Questionnaire/history: Onset and duration of symptoms? Unilateral or bilateral? Onset simultaneous if both eyes affected? Perceived visual changes? Pain and severity of pain? Itch? Foreign body sensation? Discharge? Photophobia? Headache? Other associated symptoms? Contact lenses? History of chemical exposure or trauma? Similar episodes in the past? Past medica history? Family history? Current medication? Drug allergies? Examination: (Note: no palpation of the eye if perforation of the globe is suspected (for instance in ocular trauma or as a complication of scleritis), but urgent ophthalmology assessment) Facial trauma? Visual acuity? Discharge from the eye(s)? Eyelids (eg trichiasis, entropion or ectropion)? Conjunctiva, including tarsal surface? Upper lid everted to check for a sub-tarsal foreign body? Pattern of redness? - Ciliary flush (limbal vessels (where the cornea meets the sclera) injected (seen in more serious causes of red eye (eg anterior uveitis and corneal causes))? Fluorescein examination (if cornea stains possibility of corneal abrasion or ulcer)? Pupils? Equal size and shape? Photophobic? Direct and consensual pupillary reflexes? Relative afferent pupillary defect? Blood pressure if subconjunctival haemorrhage is suspected? Red flag signs and symptoms? Management: Chemical eye injury? - Immediate irrigation with water or 0.9% saline until pH returns to normal Not facility to check pH? - Refer immediately after copious irrigation High-velocity injury (eg while hammering or chiselling) or injury involving glass? - Immediate referral to the emergency eye service Same-day assessment by an ophthalmologist if suspected serious, and potentially sight-threatening, cause? - Acute glaucoma? - Corneal laceration? - Corneal ulcer, contact lens-related ulcer and corneal foreign body which could not be removed? - Endophthalmitis? - Intraocular foreign body? - Neonatal conjunctivitis (discuss with paediatrics or ophthalmology depending on clinical judgement)? - Trauma (eg penetrating eye injury or high-velocity foreign body)? - Chemical injury? Refer within 24 hours to local eye clinic if: - Anterior uveitis? - Scleritis? Not requiring urgent referral? - Subconjunctival haemorrhage (check BP and INR if on warfarin) (will clear in 2-3 weeks)? - Episcleritis (usually self-limiting? - Ectropion (can cause exposure keratopathy)? - Entropion (can cause corneal irritation and abrasion)? - Trichiasis (can cause corneal irritation and abrasion)? - Blepharitis? - Infective and allergic conjunctivitis? - Subtarsal or conjunctival body? - Corneal abrasion? - Dry eye? Reference(s): NICE CKS: Red eye