RESUMO
PURPOSE: The purpose of the present study was to investigate the incidence and severity of iridial pigmentation under latanoprost topical use on brown eyes in Taiwan. METHODS: Retrospective review study was conducted from April 1999 to October 2001 in the Department of Ophthalmology, Taipei Veterans General Hospital, Taiwan, for glaucoma clinic monthly follow-up patients; 140 open-angle glaucoma patients on 0.005% latanoprost were enrolled. Analyses of iridial pigmentation incidence, grading, patient age distribution, side effect, and time course were performed. Boys-Smith pigment gradation lens was used as standard for semiquantitative iris pigmentation grading. RESULT: Before 0.005% latanoprost use, 90% of the patients enrolled were noted with iridial pigmentation grade I, and 10% were with grade I-II, but not reaching grade II scale standard. A total of 60 patients on 0.005% latanoprost developed increased pigmentation of the iris during the follow-up period. An increase of iris pigmentation was noted after an average of 7.27 months use of latanoprost (range 1-19 months, SD 2.65 months). For iridial pigmentation grading, 57.1, 30.7, 10.0, and 2.1% of our patients were noted to have grade I, II, III, and IV respectively. Most patients with latanoprost-induced iris hyperpigmentation were with grade II iridial pigmentation. There were 15 patients (10.7%) (10 female and five male) with hypertrichosis in the study group who were not compatible with the iridial pigmentation status. Among these patients, female patients had higher incidence of hypertrichosis than males, but this did not bother them. Only four patients (2.8%) were with conjunctiva chemosis and three patients (2.1%) with lid margin hyperpigmentation. CONCLUSION: Contrary to the belief that latanoprost rarely caused iris hyperpigmentation in yellow-brown eyes, our study showed that 42.8% iris hyperpigmentation did occur, especially after continual use for around 7 months. Higher hyperpigmentation incidence were noted in male than in female patients. This might be due to stronger adrenergic incidence in male than in female patients. Although hypertrichosis and increasing eyelid pigmentation together with iridial pigmentation represented a potentially permanent cosmetic side effect, they are very rare and occurred in no more than 3% in our patients. It is a good way to take Boys-Smith pigment gradation lens for iridial pigmentation grading and for long-term continual evaluation. The doctors should exert great care in differentiating drug-induced iris pigmentation and iris nevi from early stage uveal melanoma.