Degree of angle closure and the intraocular pressure-lowering effect of latanoprost in subjects with chronic angle-closure glaucoma

Abstract

Objective: To examine the relationship between the configuration of the drainage angle and intraocular pressure (IOP)-lowering efficacy of latanoprost in subjects with chronic angle-closure glaucoma (CACG).

Design: Prospective observational case series.

Participants: One hundred thirty-seven Asian subjects with CACG.

Methods: Study subjects had participated in a 12-week, randomized, double-masked study that assessed the IOP-reducing effect of latanoprost. Chronic angle-closure glaucoma was defined as optic neuropathy with or without a visual field defect, an anterior chamber angle in which the trabecular meshwork was not visible for at least 180 degrees on gonioscopy, and evidence of peripheral anterior synechiae (PAS) in association with a chronically elevated IOP. Static and dynamic gonioscopy was performed at baseline. The angles were graded in each quadrant according to the Shaffer scheme, and the number of clock hours of PAS was recorded. The change in daily IOP (defined as the mean of the 9:00 am and 5:00 pm IOP time point values) from baseline to week 12 was analyzed and correlated with mean angle width and extent of PAS.

Results: One hundred thirty-seven Asian subjects with CACG completed the study in the latanoprost-treated group. Most subjects were female (75%), and the mean age was 62.6+/-9.4 years. At baseline, the mean angle width was 0.84+/-0.55, and the mean number of clock hours of PAS was 4.67+/-2.95. After 12 weeks of treatment, latanoprost reduced IOP from 25.0+/-5.5 mmHg to 17.5+/-5.0 mmHg (P<0.001). The percent change in IOP produced by latanoprost was not associated with mean angle width (Spearman's r = 0.04, P = 0.64) or the number of clock hours of PAS (Spearman's r = -0.15, P = 0.08).

Conclusions: In subjects with CACG, the IOP-reducing efficacy of latanoprost was not affected by the degree of angle narrowing or extent of synechial angle closure.