These effects are seen in 50 to 60% of individuals using bimatoprost. In carefully performed studies comparing pre-treatment and post-treatment iris color images, increased iris pigmentation is seen in up to 70% of eyes.

Can bimatoprost cause dark circles under eyes?

This medication may slowly (over months to years) cause brown discoloration of the colored portion of the eye (iris). If you are using bimatoprost in only one eye, only that iris may change color.

Why does bimatoprost cause dark circles?

Change in Eye Color

Bimatoprost, the active ingredient in Latisse, can stimulate the production of melanin. When this ingredient comes into direct contact with your eyes, it can cause the melanosomes in your irises (the colored part of your eye) to produce more melanin than normal, affecting their color.