Abstract
Purpose :
We performed a secondary analysis of data from a clinical cohort study to determine the change and rate of change in central corneal thickness (CCT) in a West African population.
Methods :
Eight hundreds and sixteen subjects (758 non-glaucomatous and 58 glaucomatous) underwent complete eye examinations at 2 different visits. The mean change between baseline and follow-up CCT was determined using a paired t-test. Comparison of mean change in CCT between non-glaucomatous and glaucomatous subjects was assessed with a GLM analysis after controlling for the difference in age between the two groups at baseline. The annual rate of change in CCT was determined for the whole study population and with GLM separately for glaucomatous and non-glaucomatous subjects after accounting for the baseline age difference.
Results :
The mean duration between baseline and follow-up visits was 8.4±0.7 years for the whole population, 8.4±0.7 years for non-glaucomatous and 8.7±0.7 years for glaucomatous subjects. The overall mean age at first examination was 59.9±9.2 at follow-up. At baseline, glaucomatous subjects were older (54.4±11.2 years) than normal subjects (51.3±9.0), p=0.012. There were 358 male and 458 female subjects. Glaucomatous and non-glaucomatous subjects had comparable CCTs at baseline (530.5±34.1 μm vs. 534.8±34.1 μm for OD, p=0.18 and 530.6±33.9 μm vs. 535.8±33.6 μm for OS, p=0.13), but CCTs differed at follow-up examination (516.1±34.5 μm vs. 526.3±34.6 μm for OD, p=0.02 and 516.8±35.0 μm vs. 526.2±34.4 μm for OS, p=0.03). In all subjects, CCT decreased by 8.9±16.7 μm in OD and 9.8±16.2 μm in OS (both p<0.0001). After controlling for age, the magnitude of the change was significantly higher in glaucomatous than non-glaucomatous subjects in right eyes only (-14.2±2.2 μm vs. -8.5±0.6 μm for OD, p=0.013 and -13.6±2.1 μm vs. -9.5±0.6 μm in OS, p=0.07). The overall rate of change was -1.07 μm/year in OD and -1.17 μm/year in OS. The rate of change in OD was -1.7 μm/year in glaucomatous vs. -1.0 μm/year in non-glaucomatous (p=0.021) and in OS -1.6 μm/year in glaucomatous vs -1.1 μm/year in non-glaucomatous (p=0.09).
Conclusions :
In this urban, West African population, CCT decreased significantly over time. The magnitude and rate of CCT change were greater in glaucomatous than normal subjects. The longitudinal rate of change was greater than that described in cross-sectional studies including the same population.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.