Which symptom set best distinguishes acute angle-closure glaucoma from conjunctivitis?

• A. Itchy eyes with watery discharge.
• B. Red eye with no pain.
• C. Red, painful eye with headache and nausea.
• D. Discharge and crusting of the lashes.

Answer: (C)

Severe, acute ocular pain with systemic symptoms such as headache and nausea points to a rapid rise in intraocular pressure, which is characteristic of acute angle-closure glaucoma rather than conjunctivitis. This emergency condition often presents with a red eye, marked pain, headaches, nausea or vomiting, and sometimes blurred vision or halos around lights; exam may reveal a firm eye and a mid-dilated pupil. Conjunctivitis, by contrast, typically causes redness with itching, tearing, or purulent or crusting discharge, and pain is usually mild without systemic symptoms like headache or nausea. So the combination of red eye plus significant pain and systemic symptoms best distinguishes angle-closure glaucoma from conjunctivitis.