A sudden, painless, unilateral vision loss may be caused by which of the following?

A. Retinal detachment is correct because it often presents as sudden, painless, unilateral vision loss. Patients may describe a curtain or shadow descending over the visual field, flashes of light, or floaters. Retinal detachment is an ophthalmic emergency, as prompt surgical intervention is required to prevent permanent vision loss. B. Corneal ulcer is incorrect because it typically causes pain, redness, tearing, photophobia, and decreased vision, not painless vision loss. Corneal ulcers are often associated with infection or trauma and are usually painful, unlike retinal detachment. C. Acute glaucoma is incorrect because acute angle-closure glaucoma presents with sudden, severe eye pain, headache, nausea, halos around lights, and blurred vision, often with a steamy cornea and mid-dilated pupil. Vision loss is usually accompanied by significant discomfort, making it a painful condition rather than painless. D. Uveitis is incorrect because it usually causes eye pain, photophobia, redness, and blurred vision, which are painful and inflammatory symptoms. Vision loss is not typically sudden and painless, and it may be bilateral depending on the underlying cause.