Painful Red Eye

First actions / assessment

• Assess ABCDE only if systemically unwell, then perform focused eye assessment. Clarify onset, unilateral or bilateral symptoms, severity of pain, nature of discomfort such as gritty or foreign-body sensation, photophobia, vision change, blurred vision, halos, headache, nausea, vomiting, trauma, chemical splash, contact lens use, discharge, itching, recent eye surgery/injection, past uveitis or glaucoma, autoimmune disease, and HSV/VZV history. Examine and document visual acuity in each eye before treatment where possible. Inspect lids and conjunctiva, note diffuse conjunctival injection versus ciliary flush, assess pupils and consensual photophobia, corneal clarity, extraocular movements, fluorescein staining when appropriate, and check for foreign body or dendritic lesions if skilled and safe. Tonometry and slit-lamp examination are useful when available, but do not delay urgent referral in obvious sight-threatening disease. Pain plus reduced vision or significant photophobia should be treated as high risk.