Academic literature on the topic 'Cornea. Corneal Topography. Myopia Contact Lenses'

ABSTRACT Purpose To report successful visual rehabilitation of post refractive surgery keratoectasia shortly after corneal collage crosslinking (CXL) procedure achieved with silicone hydrogel mini-scleral (SHmS) contact lens. Materials and methods A 29-year-old woman attended to our clinic with complaints on decreased vision in her left eye. Twelve years earlier she underwent bilateral laser-assisted in situ keratomileusis (LASIK) procedure for myopia correction. Corneal topography revealed bilateral central keratoectasia with maximal keratometry values of 55.4 Diopter (D) for her right eye and 59.7 D for the left, corneal thicknesses were 422 and 443 respectively. The patient underwent an uneventful CXL procedure in her left eye and was fitted with SHmS lens 5 weeks later. The lens was designed to rest over the patients’ sclera and perilimbal cornea and vault the central cornea with minimal support over it. Results SHmS lens fitting resulted in significant subjective improvement in visual acuity (from 20/200, unaided to 20/25, contact lens corrected). The patient was able to wear the lens upto 10 hours a day with stable contact lens corrected vision. No contact lens related complications, such as edema or neovascularization were observed during 3 months follow-up period. As a result of successful restoration of vision in the CXL-treated eye, the patient was scheduled for the procedure in her other eye. Conclusion SHmS contact lens should be considered as an option for the visual rehabilitation of corneas shortly after collagen corneal crosslinking procedure. This novel contact lens modality made from flexible and highly gas permeable material minimizes contact lens influence on corneal recovery after CXL and provides an excellent visual outcome. How to cite this article Severinsky B. Silicone Hydrogel Mini-scleral Contact Lenses after Corneal Collagen Crosslinking for Post-LASIK Keratoectasia. Int J Kerat Ect Cor Dis 2014;3(3):127-129.

Contact lens wear causes mutual interactions between the ocular surface and the lens, which may affect comfort as well as vision. The aim of this study was to examine deformations in modern positive- and negative-powered silicone hydrogel soft contact lenses (SiH SCLs) after 7 days of continuous wear. This pre-post interventional study included 64 eyes: 42 eyes with myopia of -3.00 D and 22 eyes with hyperopia of +3.00 D. All patients underwent general ophthalmic examination, corneal topography/tomography, total corneal and epithelial thickness mapping, and specular microscopy before and after the wearing period. SiH SCLs made of senofilcon A were worn continuously for 7 days on all eligible eyes. The geometry of the new and used lenses was measured 3 to 6 minutes after removal in two perpendicular planes using a custom-made swept source optical coherence tomography (SS-OCT) system for in vitro measurements. The anterior and posterior radii of curvature decreased in -3.00 D lenses in two perpendicular planes. This effect correlated significantly with average keratometry of the cornea. Sagittal lens height was lower in +3.00 D lens after wear, which correlated moderately with the corneal sagittal height. A significant decrease in central corneal epithelial thickness was observed after wearing +3.0 D lenses. In conclusion, SiH SCLs made of senofilcon A undergo minor deformations after 7-day continuous wear. Geometry modifications are different for -3.00 D and +3.00 D lenses, and they imitate the shape of the anterior eye surface. These geometric changes are accompanied by a decrease in the central thickness of corneal epithelium after +3.00 D lens wear.

Keratoconus is the most common corneal distrophy. It’s a noninflammatory progressive thinning process that leads to conical ectasia of the cornea, causing high myopia and astigmatism. Many treatment choices include spectacle correction and contact lens wear, collagen cross linking, intracorneal ring segments implantation and finally keratoplasty. Contact lenses are commonly used to reduce astigmatism and increase vision. There are various types of lenses are available. We reviewed soft contact lenses, rigid gas permeable contact lenses, piggyback contact lenses, hybrid contact lenses and scleral-semiscleral contact lenses in keratoconus management. The surgical option is keratoplasty, but even after sutur removal, high astigmatism may stil exists. Therefore, contact lens is an adequate treatment option to correct astigmatism after keratoplasty.

Corneal topography has been widely used in medical practice over recent years and it has helped to detect keratectasias of various genesis more often and in the earlier stages. The emergence of the new polymer materials with high oxygen permeability made it possible to wear scleral contact lenses safely, that also resulted in their popularization. Scleral gas permeable lenses are an effective method of vision correction not only for various ectasias, but also for ametropia, presbyopia and other refractive pathologies. Scleral contact lenses do not directly touch the cornea and the limbus area, whereas tear firm under the lens physically smoothes out all of the existing defects and irregularities of the corneal surface, thus creating a ”cornea-tear-lens“ unified optical system. As a result, visual acuity increases significantly. In addition, scleral lenses ensure excellent comfort starting from the first minutes of wearing due to a larger diameter, no direct contact with the cornea and relatively low mobility. Scleral lenses ensure high visual functions and comfort owing to their specific self-supporting design, which is rested on the sclera. Selection and fitting of scleral contact lenses is simple and can be mastered by any ophthalmologist

The world-wide use of scleral contact lenses has dramatically increased over the past 10 year and has changed the way that we manage patients with corneal irregularity. Successfully fitting them can be challenging especially for eyes that have significant asymmetries of the cornea or sclera. The future of scleral lens fitting is utilizing corneo-scleral topography to accurately measure the anterior ocular surface and then using software to design lenses that identically match the scleral surface and evenly vault the cornea. This process allows the practitioner to efficiently fit a customized scleral lens that successfully provides the patient with comfortable wear and improved vision.

Goal. To introduce ophthalmologists and optometrists to the basics of corneal topography. Corneal topography is the main method for assessing corneal surface regularity, the violation of which leads to a deterioration in its refractive properties and a decrease in the quality of vision. The first part of the workshop (The EYE GLAZ. 2020 (22), № 2) presented the main types of topography maps and keratometry data. In the second part, considerations are made regarding mastering the skills of capturing high-quality images and choice of color maps for analysis. Topography patterns as well as topographic signs of keratoconus are also discussed. Conclusion. Placido-based corneal topographers are a useful tool for evaluating the anterior corneal surface, fitting contact lenses and diagnosing keratoconus. Slit-scanning topographers, additionally, are capable of corneal pachymetry and analyzing the posterior surface of the cornea, which allows for carrying out a more detailed assessment and diagnosing keratoconus at preclinical stage.

Corneal topography is the main method for assessing the regularity of the surface of the cornea. Corneal irregularity leads to a deterioration in its refractive properties and a decrease in the quality of vision. Learning the basics of corneal topography will help determine the choice of a color map for a specific situation, as well as understand and analyze the data associated with these maps. This article describes the main types of topographic maps, various patterns of corneal shape in normal and pathological conditions and how to use the data obtained to design and fit contact lenses. Despite the fact that images may vary depending on topographers used, the information presented in this article is universal.

Corneal topography is the main method for assessing the regularity of the surface of the cornea. Corneal irregularity leads to a deterioration in its refractive properties and a decrease in the quality of vision. Learning the basics of corneal topography will help determine the choice of a color map for a specific situation, as well as understand and analyze the data associated with these maps. This article describes the main types of topographic maps, various patterns of corneal shape in normal and pathological conditions and how to use the data obtained to design and fit contact lenses. Despite the fact that images may vary depending on topographers used, the information presented in this article is universal.

Purpose. To report a case of pigmented corneal iron lines following use of tinted soft contact lenses (CL).Methods. A retrospective case report.Results. A 16-year-old girl was referred with suspected CL-related keratopathy OU, having recently switched to tinted soft monthly disposable CLs (8.4/14.0 −3.00 OD, −3.25 OS Aquamarine SofLens Natural Colours, Bausch and Lomb, New York, USA). Both corneas exhibited symmetric superficial corneal pigmented iron lines, which gradually disappeared following discontinuation of CL wear.Conclusions. Pigmented corneal rings have been reported in normal ageing corneas, in certain pathological conditions, and in association with altered corneal topography following LASIK and orthokeratology. We suspect a poorly fitting CL resulted in localised tear pooling between the CL and cornea, and subsequent iron pigment deposition, similar to that seen with orthokeratology. Cosmetic CLs bought via the Internet can be used in an unsupervised manner, with possible impacts on visual function and potential complications.

Objective- Providing a healthy satisfactory visual acuity approach to a patient of Keratoconus fitted with a Rose-K contact lens. Introduction- Rose K lens is an effective option for visual improvement in irregular cornea such as Keratoconus. Contact lenses are the mainstay therapy for Keratoconus and are the treatment modality of choice in 90% of patients due to corneal surface irregularity. Case History- A 32-year-old female patient visited at Ahooja Eye & Dental Institute, Gurugram, with the chief complaint of diminished vision in her left eye for the last one month. The patient did not complain about diminished vision in the right eye. Earlier, the patient had diagnosed with the case of Keratoconus somewhere else and suggested to be continued with the glasses. The patient had a history of spectacles in the last 7 years and using the current prescription for the last 4 months. Visual acuity for distance & near, with glass and the current prescription was recorded. Conclusion- In our case, after all the presented findings and trial, one pair of Rose K2 lenses of varying total diameter and optic zone diameter was ordered. The patient was asked to visit for lens collection and follow up after 6 months. Lastly, it is advised that all Rose k practitioners keep at least two to three trial lenses, assess the fit in each fit, and choose lenses based on corneal topography. Key words: Rose K Contact Lenses, Keratoconus, Visual Acuity, Topography.

Orthokeratology (OK) is the reduction, modification or elimination of myopia through application of contact lenses. With the development of high Dk/t lens materials, overnight therapy has become the modality of choice for OK. Overnight OK lens wear has been previously investigated in terms of its efficacy to reduce myopia. However, the underlying effects of overnight OK lens wear on the human cornea have received less attention. As well as the clinical efficacy of overnight OK, this study investigated the effects of overnight OK on topographical corneal thickness and the overnight corneal edema response, and corneal tissue changes with overnight OK. Eighteen subjects participated as the OK lens-wearing group, wearing BE lenses (UltraVision, Brisbane, Queensland) in both eyes. A further ten subjects participated as control subjects, wearing conventional rigid lenses (J-Contour, UltraVision) in the right eye (RE) only. The left eye (LE) acted as a non-lens-wearing control. Both groups wore lenses overnight only, with no lens wear during the day. Measurements were conducted at baseline then on day 1, 4, 10, 30, 60, and 90 for the OK lens-wearing eyes; and up to day 30 for the control group, in the morning (after overnight lens wear) and in the evening (after 8-10 hours of lens removal). Variables measured included best vision sphere (BVS), unaided logMAR visual acuity (VA), refractive astigmatism, apical corneal power (ACP), simulated K readings (Medmont E300 corneal topographer), topographical corneal thickness (Holden-Payor optical pachometer), and keratocyte and endothelial cell densities (ConfoScan2 confocal microscope). Approximately 75% of myopia was corrected after the first night of OK lens wear and the changes in refractive error stabilised by day 10. By day 90, myopia reduction averaged 2.54 ?? 0.63 D. This was associated with significant improvement in unaided VA of about 82% after the first night of lens wear. There was no change in refractive astigmatism over the 3-month period. There was significant reduction in ACP in the OK lens-wearing eyes after the first night of lens wear, which accounted for more than 70% of the total ACP change over the 3-month period (RE: -2.16 ?? 0.53 D; LE: -2.11 ?? 0.86 D). There was significant central epithelial thinning (about 30%) and significant thickening (about 3%) in the mid-peripheral stroma in the OK lens-wearing eyes. Significant central epithelial thinning was found after the first night of lens wear while thickening in the mid-peripheral stroma reached statistical significance by day 4. Further analysis suggests that topographical corneal thickness changes account for the refractive error changes with overnight OK lens wear, rather than corneal bending. The central overnight stromal edema response was significantly reduced in the OK lens-wearing eyes (1.2 ?? 0.5%) to a level lower than in the conventional RGP (6.2 ?? 1.2%) and non-lens-wearing eyes (2.5 ?? 0.9%) in the control group. Mid-peripheral and peripheral stromal edema responses showed similar levels to those predicted based on lens Dk/t. A single overnight wear of BE and Paragon Corneal Refractive Therapy (CRT) lenses showed that the edema response to BE lens wear is significantly less than in the CRT lens-wearing eyes (BE: 2.5 ?? 0.7%; CRT 3.5 ?? 1.3%) immediately on eye opening. No significant changes were found in either central stromal keratocyte or endothelial cell densities in either OK or control groups over the study period. In conclusion, overnight OK lens wear induces significant reductions in myopia after the first night of lens wear associated with improvement in unaided VA. Overnight OK lens wear causes significant thinning in the central epithelium and significant mid-peripheral stromal thickening which results in flattening of the central cornea and steepening in the mid-periphery. Although there were no significant changes in central stromal keratocyte and endothelial cell densities, thinning of the central epithelial layer raises concerns regarding the safety of the procedure, especially with the alarming number of corneal infections reported recently in the literature.