While you are using latanoprost, the iris (colored part) of your treated eye(s) may slowly become more brown in color. This is more likely to happen if you have blue-brown, gray-brown, green-brown, or yellow-brown eyes. The change in color of the iris is noticeable usually within several months or years from the start of treatment with latanoprost. In addition, there may be a darkening of eyelid skin color. Also, your eyelashes may become longer, thicker, and darker. These changes to the iris, eyelid, and lashes may be permanent even if you stop using latanoprost. Also, these changes to the iris, eyelid, and lashes will affect only the eye being treated with latanoprost. Therefore, if only one eye is being treated, only that eye may develop darker iris, eyelid, and eyelashes and other changes to the eyelashes, and you may have differently appearing eyes. Check with your doctor if you have any questions about this.
Latanoprost may cause your eyes to become more sensitive to light than they are normally. Wearing sunglasses and avoiding too much exposure to bright light may help lessen the discomfort.