Red eye, ocular injury and discharge

Separate irritation from threatened vision

A red eye with reduced visual acuity, substantial pain, photophobia, corneal opacity, abnormal pupil or injury is potentially sight-threatening. Ask about contact lenses, chemicals, high-velocity work, trauma, recent surgery and immunosuppression. Check acuity separately in each eye and examine pupils, lids and cornea. Mild conjunctivitis usually causes discharge or irritation with preserved vision, but this diagnosis must not be used to explain unexplored severe pain. Refer promptly when the examination is incomplete and the history contains major warning signs.

Bacterial, viral and allergic conjunctivitis have overlapping presentations. Allergic disease often causes itching and bilateral symptoms; viral infection can spread readily and may accompany respiratory illness. Offer hygiene advice and appropriate treatment without implying every red eye needs antibiotic drops. Copious purulent discharge with severe inflammation raises gonococcal infection, requiring urgent systemic treatment and specialist care. Neonatal conjunctivitis requires age-specific assessment because invasive infection and corneal damage can occur. Contact-lens wearers with pain need keratitis assessment, not routine reassurance.

Keratitis, uveitis and glaucoma

Corneal abrasion causes pain and tearing, often after a minor scratch. Fluorescein can identify an epithelial defect once open-globe injury is excluded. Retained foreign material beneath a lid may cause linear scratches; lid eversion is appropriate only when safe. A contact-lens-related infiltrate or ulcer raises bacterial keratitis and requires urgent ophthalmological antimicrobial treatment. Do not patch a potentially infected contact-lens eye or provide topical steroid empirically. Steroids can worsen an undiagnosed infection, and repeated topical anaesthetic use can damage the cornea.

Anterior uveitis can cause aching, photophobia and ciliary injection, sometimes with a small pupil. Severe deep pain with scleral inflammation raises scleritis and systemic autoimmune disease. Acute angle closure may produce a painful red eye, headache, vomiting, halos, cloudy cornea and a poorly reactive mid-dilated pupil. It requires emergency pressure-lowering treatment and ophthalmological care. A vomiting patient can therefore have an eye emergency rather than gastroenteritis. Drug choice and definitive laser treatment follow the specialist pathway; do not wait for a routine clinic appointment.

Chemical exposure and penetration

Chemical injury requires immediate copious irrigation, removing contact lenses and accessible particulate material while calling for assistance. Do not delay irrigation to obtain a detailed history or a preferred solution. Check ocular surface pH and continue the local irrigation/reassessment pathway. Alkali can penetrate deeply; apparent early improvement does not eliminate risk. After initial decontamination, assess vision and obtain urgent specialist advice. Protect the rest of the patient and assess inhalation, skin or systemic chemical injury as appropriate.

Suspected open globe follows penetrating or high-energy trauma, with possible distorted pupil, very low vision or extrusion. Avoid pressure, tonometry and manipulation; place a rigid protective shield without compressing the eye, keep nil by mouth and arrange urgent ophthalmology. A high-velocity metal fragment can be intraocular despite a small external mark. CT is often used; MRI is unsafe when a metallic foreign body is possible. Do not remove an embedded object in the clinic. Analgesia, antiemetic, antimicrobial and tetanus decisions belong to the emergency pathway.

Swollen eyelids and orbits

Preseptal cellulitis affects tissues anterior to the orbital septum, with lid swelling but preserved ocular movements and no proptosis. Orbital cellulitis is suggested by painful/restricted movements, proptosis, visual impairment or a relative afferent pupillary defect. It is an emergency needing hospital IV antibiotics, imaging and ophthalmology/ENT input. In children, swelling can make examination difficult; inability to assess the eye safely may itself justify escalation. Fever and sinus symptoms support infection but their absence does not safely rule out orbital disease.

A retrobulbar haemorrhage after trauma can produce orbital compartment syndrome with pain, proptosis, tense lids and threatened vision. Immediate specialist or appropriately trained emergency decompression may be required; imaging must not delay treatment when the diagnosis is clear and vision is deteriorating. Hyphaema needs eye protection and pressure/bleeding assessment. Blunt trauma can also cause retinal or lens injury, so a visible abrasion should not become the only diagnosis. Record visual findings before and after intervention where practical.

Applied triage

A student with itchy bilateral eyes, normal acuity and no photophobia may have allergic conjunctivitis. A contact-lens wearer with a painful focal corneal opacity needs urgent keratitis care. A factory worker splashed with alkali needs irrigation immediately, before a full visual chart. A child with swollen lids, proptosis and painful eye movement needs emergency orbital assessment. In each case, explain the urgency, confirm a receiving service and provide explicit return precautions. Never allow a reassuring external appearance to outweigh reduced vision or a high-risk mechanism.

RCH acute red eye, RCH acute eye injury and NSW Eye Emergency Manual.

Review checkpoints

• Reduced vision, photophobia or severe pain makes simple conjunctivitis less likely.
• Chemical eye injury requires immediate irrigation before a lengthy history.
• Suspected penetrating injury needs eye protection without pressure or manipulation.