Painless Red Eye

First actions / assessment

• Assess focused eye history and document visual acuity in each eye before treatment where possible. Clarify onset, unilateral or bilateral redness, discharge, itch, watering, foreign-body sensation, morning crusting, contact lens use, trauma, chemical splash, photophobia, headache, nausea, recent URI, allergy history, past glaucoma or uveitis, surgery, and whether vision is genuinely normal. Examine conjunctival injection pattern, lids, pupils, corneal clarity, discharge, extraocular movements, and fluorescein staining if appropriate and available. Diffuse conjunctival redness with discharge and little pain suggests conjunctivitis
• a sharply demarcated blood patch with otherwise normal eye and vision suggests subconjunctival haemorrhage
• sectoral redness with mild irritation and normal vision suggests episcleritis. If symptoms do not fit a clearly benign pattern, reassess for painful red eye or vision-threatening disease.