The effect of different thickness scleral lens on corneal parameters in eyes with keratoconus.

Purpose: To investigate the impact of different-thickness scleral lenses (SLs) on corneal thickness, curvature, and fluid reservoir thickness in keratoconic eyes. Methods: Schiempflug imaging and AS-OCT was captured before and immediately following 6 h of SL wear. Different-thickness lenses were used while keeping the other parameters the same. The timing of the measurement for day 1 and day 2 was matched to allow for the control of the confounding influence of diurnal variation. Results: Immediately after 6 h of lens wear, no statistically significant difference (P > 0.05) was noted in corneal edema in any region and quadrants between thin- and thick-lens wearers. The calculated percentage of corneal edema was also within the range of overnight closed eye physiological swelling. Pentacam measured higher central corneal thickness compared to AS-OCT in both baselines and after 6 h of lens wear. The current investigation reported minimal but not statistically significant (P > 0.05) flattening in anterior and steepening in posterior curvature parameters in both thin and thick SLs. The mean reduction in the fluid reservoir thickness was 80.00 ± 3.99 and 79.36 ± 3.84 microns after 6 h of thin- and thick-lens wear, respectively, which was not statistically significant (P > 0.05). A statistically significant positive correlation (r = 0.67, P = 0.02) was found between lens thickness and change in anterior steep k with thick-lens wear. Conclusion: Central lens thickness of 200-400 µm did not cause any significant change in corneal curvature and fluid reservoir thickness and did not induce clinically significant corneal edema after short-term SL wear.

Impact of Scleral Lens on Corneal Curvature and Pachymetry in Keratoconic Eyes.

PURPOSE: The aim of this study was to evaluate the influence of scleral lens on corneal curvature and corneal thickness in keratoconic patients. METHODS: Scheimpflug imaging was captured before lens insertion, immediately after removal at 6 hours, and, again, the next day morning. Anterior flat, steep, and maximal keratometry (Kflat, Ksteep, and Kmax, respectively) and pachymetry values were compared. RESULTS: Minimal corneal flattening was observed for all 3 curvature parameters immediately after lens removal but was not statistically significant. The average Kflat was 0.28 ± 0.31 (D) flatter (P = 0.37), Ksteep was 0.37 ± 0.09 (D) flatter (P = 0.11), and Kmax was 0.19 ± 0.24 (D) flatter (P = 0.53), which returned to baseline level after one night of lens removal. After 6 hours of a 16-mm scleral lens wear, central corneal pachymetry showed that a marginal thickening of 7.76 ± 3.00 µm (P = 0.06) was causing 1.77 ± 0.67% of corneal edema, which returned to baseline after one night of lens removal. There was no significant correlation noted between corneal flattening and change in corneal thickness (r = 0.09, P = 0.78) and between central corneal clearance and change in corneal curvature (r = -0.23, P = 0.51). CONCLUSIONS: Minimal transient alteration in the anterior corneal curvature and corneal thickness was observed after 6 hours of scleral lens wear. These temporary changes regressed to baseline after overnight discontinuation of the lens.

Impact of modulus of elasticity of silicone hydrogel contact lenses on meibomian glands morphology and function.

Clinical relevance: It is important to investigate the effect of modulus of silicone hydrogel contact lens on meibomian glands. Evaluating meibomian gland health and function in follow-up appointments should be considered, with the option of changing lens modulus.Background: To evaluate and compare the effect of modulus of elasticity of silicone hydrogel contact lenses on morphological and functional parameters of the meibomian glands.Methods: A prospective study was conducted on soft silicone hydrogel contact lens wearers of different modulus of elasticity and age and gender-matched controls. Morphological and functional parameters were assessed along with standard patient evaluation of the eye dryness questionnaire.Results: A statistically significant difference was noted in meibomian gland loss in the upper lid (percent) between the low modulus (18.23 ± 6.63) and high modulus group (27.40 ± 10.21) (p < 0.001) and between high modulus (27.40 ± 10.21) and non-contact lens wearers (19.57 ± 7.65) (p = 0.001). The current study reported significantly higher total meiboscore grading in the high modulus group 3 (2-3) compared to the low modulus 2(2-3) (p = 0.007) and non-contact lens wearing groups 2 (2-3) (p = 0.012). Meibum quality was significantly compromised in the high modulus group 1 (0-1) compared to the low modulus 0 (0-0.75) group (p = 0.01). Standard patient evaluation of the eye dryness questionnaire was found to be significantly higher (p = 0.01) in high modulus 4 (2-8) compared to low modulus wearers 2 (2-4). A significant difference was noted (p < 0.001) in corneal staining grading only between high modulus 0 (0-1) and non-contact lens wearers 0 (0-0) group. A positive correlation was noted in the low modulus group between total meiboscore and meibomian gland expressibility (Rs = +0.69, p < 0.001) and also noted between standard patient evaluation of the eye dryness questionnaire scoring and meibomian gland expressibility (Rs = +0.45, p = 0.012) in the high modulus group.Conclusion: Higher modulus of elasticity of silicone hydrogel contact lens may influence meibomian gland morphology and function over a period of contact lens wear.

Case Report: Post-keratoplasty Filamentary Keratitis Managed with Scleral Lens.

SIGNIFICANCE: This case report details a unique case of filamentary keratitis after penetrating keratoplasty managed with a scleral contact lens. The positive effect on vision and comfort are reported, and the challenges related to hypoxia are discussed. PURPOSE: The purpose of this study was to report the outcome of scleral lens use in the treatment of filamentary keratitis post-penetrating keratoplasty. CASE REPORT: A patient who underwent penetrating keratoplasty twice in both eyes for keratoconus presented with filamentary keratitis in the left eye. The prosthetic replacement of the ocular surface ecosystem scleral lens trial was performed for improving vision and comfort. After 6 hours of wearing prosthetic replacement of the ocular surface ecosystem device, the left eye showed complete resolution of filaments with an improved visual acuity and better comfort in both eyes. Corneal swelling indicating hypoxia was noticed in both eyes with scleral lenses and was managed accordingly. CONCLUSIONS: Scleral lenses are a viable treatment option for patients with corneal filamentary keratitis after penetrating keratoplasty for achieving better vision and improved comfort. However, the risk of hypoxia cannot be undermined, which necessitates careful evaluation, follow-up, and management for safe lens wear.

Does Occupation Influence Selection of Contact Lens Material?

OBJECTIVE: Long-term follow-up of contact lens (CL) wearers leads to better understanding of the factors leading to changes in CL trends. This study is an attempt to ascertain these factors in an emerging market like India. Factors like occupation were analyzed to determine if these contributed to changes in selection of CL materials in this article. METHODS: Occupations were categorized as per the norms of International Standard Classification of Occupations-2008 (International Labor Organization, United Nations organization). RESULTS: A majority of lens wearers were professionals and hydrogel lens materials were the lenses of choice among most of the lens wearers. There was a significant variation in CL material with different occupations (χ=19.29, P=0.037). CONCLUSION: To conclude, employment and affordability influenced the selection of lens materials.

Contact lens trends over three decades in a hospital-based practice in India.

BACKGROUND: Contact lens fittings in a hospital-based practice are different from those in private practices because of specialised conditions. Few studies have been published on material preferences of such wearers, especially in long-term wearers. The aim of this study is to document contact lens prescribing trends in a hospital-based practice among long-term lens wearers and to identify their demographic profile. METHODS: Subjects reporting to a contact lens clinic of a tertiary eye-care centre in India from 1 January 2014 to 31 December 2014, with a minimum of five years of lens wear, were included in the study. Data were collected retrospectively from the electronic medical charts of these subjects. RESULTS: Three hundred and sixty subjects were included in the study. The average duration of contact lens wear among the subjects was 9 ± 5 years (range: 5-35 years). The average age of the subjects was 31.38 ± 11.75 years (age range: 5-78 years). Hydrogel material and soft spherical type were preferred by most of the soft lens wearers (53 per cent). Eighty per cent of subjects followed hand hygiene and cleaning regimen practices. CONCLUSION: The preference for monthly replacement lenses and silicone hydrogel material increased over the years. Regular after-care consultations could enforce the need for compliance with hand hygiene and cleaning regimens among lens wearers.

Quality of life and handling experience with the PROSE device: an Indian scenario.

BACKGROUND: PROSE (prosthetic replacement of ocular surface ecosystem) device is a custom-designed, corneal vaulting scleral contact lens, which is used in the treatment of irregular corneal conditions to improve vision and comfort. The present study aimed at assessing the success of the PROSE device in an Indian scenario in terms of change in quality of life and to understand the handling issues related to the device use. METHODS: Thirty-two subjects with various irregular corneal conditions meeting the inclusion criteria were included in the study. Subjects were followed for three months after dispensing the PROSE device. Subjects' demographic details, high and low contrast visual acuity with habitual correction and PROSE device, Visual Function Questionnaire scores (NEI VFQ-25) and Ocular Surface Disease Index (OSDI) scores pre- and post-PROSE treatment were collected and compared. An indigenously developed questionnaire was also administered during the follow-up visit for assessing the handling-related issues faced by the subjects while using the device. RESULTS: Forty eyes of 32 subjects were included in the study, of whom 30 reported for follow-up. The median NEI VFQ-25 score improved from 47.33 points to 77.27 points over a period of three months, which was statistically significant (p < 0.05). There was a statistically significant decrease in median OSDI score from 51.14 points to 13.63 points post-PROSE treatment (p < 0.05). Subjects reported no or very minimal handling-related difficulties associated with the use of the PROSE device. CONCLUSION: The PROSE treatment can be an effective mode of managing patients with irregular corneal conditions and significantly improved the vision-related quality of life of patients suffering from these conditions. The handling of the device is easy and can be mastered with adequate training.

Visual performance with changes in eccentricity in PROSE device: a case report.

This case report describes the variations in visual performance of a subject with moderate keratoconus with changes in front surface eccentricities (FSEs) of PROSE (Prosthetic Replacement of Ocular Surface Ecosystem). PROSE device of 0.6 FSE provided maximum visual improvement and reduction in Higher Order Aberrations (HOAs) compared to 0, 0.3 and 0.8 FSEs in this clinical condition.

Unique hard scleral lens post-LASIK ectasia fitting.

PURPOSE: This case report describes an experience with prosthetic replacement of ocular surface ecosystem (PROSE) device in an Indian patient with post-LASIK corneal ectasia. CASE REPORT: Keratoconus and corneal ectasia (post-LASIK) are characterized by progressive thinning and steepening of the cornea. Common symptoms experienced by patients in such conditions range from mild to severe vision impairments to an array of visual symptoms such as glare and ghosting. Scleral lenses are considered a vision-saving device when all other modalities fail. The patient in this case report had larger palpebral aperture, steeper cornea, and increased toricity of the sclera. Although a larger-diameter device is preferable in steeper corneas, a device with a smaller diameter and a flatter haptic was prescribed because of scleral toricity. There is a need to study scleral profile as well because scleral toricity can produce symptoms in patients even after 6 hours of device wear. After a few days of adaptation, the vault of the PROSE device can change because of haptic alignment on the sclera. CONCLUSIONS: This case report gives an overview of how the scleral profile can have an effect on the corneal/contact lens relationship when using a PROSE device.

An ocular surface prosthesis for keratoglobus and Terrien's marginal degeneration.

PURPOSE: This case report describes the challenges in fitting corneas using the prosthetic replacement of ocular surface ecosystem (PROSE) device in a unique case of bilateral keratoglobus (KG) with Terrien's marginal degeneration (TMD). CASE REPORT: KG and TMD are uncommon corneal ectatic conditions, characterized by protrusion and thinning of the cornea. Optical correction with spectacles is limited, as this may not provide the best-corrected visual acuity because of irregular corneal astigmatism. Corneal gas-permeable lenses can provide optimal vision, but they have poor fitting characteristics in advanced stages. The PROSE device has the advantage of masking the irregularity of the cornea with a tear lens and a contact lens power that provides a smooth refractive surface. This case report describes the fitting aspects of the PROSE device in a case diagnosed with KG and TMD. A generous vault allows the PROSE device to sink into the conjunctiva more, causing impingement, but a PROSE with higher vault is required as corneal clearance decreases with wear time. Corneal thickness measurements during the trial can give a better idea of corneal edema expected after prescribing the PROSE device. Optical coherence tomography is a useful tool for measuring diurnal changes in the corneal thickness and vault over a period in such challenging cases. CONCLUSIONS: Modification of not only the vault but also the haptic and total diameter of the device is required to achieve an optimal fit. Though challenging, successful fitting of the scleral lens in ectatic corneas is attainable, with the aid of anterior imaging and spline technologies.

PROSE for irregular corneas at a tertiary eye care center.

OBJECTIVE: The aim of this study was to report and discuss the clinical experience with PROSE (Prosthetic Replacement of Ocular Surface Ecosystem) practice at a tertiary eye care hospital. METHODS: Retrospective data of patients who were prescribed PROSE during April 2011 to March 2012 in a tertiary eye care center in south India were analyzed. Data collected include patient demographics, indications of scleral lens fitting, previous correction modality, PROSE parameters, best-corrected visual acuity (BCVA) with spectacles, and BCVA with PROSE at initial assessment and few hours of wear. The BCVA before (with glasses) and after PROSE fitting was recorded in logMAR units. RESULTS: The age of the patients ranged between 13 and 68 years (male:female 60:25) with a mean age of 32.44±13.45 years. Mean BCVA improved by 0.3 logMAR units (3 lines) after fitting with PROSE. There was a statistically significant difference between pre- and post-PROSE BCVA (P=0.0001). Failure of rigid gas-permeable lens fitting or intolerance was the common indication for PROSE in corneas with irregular astigmatism (refractive conditions). The other reasons for which PROSE was prescribed were pain, photophobia, comfort, ghosting of images, and frequent loss of smaller lenses. Toric scleral haptic was indicated in 62 eyes. The diameter, vault, and haptic measurements of PROSE in ocular surface disorders were much less and flatter than that of refractive conditions. CONCLUSIONS: PROSE device is a very useful alternative for irregular corneas to improve visual acuity, to improve comfort, and for symptomatic relief.

Comparison of conventional method of contact lens fitting and software based contact lens fitting with Medmont corneal topographer in eyes with corneal scar.

PURPOSE: To compare conventional method of contact lens fitting with software based contact lens fitting using Medmont corneal topographer in eyes with nebular and macular corneal scars. METHODS: Fifteen participants who were diagnosed with nebular and macular scars were fitted with rigid gas permeable lenses using conventional method of contact lens fitting. During the lens dispensing visit, participants underwent Medmont corneal topography. Agreement between the two methods of contact lens fitting was studied. RESULTS: Parameters of contact lenses which were concluded using conventional method was compared to that of software based fitting. Mean difference in base curve of contact lens between the two methods was 0.094 mm±0.147 mm (95% CI: +0.383 to -0.194). Mean difference in diameter of contact lens between the two methods was 0.16 mm±0.172 mm (95% CI: +0.497 to -0.177). Contact lens parameters that were achieved using two different methods of fitting showed good correlation. Correlation coefficients, as comparison of two methods in base curve and diameter were 0.96 (P<0.05) and 0.94 (P<0.05), respectively. CONCLUSION: Software based contact lens fitting would be useful for contact lens practitioners to predict initial base curve of contact lens in corneal scars.

Retrospective study of contact lens fitting in pellucid marginal degeneration.

PURPOSE: To find a novel method for calculation of the initial trial spherical rigid gas-permeable contact lens fitting in pellucid marginal corneal degeneration (PMCD) to reduce the number of trial fitting required to achieve a best fit. METHOD: A retrospective data of 16 subjects (8 men and 8 women) who were diagnosed to have PMCD and under went contact lens trial were selected after reviewing the medical records of the patients who visited medical research foundation over a period of year. The demographic details, refractive error, details of lens trial, dispensed lens parameters, fluorescein pattern achieved, and simulated keratometry (Sim-K) reading were noted. RESULTS: Of the 32 eyes (16 subjects), 6 eyes (4 subjects) continued with glasses. Three eyes were advised deep anterior lamellar keratoplasty (DALK). Twenty-three eyes were fitted successfully with gas-permeable lens and achieved vision between 6/9 and 6/6. The base curve of the final lens achieved was compared with the calculated appropriate base curve by stability factor method, flat keratometry readings, and average keratometry readings. Analysis showed no significant difference between the final lens base curve and the calculated appropriate base curve by stability factor method, with a P value of 0.71 and correlation coefficient of 0.77. The average lens diameter was 9.02 mm, with average optic zone of 7.5 mm. CONCLUSIONS: Calculation of appropriate base curve of the lens by stability factor method is found to be the best method to start with a trial in PMCD.