Which symptom is most characteristic of acute angle-closure glaucoma?

• A. Halos around lights
• B. Photophobia
• C. Redness of the eye
• D. Conjunctival discharge

Answer: (A)

Halos around lights appear because a sudden rise in intraocular pressure during acute angle-closure glaucoma causes corneal edema, which diffracts light and creates those visible halos. This diffraction from the swollen cornea is a distinctive clue that points to a rapid glaucomatous event. Other symptoms like photophobia, redness, or conjunctival discharge can occur with different eye conditions—photophobia with inflammatory or corneal problems, redness in many etiologies, and discharge with infection or allergy—so halos stand out as the more characteristic feature of this acute crisis. If halos accompany sudden eye pain or vision changes, it’s a medical urgent situation.