Which condition most often presents with sudden, painless vision loss?

• A. Orbital cellulitis.
• B. Acute angle-closure glaucoma.
• C. Central retinal artery occlusion.
• D. Periorbital cellulitis.

Answer: (C)

Sudden, painless vision loss points to retinal or vascular causes rather than inflammatory or painful eye conditions. Central retinal artery occlusion fits best because an abrupt, painless loss of vision in one eye is the classic presentation of an arterial blockage of the retina. The hallmark exam finding is retinal whitening with a cherry-red spot at the fovea, reflecting inner retinal ischemia from the arterial occlusion. This is a medical emergency with time-sensitive management to try to restore perfusion.

In contrast, acute angle-closure glaucoma causes sudden vision loss that is painful, with a red eye, headache, halos, and a mid-dilated fixed pupil, along with very high intraocular pressure. Orbital cellulitis and periorbital cellulitis typically present with facial swelling, eyelid tenderness, fever, and pain with eye movements; vision loss, if present, is not the defining feature and pain is prominent.