Purchase this article with an account.
L. Grunwald, R. M. Niknam, G. Ying, P. Sankar, C. Nduaguba, E. Miller; Effect of Corneal Thickness on Intraocular Pressure Reduction. Invest. Ophthalmol. Vis. Sci. 2007;48(13):1279.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To investigate the relationship between central corneal thickness (CCT) and the reduction in intraocular pressure (IOP) following glaucoma medication administration.
224 patients with glaucoma (open angle, closed angle or glaucoma suspect) or ocular hypertension were included in this retrospective chart review. Subjects underwent a monocular trial with alpha agonists (AA), beta blockers (BB), carbonic anhydrase inhibitors (CAI) or prostaglandin analogues. The subject population included 136 females & 175 African Americans. The mean age was 66 ± 13 years (range 33-93). IOP was measured using Goldmann applanation tonometry at the beginning of the trial, and then 1 to 17 weeks after the initiation of treatment. CCT was measured with ultrasonic pachymetry before treatment. To minimize the effect of diurnal fluctuation on IOP, the % change in IOP in the treated eye was calculated as the difference in IOP from baseline between the treated and the contralateral eye divided by the baseline IOP of the treated eye. The % change of IOP was compared between 3 groups: CCT <520 µ (Group 1, N=93), 520-559 µ (Group 2, N=83), and >560 µ (Group 3, N=48). Similar comparisons were made between CCT and the effect of each medication class through univariate and multivariate analysis.
The study medication was the first IOP lowering drop in 169 patients. The mean % decrease in IOP in 169 previously untreated eyes was 22.3, as compared to 15.2 in 55 previously treated eyes (p=0.005). Overall, IOP change was not associated with CCT. The % decrease in IOP was 21.1 ± 1.71 in group 1, 21.2 ± 1.81 in group 2 and18.7 ± 2.38 in group 3 (p = 0.66). Analysis by medication class showed that beta blockers were more effective in thinner corneas (p=0.02 for test of linear trend), while no such association was found for Prostaglandins, AAs or CAIs. * adjusted by baseline IOP of study eye and prior treatment.
Beta Blockers appeared to be more effective in thinner corneas. No such association was found for Prostaglandins, AAs or CAIs. Eyes in which the study medication was added to previous treatment had a smaller IOP reduction than eyes that were not treated before.
This PDF is available to Subscribers Only