Painful red eye

A painful red eye is redness of the eye with pain, grittiness, photophobia or reduced vision. It indicates conditions from simple corneal abrasion to sight threatening emergencies: acute angle closure glaucoma, keratitis and corneal ulcer, anterior uveitis, scleritis, endophthalmitis and orbital cellulitis.

Pathophysiology. Corneal and ciliary pain arises from trigeminal innervation of the cornea and iris. Ciliary flush, photophobia and consensual pain suggest keratitis or uveitis. Severe pain with headache and nausea suggests angle closure.

Classification. Anterior segment (cornea, conjunctiva, sclera, anterior chamber, iris, lens), posterior segment (endophthalmitis, posterior scleritis), and orbit (orbital cellulitis, thyroid eye disease).

Key distinctions. Fixed mid-dilated pupil with cloudy cornea and halos points to acute angle closure. Pain with a small irregular pupil and photophobia points to anterior uveitis. A white corneal opacity with staining points to corneal ulcer. Dendritic fluorescein staining points to herpes simplex keratitis. Severe boring pain with tender globe points to scleritis.

History.

• Onset, severity, character, photophobia, tearing, discharge, vision change, halos around lights, headache, and nausea and vomiting.
• Contact lens use and hygiene (swimming, sleeping in lenses), trauma, foreign body, welding or ultraviolet exposure, chemical exposure, previous herpes, and rash.
• Systemic symptoms: back pain, joint pain, bowel disease, mouth ulcers, genital ulcers, rash, cough, weight loss.
• Sexual history, HIV and immunosuppression, and previous eye surgery.

Drug history. Topical steroids (herpes, glaucoma, cataract), anticholinergics, topiramate, sulphonamides and other drugs causing angle closure, bisphosphonates (scleritis and uveitis), immune checkpoint inhibitors, and rifabutin.

Examination.

• Visual acuity (each eye, pinhole), pupils (size, shape, reaction, relative afferent defect), and intraocular pressure.
• Lids, conjunctiva (ciliary flush), and cornea (clarity, epithelial defect, infiltrate, dendrite, fluorescein staining, Seidel test for leakage).
• Anterior chamber (depth, cells and flare, hypopyon, hyphaema), iris and lens, red reflex, and fundus.
• Eye movements, orbit (proptosis, lid swelling), preauricular nodes, and skin (zoster vesicles, rash).

Red flags

• Reduced vision, cloudy cornea, or fixed mid-dilated pupil
• Corneal infiltrate, ulcer, hypopyon or dendritic staining
• Severe pain with nausea, vomiting and headache (angle closure)
• Penetrating injury, chemical burn or high speed foreign body
• Contact lens wearer with pain
• Severe pain, tender globe and violaceous sclera (scleritis)
• Proptosis, painful eye movements, diplopia or lid swelling with fever (orbital cellulitis)
• Recent eye surgery or injection with pain and falling vision (endophthalmitis)
• Zoster rash on the nose tip or forehead (zoster ophthalmicus)
• Systemic illness with sepsis or immunosuppression

Special groups. Children: orbital cellulitis, trauma, and juvenile idiopathic arthritis associated uveitis (often painless). Pregnancy: avoid systemic tetracyclines and fluoroquinolones, and give topical therapy only. Older adults: angle closure and herpes zoster ophthalmicus. Region specific: trachoma, onchocerciasis, vitamin A deficiency (xerophthalmia and corneal ulceration), and fungal keratitis after plant injury.

Corneal

• Corneal abrasion and foreign body, chemical and ultraviolet keratitis (arc eye)
• Bacterial keratitis and corneal ulcer, fungal keratitis, acanthamoeba keratitis
• Herpes simplex keratitis, herpes zoster ophthalmicus
• Contact lens related keratitis, exposure keratopathy, dry eye
• Peripheral ulcerative keratitis (rheumatoid arthritis, granulomatosis with polyangiitis)
• Recurrent corneal erosion, trichiasis

Intraocular

• Acute angle closure glaucoma
• Anterior uveitis (acute): HLA-B27 associated (ankylosing spondylitis, inflammatory bowel disease, reactive arthritis, psoriasis), herpetic, sarcoidosis, tuberculosis, syphilis, Behcet disease, juvenile idiopathic arthritis, trauma
• Endophthalmitis (postoperative, endogenous), hyphaema, lens induced uveitis

Scleral and orbital

• Scleritis (anterior, posterior, necrotising)
• Orbital cellulitis, preseptal cellulitis, orbital abscess
• Thyroid eye disease, orbital inflammatory disease, carotid cavernous fistula, cavernous sinus thrombosis
• Dacryocystitis, dacryoadenitis, ruptured globe

Other

• Conjunctivitis with corneal involvement, blepharitis, chalazion, stye
• Cluster headache and migraine with redness, trigeminal neuralgia, giant cell arteritis (ocular)

Reasoning. Measure vision and pressure, stain the cornea, examine the anterior chamber, and identify the cause. Image the orbit and send cultures in severe or atypical disease.

First line. Visual acuity, pupils, fluorescein staining, slit lamp examination, applanation tonometry, and dilated fundus examination by ophthalmology after angle closure is excluded.

Targeted tests.

• Corneal scrape for Gram stain, culture, fungal stain and acanthamoeba for ulcers over 2 mm, central ulcers, severe or non-responding keratitis (by ophthalmology). Polymerase chain reaction for herpes simplex and varicella zoster.
• Gonioscopy and anterior segment optical coherence tomography for angle closure.
• Anterior uveitis work up when recurrent, bilateral, granulomatous or severe: HLA-B27, full blood count, ESR, C reactive protein, angiotensin converting enzyme, syphilis serology, interferon gamma release assay, chest radiograph, antinuclear antibody, and urinalysis; sacroiliac imaging when back pain.
• CT or MRI orbits with contrast for orbital cellulitis, proptosis, or suspected abscess. B scan ultrasound for posterior scleritis and endophthalmitis.
• Vitreous tap and intravitreal injection (by ophthalmology) for endophthalmitis. Blood cultures for orbital cellulitis and endogenous infection.
• Fluorescein dye test (Seidel test) for leaking wound.

Limitations. Intraocular pressure can be normal in intermittent angle closure. Corneal culture yield is limited when antibiotics have been given.

Acute angle closure (same day ophthalmology).

• Lie the patient supine.
• Acetazolamide 500 mg IV or orally, then 250 mg orally every 6 hours. Avoid in sulphonamide allergy, severe renal impairment and sickle cell disease.
• Timolol 0.5 percent 1 drop (avoid in asthma, heart block and bradycardia).
• Apraclonidine 1 percent or brimonidine 0.2 percent 1 drop.
• Pilocarpine 2 percent 1 drop every 5 minutes for 3 doses once pressure is falling (not in anterior chamber crowding with lens swelling).

Give analgesia and an antiemetic (ondansetron 4 mg IV, maximum 16 mg in a single dose; QT warning). Definitive laser peripheral iridotomy is by ophthalmology.

Bacterial keratitis and corneal ulcer. Same day ophthalmology: corneal scraping, then fortified topical antibiotics or fluoroquinolone monotherapy (ofloxacin 0.3 percent or moxifloxacin 0.5 percent). Give 1 drop every 15 to 60 minutes for the first 24 to 48 hours, then reduce. Add cycloplegia (cyclopentolate 1 percent 1 drop twice daily) for pain. Do not patch.

Fungal keratitis: natamycin 5 percent 1 drop every 1 to 2 hours (ophthalmology care).

Acanthamoeba: polyhexanide 0.02 percent and propamidine 0.1 percent by specialists.

Stop contact lens use and keep lens cases for culture.

Herpes simplex keratitis. Aciclovir 3 percent ointment 5 times daily or ganciclovir 0.15 percent gel 5 times daily until the ulcer heals and for at least 3 days after. Avoid topical steroids in epithelial disease. Oral valaciclovir 500 mg twice daily is prophylaxis for recurrent disease.

Herpes zoster ophthalmicus. Valaciclovir 1 g orally three times daily for 7 days, with eye lubricants and analgesia. Arrange same day ophthalmology review for keratitis and uveitis.

Adjust valaciclovir for kidney function: creatinine clearance 30 to 49 mL/min, 1 g every 12 hours; 15 to 29 mL/min, 1 g daily; under 15 mL/min, 500 mg daily.

Anterior uveitis. Ophthalmology: prednisolone acetate 1 percent drops (1 drop every 1 to 2 hours initially, tapered over 4 to 6 weeks) and cycloplegic drops (cyclopentolate 1 percent 1 drop twice to three times daily, or atropine 1 percent once daily for severe disease). Treat the systemic cause. Recurrent HLA-B27 uveitis: specialist systemic immunosuppression (adalimumab or sulfasalazine).

Corneal abrasion and foreign body. Use topical anaesthesia for examination only. Remove the foreign body, then give chloramphenicol 0.5 percent drops 4 times daily or ointment 3 to 4 times daily for 5 days (ofloxacin 0.3 percent in contact lens wearers). Add lubricants and oral analgesia (paracetamol 1 g every 4 to 6 hours, ibuprofen 400 mg every 6 to 8 hours). Review at 24 to 48 hours. No patching. Do not give topical anaesthetic drops for home use.

Chemical injury. Immediate irrigation with at least 1 to 2 L of normal saline or water (lid retraction) until pH is 7.0 to 7.4 (check after 5 minutes of rest), then same day ophthalmology review (more urgent for alkali).

Ultraviolet keratitis. Lubricants, cycloplegic drops, oral analgesia and review in 24 hours; recovery in 24 to 72 hours.

Scleritis. Same day ophthalmology and rheumatology. Give an oral NSAID (ibuprofen 400 mg three times daily or indometacin 25 to 50 mg three times daily with food, with gastric protection). For severe, necrotising or posterior disease, give prednisolone 1 mg/kg daily (maximum 60 to 80 mg) with immunosuppression. Search for vasculitis, rheumatoid arthritis and infection.

Endophthalmitis. Emergency ophthalmology: vitreous tap and intravitreal vancomycin 1 mg in 0.1 mL and ceftazidime 2.25 mg in 0.1 mL, with vitrectomy for severe loss of vision; systemic antibiotics for endogenous infection.

Orbital cellulitis. Admit.

Give ceftriaxone 2 g IV every 12 hours (children 50 mg/kg every 12 hours, maximum 2 g) plus metronidazole 500 mg IV every 8 hours (children 7.5 mg/kg every 8 hours).

Add vancomycin when meticillin resistant Staphylococcus aureus is possible: 25 to 30 mg/kg IV loading dose (maximum 3 g), then 15 to 20 mg/kg every 8 to 12 hours adjusted to creatinine clearance and levels.

Urgent CT; ophthalmology, ENT and, when intracranial extension, neurosurgical review.

Surgical drainage for abscess, or deteriorating vision or failure to improve in 24 to 48 hours.

Preseptal cellulitis. Amoxicillin with clavulanic acid 625 mg orally three times daily for 7 days (children 40 to 50 mg/kg amoxicillin component daily in 3 divided doses), with review at 24 to 48 hours; admit for systemic illness or any orbital sign.

Dacryocystitis. Warm compresses, amoxicillin with clavulanic acid 625 mg orally three times daily for 7 days, and ENT or ophthalmology referral for drainage.

Ruptured globe or penetrating injury. Rigid shield (no pressure), nil by mouth, tetanus prophylaxis, IV antibiotics (ceftazidime 1 g IV every 8 hours plus vancomycin 1 g IV every 12 hours), antiemetic, and emergency ophthalmology.

Pain control. Paracetamol 1 g orally every 4 to 6 hours (maximum 4 g in 24 hours), ibuprofen 400 mg orally every 6 to 8 hours with food (maximum 2.4 g in 24 hours), cycloplegic drops for keratitis and uveitis. Avoid topical NSAID and steroid drops without ophthalmology advice.

Monitoring. Same day ophthalmology review for all red flag conditions. Review at 24 to 48 hours for corneal abrasion and ulcer, and at 1 week for uveitis, with intraocular pressure monitoring during steroid treatment.

Referral and escalation. Immediate ophthalmology for any red flag. Rheumatology for scleritis and systemic disease associated with uveitis. Public health for outbreaks.

Admission criteria. Angle closure not settling, severe keratitis, endophthalmitis, orbital cellulitis, penetrating injury, necrotising scleritis, or systemic sepsis.

Discharge and safety netting. Advise on contact lens hygiene, avoidance of eye rubbing, and sun protection. Return for worsening pain, reduced vision, new discharge, photophobia, fever, headache, vomiting, or swelling of the eyelids.