Painful Red Eye Station
Author – Dr Aditi Arya Editor – Dr Daniel Arbide
Last updated 20/06/2025
Table of Contents
How to Use
Candidate:
- Read the brief below (1 minute).
- Take a brief history and perform a focused examination (7 minutes).
- Answer the viva questions (3 minutes).
Patient/Examiner:
- Familiarise yourself with the history & examination findings
- After completing the history, EITHER viva the candidate OR act as the patient
Candidate Brief
A 62 y/o woman named Katherine Wu (likes to be called Katie) presents to the emergency department with a severely painful and red left eye.
Please take a history, perform a focused examination of the eye and answer the subsequent questions.
Presenting complaint:
Painful red eye
Symptoms:
- Site: Left eye
- Onset: Started suddenly, over a matter of minutes, while watching TV
- Character: Sharp, throbbing pain all over the eye
- Radiation: Radiates through head with associated headache
- Associated Symptoms: Nausea, she has vomited 3 times since the onset of her symptoms, associated throbbing headache. She is struggling to see with her left eye
- Timing: 1 hour since onset of her symptoms
- Exacerbating and Relieving Factors: Nothing is making the pain better
- Severity: 9/10 pain
Other relevant positive and negative findings:
- No history of any injury to the eye
- This has never happened before
- Her eye is red & watering but not exuding pus. Mild swelling present
- Her vision has become more blurry in her left eye and she is struggling to look at bright light
- If asked about if she sees halos around lights: yes
- No eye grittiness/dryness
- No eye itching
- No flashes or floaters in vision
- No “curtain coming down” on vision
- She wears glasses and has a number of +2.25 in her R eye and +2.50 in her L eye. (Hypermetropia)
Systemic Symptoms:
- Fatigue: None
- Fever: None
- Night Sweats: None
- Unintended Weight Loss: None
- Chest or Shoulder Tip Pain: None
- Shortness of Breath or Cough: None
- Oedema: None
- Rashes or Skin Changes: None
- Headache: 9/10 severe headache, throbbing, constant
- Mood Changes: None
- Sleep Disturbances: None.
- Change in Bowel Habits: None
- Urinary symptoms: None
Past Medical History:
- Migraines since she was in her early 20s
- Eczema
- No other relevant PMHx
Drug History:
- Amitriptyline
- Uses over-the-counter 1% hydrocortisone for eczema, in addition to emollients
Allergies:
- NKDA
Family History:
- Patient’s mother had migraines
Social History:
- Occupation: She trained as an accountant but has now reduced her work duties to spend more time with her grandchildren.
- Lifestyle: She tries to stay active and does regular yoga. Eats balanced meals as much as she can, usually containing big portions of cooked and raw vegetables, meat and fish.
- Activities of Daily Living & Hobbies: Very active, doing well for her age, goes on 20km walks with her friends every weekend in the countryside.
- Pets at home: A cat named Cindy.
- Smoking: Never smoked.
- Alcohol: Occasionally drinks alcohol socially, perhaps 1 or 2 cocktails at a bar with her friends every other month.
- Recreational Drug Use: Never done.
Ideas, Concerns, and Expectations:
- Ideas: “I have no idea what is going on doctor, this has never happened before!”
- Concerns: “I am concerned that I may lose my vision in my left eye.”
- Expectations: ”Please help me doctor, please give me some medication to make this stop!”
Observations:
- Respirations (Breaths/min): 15
- Oxygen Saturation (%): 99%
- Air or Oxygen?: Air
- Blood Pressure (mmHg): 110/67
- Pulse (Beats/min): 100
- Consciousness (AVPU): A
- Temperature (Celsius): 37.1
NEWS Total Score: 2
Eye Examination:
General Inspection
- Patient appears unwell and in visible discomfort.
- Sitting with eyes partially closed, avoiding bright light (photophobia).
- Left eye appears red, congested, watery and mildly swollen with corneal oedema.
Inspection with Pen Torch
Author: Jonathan Trobe, M.D. Source: The Eyes Have It. Wikimedia Commons. CC BY 3.0.
- Left eye: Ciliary injection, hazy (oedematous) cornea, shallow anterior chamber (crescentic shadow seen on oblique lighting).
- Right eye: No abnormal findings; deeper anterior chamber noted.
Pupillary Assessment
- Left pupil: Mid-dilated, fixed, sluggish response to light.
- Right pupil: Normal size, round, brisk direct and consensual responses.
- No relative afferent pupillary defect (RAPD) noted.
Visual Acuity (VA)
Unaided:
- Left eye (OS): Markedly reduced – able to count fingers at 1 metre.
- Right eye (OD): Slightly reduced – 6/9 unaided.
With correction (spectacles):
- Left eye: No significant improvement due to corneal oedema.
- Right eye: Improves to 6/6 with +2.25D hyperopic correction.
Visual Fields
- Gross confrontation fields appear normal in the right eye.
- Unable to reliably assess the left eye due to pain and visual impairment.
Eye Movements
- Full range of movement in both eyes.
- No diplopia.
- Movements are painful in the left eye, particularly on elevation.
Fundoscopy
- Left eye: Fundus view obscured due to corneal oedema.
- Right eye: Normal optic disc with sharp margins, healthy macula and vessels.
Intraocular Pressure (if measured)
- Left eye: Elevated intraocular pressure (e.g. >50 mmHg).
- Right eye: Normal intraocular pressure.
Patient Questions:
1. “Doctor, what is happening to me?”
Exemplar answer: “You’ve had a sudden increase in pressure inside your left eye, which is causing pain and blurred vision. This condition is called acute angle closure glaucoma, and it needs urgent treatment — which we’ve already started — to protect your sight.”
2. “Could this have been prevented by me? I try to stay healthy . I don't know what happened!”
Exemplar answer: “You’ve done nothing wrong. This condition can happen to healthy people, especially those with certain eye shapes, like being long-sighted. It’s not something you could have predicted or prevented.”
3. “Will you be able to cure me?”
Exemplar answer: “With prompt treatment, we can relieve the pressure and prevent further damage. You may need a laser procedure to stop this from happening again. While we can’t undo any damage already done, we’re doing everything we can to protect your vision going forward.”
Examiner Questions:
1. What is the most likely diagnosis?
Acute angle closure glaucoma
2. Name 4 risk factors from the history for AACG
Possible answers:
- Increased age
- East asian or Inuit ethnicity
- Female
- Use of medication that can induce angle narrowing, such as amitriptyline
- Far-sightedness (hypermetropia)
- Shallow anterior chamber
3. How would you differentiate AACG from anterior uveitis?
AACG presents with high intraocular pressure, a mid-dilated fixed pupil, and corneal oedema, whereas anterior uveitis typically shows a small, irregular pupil with photophobia and may have keratic precipitates on slit lamp examination. Intraocular pressure in uveitis may be normal or low initially, with an open angle on gonioscopy.
4. What is the role of pilocarpine in AACG and when should it be given?
Pilocarpine is a miotic agent that constricts the pupil and pulls the iris away from the trabecular meshwork, helping open the drainage angle. However, it should only be used after intraocular pressure begins to fall, as a very high IOP may render the iris ischaemic and unresponsive.
5. What are the main investigations required?
Diagnostic Tests:
- Fundoscopy: To rule out conditions such as optic neuritis. May show evidence of damage to the optic nerve due to raised pressure, e.g. large optic cup and nerve fibre loss.
- Findings in this case: corneal oedema.
- Slit lamp examination: To rule out other conditions causing acutely painful red eye such as anterior uveitis.
- Findings in this case: Conjunctival injection, cloudy cornea, shallow anterior chamber, mid-dilated, fixed pupil.
- Goldmann applanation tonometry: measures intraocular pressure, would show raised IOP in conditions such as acute angle closure glaucoma.
- Findings in this case: Pressure of 51mmHg (normal 10-21mmHg)
- Gonioscopy: to measure angle closure (GOLD STANDARD diagnostic test)
- Findings in this case: closed angle seen.
- Retinal optical coherence tomography: Can be used to assess loss of nerve tissue in and around the optic nerve objectively and quantitatively.
6. What are the differentials for AACG, and how would you differentiate between them?
Condition | Key Tests | Features to Rule Out |
Anterior uveitis (iritis) | Slit lamp (cells/flare) | Small, irregular pupil; photophobia; no raised IOP |
Conjunctivitis | Clinical exam | Diffuse redness; no pain or photophobia; normal vision and pupil; IOP normal; N+V atypical; open angle on gonioscopy |
Scleritis | Slit lamp with scleral exam | Severe pain and deep redness; no raised IOP; open angle on gonioscopy; anterior chamber depth normal |
Keratitis / Corneal ulcer | Fluorescein staining | Corneal epithelial defect; not typically N+V; not typically raised IOP; gonioscopy shows open angle, normal anterior chamber depth |
Endophthalmitis | Vitreous tap, B-scan ultrasound | Post-surgical or post-trauma; marked inflammation; visual loss |
Optic neuritis | Visual evoked potentials, MRI | Pain on eye movement; RAPD; central vision loss; normal anterior segment and IOP; gonioscopy shows open angle |
7. Please elaborate on the management of AACG
Treatment:
- AACG is a sight-threatening emergency.
- It requires same-day ophthalmology referral and often hospital admission.
Immediate management:
- Lower intraocular pressure (IOP) rapidly: Lie the patient down on their back without a pillow.
- Pilocarpine eye drops
- Acetazolamide 500mg orally.
- Analgesia & anti emetics if required.
Medical management:
Medication | Route | Purpose | Source |
Acetazolamide (500 mg stat) | IV or oral | Carbonic anhydrase inhibitor to reduce aqueous production | NICE, Oxford, RCOphth |
Topical beta-blocker (e.g. timolol 0.5%) | Eye drops | Lowers IOP by reducing aqueous humour | NICE, Oxford |
Topical alpha-agonist (e.g. apraclonidine or brimonidine) | Eye drops | Reduces aqueous production and increases outflow | NICE, BMJ |
Topical prostaglandin analogue (e.g. latanoprost) | Eye drops | Increases uveoscleral outflow | RCOphth |
Topical pilocarpine (2%) | Eye drops (after IOP starts to fall) | Causes miosis to pull open angle | Oxford Handbook, RCOphth |
Analgesia and antiemetics (e.g. paracetamol, cyclizine) | Oral or IV | Symptom relief | NICE, Oxford |
Definitive treatment:
Procedure | Purpose | Source |
Laser peripheral iridotomy (LPI) | First-line definitive treatment: creates a hole in the peripheral iris to equalise pressure between chambers and open the angle | RCOphth, Oxford Ophthalmology, AAO |
YAG laser iridotomy (preferred method) | Performed in both eyes (prophylactic in the fellow eye) | BMJ Best Practice, NICE |
Lens extraction (phacoemulsification) | Considered if angle remains narrow or if lens-induced mechanism suspected | RCOphth, Oxford Ophthalmology |
Surgical iridectomy or drainage surgery | Rarely required unless refractory to laser | AAO, Oxford |
Management of the unaffected eye:
- Even if asymptomatic, the other eye is at high risk.
- Perform prophylactic laser iridotomy in the unaffected eye.
- BMJ Best Practice, 2024. Primary angle closure glaucoma. [online] Available at: https://bestpractice.bmj.com/ [Accessed 17 May 2025].
- Denniston, A. and Murray, P., 2018. Oxford Handbook of Ophthalmology. 4th ed. Oxford: Oxford University Press.
- Foster, P.J., Buhrmann, R., Quigley, H.A. and Johnson, G.J., 2002. The definition and classification of glaucoma in prevalence surveys. British Journal of Ophthalmology, 86(2), pp.238–242. doi:10.1136/bjo.86.2.238.
- Geeky Medics, 2024. Eye Examination – OSCE Guide. [online] Available at: https://geekymedics.com/eye-examination-osce-guide/ [Accessed 17 May 2025].
- National Institute for Health and Care Excellence (NICE), 2022. Glaucoma – Clinical Knowledge Summary. [online] Available at: https://cks.nice.org.uk/topics/glaucoma/ [Accessed 17 May 2025].
- Royal College of Ophthalmologists, 2021. Guidelines for the Management of Glaucoma. [online] Available at: https://www.rcophth.ac.uk/standards-publications-research/clinical-guidelines/ [Accessed 17 May 2025].
- Weinreb, R.N., Aung, T. and Medeiros, F.A., 2014. The pathophysiology and treatment of glaucoma: a review. JAMA, 311(18), pp.1901–1911. doi:10.1001/jama.2014.3192.
- Wilkinson, I.B., Raine, T., Wiles, K., Goodhart, A., Hall, C. and O’Neill, H., 2020. Oxford Handbook of Clinical Medicine. 10th ed. Oxford: Oxford University Press.