In emergency medicine, ophthalmology in the ED usually means dealing with acute eye pain, red eye, visual disturbance or trauma. Most red eyes are benign (e.g. conjunctivitis), but a crucial minority are sight-threatening or life-threatening, such as acute angle-closure glaucoma, keratitis, uveitis, scleritis, orbital cellulitis and chemical injury. (Clinical Knowledge Summaries)


RCEMLearning and RCOphth emphasise that emergency eye care should rapidly identify “red flag” symptoms (sudden visual loss, severe pain, photophobia, trauma, distorted pupil, or systemic upset) and route those patients to specialist care early. (rcemlearning.co.uk)


For the FRCEM SBA, ophthalmology questions commonly test whether you can distinguish simple conjunctivitis from conditions that need urgent treatment or same-day ophthalmology review.


How Ophthalmology Appears in the FRCEM SBA Exam


Typical angles you’ll see:


  • Diagnosis / recognition
    • Differentiating benign conjunctivitis from acute angle-closure glaucoma, anterior uveitis, keratitis, scleritis. (Clinical Knowledge Summaries)
    • Recognising orbital cellulitis vs preseptal/periorbital cellulitis. (rcemlearning.co.uk)
    • Sudden painless monocular vision loss → CRAO, retinal detachment, vitreous haemorrhage.


  • Initial investigation choice
    • Visual acuity, pupillary reflexes, fields, fluorescein staining, IOP measurement (if safe), fundoscopy or slit lamp, CT orbit for suspected orbital cellulitis. (rcemlearning.co.uk)


  • First-line management
    • Immediate steps in chemical eye injury (prolonged irrigation, pH testing, urgent ophthalmology). (The Royal College of Ophthalmologists)
    • Managing acute angle-closure glaucoma, microbial keratitis, endophthalmitis, orbital cellulitis: analgesia, antiemetics, IV/ topical meds, and fast specialist referral.




Core Concepts You Must Know About Ophthalmology in the ED


We’ll focus on the red flag ophthalmology conditions examiners love: acute red eye differentials, orbital cellulitis, chemical injury, and sudden vision loss.


Definitions & Key Criteria


Red flag “acute red eye” causes (vs simple conjunctivitis) include: (Clinical Knowledge Summaries)


  • Acute angle-closure glaucoma (AACG) – sudden ↑ intraocular pressure with painful red eye, headache, N/V, haloes, mid-dilated fixed pupil, cloudy cornea. (Moorfields Eye Hospital)
  • Microbial keratitis / corneal ulcer – painful red eye, photophobia, reduced vision, focal corneal opacity or ulcer, usually in contact lens wearers or after trauma. (Clinical Knowledge Summaries)
  • Anterior uveitis (iritis) – unilateral painful red eye, photophobia, ciliary flush, small irregular pupil, sometimes hypopyon. (Clinical Knowledge Summaries)
  • Scleritis – severe boring eye pain often radiating to face/head, diffuse deep redness that does not blanch with topical vasoconstrictors; often associated with systemic autoimmune disease. (Clinical Knowledge Summaries)


Orbital vs preseptal cellulitis:

  • Orbital cellulitis – infection posterior to orbital septum: painful eye movements, proptosis, reduced vision, relative afferent pupillary defect, systemic upset; sight- and life-threatening. (rcemlearning.co.uk)
  • Preseptal cellulitis – eyelid erythema and swelling without orbital signs.


Chemical eye injury – alkali or acid in the eye, causing immediate burning, pain, red eye and photophobia; alkali burns penetrate deeper and are especially dangerous. (The Royal College of Ophthalmologists)


Sudden vision loss – CRAO, retinal detachment, vitreous haemorrhage, optic neuritis and ischaemic optic neuropathy are key ED considerations.


Assessment & Investigations


RCEMLearning and NICE CKS are very consistent on first steps: (rcemlearning.co.uk)


  • History red flags
    • Sudden onset of visual loss or field defect
    • Severe pain, photophobia
    • Trauma or chemical exposure
    • Contact lens use
    • Systemic features (fever, headache, neurological symptoms)
    • Recent eye surgery or intravitreal injection → concern for endophthalmitis. (The Royal College of Ophthalmologists)


  • Minimum ED eye exam
    • Visual acuity (with pinhole if necessary) – treat as a vital sign. (rcemlearning.co.uk)
    • Pupil reactions (RAPD), visual fields (by confrontation).
    • External inspection for swelling, asymmetry, proptosis, trauma.
    • Fluorescein staining for corneal defects / dendritic lesions.
    • Measure IOP (e.g. tonopen) only if no suspicion of globe rupture.
    • Fundoscopy / slit-lamp if available.


  • Orbital cellulitis suspected
    • FBC, CRP, blood cultures if systemically unwell.
    • Urgent CT orbit + sinuses ± contrast to assess for abscess or intracranial spread. (rcemlearning.co.uk)



Initial ED Management


General principles

  • ABCDE, analgesia, antiemetics.
  • Consider eye protection (shield) in trauma or suspected globe rupture.
  • Avoid topical anaesthetics for repeated use or discharge; they are for examination only.


Acute angle-closure glaucoma (Moorfields Eye Hospital)

  • Analgesia + antiemetics, keep patient supine with head elevated.
  • Start IOP-lowering regimen as per local protocol (e.g. topical beta-blocker and carbonic anhydrase inhibitor, plus systemic acetazolamide if no contraindication), and urgent ophthalmology referral for definitive management (e.g. laser iridotomy).


Microbial keratitis / corneal ulcer (Clinical Knowledge Summaries)

  • Stop contact lens use immediately.
  • Do not start steroid drops in ED.
  • Begin intensive topical antibiotics where protocol allows, and arrange urgent ophthalmology assessment (same-day).


Anterior uveitis / scleritis

  • Analgesia, avoid pupil-constricting drops; don’t start steroids unless directed by ophthalmology.
  • Same-day eye casualty review – especially with reduced vision or severe pain. (Clinical Knowledge Summaries)


Orbital cellulitis (rcemlearning.co.uk)

  • Admit, IV broad-spectrum antibiotics, analgesia, keep nil by mouth in case surgical drainage needed.
  • Urgent ENT/ophthalmology input, CT orbit/sinuses.
  • Close neuro and visual observations.


Chemical eye injury (The Royal College of Ophthalmologists)

  • This is one of the few true “don’t wait for clerk-in” emergencies.
  • Immediate and copious eye irrigation (e.g. 30–60 mins) with saline or water.
  • Check pH until normalised, evert lids and sweep fornices.
  • Analgesia, topical anaesthetic for exam, consider cycloplegic.
  • Urgent ophthalmology review once initial decontamination complete.


Red Flags and Pitfalls


From NICE CKS, College of Optometrists and RCOphth material, key red flags include: (Clinical Knowledge Summaries)

  • Sudden onset visual loss or field defect
  • Severe eye pain or headache, especially with nausea/vomiting
  • Photophobia, distorted pupil, cloudy cornea
  • Reduced eye movements, pain on movement, proptosis
  • Recent eye surgery or intravitreal injection with pain or reduced vision
  • Chemical injury or penetrating eye trauma


Classic pitfalls:

  • Assuming every red eye is conjunctivitis and missing glaucoma, uveitis or keratitis.
  • Treating contact-lens wearers with simple chloramphenicol for “conjunctivitis” when they actually have early microbial keratitis.
  • Labeling painful red eye with systemic symptoms as “preseptal cellulitis” without checking eye movements and vision.
  • Failing to irrigate chemical injuries immediately while waiting for ophthalmology.


Special Populations

  • Children – difficult exam; orbital cellulitis more common; low threshold for admission and imaging. (entuk.org)
  • Immunocompromised – higher risk of severe keratitis, endophthalmitis and orbital infection; early IV therapy and specialist input.


Common FRCEM SBA Traps Related to Ophthalmology


  • “Conjunctivitis” with photophobia & reduced VA
    • Trap: Dismissing red eye with photophobia as viral conjunctivitis.
    • Fix: Photophobia + reduced vision = red flag → consider keratitis or uveitis and refer.
  • Painful, hard red eye with headache & N/V
    • Trap: Diagnosing migraine.
    • Fix: This is classic angle-closure glaucoma; check IOP (if safe) and refer urgently. (Moorfields Eye Hospital)
  • Preseptal vs orbital cellulitis
    • Trap: Treating a patient with proptosis and painful eye movements as simple preseptal cellulitis with oral antibiotics.
    • Fix: Any orbital signs → emergency admission, IV antibiotics, CT and ENT/ophthalmology involvement. (rcemlearning.co.uk)
  • Delaying irrigation in chemical eye injury
    • Trap: Waiting for ophthalmology to assess before irrigating.
    • Fix: Irrigate first, ask questions later. Ophthalmology can’t reverse alkali damage that’s already been done. (The Royal College of Ophthalmologists)
  • Not checking visual acuity
    • Trap: Skipping VA because “the eye hurts too much”.
    • Fix: Visual acuity is the BP of ophthalmology – document it somehow (pinhole, near chart, even counting fingers).


High-Yield Clinical Patterns for Ophthalmology in the ED


Classic Presentation

1. Acute Angle-Closure Glaucoma

67-year-old woman with sudden severe right eye pain, blurred vision, haloes around lights and vomiting.VA: 6/60 right, 6/9 left; right cornea hazy, mid-dilated fixed pupil, very firm globe on palpation.

2. Orbital Cellulitis

9-year-old boy post recent sinusitis with swollen, red left eyelid, fever and malaise.VA slightly reduced, painful/restricted eye movements, mild proptosis, relative afferent pupillary defect.


Atypical Presentation

  • Older patient with “headache and nausea” who only later mentions a bad red eye.
  • Contact lens wearer with mild discomfort and subtle corneal infiltrate – early keratitis rather than conjunctivitis. (Patient)


Dangerous Mimics

  • Migraine vs angle-closure glaucoma – the red hard eye and haloes are the giveaway. (Moorfields Eye Hospital)
  • Viral conjunctivitis vs keratitis – keratitis has focal corneal staining and often more pain/photophobia. (Clinical Knowledge Summaries)
  • Preseptal cellulitis vs orbital cellulitis – think EOM pain, proptosis, reduced VA.


How to Revise Ophthalmology Efficiently for the FRCEM SBA


Use Question Banks First, Then Guidelines

  1. Do a block of ophthalmology SBAs: 
    • Acute red eye, orbital cellulitis, chemical injury, sudden visual loss.
  2. Then skim: 


Build Mini-Notes or Flashcards from Mistakes

For each eye SBA you get wrong, write:

  • Stem focus – “angle-closure glaucoma vs migraine”, “keratitis vs conjunctivitis”, “preseptal vs orbital”.
  • Your error – e.g. you ignored haloes, photophobia, or pain on eye movement.
  • One-liner rule
    • “Photophobia + reduced VA = refer.”
    • “Hard, mid-dilated red eye with haloes = AACG until proven otherwise.”
    • “Proptosis + painful eye movements = orbital cellulitis → IV antibiotics + CT.”


Mix Text-Based and Image-Based Questions

  • Use SBAs with slit-lamp photos (corneal ulcers, hypopyon, dendritic lesions) and fundus photos (retinal detachment, CRAO).
  • Mix in data and imaging (CT orbit, pH strips, visual acuity charts) to keep it realistic.


How StudyMedical Covers Ophthalmology in Its FRCEM SBA Question Bank


StudyMedical threads ophthalmology SBAs throughout Head & Neck, Neurology, Trauma and Resuscitation categories so they appear just like in the real exam:

  • Curriculum-mapped eye questions
    • Acute red eye differentials, orbital/periorbital cellulitis, chemical burns, globe injury, and sudden monocular visual loss – all written with full vitals and ED context.
  • Image-based SBAs
    • Red eye photos, slit-lamp pictures, simple CT orbit images and fundoscopy views to train pattern recognition under exam pressure.
  • Guideline-linked explanations
    • Explanations reference RCEMLearning, NICE CKS “Red eye”, RCOphth emergency eye care and College of Optometrists red-flag documents so you automatically align with UK practice. (rcemlearning.co.uk)
  • Targeted revision modes
    • You can drill new, incorrect, or flagged eye questions so that angle-closure, keratitis and orbital cellulitis move from “panic” to “pattern”.



FAQs About Ophthalmology in the FRCEM SBA


How often do ophthalmology topics appear in the FRCEM SBA?

Not every paper is eye-heavy, but you can reliably expect a handful of questions on red eye, visual loss or orbital infection.

What’s the single most important thing to remember about ophthalmology for the exam?

Always distinguish benign red eye from sight-threatening red flag conditions by focusing on pain, photophobia, visual acuity, pupil, and eye movements.

Are there must-know guidelines or resources?

Yes:

How many ophthalmology-related questions should I do before the exam?

Aim for at least 20–30 focused eye SBAs, plus mixed acute medicine papers where red eyes and sudden visual loss crop up in broader vignettes.


Key Takeaways: Ophthalmology in the ED for FRCEM in 5 Bullet Points

  • Treat visual acuity as a vital sign in every eye presentation. (rcemlearning.co.uk)
  • Distinguish benign conjunctivitis from red-flag causes using pain, photophobia, VA, pupil, eye movements and history. (Clinical Knowledge Summaries)
  • Angle-closure glaucoma, keratitis, uveitis, scleritis, orbital cellulitis and chemical injuries all need urgent assessment and often same-day specialist care. (rcemlearning.co.uk)
  • Orbital cellulitis = proptosis, painful EOMs, systemic upset → IV antibiotics + CT + ENT/ophthalmology. (rcemlearning.co.uk)
  • The fastest way to pass eye questions is pattern recognition via SBAs, then consolidating with RCEM/NICE/RCOphth guidance.


Ready to Test Yourself on ED Ophthalmology?

Ophthalmology in the ED is high-yield, pattern-based and very passable once you know the red flags.

  • You don’t need to be an ophthalmologist – you just need to spot danger, start safe initial management and refer appropriately.
  • Repeated exposure to FRCEM-style SBAs turns messy red-eye presentations into quick, confident decisions.