Will Green Irises Change After Using Latisse?

It is a very rare risk but you may experience an increase in brown pigmentation in your irises. However, I haven't noticed this in any of my patients to date, and in fact, a staff member who works at my practice hasn't had this happen to her even though she has green eyes. If you see this happening to you, you should stop using Latisse, however, there is a risk that the change may be permanent.

Latisse was discovered when Lumigan, the same medication used for glaucoma, was applied into the eye and some patients had darkening or changing eye color which is permanent in some cases. It is of greatest risk when there is a degree of brown pigment already present.
That being said, there have been no cases reported of darkening of the iris with Latisse and the reason is that it is carefully placed on the lashes and not in the eye if used as directed. Therefore you are probably safe to use Latisse and not have any problems, but it might be best to apply it sparingly to avoid any getting into your eyes. Even if some were to get in your eyes, the chances of pigment changes is still low.
You may wish to discuss this further with your doctor who can help you make the final judgement.

If you are in doubt about the potential to change color, it is always best to have your eyes examined by a "slit lamp" (magnified lenses especially designed to see details of the eye and iris) exam by an Ophthalomologist.
The culprit that causes the iris to change the color of blue or green eyes is if you have any sign of brown speckling withing the tissue of the iris. Pure green and blue colors are not likely to change to brown.

In the FDA studies leading up to its approval, there were no cases reported of darkening of the iris. HOWEVER, Latisse was serendipitously discovered to cause eyelash growth after ophthalmologists treating glaucoma patients with Lumigan noticed thicker, longer eyelashes in their patients. The ophthalmologists ALSO noted darkening of blue and green irises in some patients.
For this reason, it is recommended that Latisse be applied to only the upper lid, to minimize entry of the drug into the eye.
I counsel all my patients using Latisse that even though the FDA studies didn't show it, eye color can darken. Latisse and Lumigan are the exact same medicine: Bimatoprost.