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).

DDx

• 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

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

History

• 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

Imaging

• 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)