(CNN) – The trend has been popular in parts of Europe for about a decade but really started taking off in the United States over the past few years after people revealed their dramatic color transformations on social media apps like TikTok and Instagram.

Procedures called iris implants have received US Food and Drug Administration approval for people who are missing part or all of their iris, but no procedure is approved for cosmetic purposes. In January, the American Academy of Ophthalmology issued a warning about the risks of vision loss and complications with two eye color change procedures: iris implants and the one Titus had, called keratopigmentation. (Read More)