The IOP-lowering effect of topical prostaglandin analogues (PGAs) was examined in relation to central corneal thickness (CCT). 75 subjects were enrolled in this post hoc analysis of a randomized prospective trial. The mean age was 62.7 ± 10.5 years; 48 were Caucasian. The mean CCT was 562.4 ± 41.4 μ. At repeated measures, ANCOVA analysis showed a significant effect of both baseline IOP (p < 0.0001) and CCT (p = 0.003) on IOP. At week 12, a regression analysis of the effect of CCT on baseline IOP showed that for every 10 μ increase in CCT there was 0.3 mm Hg less IOP decrease from baseline.
It was found a statistically significantly association between a lower mean IOP and a thinner cornea when baseline IOP is controlled for. The magnitude of the relationship is small but may be clinically significant in patients with either very thin or very thick corneas «Birt CM, Buys YM, Kiss A ym. The influence of cent...»1.
In another study the long-term effect of latanoprost was evaluated on central corneal thickness (CCT) in patients with normal tension glaucoma (NTG). This was a retrospective study and included 166 eyes of 166 patients [128 with NTG and 38 with glaucoma suspect, suspicious discs with normal visual fields, and an intraocular pressure (IOP) ≤21 mmHg as the control group]. Patients with newly diagnosed NTG and who had not had previous topical glaucomatous treatment were followed ≥24 months and received latanoprost 0.005 % monotherapy once a day. CCT measurements were performed with an ultrasound pachymeter. CCT measurements before treatment and 24 months after treatment were analyzed.
There were no significant differences between the latanoprost group and the control group with respect to sex, age, baseline IOP, and CCT. A statistically significant reduction in the mean CCT was observed in the latanoprost group [535.5 ± 37.9 vs. 530.1 ± 36.4 μm (n = 128), P < 0.01], but not in the control group [543.1 ± 40.2 vs. 542.6 ± 37.0 μm (n = 38), P = 0.786]. Long-term use of latanoprost may decrease the CCT in patients with NTG «Kim HJ, Cho BJ. Long-term effect of latanoprost on...»2.