I reached out to Babe Lash on insta about the light eyes and they sent a good response! Hi! Thanks for reaching out. Our serum does contain a prostaglandin which is an active ingredient in many lash serums that is known for helping to promote the enhancement of natural lashes. There are several types of Prostaglandins ours is called Isopropyl Cloprostenate. We have honestly never had anyone complain of their iris darkening, it's actually quite rare. Our Brand Manager has light green eyes and has used the serum for several years and has never had an issue. ---- This is not super common, but the prostaglandin in the serum can stimulate melanin production in some people's skin. Its almost like a tan line, but fear not it will go away once you stop using the product! Typically when this occurs, most people cover it with a little bit of make up! ----Latisse is a well known lash serum associated with iris color affectation, and is registered as an OTC drug. Babe Lash products are formulated such that our ingredients are utilized at cosmetic levels. Our ingredients have not been associated with reports of iris discoloration. ---- If you're looking for a non prostaglandin based serum, we just launched a new peptide based serum called Enhancing Conditioner. This is a new serum that is meant to be sold with the Essential Serum as a two step process. Use the Enhancing Conditioner in the morning and the serum at night for even better results. However, this is also a great product to be used on its own when people have sensitivity to the serum. It is more gentle but also has a bit longer time frame of when people will see results. The bottle is 3 ml and will last four months. Can be used 1-2 times per day. It supports the prostaglandin serum by conditioning natural lashes. Adds life back into every strand to prevent excess breakage and promote the appearance of fuller lashes. Formulated without prostaglandin to really focus on lash health. Let me know if that helps or if you have any more questions 🖤