Mooren ulcer is a rare, severe inflammatory condition that affects the cornea, the transparent front part of the eye. This chronic disorder is characterized by a progressive thinning of the peripheral cornea, the outer edge of the cornea. It is considered a non-infectious condition. The exact cause is unknown, but it is believed to involve an autoimmune process where the body’s immune system mistakenly attacks its own corneal tissue.
Understanding Mooren Ulcer
Mooren ulcer presents as a crescent-shaped or circumferential ulceration that begins at the limbus, the border between the cornea and the white part of the eye. This ulceration then progresses across the cornea, sometimes affecting only one eye (unilateral) or both eyes (bilateral). The condition starts with a gray swelling that rapidly develops into a furrow, eroding the superficial layers of the cornea and then advancing both around the circumference and towards the center.
Mooren ulcer presents in different forms:
Unilateral Form
This type is seen in older patients and is often painful, affecting one eye with progressive ulceration.
Bilateral Aggressive Form
More common in younger individuals, this form progresses rapidly around the entire circumference of the cornea before moving towards the central area.
Bilateral Indolent Form
Found in middle-aged patients, this form involves progressive peripheral corneal guttering in both eyes with less severe inflammation.
Individuals with Mooren ulcer experience severe eye pain, redness, tearing, and sensitivity to light (photophobia). Vision changes, including decreased visual acuity, also occur due to irregular astigmatism from corneal thinning or central corneal involvement. The pain can be debilitating and may seem disproportionate to visible inflammation. As the ulcer progresses, the affected cornea becomes thin, scarred, and vascularized, with blood vessels growing into the damaged tissue.
Diagnosing Mooren Ulcer
Diagnosing Mooren ulcer relies on a clinical examination and the exclusion of other conditions that can cause similar corneal damage. An ophthalmologist performs an eye examination, including a slit-lamp examination, which allows for a magnified view of the eye’s structures. It helps identify the characteristic crescent-shaped peripheral corneal ulcer with an undermined central edge.
No specific laboratory tests definitively diagnose Mooren ulcer. However, various tests are conducted to rule out other underlying causes. Corneal scrapings may be taken for microbiological analysis to exclude infectious keratitis.
Blood tests may also check for systemic autoimmune diseases or vasculitic conditions that present with peripheral ulcerative keratitis, as Mooren ulcer is a diagnosis of exclusion. Differentiation from other peripheral ulcerations, such as those caused by infections or systemic autoimmune disorders like rheumatoid arthritis or granulomatosis with polyangiitis, is important.
Approaches to Treatment
Managing Mooren ulcer is complex and requires a multi-pronged approach aimed at controlling inflammation, preventing further progression, and preserving vision. Medical treatments are often the first line. Topical corticosteroids, administered as eye drops, are used to reduce inflammation directly in the eye. However, their long-term use can lead to complications such as increased intraocular pressure or cataract formation.
Systemic corticosteroids, taken orally or intravenously, are prescribed to suppress the immune response and control inflammation throughout the body. Immunosuppressive agents, such as cyclosporine, methotrexate, or azathioprine, may be used when corticosteroids alone are insufficient or to reduce reliance on long-term corticosteroid therapy. These medications work by modulating the immune system to prevent it from attacking corneal tissue.
When medical treatments are not effective or if there is a risk of corneal perforation, surgical interventions are considered.
- Conjunctival resection: This involves removing a strip of the adjacent conjunctiva to eliminate inflammatory cells that contribute to the ulcer’s progression.
- Lamellar keratoplasty: Only the diseased layers of the cornea are replaced to reconstruct the corneal surface.
- Penetrating keratoplasty: In cases of severe corneal thinning or perforation, a full-thickness corneal transplant is necessary to restore eye integrity and potentially improve vision.
Living with Mooren Ulcer
Mooren ulcer is a chronic condition that requires monitoring and management to prevent recurrences and complications. Even after successful initial treatment, individuals may need long-term follow-up with their ophthalmologist to ensure the condition remains stable. The chronic nature means that flare-ups or periods of increased inflammation can occur, necessitating adjustments to the treatment plan.
Potential complications of Mooren ulcer include:
- Corneal perforation: A hole develops in the cornea, which is a serious complication.
- Secondary infections: These can occur in compromised corneal tissue, complicating the disease course.
- Vision loss: Ranging from mild impairment to severe visual disability, this is a risk due to corneal scarring, irregular astigmatism, or central corneal involvement.
Adherence to prescribed treatment regimens and regular follow-up appointments are important for managing the condition and minimizing the risk of these complications.