A red inflamed eye is a common presentation in both primary care and emergency settings. It can result from a wide range of causes, from minor conditions like conjunctivitis to serious diseases such as acute glaucoma. A careful history and examination are crucial to identify potentially sight-threatening conditions. Following NICE and Royal College of Ophthalmologists guidelines ensures safe and effective care.
Causes
There are multiple causes of red inflamed eye, including:
- Infective conjunctivitis: Viral or bacterial infection of the conjunctiva
- Allergic conjunctivitis: Eye inflammation due to allergens like pollen
- Dry eye syndrome: Due to reduced tear production or poor-quality tears
- Blepharitis: Inflammation of the eyelid margins
- Keratitis: Inflammation or infection of the cornea
- Acute angle-closure glaucoma: A medical emergency where intraocular pressure rises suddenly
- Scleritis and episcleritis: Inflammation of the sclera or its outer layer
- Uveitis: Inflammation inside the eye (uvea)
- Foreign body in the eye
- Trauma or chemical injury
Pathophysiology
The redness in an inflamed eye is primarily due to dilation of blood vessels in response to irritation, infection, or injury. Infections trigger an immune response, leading to inflammatory cell infiltration. Allergies cause histamine release, resulting in vascular leakage and redness. In glaucoma, the blockage of aqueous humour drainage increases pressure, causing vascular congestion and pain.
Signs and Symptoms
Patients with a red inflamed eye may report:
- Redness in one or both eyes
- Gritty, burning, or stinging sensation
- Discharge (watery, mucous, or purulent)
- Itching, especially in allergies
- Blurred vision or halos around lights (in glaucoma)
- Photophobia (sensitivity to light)
- Eye pain or headache
- Swelling of the eyelids
- Foreign body sensation
- Decreased vision (a red flag symptom)
Risk Factors
Several factors increase the risk of developing a red inflamed eye:
- Poor hand hygiene and contact lens use (risk of infections)
- Allergies such as hay fever
- Autoimmune conditions like rheumatoid arthritis (associated with scleritis, uveitis)
- Trauma or occupational exposure to chemicals or particles
- Previous eye surgeries or interventions
- Smoking (impairing eye surface health)
- Older age (associated with dry eyes and glaucoma)
Investigation
Most cases can be diagnosed clinically, but further investigations may be needed if serious conditions are suspected:
- Visual acuity testing: Essential for all red eye assessments
- Slit lamp examination: To inspect corneal and anterior chamber health
- Fluorescein staining: To detect corneal abrasions or ulcers
- Tonometry: To measure intraocular pressure (important for glaucoma)
- Conjunctival swab: For microbiology if infectious conjunctivitis is suspected
- Blood tests: Including autoimmune screening if scleritis or uveitis is suspected
- Ocular ultrasound: In cases where the view to the retina is blocked
- CT/MRI scan: If orbital cellulitis or deeper infection is suspected
Management
1. Non-Pharmacological Management
- Cold compresses: Especially helpful in allergic conjunctivitis.
- Artificial tears: For dry eye syndrome.
- Avoidance of allergens or irritants: In allergic or chemical conjunctivitis.
- Proper contact lens hygiene: To prevent infective keratitis.
- Patient education: Warning signs that require urgent reassessment (e.g., vision loss, severe pain).
2. Pharmacological Management
- Topical antibiotics: Such as chloramphenicol for bacterial conjunctivitis.
- Antihistamine or mast cell stabiliser drops: For allergic conjunctivitis.
- Steroid eye drops: Only under specialist supervision for severe inflammation (e.g., scleritis, uveitis).
- Antiviral agents: Such as aciclovir for herpes simplex keratitis.
- Antiglaucoma medications: Like acetazolamide and topical beta-blockers in acute glaucoma.
- Lubricating eye drops: For dry eyes and mild irritative symptoms.
3. Surgical Management
- Emergency laser or surgical intervention: In acute angle-closure glaucoma
- Foreign body removal: Using sterile techniques under magnification
- Surgical drainage: For abscesses in orbital cellulitis
- Corneal transplantation: Rarely required in severe cases of corneal ulceration leading to perforation
Complications
If not properly managed, a red inflamed eye can lead to:
- Permanent vision loss (e.g., untreated glaucoma, corneal ulcers)
- Corneal scarring
- Chronic dry eye disease
- Recurrence of infection or inflammation
- Spread of infection to deeper orbital or systemic structures (orbital cellulitis, meningitis)
- Psychosocial impact from persistent discomfort or cosmetic issues
References
- National Institute for Health and Care Excellence (NICE) – Conjunctivitis, Red Eye Clinical Knowledge Summary
- Royal College of Ophthalmologists – Management of Red Eye
- ENT UK and Ophthalmology Guidelines – Eye Emergencies in Primary Care
- British National Formulary (BNF) – Ocular Therapeutics
- General Medical Council (GMC) – Good Clinical Practice Standards