Acute Visual Loss

Vision can disappear for several reasons that look similar to the patient but demand different emergency pathways. Establish whether the deficit is truly monocular, when it began, and whether it is painful, transient, or persistent. A fixed, painless monocular deficit should be treated as a retinal stroke emergency until central retinal artery occlusion (CRAO) is excluded. In a patient aged 50 or older, any visual symptom accompanied by new headache, scalp tenderness, jaw or tongue claudication, constitutional symptoms, or polymyalgia symptoms raises concern for giant cell arteritis (GCA); glucocorticoids should not wait for biopsy or imaging. Severe ocular pain with a red eye points toward acute angle-closure glaucoma, while flashes, new floaters, or a curtain-like field defect suggest retinal detachment. The first clinical split is therefore not simply “eye problem or not.” It is which tissue is threatened, whether vision can still be saved, and whether the fellow eye is at immediate risk.