aka Ophthalmology Befuddler 002
Things are humming along nicely in the ‘Fast track’ area of the emergency department. You check the triage note of the next patient – RED EYE is written capitals.
Photo by PeterPan23 (Click image for source)
Questions
Q1. There are many causes of ‘red eye’ — how can they broken down as an approach to diagnosis and management?
Of course there are myriad ways of doing this. I like Jeff Mann’s approach — he has a simple way of breaking the causes down into 3 groups:
- extra-ocular causes
(e.g. orbital cellulitis, cavernous sinus thrombosis, carotid-cavernous fistula, cluster headache)- external eye disease
(e.g. eye lid and conjunctival disease)- internal eye disease
(e.g. iritis, glaucoma)
Once an extra-ocular cause is excluded (this will be discussed in a later post), a helpful approach is to divide up the causes of red eye as follows:
- Painless — is there diffuse or localised redness?
- Painful?
The next step is to consider which structures are abnormal:
- Lid, conjunctiva, cornea, sclera, or anterior chamber?
This approach gets you off to a good start in narrowing down the causes of a red eye.
Q2. What are the causes of a painless red eye?
These can be classified according to whether the redness is diffuse or localised.
- diffuse —
usually this is an eyelid abnormality as most cases of conjunctivitis are painful: e.g. blepharitis, ectropion, trichiasis, entropion, eyelid lesion (e.g. tumour, stye) - localised —
e.g. pterygium, corneal foreign body, ocular trauma, subconjunctival hemorrhage
If you’re stuck for a differential diagnosis, fall back on working through the anatomical components of the eye and running through a pathophysiological sieve.
Q3. What are the causes of a painful red eye?
These can be classified according which structure is abnormal:
- abnormal cornea —
e.g. herpes simplex keratitis, corneal ulcer, marginal keratitis, corneal abrasion, - abnormal eyelid —
e.g. chalazion/ stye, acute blepharitis, herpes zoster ophthalmicus - diffuse conjunctival injection —
e.g. viral conjunctivitis, allergic conjunctivitis, bacterial conjunctivitis, dry eyes, acute glaucoma - ciliary injection/ scleral involvement —
e.g. scleritis - anterior chamber involvement —
e.g. acute anterior uveitis (iritis), hypopyon, hyphema
Q4. What 4 features usually suggest an internal cause of a red eye?
- severe eye pain (unrelieved by topical anesthetics)
- impaired vision
- poorly reactive pupils
- abnormal slit lamp examination +/- abnormal intra-ocular pressure
Q5. What 6 features on history and exam suggest an external cause for red eye?
- pain sensation is usually itching, gritty, scratching, or burning
(not a deep-seated ache) - pain is significantly improved by topical anesthetics
- eye discharge is common
(watery, mucoid or purulent depending on etiology) - photophobia and blepharospasm may be present
- visual acuity is usually normal or near-normal
(there may be some blurriness) - preauricular lymphadenopathy may be present
(e.g. viral or chlamydial conjunctivitis)
Q6. What 7 features on exam should be present if the cause of a red eye is not serious?
- cornea clear
- anterior chamber clear
- pupils normal in size and reactivity
- visual acuity normal or near-normal
- extraocular eye movements normal
- proptosis absent
- eyeball is not tender on palpation
Q7. What is the likely diagnosis of a red eye in a middle-aged woman with the following findings?
- mid-dilated unreactive pupil, steamy cornea, peri-orbital pain , nausea/vomiting and increased intra-ocular pressure
angle closure glaucoma - small irregular pupil, deep-seated eye pain that is worse on eye movement and accomodation, consensual photophobia and positive slit lamp signs of flare and cells
iritis - deep-seated eye pain that is worse at rest and at night, pain on palpation of the eye and violaceous appearance of the sclera
scleritis - proptosis, congested chemosis, painful external ophthalmoplegia, and visual loss with a relative afferent pupillary defect
orbital cellulitis or cavernous sinus venous thrombosis
Q9. What potentially serious causes of a red eye are suggested by the following features on history or examination?
- Severe eye aching
Iritis, keratitis, acute angle-closure glaucoma, scleritis, orbital cellulitis, cavernous sinus thrombosis (CST) - Prominent photophobia
Iritis, keratitis - Impaired vision
Iritis, keratitis, acute angle-closure glaucoma, orbital cellulitis, CST - Cloudy cornea
Keratitis, acute angle-closure glaucoma - Corneal opacification
Keratitis – chemical or infectious - Circumcorneal conjunctival injection
Iritis, keratitis - Cloudy anterior chamber
Iritis - Pain on eyeball palpation
Scleritis (+++), orbital cellulitis, CST - Proptosis
Orbital cellulitis, CST, posterior scleritis - Impaired, or painful, extraocular eye movements
Orbital cellulitis - Fever, toxic appearance
Orbital cellulitis (+), CST (++) - Hyperpurulent discharge from an “angry” eye
Gonococcal conjunctivitis/endophthalmitis - Prominent nausea and vomiting
Acute angle-closure glaucoma - Small, irregular, poorly-reactive pupil
Iritis - Fixed mid-dilated pupil
Acute angle-closure glaucoma - Increased intra-ocular pressure
Acute angle-closure glaucoma, iritis (secondary complication) - History of connective tissue disease, or granulomatous disease
Iritis, scleritis
References
- Ehlers JP, Shah CP, Fenton GL, and Hoskins EN. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease (5th edition). Lippincott Williams & Wilkins, 2008.
- Jeff Mann’s EM Guidemaps. Red eye. [many of the Q&A's in this post are a rearrangement of the major learning points from this web page]
- Mahmood AR, Narang AT. Diagnosis and management of the acute red eye. Emerg Med Clin North Am. 2008 Feb;26(1):35-55, vi. PMID: 18249256.
- Marx JA, Hockberger R, Walls RM. Rosen’s Emergency Medicine: Concepts and Clinical Practice, 7th edition (2009) Mosby, Inc. [mdconsult.com]
- NSW Statewide Opthalmology Service. Eye Emergency Manual — An illustrated Guide, 2007. [link to free pdf]
About Chris Nickson
this is a conscise and excellent approach to red eye
I am a little confused about the painful/not painful classification. In my med school and my textbooks it says conjunctivitis on its own is NOT painful. Thus, if there is any pain, another structure, usually the cornea is involved too. Here you mention conjunctivitis under “painful red eye”.
Can you comment on that?
Excellent posts btw! Thanks for all the great works!
Conjunctivitis typically results in an uncomfortable gritty sensation on the surface of the eye.
Is this pain, is is it not pain?… that is the question.
Perhaps pain is in the eye of the beholder…
C
Guess you’re right. Thanks for clearing that up.
By the way, I found a way to access Jeff Mann’s EM Guide Map’s:
http://web.archive.org/web/20050305154008/http://emguidemaps.homestead.com/JeffMannEMguidemaps.html
It might not be the newest version, but still worth to read.