Red Eye

  1. In addressing eye complaints, always assess visual acuity using history, physical examination, or the Snellen chart, as appropriate.
  2. In a patient with a red eye, distinguish between serious causes (e.g., keratitis, glaucoma, perforation, temporal arteritis) and non-serious causes (i.e., do not assume all red eyes are caused by conjunctivitis):
  3. Take an appropriate history (e.g., photophobia, changes in vision, history of trauma).
    1. Do a focused physical examination (e.g., pupil size, and visual acuity, slit lamp, fluorescein).
    2. Do appropriate investigations (e.g., erythrocyte sedimentation rate measurement, tonometry).
    3. Refer the patient appropriately (if unsure of the diagnosis or if further work-up is needed).
  4. In patients presenting with an ocular foreign body sensation, correctly diagnose an intraocular foreign body by clarifying the mechanism of injury (e.g., high speed, metal on metal, no glasses) and investigating (e.g., with computed tomography, X-ray examination) when necessary.
  5. In patients presenting with an ocular foreign body sensation, evert the eyelids to rule out the presence of a conjunctival foreign body.
  6. In neonates with conjunctivitis (not just blocked lacrimal glands or ‘‘gunky’’ eyes), look for a systemic cause and treat it appropriately (i.e., with antibiotics).
  7. In patients with conjunctivitis, distinguish by history and physical examination between allergic and infectious causes (viral or bacterial).
  8. In patients who have bacterial conjunctivitis and use contact lenses, provide treatment with antibiotics that cover for Pseudomonas.
  9. Use steroid treatment only when indicated (e.g., to treat iritis; avoid with keratitis and conjunctivitis).
  10. In patients with iritis, consider and look for underlying systemic causes (e.g., Crohn’s disease, lupus, ankylosing spondylitis).


  • Extra-ocular
    • Orbital cellulitis
    • Cavernous sinus thrombosis
    • Carotid-cavernous fistula
    • Cluster headache
  • External eye disease (Itchy pain improved by topic anesthetics, eye discharge, photophobia/blepharospasm, VA near-normal, preauricular lymphadenopathy)
    • Eyelid disease
    • Conjunctival disease
  • Internal eye disease (Severe deep-seated eye pain, impaired VA, poorly reactive pupils, abnormal slit lamp, abnormal IOP)
    • Iritis
    • Glaucoma


  • Painless
    • Diffuse
      • Eyelid abnormality (blepharitis, ectropion, entropion, trichiasis, eyelid lesion [eg. stye, tumour])
    • Localized redness
      • Pterygium, corneal foreign body, ocular trauma, subconjunctival hemorrhage
  • Painful
    • Eyelid
      • Chalazion/Stye, acute blepharitis, herpes zoster ophthalmicus
    • Diffuse Conjunctival Injection
      • Viral/allergic/bacterial conjunctivitis, dry eyes, acute glaucoma
    • Ciliary injection, scleral involvement
      • Scleritis
    • Cornea
      • Herpes simplex keratitis, corneal ulcer, marginal keratitis, corneal abrasion
    • Anterior chamber
      • Acute anterior uveitis (iritis), hypopyon, hyphema

Red Flags

  • Red Flags
    • Severe deep-seated eye pain
    • Vision loss/change
    • Prominent photophobia, circumcorneal conjunctival injection (Iritis, keratitis)
    • Cloudy cornea (keratitis, acute angle-closure glaucoma)
    • Cloudy anterior chamber, small irregular poorly-reactive pupil (Iritis)
    • Proptosis, Pain on eyeball palpation (Scleritis, orbital cellulitis, cavernous sinus thrombosis)
    • Impaired/painful EOM (orbital cellulitis)
    • Hyperpurulent discharge from an "angry" eye (Gonocooccal conjunctivitis. endophthalmitis)
    • Fixed mid-dilated pupil, increased IOP (acute angle-closure glaucoma)
  • Benign if
    • Cornea, anterior chamber clear
    • Pupils normal in size and reactive
    • Visual acuity (VA) normal or near-normal
    • EOM normal
    • Proptosis absent
    • Eyeball not tender on palpation


  • OPQRST, similar episodes (seasonal)
  • Decreased VA (acute vs. chronic)
  • Pain, foreign body sensation (if unable to open eye or keep it open = corneal invovlement)
  • History of trauma (chemical vs. foreign body)
  • Contact lens (risk for bacterial, pseudomonas or Acanthamoeba keratitis)
  • Sick contacts, recent respiratory illness
  • Discharge, tearing, crusting
  • Photophobia
  • Medications

Physical Exam

  • Preauricular lymph nodes
  • Eye exam
    • Visual acuity, Visual Fields
    • Pupils (normal 2-4mm, equallyreactive)
      • Photophobia in uveitis/keratitis (shine penlight at 15cm for two seconds)
      • Swinging flashlight test for afferent pupillar defect (optic neuritis)
      • Oblique flashlight test (positive in IOP>40mmHg, see image to the right)
    • EOM, alignment
    • Fluorescein stain, Wood lamp
    • Tonometry (IOP)
    • External exam (orbits, eyelid, lashes)
    • Anterior segment exam
      • Ciliary (perilimbal) flush suggests anterior chamber disease (uveitis)
      • Cornea haziness
      • Slit lamp for cell/flare, hyphema, hypopion
    • Posterior segment exam (fundoscopy)


  • MRI for optic neuritis
  • CT for orbital cellulitis
  • Ultrasound (usually in cases of vision loss r/o retinal detachment, not red eye)

Emergency Ophthalmology Consultation

  • Trauma and signs of hyphema or corneal penetration
  • Acute angle-closure glaucoma (Topical BB/cholinergic, Acetazolamide IV and Mannitol IV)
  • Orbital cellulitis (Blood cultures, IV Abx, CT orbit and paranasal sinus)
  • Infectious keratitis, scleritis
  • Anterior uveitis or iritis (cycloplegic)
    • Ciliary (perilimbal) flush, inflammatory cells in anterior chamber or hypopyon
  • Optic neuritis (high-dose steroids)
    • Painful loss of vision, positive RAPD

Note: Other causes of acute vision loss should be referred emergently (not covered in Red Eye) such as CRAO, temporal arteritis, retinal detachment)


Viral Conjunctivitis

  • Often associated with URI, Adenovirus highly contagious, HSV less likely to spread
  • Treatment:
    • Spontaneous remission 1-2w
    • Supportive, cold compresses, ocular decongestants, artificial tears
    • Strict hand washing/hygiene, avoid work if healthcare worker until eye discharge ceases
    • Refer if not resolved after 14d
  • Ophthalmology referral if
      • Herpes Zoster Ophtalmicus (vesicular eruption)
      • Herpes Simplex Virus (dendritic epithelial defect)

Bacterial Conjunctivitis

  • Spread through direct contact
  • Treatment
    • Antibiotic therapy in healthcare workers, immunocompromised, comorbidity, contact lens wearers, unreliable
      • Staph aureus in adults
      • Strep pneumoniae, H influenzae in children
    • Suspect chlamydial conjunctivitis if sexually active, do not respond
      • Treat with erythromycin ophthalmic ointment, and azithromycin 1g PO
    • Delay antibiotic therapy in patients willing as self-limiting
      • Follow-up at day 4 of symptoms, if not improved start antibiotics
        • Fucidin 1% ophthalmic 1 drop BID x 7 days
        • Erythromycin ointment 1.25cm QID x 5-7 days
      • If severe or contact lens, cover for pseudomonas
        • Ciprofloxacin 0.3% (or oflaxacin) QID x 5-7 days
  • Ophthalmology referral if
    • Hyperacute copious purulent discharge usually N. gonorrhea (see image to the right)
    • Chronic >4w bacterial conjunctivitis

Allergic Conjunctivitis

  • Atopy (allergic rhinitis, eczema, asthma)
  • Seasonal, itching
  • Treatment
    • Avoid exposure, artifical tear, topical antihistamine H1 antagonist
    • Olopotadine (Pataday) 0.2% 1 drop daily x 2w

Dry Eye (keratoconjunctivitis sicca)

  • Risk: Age, female, medications (anticholinergic)
  • Rule out Sjögren syndrome
  • Treatment
    • Artificial tears in day, lubricant ointments at night


  • Rule out seborrheic dermatitis or rosacea
  • Treatment
    • Indefinite eyelid hygiene, gentle lid massage, warm compresses

Corneal abrasion

  • Check for retained foreign body under upper eyelid
  • Treatment
    • Supportive
    • Topical NSAIDs (diclofenac 0.1% [Voltaren], ketorolac 0.4% [Acular LS] 1 drop QID x 2 days maximum)
    • Topical Antibiotic (erythromycin 0.5% opht oint, polymyxin B/trimethoprim (Polytrim) opht solution, and sulfacetamide 10% opht oint QID x 5d or until asymptomatic x 24h)
      • If contact lens wearer, cover for pseudomonas (Ciprofloxacin, Gentamicin, Ofloxacin)
        • Refer to opthalmology if corneal infiltrates
        • Close follow-up
        • Avoid contact lens until healed
        • Low threshold for referral
    • Ophthamology if
      • Symptoms worsen or do not resolve in 48h
      • Branching staining suggests HSV
      • Chemical or flash burns
      • Penetrated cornea, Positive Seidel test (surround leak site, see image to right)
    • AVOID topical anesthetics (delay healing, symptom masking), patching, cycloplegics

Subconjunctival hemorrhage

  • Rule out bleeding disorder
  • Treatment
    • Warm compresses, lubricants


  • Differentiate from scleritis (emergency)
    • Phenylephrine (2.5%) eye drops leads to swift, transient resolution of episcleral redness in episcleritis
    • Non-tender on palpation in episcleritis (tender in scleritis)
    • Pink-red in episcleritis (blue-purple hue in scleritis)
    • Radial pattern of sclera maintained in episcleritis (loss of radial pattern of sclera in scleritis)
  • Rule out systemic disease (RA)
  • Treatment
    • No treatment, self-limiting up to 3w
    • May consider symptomatic treatment with Topical lubricants, NSAIDs, steroids or Oral NSAIDs, steroids