Bimatoprost ophthalmic solutions have been reported to cause changes to pigmented tissue. The changes include increased pigmentation and growth of eyelashes and increased pigmentation of the iris and periorbital tissue (eyelid).
The increased iris pigmentation may be permanent.Bimatoprost ophthalmic solution may gradually change eye color, increasing the amount of brown pigment in the iris by increasing the number of melanosomes
(pigment granules) in melanocytes. The long-term effects on the melanocytes and the consequences of potential injury to the melanocytes and/or deposition of pigment granules to other area of the eye are currently unknown.
The change in iris color occurs slowly and may not be noticeable for several months to years.Pigmentation is expected to increase as long as bimatoprost ophthalmic solution is administered. In a 12-month clinical study, iris colour change was reported in 0.5%of patients treated with bimatoprost ophthalmic solution 0.01%.