A 37-year-old woman recently went to her eye doctor complaining of itching and watering eyes. While taking a close look, the doctor saw this freaky sight staring back.
Image: S. Li and L. Liang/NEJM
As reported in the New England Journal of Medicine, the condition is called “protruding iris collarette”, and despite how things look, it’s absolutely nothing to worry about.
It’s a rare, benign condition that doesn’t affect vision (the woman has 20/20 vision), carries no symptoms, and requires no treatment. Scientists have documented cases of protruding iris collarettes before, but this example is particularly striking. Scientists aren’t entirely sure what causes this feature, but genetics could be involved. As noted by the Chinese scientists who wrote up the case study, “This finding is a normal variant.”
The iris collarette marks the thickest region of the iris, and it separates the inner pupillary portion of the eye from the outer ciliary portion. It’s also the part of the eye where the sphincter muscle (no, not that sphincter muscle), and the dilator muscle overlap. Iris collarettes are typically flat, but as seen in this patient, they can sometimes extrude outwards in a distinctive ring-like pattern.
As for the patient, her itching and watering eyes were the result of an allergic reaction, and not related in any way to her strange iris (a so-called “incidental finding”). As noted in the NEJM, the “patient received treatment for allergic conjunctivitis and reassurance about this incidental finding”.
“Reassurance” being the key word.
We reached out to the doctors for more information but had not heard back at time of writing.