Assessment of chamber angle pigmentation during longterm latanoprost treatment for open-angle glaucoma

Purpose: This study aimed to determine whether the longterm use of latanoprost is associated with an increase in trabecular pigmentation, especially in subjects in whom iris pigmentation has increased. Methods: We enrolled 50 subjects for whom treatment was to start for ocular hypertension, primary open-angle glaucoma or normal tension glaucoma. All subjects received latanoprost 0.005% daily. Trabecular pigmentation was documented using gonioscopic photography of the inferior quadrant at baseline, every 3 months for the first year and every 6 months for the second and third years. Three glaucoma specialists evaluated the series of gonioscopic photographs for each eye of each subject in a masked fashion. The intraocular pressure (IOP) was also recorded at each visit. Results: A total of 41 subjects (79 eyes) completed 3 years of follow-up, and none showed any increase in the grade of trabecular pigmentation, including 10 subjects (20 eyes) in whom the iridial pigment increased. Conclusion: Although latanoprost increased iridial pigmentation in some subjects, we found no evidence of an increase in trabecular pigmentation over the 3 years of follow-up.