Mooren's Ulcer

Mooren's ulcer affects the cornea, the clear front window of the eye, and is described as a painful autoimmune form of peripheral ulcerative keratitis. The immune system is thought to target a specific molecule in the corneal stroma in people who are genetically susceptible, with the reaction sometimes provoked by a prior trigger such as ocular trauma, surgery, or certain infections, though a specific cause is not identified in every case.

A 2025 review described it as rare and noted that it occurs more often in parts of the Indian subcontinent, China, and central Africa than in the northern hemisphere, with incidence and severity varying by region, and it still lacks large-scale prevalence data and standardized diagnostic criteria. It can progress to corneal thinning and perforation and carries a risk of vision loss, so it needs prompt care from an eye specialist.

Common signs

Severe eye pain that can seem out of proportion to what is visible, marked redness, strong light sensitivity, and tearing, with progressive thinning at the edge of the cornea.

This is a plain-language summary for orientation, not a diagnosis. Mechanisms are described as current understanding, not settled fact. Work with your own clinician for your care.