Mooren's corneal ulcer, left eye

This code signifies a diagnosis of Mooren's corneal ulcer affecting the left eye. Mooren's ulcer is a rare, chronic, and progressive peripheral corneal thinning disorder, often characterized by severe pain and inflammation, and can lead to significant vision impairment or loss if untreated. It is an idiopathic ulcerative keratitis that typically begins at the limbus and spreads circumferentially and centrally.

Apply this code when documentation explicitly states a diagnosis of Mooren's corneal ulcer in the patient's left eye. This diagnosis is typically made by an ophthalmologist based on characteristic clinical findings, such as a crescent-shaped peripheral corneal excavation with an undermined leading edge. Supporting documentation should include findings from a slit-lamp examination confirming the location and nature of the ulcer.

• Ensure the laterality (left eye) is clearly documented and matches the code.
• Differentiate from other types of peripheral ulcerative keratitis, such as those associated with systemic autoimmune diseases.
• Consider additional codes for any associated complications, such as corneal perforation (H18.4x) or secondary glaucoma (H40.x).