some corneal topographic metrics can aid in the selection of the first trial lens to be fitted; and at last, that other devices (such IOLMaster) or techniques (ImageJ) can provide objective values of the central corneal clearance and can be substitutes for the standard subjective measure. The last part of the study showed that scleral lenses promote large gains of visual acuity and quality and that those improvements are stable over a follow-up time. It was also possible to conclude that other measurements – rather than the classic VA measurement – will aid in quantify those changes more precisely (aberrometry and night vision disturbances). The evaluations performed aid to conclude that scleral lenses are safe for both diseased and non-diseased eyes.
As lentes esclerais são uma das melhores opções para correção visual disponíveis nos dias de hoje. Apesar do grande aumento do número de artigos publicados nos últimos anos, o impacto destes dispositivos na superfície ocular anterior, bem como o conforto e melhorias visuais ao longo do tempo ainda não foi profundamente estudado. O principal objetivo deste trabalho foi investigar as interações a curto, médio e longo prazo das lentes esclerais com a superfície ocular e quantificar os ganhos a nível visual e de conforto em pacientes com córneas irregulares e regulares. Outro objetivo foi avaliar a taxa de sucesso e Curva de Aprendizagem da adaptação destas lentes e desenvolver novas medidas que auxiliem o profissional durante o processo de adaptação. Noventa e cinco pacientes foram recrutados e divididos em dois grupos de acordo com a sua condição corneal (córneas irregulares e córneas regulares). Todos os pacientes foram adaptados com lentes da Procornea e avaliados ao longo 1 ano no CEORLab (Universidade do Minho, Portugal). Os resultados mostraram que estas lentes já foram adotadas como potenciais dispositivos para correção visual por um numero significativo de profissionais em Portugal e no Brasil. Também, que um profissional consegue reduzir significativamente o numero de lentes de teste e novos pedidos de lente após as primeiras adaptações. Sugerimos novas abordagens que podem auxiliar os profissionais durante o processo de adaptação e avaliação das lentes: primeiro concluímos que os novos topógrafos esclerais conseguem quantificar as mudanças que ocorrem na conjuntiva após o uso destas lentes; em segundo, que embora estas lentes não toquem na córnea, alguns dados de topografia corneal conseguem auxiliar na seleção da primeira lente; e, por último, que outros dispositivos (como IOLMaster) e técnicas (como ImageJ) conseguem fornecer valores objetivos da separação córnea-lente e podem substituir as medidas subjetivas. A última parte do presente estudo demonstrou que as lentes esclerais promovem grandes melhorias da qualidade visual e que estas são estáveis ao longo do tempo, e que outras medidas para além da acuidade visual devem ser consideradas para caracterizar os ganhos visuais (aberrometria e avaliação das distorções luminosas). As medidas feitas ao longo dos 12 meses também permitiram concluir que as lentes esclerais são uma modalidade segura (em córneas normais e irregulares).
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Yang, Yu Chen, and 楊譽禎. "Curcumin laden lipid nanocarriers for in vitro scleral and corneal delivery." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/55886153799471878511.
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