Safety and Efficacy of Scleral Lenses for Keratoconus.

SIGNIFICANCE: This study affirms the long-term safety and efficacy of scleral contact lens use in patients with keratoconus. PURPOSE: This study aimed to evaluate the safety and efficacy of contemporary scleral contact lenses in the visual rehabilitation of the keratoconic population. METHODS: A retrospective study of keratoconic subjects examined between 2013 and 2018 was conducted. Subjects were included regardless of age, sex, pre-existing morbidity, or scleral lens design. Only eyes fit successfully with scleral contact lenses for ≥1 year were included. Exclusion criteria were prior corneal surgery, dystrophy, degeneration, and trauma. RESULTS: A total of 157 eyes of 86 subjects met the study criteria. The mean Keratoconus Severity Score at initial fitting was 3.6 ± 1.0. Lenses were gas-permeable and nonfenestrated, with a mean overall diameter of 15.8 ± 0.6 mm and 70.1% toric scleral periphery. Physiological adverse events occurred in 9.6% of eyes, including microbial keratitis (0.6%), phlyctenulosis (0.6%), corneal abrasion (1.3%), contact lens-induced acute red eye (1.3%), corneal infiltrative events (1.3%), pingueculitis (1.3%), and hydrops (3.2%). Lens-related adverse events were documented in 55.4% of eyes. Adverse events related to surface issues included poor wetting in 1.9%, handling in 3.8%, reservoir fogging in 7.0%, lens intolerance in 7.6%, deposit in 8.9%, and broken lenses in 26.1% of eyes. The most common management strategies involved refits (54.0% of interventions), patient reeducation (29.5%), medical treatment (5.5%), surgical referral (6.8%), adjustment to wear time (2.5%), surface treatment (1.2%), and lens replacement (0.6%). Best-corrected distance logMAR visual acuity improved significantly from a mean of 0.50 in spectacles to a mean of 0.08 in scleral lenses (P < .0001). During the study period, 14.6% of eyes lost best-corrected scleral lens visual acuity, all from keratoconus progression. CONCLUSIONS: Consistent with other groups, our study demonstrates excellent safety and efficacy of scleral contact lenses in subjects with keratoconus.

Neophyte Skill Judging Corneoscleral Lens Clearance.

PURPOSE: This study examines the accuracy of neophyte clinicians' assessments of central corneal clearance (CCC) of a corneoscleral lens using lens center thickness (CT) as a biometric scale. METHODS: A normal participant was fit with a corneoscleral lens on both eyes. Observers (n = 34) from the final semester of their fourth year in optometric clinical training were instructed to estimate the amount of CCC through the approximate geometrical center of the lens using a standardized script which included a photograph identifying various zones. Observer estimates were then compared against anterior segment-OCT (AS-OCT) values obtained during calibration. RESULTS: Mean observer estimates of central corneal clearances were OD 220.5 ± 121.microns (range 50 to 480 microns) and OS 398.0 ± 159.1 microns (range 140 to 800 microns). The mean AS-OCT values were OD 105.5 ± 11.microns (range 84 to 121 microns) and OS 340.8 ± 15.2 microns (range 315 to 362 microns). Mann-Whitney test was statistically significant for comparison of median values OD (177.0; p = 0.001) and OS (260.0; p = 0.012). CONCLUSIONS: Neophyte clinicians in the final semester of their fourth year of optometric clinical training tend to significantly overestimate the amount of CCC in a normal subject with declining accuracy as the amount of clearance diminishes.

Noninvasive tear breakup times and ocular surface disease.

PURPOSE: To investigate the correlation between the Ocular Surface Disease Index (OSDI) Questionnaire and noninvasive tear breakup times (NITBUTs) obtained by the Keratograph 4 (Oculus, Wetzlar, Germany) device. METHODS: A prospective sequential study of subjects (N = 99) unmatched for sex and without a significant difference in age by sex was performed. Testing included administration of OSDI, followed by Keratograph 4 measurements of the first NITBUT (NITBUT(f)) and average NITBUT (NITBUT(av)). RESULTS: The NITBUT(f) was significantly shorter than NITBUT(av), as tested by Mann-Whitney statistic (U = 7331.5, <0.0001). The NITBUT(f) and NITBUT(av) demonstrated identical statistically significant Spearman correlations with OSDI (r(s) = -0.20, p = 0.05). CONCLUSIONS: Ocular Surface Disease Index and NITBUT testing by Keratograph 4 device demonstrate a weak, but statistically significant, negative correlation.

Variations in corneal asphericity (Q value) between African-Americans and whites.

PURPOSE: To search for differences in corneal asphericity on the basis of ethnicity between African-American and white populations. METHODS: A prospective cohort design was used to analyze corneal asphericity (Q value) data obtained by Pentacam HR (Oculus, Wetzlar, Germany) on right eyes from African-American (n = 80) and white (n = 80). Subjects were stratified by ethnicity, age, and spherical equivalent (SE) refractive error. Q values were obtained from each quadrant (superior, nasal, inferior, and temporal) and two meridians (horizontal and vertical). RESULTS: The mean Q values were African-Americans -0.26 ± 0.19 and whites -0.20 ± 0.12, indicating that the eyes of African-Americans were significantly more prolate (p = 0.003) than those of whites. There was a significant difference between mean Q values for ethnic groups only in the 30- to 39-year olds (p = 0.01) and there was a lack of correlation with age in both ethnic groups. Q value contrasts by gender were only significant between males (p = 0.01). There was a lack of correlation between Q value and SE for either ethnic group. Age group contrasts between ethnic groups found significant differences for those with SE greater than 0.00 D to -3.00 D (p = 0.05) and greater than 0.00 D to +3.00 D (p = 0.05). Comparison of mean Q values in opposing meridians within and across ethnic groups were significant, although neither group showed significant differences between horizontal and vertical meridians. CONCLUSIONS: Corneal asphericity as represented by mean Q value varies significantly between African-Americans and whites. The greatest differences are evident in opposing quadrants and appear to be little influenced by age, gender, or SE.