Time Dependent Changes in Central Corneal Thickness in the Ocular Hypertension Treatment Study (OHTS)

Abstract

Purpose: : To compare baseline central corneal thickness (CCT) to repeat measures performed an average of 3.8 years later.

Methods: : First and second CCT measurements were performed using an ultrasonic pachymeter with the same protocol. First and second CCT measurements were completed for 76% of 1,636 participants. By the time of the second CCT measurement, participants originally randomized to observation had been on topical hypotensive medications for a mean of 12 months. Medication exposure was calculated by adding the number of medications multiplied by months of usage. Participants who had undergone incisional intraocular or keratorefractive surgery were excluded from this analysis.

Conclusions: : The rate of CCT thinning over 3.8 years is comparable to the cross–sectional age differences reported in OHTS at the first measurement (0.6 µM/year) and comparable to other cross–sectional studies. Use of topical medications, in particular topical prostaglandin analogues, may be associated with a slightly higher rate of thinning. The modest age– and drug–related rates of thinning described are unlikely to influence tonometry or clinical decision–making.

Keywords: clinical (human) or epidemiologic studies: risk factor assessment • intraocular pressure • drug toxicity/drug effects