Red eye & eye pain: documentation that holds up

Most red eyes are conjunctivitis — but a handful threaten vision within hours, and the chart that just says "pink eye, drops" is the one that doesn't hold up. The defensible note records the visual acuity, the fluorescein exam, the contact-lens history, and that the vision-threatening causes were considered before a benign label.

01What's at stake

The dangerous red eye announces itself with pain, photophobia, reduced vision, or a contact-lens history — not with itch and discharge. Acute angle-closure glaucoma blinds through pressure, a corneal ulcer through infection (and a contact-lens wearer is a Pseudomonas ulcer until proven otherwise), endophthalmitis after surgery or injection, and orbital cellulitis through the orbit. Visual acuity is the vital sign of the eye — its absence from the chart is the recurring failure.

02Can't-miss diagnoses

• Acute angle-closure glaucoma — severe pain, headache/vomiting, halos, a mid-dilated fixed pupil, a hard eye; check intraocular pressure. → measure IOP
• Corneal ulcer / keratitis — pain, photophobia, a fluorescein-staining infiltrate; contact-lens wear is the classic risk. → fluorescein
• Endophthalmitis — pain and vision loss after intraocular surgery, injection, or penetrating trauma → emergent ophthalmology.
• Orbital (vs preseptal) cellulitis — pain with eye movement, proptosis, ophthalmoplegia, decreased vision → CT, IV antibiotics, ophthalmology.
• Iritis/uveitis (ciliary flush, photophobia, consensual photophobia), scleritis, and herpetic keratitis (dendrite, hypoesthesia).

03History & exam

• Visual acuity in each eye — the single most important measurement; reduced acuity moves the eye out of the "benign" category. → document VA
• Pain (vs gritty/itchy), photophobia, halos, discharge type, contact-lens wear, trauma, prior surgery/injection.
• Fluorescein for abrasion/ulcer/dendrite; pupil size/reactivity; ciliary flush; intraocular pressure when angle closure is possible.
• Penlight/slit-lamp: hypopyon, hyphema, infiltrate; extraocular movements and proptosis for orbital disease.

04Workup & management

• Acute angle-closure: IOP-lowering therapy (topical + acetazolamide) and emergent ophthalmology.
• Corneal ulcer: topical antibiotics, no patching of a contact-lens-related ulcer, urgent ophthalmology; cover Pseudomonas in lens wearers.
• Endophthalmitis / orbital cellulitis: emergent ophthalmology; CT and IV antibiotics for orbital cellulitis.
• Iritis: cycloplegia and topical steroids in conjunction with ophthalmology.
• Conjunctivitis / abrasion / subconjunctival hemorrhage: supportive care, contact-lens counseling, and clear ophthalmology follow-up; never prescribe topical anesthetics for home use.

05What to document

06Where charts fail

• No documented visual acuity — the eye's vital sign.
• Calling a painful, photophobic, or vision-reduced eye "conjunctivitis."
• Missing the contact-lens ulcer (no fluorescein, patched the eye, no Pseudomonas coverage).
• Not measuring IOP in a painful red eye with headache/vomiting and halos.
• Missing orbital cellulitis (pain with eye movement, proptosis) or prescribing topical anesthetics for home use.

07Sources

• Cronau H, Kankanala RR, Mauger T. Diagnosis and management of red eye in primary care. Am Fam Physician. 2010;81(2):137-144.
• Gilani CJ, Yang A, Yonkers M, Boysen-Osborn M. Differentiating urgent and emergent causes of acute red eye for the emergency physician. West J Emerg Med. 2017;18(3):509-517.
• American Academy of Ophthalmology. Conjunctivitis Preferred Practice Pattern. Ophthalmology. 2019.
• Tarff A, Behrens A. Ocular emergencies: red eye. Med Clin North Am. 2017;101(3):615-639.

© 2026 Kim Trinh, MD. All rights reserved. Educational only — synthesized from primary literature and guidelines. Synthetic examples. Not medical advice — apply local protocol and judgment.