When applied to the eyeball as a drop for glaucoma, bimatoprost has been found to increase melanin in darker eyes (brown and hazy eyes). Blue eyes do not contain melanin and are unlikely to darken with treatment. LATISSE, similar to bimatoprost, has a product warning that eye color may darken with treatment, although the chance of this is rare. When this happens, it will permanently darken the eye color. Eyelid skin darkening may also occur but is usually reversible if the product is discontinued.