A patient presents with a painful red eye and a corneal epithelial defect on examination. Which diagnosis is most likely?

• A. Corneal Ulcer
• B. Hyphema
• C. Photophobia
• D. Ophthalmoplegia

Answer: (A)

The main idea here is that a painful red eye with a corneal epithelial defect seen on examination points to involvement of the cornea, most classically a corneal ulcer. The cornea is highly innervated, so disruption of its surface causes significant pain and redness. When you shine a dye like fluorescein, a corneal epithelial defect shows up as a bright green area where the surface is missing, which is the hallmark finding of a corneal ulcer. This condition often results from infection or trauma and requires prompt treatment to prevent spread into the corneal stroma or scarring.

Different parts of the red-eye picture help distinguish it from other possibilities. A hyphema would present with blood in the anterior chamber and lacks an epithelial defect. Photophobia can accompany corneal disease but isn’t itself a diagnosis. Ophthalmoplegia involves restricted eye movements, not a corneal surface problem. So the combination of a painful, red eye plus a detectable corneal epithelial defect makes corneal ulcer the most likely diagnosis, warranting urgent eye care and appropriate topical treatment.