Objective: The aim of this study was to compare the intraocular pressure (IOP)-lowering effect of latanoprost and bimatoprost as primary therapy in patients with chronic angle-closure glaucoma (CACG) after peripheral iridotomy.

Methods: Eighty-two (82) consecutive CACG patients with an IOP greater than 19 mmHg after a peripheral iridotomy were recruited. CACG was defined as chronic elevated IOP, glaucomatous optic neuropathy, and a corresponding visual field defect in eyes with occludable angle and peripheral anterior synechiae on gonioscopy. Patients were randomly assigned to two groups based on daily treatment with either latanoprost 0.005% or bimatoprost 0.03% in the evening for 12 weeks. The IOP was measured at 9 AM and 4 PM on the same day at baseline and also at 4, 8, and 12 weeks. Between-group differences in mean diurnal IOP and IOP reduction were analyzed.

Results: After 12 weeks of treatment, mean IOP for both the latanoprost and bimatoprost groups was significantly reduced when compared to the baseline value (21.6 +/- 1.9 to 16.4 +/- 2.5 mmHg and 22.1 +/- 2.0 to 16.9 +/- 2.4 mmHg, respectively; P < 0.001 for both). There was no significant difference in IOP reduction between the two treatment groups (P = 0.40). At 4 and 8 weeks, the IOP changes from baseline were statistically significant at both times for both drugs (all P < 0.001).

Conclusions: Both latanoprost and bimatoprost significantly reduced IOP in CACG patients who were inadequately treated by laser peripheral iridotomy.