To investigate the topical use of travoprost [Trademark: Travatan (Alcon laboratories Inc, TX)] and the incidence of iridial pigmentation change in the brown irises of Chinese eyes.
Materials and Methods
Design: Prospective, masked, observational study. Enrolled in the study were 37 Chinese subjects (73 eyes) with primary open-angle glaucoma who were being treated for the first time with travoprost eye drops (patient-group). Twenty-one Chinese volunteers with normal eyes (42 eyes) served as the control-group. To evaluate iris pigmentation, photographs were taken of the control-group's irises using a slit-lamp biomicroscope with attached digital camera. Before the start of travoprost treatment and 3 months after the start of travoprost treatment, photographs of the irises of the patient-group were taken using the same photographic methods. Five glaucoma specialists independently read the series of photographs to determine if there was an increase in iris pigmentation. Three of the 5 observers had to be in agreement that there was an increase from the baseline. “Picture Color Analyzer” computer software was also used to calculate the color value of each iris picture.
Observation with eyes: Twenty-six eyes (35.6%) in the patient-group developed an increase in iris pigmentation compared with zero subjects (0%) in the control-group (P=0.000, χ2 test). Results with Picture Color Analyzer software: On the basis of the threshold value that was obtained from the control-group, 22 eyes (30.1%, n=73) in the patient-group were shown to have developed an increase in iris pigmentation.
Contrary to the previous studies that noted that the percentage of iris hyperpigmentation caused by travoprost in homochromic brown eyes was very low, our study showed that 35.6% iris hyperpigmentation did occur, which is a considerably higher percentage than that reported in whites.