Have been using Latisse for a few months. Noticed the gray area of my pupils increasing and more green. Should I stop? (photo)

When applied as directed to the top of the lids, Latisse should not affect the color of the eye. Keep in mind, no patients in any of Allergan’s studies for Latisse reported alterations in their eye color, so this would be an extremely rare side effect. Prp and viviscal can also help improve eyelash growth. Best, Dr. Emer

This is not due to your use of Latisse.  The only iris discoloration associated with this  medication is the formation of brown spots, and these don't occur if the medication is used correctly.  This happens due to enhancement of the iris's pigment in random spots.  Because you have blue eyes, you are actually one of the least likely to have any discoloration - even if you are using it incorrectly and getting the Latisse IN your eye instead of just on the lid.  
The most common way to tell if you are getting it into your eyes is the sensation of itching, burning or redness after using it.  This usually happens because the one drop that is supposed to be used often feels dry when it is applied, so patients use more than one drop, resulting in the product running down into the eye itself and causing the symptoms mentioned above.  
Feel free to continue to use your Latisse as it is not causing this change in your eyes!  It's a great product that gives great results!
Best, Dr. Cayton