Twelve studies involving 3048 patients with open-angle glaucoma or ocular hypertension were included in the meta-analysis comparing timolol with prostaglandin analogs «Li N, Chen XM, Zhou Y ym. Travoprost compared with...»1. Participants received either travoprost, other prostaglandin analog or timolol.
There was an increased incidence of iris pigmentation with travoprost 0.004 % when compared to timolol 0.5 % (OR = 11.06, 95 % CI 2.07-59.08, P = 0.005). There was no statistically significant difference between travoprost 0.004 % and latanoprost 0.005 % (OR = 0.74, 95 % CI 0.38-1.46, P = 0.4) in iris pigmentation.
In another meta-analysis comparing latanoprost with timolol in patients with open-angle glaucoma «Zhang WY, Po AL, Dua HS ym. Meta-analysis of rando...»2, latanoprost caused hyperaemia and iris pigmentation more often than timolol (RR = 2.20, 95 % CI 1.33-3.65). The number needed to harm was 21 (CI 14-42) when compared to timolol. Moreover, of 478 patients who were treated with latanoprost, 21 (4.39 %) developed iris pigmentation. In contrast, none of the patients treated with timolol showed this effect (0/387).
A systematic review compared timolol with brimonidine (α2 adrenergic agonist), prostaglandin analogs (travoprost, latanoprost), other β adrenergic antagonists, and placebo «Boland MV, Ervin AM, Friedman DS ym. Comparative e...»3. As to the comparison of timolol with travoprost or latanoprost, both drugs significantly increased iris pigmentation (travoprost OR 11.06, CI 2.07-59.08 and latanoprost OR 8.01, Cl 1.87-34.30).
The 5-year, randomized, open-label safety study «Goldberg I, Li XY, Selaru P ym. A 5-year, randomiz...»4 compared once-daily latanoprost with usual care, defined as any commercially available IOP-reducing medication except latanoprost. The study was conducted at 406 centers in 14 countries. Patients were excluded if they had previously been or currently were being treated with latanoprost or another prostaglandin. In all, 5893 patients were randomized, and 5854 (99.3 %) received at least one dose of study medication
The first subject visit occurred 1999, and the last was on 2005. In the total safety population, 3936 (67 %) patients were randomized to latanoprost, and 2707/3936 (69 %) completed the study. 1918 patients were initially randomized to usual care, and 1285/1918 (67 %) completed the study. At baseline, approximately 95 % of patients were receiving IOP-reducing medications, with 78 % being treated with ß-adrenergic antagonists and 20 % receiving topical carbonic anhydrase inhibitors.
Among patients ever treated with latanoprost, investigators judged that 577/4638 (12 %) had increased iris pigmentation compared to those who used any other IOP reducing agent.