Peripheral ulcerative keratitis

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Peripheral Ulcerative Keratitis (PUK) is a group of inflammatory diseases that affect the outer edge of the cornea. It causes eye pain, redness, sensitivity to light, tearing, blurred vision, and a feel­ing of something in the eye. The main sign is crescent-shaped thinning of the peripheral cornea, which can lead to perforation if untreated.

Causes and associations:
Many cases are linked to immune system problems. PUK often occurs with systemic diseases such as rheumatoid arthritis, Wegener’s granulomatosis (granulomatosis with polyangiitis), and polyarteritis nodosa. Mooren’s ulcer is a well-known form of PUK.

What happens:
Inflammation at the edge of the cornea triggers immune responses. Immune cells release enzymes that damage the cornea, and inflammatory signals worsen thinning.

Diagnosis:
Doctors take a detailed history, examine the eye, and look for infection or other diseases. Blood tests, chest imaging, and sometimes eye samples help find the cause.

Treatment:
Goals are to stop inflammation and protect vision. Treatments include:
- Medications: topical steroids for mild cases; systemic steroids for more severe cases; immunosuppressants (such as azathioprine, cyclophosphamide, methotrexate); and some biologic drugs that block specific parts of the immune system.
- Surgery: removing inflamed tissue, sealing the cornea with glue, or corneal transplantation in severe cases.

If infection is present, targeted antibiotics, antifungals, or antivirals are used. Incidence is about 3 per million people per year, and outcomes vary; early, combined medical and surgical treatment offers the best chance of preserving vision.