Longitudinal changes in visual acuity in keratoconus.

PURPOSE: The present investigation aimed to identify factors that predict reduced visual acuity in keratoconus from a prospective, longitudinal study. METHODS: This report from the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study used 7 years of follow-up data from 953 CLEK subjects who did not have penetrating keratoplasty in either eye at baseline and who provided enough data to compute the slope of the change over time in high- or low-contrast best-corrected visual acuity (BCVA). Outcome measures included these slopes and whether the number of letters correctly read decreased by 10 letters or more in at least one eye in 7 years. RESULTS: Mean age of the subjects at the first follow-up visit was 40.2 +/- 11.0 years (mean +/- SD). Overall, 44.4% were female, and 71.9% were white. The slope of the change in high- and low-contrast BCVA (-0.29 +/- 1.5 and -0.58 +/- 1.7 letters correct/year, respectively) translated into expected 7-year decreases of 2.03 high- and 4.06 low-contrast letters correct. High- and low-contrast visual acuity decreases of 10 or more letters correct occurred in 19.0% and 30.8% of subjects, respectively. Independent predictors of reduced high- and low-contrast BCVA included better baseline acuity, steeper first definite apical clearance lens (FDACL), and fundus abnormalities. Each diopter of steeper baseline FDACL predicted an increased deterioration of 0.49 high- and 0.63 low-contrast letters correct. CONCLUSIONS: CLEK Study subjects with keratoconus exhibited a slow but clear decrease in BCVA during follow-up, with low-contrast acuity deteriorating more rapidly than high-contrast. Better baseline BCVA, steeper FDACL, and fundus abnormalities were predictive of greater acuity loss with time.

Differences in keratoconus as a function of gender.

PURPOSE: To characterize gender differences in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study. DESIGN: Observational, longitudinal study. METHODS: A total of 1209 subjects at 16 clinics. For eye-specific categorical variables, the number of eyes per subject with the characteristic was counted. For eye-specific continuous variables, the mean of both eyes was calculated. Multivariate linear (for continuous outcomes) and logistic (for categorical outcomes) regression models were created for each baseline characteristic with statistically significant (P < or = .05) differences between men and women. Age, race, education, and corneal curvature were covariates. RESULTS: The women were older, more likely to report a family history of keratoconus, more likely to be nonwhite, and less likely to complete college than men. Vogt's striae and monocular and binocular high-contrast entrance acuity were the only visual characteristics that varied between men and women in the multivariate model. Women were more likely than men to report ocular symptoms of dryness and complaints based upon a composite score of ocular symptoms. Women reported more hours per day of near work and were less likely to report the ability to wear contact lenses for enough hours to permit reading at home in the evening. Women reported more visits to their eye care practitioner during the previous 12 months. NEI-VFQ results revealed differences in self-reported difficulty with distance activities and driving. CONCLUSIONS: Gender differences exist in patient history, vision, and ocular symptoms in keratoconus patients.

Between-eye asymmetry in keratoconus.

PURPOSE: To report baseline differences between eyes on key variables in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study cohort compared with a retrospectively assembled group of myopic contact lens wearers without ocular disease. METHODS: A total of 1,079 keratoconus patients who had not undergone a penetrating keratoplasty in either eye before their baseline visit were enrolled and examined at baseline. Records from 330 contact lens-wearing myopes were reviewed. Corneal curvature (keratometry), visual acuity, refractive error (manifest refraction), and corneal scarring were measured. RESULTS: The mean differences between keratoconic eyes are as follows (better eye-worse eye for each variable, separately). Flat keratometry: -3.59 +/-4.46 D and steep keratometry: -4.35 +/-4.41 D; high-contrast best-corrected visual acuity: 7.30 +/-6.83 letters; low-contrast best-corrected visual acuity: 8.53 +/-7.51 letters; high-contrast entrance visual acuity: 9.03 +/-8.40 letters; low-contrast entrance visual acuity: 9.43 +/-7.88 letters; spherical equivalent refractive error: 3.15 +/-3.84 D; and refractive cylinder power 1.55 +/-1.42 D. Twenty-one percent of the keratoconus patients had corneal scarring in only one eye. There is an association between patient-reported unilateral eye rubbing and greater asymmetry in corneal curvature, and between a history of unilateral eye trauma and greater asymmetry in corneal curvature and refractive error, with the rubbed/traumatized eye being the steeper eye most of the time. CONCLUSIONS: Keratoconus is asymmetric in the CLEK Study sample.

Efficacy of cyclosporine 0.05% ophthalmic emulsion in contact lens wearers with dry eyes.

PURPOSE: To assess the efficacy of cyclosporine 0.05% ophthalmic emulsion (Restasis; Allergan, Inc., Irvine, CA) in the treatment of contact lens wearers with dry eyes. METHODS: Contact lens wearers citing dry eye problems were identified through chart review. Participants were randomly assigned to a treatment group, receiving vials of cyclosporine 0.05% ophthalmic emulsion to use twice daily, or a placebo group, receiving vials of rewetting drops (Refresh Preservative Free Artificial Tears; Allergan, Inc.) to use twice daily. Corneal staining, tear film breakup time, and Schirmer test results were documented at baseline and after 3 months. Participants also completed questionnaires, the Ocular Surface Disease Index, and the National Eye Institute Refractive Error Quality of Life Instrument at baseline and after 3 months. RESULTS: For all parameters, including objective findings and subjective reporting of symptoms, there was no statistically significant difference between the treatment and placebo groups. CONCLUSIONS: This study did not detect a beneficial effect in using cyclosporine 0.05% ophthalmic emulsion over rewetting drops for contact lens wearers. This may be attributable to the small sample size. It is also possible that the mechanism of the dry eye state in contact lens wearers may be different from that of other dry eye states and thus make cyclosporine 0.05% ophthalmic emulsion an ineffective treatment.

Aging-related changes in the multifocal electroretinogram.

The multifocal electroretinogram (MERG) was recorded in the central 36 degrees-diameter field in 26 young (19-30 yr) and 20 old (60-74 yr) adults in normal retinal health according to a fundus grading scale. The mean amplitude densities of the first-order and second-order responses in this retinal region were lower for old adults compared with young. The aging-related reduction of the first-order amplitude density was greatest at the fovea and decreased as a function of eccentricity. Similarly, the amplitudes of the first negative and positive peaks of the first-order MERG waveform were reduced with age, and the pattern of reduction followed a similar eccentricity dependency. The aging-related changes in the MERG waveform may be due to slowed temporal adaptation in the aged retina.