About eye drops that change the color of your eyes

There is one category of medication in eye drop form that can change the colour of the eye; this is the category known as prostaglandin analogues. Prostaglandin analogues include Lumigan, Xalatan and Travatan. These eye drops are all used to lower eye pressure in patients who have, or are at risk, for developing glaucoma. The active ingredient in Lumigan, known as bimatoprost, has also been marketed as Latisse for its ability to enhance eyelash growth.

The eye gets its colour from the iris. The iris has a front and a back layer. The back layer is composed of black pigment in nearly everyone. The front layer of the iris, nearer to the cornea, is where your eye colour is determined. The more pigment that the cells in the front layer of the iris produce, the darker your eye colour.

The prostaglandin analogue eye drops can cause the pigment cells in the iris to release more pigment. This increase in pigment causes darkening of the eye colour of a person with lighter coloured eyes, such as blue or green. These changes do not occur in all people who use the eye drops. However, when they do occur, the colour change is permanent.

Darkening of the colour of the iris is classified as a side effect of the prostaglandin analogue eye drops. As such, eye colour is not affected by these eye drops in all people. Those with blue eyes or green eyes have a larger risk for eye colour change as their eyes have a greater potential to become darker. According to RxList, the range of risk for eye colour change across all the prostaglandin analogues is between 1 per cent and 15 per cent.

Because eye colour change from the prostaglandin analogues is permanent, one must be careful when using the eye drops in one eye only. If the one eye has a colour change, the patient could be left with two different eye colours. If a prostaglandin analogue is required for one eye only, and the eye colour is altered, the person's eye colour can be corrected with a coloured contact lens.

The prostaglandin analogue eye drops, particularly Latisse, can cause the skin colour around the eye lashes to be altered. Most often, people with darkly pigmented eyelid skin may experience lightening of the skin on the eyelids. These changes are also permanent.