Latanoprost-induced Iris Color Darkening: A Case Report With Long-term Follow-up

PURPOSE:To determine the effect on iris color of discontinuing latanoprost (LP) treatment in a patient with pronounced iris color darkening, and to assess the possible role of sympathetic innervation. METHODS:In a patient demonstrating pronounced iris color darkening in both eyes after treatment with LP for 6 months, magnified iris color photographs were taken at 3- to 6-month intervals for 5 years after discontinuation of LP treatment. Pupillary testing for sympathetic insufficiency was performed with cocaine 10% or hydroxyamphetamine 1%. RESULTS:The iris color did not appreciably change after discontinuing LP. The cocaine-induced increase in pupillary diameter was considerably greater for the control subject than for the patient who demonstrated the LP-induced color change. CONCLUSIONS:Latanoprost-induced iris color darkening does not appreciably change for several years after discontinuing treatment. Some eyes that show LPinduced darkening may have relative ocular sympathetic insufficiency.