Painful Sudden Loss of Vision

First actions / assessment

• Assess ABCDE only if systemically unwell, then perform focused emergency eye assessment. Clarify exact onset and tempo, monocular versus binocular symptoms, severity of visual loss, eye pain versus headache, photophobia, halos, nausea/vomiting, redness, discharge, trauma, chemical splash, contact lens use, recent eye surgery/injections, autoimmune disease, prior glaucoma or uveitis, HSV/VZV history, and giant cell arteritis symptoms such as temporal headache, jaw claudication, scalp tenderness, polymyalgia symptoms, or constitutional upset. Document visual acuity in each eye before treatment where possible. Examine pupils including RAPD if possible, external eye, conjunctival injection pattern, ciliary flush, corneal clarity, fluorescein staining when appropriate, ocular movements, and gross visual fields. Tonometry and slit-lamp examination are helpful if available, but do not delay urgent referral in obvious sight-threatening disease. If giant cell arteritis is suspected, check ESR/CRP and arrange urgent specialty assessment, but treatment should not be delayed while waiting for results.