This NHS content is written for people in England. Medicine names, availability, prescribing and services may differ in other countries.
Common side effects of bimatoprost
These common side effects of bimatoprost happen in more than 1 in 100 people. There are things you can do to help cope with them:
Change in eye colour
Bimatoprost eye drops may increase the amount of brown colour in the iris of the eye you're treating. Talk to your doctor before you start using bimatoprost if you're worried about this.
If this happens, you may not notice any change until you have been using the eye drops for several months or years.
This colour change can be permanent and may be more obvious if you're only using the eye drops in one eye.
An itchy or painful eye and a feeling that something's in your eye, blurred vision, or watery eyes
This should go away when your body gets used to bimatoprost, but talk to your doctor or pharmacist if you're worried about this. A cold water compress on the closed eye may help.
If the eye drops irritate your eyes and make them water so much that you think about stopping using the drops, talk to your doctor straight away. They may prescribe something different for you.
Do not drive, cycle, use tools or operate heavy machinery until your eyes feel comfortable again and your vision is clear.
Changes to your eyelashes – growing longer and thicker
If this happens, you may not be able to do anything about it. But your eyelashes would likely return to normal if you ever stop using bimatoprost.
Talk to your pharmacist or doctor if you're worried about this.
Changes to the skin around your eye
You might notice some changes to the skin around your eye. Changes may include red and itchy eyelids, darker skin colour around your eye and hair growth around your eye. Any redness or darkening may be less obvious on brown or black skin.
Try to avoid the eye drop liquid touching your skin too often to reduce the chance of this happening.
These changes are usually mild and may disappear if you ever stop using bimatoprost. Talk to your doctor or pharmacist if you're worried about this.
Changes to your eyelids and the area around your eye
You may lose some of the fat in the area around the eye you're treating. This can lead to your eyelid crease becoming deeper, your eye looking sunken, a drooping eyelid, tighter skin around your eye, and more of the lower white part of your eye showing.
These changes are usually mild and may disappear if you ever stop using bimatoprost. Talk to your doctor or pharmacist if you're worried about this.
Keep using the medicine, but talk to your doctor or pharmacist if the advice on how to cope does not help and these side effects bother you or do not go away.
View the original NHS website page ↗. Refreshed 19 August 2026.
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