Eye Scar
The person with this unique eye preferred to stay anonymous, but he shared this photo of his eye on Reddit for the world to see (in case you aren’t familiar with Reddit, it’s a platform where you can pretty much find the answer to everything you’ve ever wondered). A scar on the pupil can appear at birth or later in life, and it might occur for a number of reasons.
In this case, the person who shared the photo of his one-of-a-kind eye (it is one of a one kind, since no two set of eyes, nor eye scars, can look the same) said he was born this way. According to this person, the scar doesn’t affect his vision. Nonetheless, he makes sure to visit the eye doctor and check it every few years.