MRCP Ophthalmology: Mastering Acute Red Eye Management Guidelines

MRCP Ophthalmology: Mastering Acute Red Eye Management Guidelines

The 'red eye' is a ubiquitous presentation in clinical practice, ranging from a benign irritation to a sight-threatening emergency. For medical students aiming for the Membership of the Royal Colleges of Physicians (MRCP) examination, a comprehensive understanding of acute red eye management is not merely an optional extra but a high-yield topic that frequently appears in both written papers (Part 1 and Part 2) and clinical stations (PACES).

As an examiner and seasoned medical professional, I've seen countless candidates struggle with distinguishing between the myriad causes of a red eye. The key to MRCP success lies in a structured, guideline-based approach, focusing on red flags, systemic associations, and initial appropriate management.

Why Acute Red Eye Matters for MRCP

Beyond basic ophthalmology, MRCP often tests your ability to:

1. Differentiate urgent from non-urgent conditions: Recognising sight-threatening emergencies is paramount.

2. Identify systemic associations: Many ocular conditions are manifestations of underlying systemic diseases (e.g., uveitis in autoimmune conditions, scleritis in rheumatoid arthritis).

3. Initiate appropriate first-line management: Knowing what to prescribe or what immediate steps to take before specialist referral.

4. Understand referral pathways: When and where to refer to ophthalmology.

The Diagnostic Algorithm: A Structured Approach

Approach every red eye presentation systematically. This framework will help you quickly narrow down differentials and manage effectively.

1. Key History Points

• Onset and Duration: Sudden or gradual? How long has it been red?

• Pain: Is it present? Character (gritty, burning, aching, sharp), severity, radiation. Severe pain is a red flag.

• Vision Changes: Any blurring, loss of vision, haloes around lights? Sudden vision loss is a red flag.

• Discharge: Watery, purulent, stringy? Unilateral or bilateral?

• Photophobia: Sensitivity to light. Severe photophobia is a red flag.

• Associated Symptoms: Headache, nausea/vomiting, fever, rash, joint pain, recent upper respiratory tract infection (URTI), history of trauma.

• Contact Lens Use: A significant risk factor for serious corneal infections.

• Previous Episodes: Recurrent red eye suggests chronic or autoimmune causes.

• Systemic Illnesses/Medications: Autoimmune diseases, diabetes, hypertension, immunosuppression.

2. Key Examination Points

Always perform a thorough eye examination. If possible, consider checking:

• Visual Acuity: Crucial baseline measurement. Always test both eyes, corrected if applicable.

• Pupil Reaction: Size, shape, direct and consensual light reflex. Fixed, mid-dilated pupil is a red flag (Acute Angle-Closure Glaucoma).

• Corneal Clarity: Look for haziness, ulcers, foreign bodies. Use fluorescein stain and a blue light (e.g., from an ophthalmoscope) to highlight corneal abrasions or ulcers.

• Conjunctival Injection Pattern:

  • Diffuse redness: Generalised, often more prominent peripherally (e.g., conjunctivitis).

  • Ciliary flush (limbal injection): Perilimbal redness, violaceous hue, suggests deeper inflammation (e.g., uveitis, keratitis, glaucoma). This is a major red flag.

• Anterior Chamber: Look for hypopyon (pus level) or hyphaema (blood level) – red flags!

• Palpation: Check for tenderness around the orbit or preauricular lymphadenopathy.

• Intraocular Pressure (IOP): If available and trained, measure IOP if glaucoma is suspected.

3. Red Flags – Immediate Ophthalmology Referral!

Memorise these critical indicators that warrant urgent referral:

• Severe eye pain

• Sudden or significant vision loss/blurring

• True photophobia (not just light sensitivity)

• Ciliary flush (circumcorneal redness)

• Corneal opacity or haziness

• Fixed or mid-dilated pupil

• Abnormal intraocular pressure

• Hypopyon or hyphaema

• Proptosis (bulging eye)

• Limited eye movements

• Associated systemic symptoms (e.g., severe headache, nausea, diplopia)

Common Causes & MRCP Focus: Guideline-Based Management

Let's break down the key conditions you need to know for MRCP:

1. Conjunctivitis:

   • Features: Diffuse redness, often bilateral, discharge (purulent for bacterial, watery for viral, stringy for allergic), usually no pain (gritty sensation), normal vision, no photophobia, no ciliary flush.

   • Management:

     • Bacterial: Topical broad-spectrum antibiotics (e.g., chloramphenicol drops/ointment) for 5-7 days. Good hand hygiene.

     • Viral: Supportive care (cold compresses, artificial tears). Highly contagious. Self-limiting.

     • Allergic: Topical antihistamines/mast cell stabilisers (e.g., olopatadine), oral antihistamines, cold compresses.

   • MRCP Tip: Differentiate based on discharge and systemic symptoms (viral often follows URTI).

2. Episcleritis vs. Scleritis:

   • Episcleritis: Localised/sectoral redness, mild discomfort, no vision change, blanches with topical phenylephrine. Often idiopathic, but can be associated with autoimmune conditions. Less serious.

     • Management: Self-limiting, artificial tears, oral NSAIDs if painful.

   • Scleritis: Severe, boring eye pain that radiates, violaceous hue, doesn't blanch with phenylephrine, may cause vision loss. Often associated with systemic autoimmune diseases (e.g., rheumatoid arthritis, SLE, vasculitis). Sight-threatening and a red flag.

     • Management: Urgent ophthalmology referral. Systemic NSAIDs, oral corticosteroids, or immunosuppressants. Requires investigation for underlying systemic cause.

   • MRCP Tip: Always ask about systemic disease history. Pain severity and colour of redness are key differentiators.

3. Acute Angle-Closure Glaucoma (AACG):

   • Features: Sudden onset severe eye pain, headache, nausea/vomiting, haloes around lights, blurred vision. Examination shows ciliary flush, steamy/hazy cornea, fixed mid-dilated pupil, and a firm globe (high IOP). Ophthalmological emergency.

   • Management:

     • Immediate medical therapy to lower IOP: Topical beta-blocker (e.g., timolol), topical alpha-agonist (e.g., brimonidine), topical pilocarpine (to constrict pupil), oral acetazolamide (500mg stat then qds).

     • Urgent ophthalmology referral for laser peripheral iridotomy.

   • MRCP Tip: Remember the triad: pain, vision loss, nausea/vomiting. The fixed mid-dilated pupil is pathognomonic.

4. Anterior Uveitis (Iritis/Iridocyclitis):

   • Features: Pain (aching), photophobia, blurred vision, ciliary flush, constricted pupil (miosis) which may be irregular due to posterior synechiae (adhesions to the lens), cells and flare in the anterior chamber (requires slit lamp). Often associated with systemic inflammatory diseases (e.g., HLA-B27 spondyloarthropathies, sarcoidosis, inflammatory bowel disease).

   • Management: Urgent ophthalmology referral. Topical cycloplegics (e.g., cyclopentolate) to relieve ciliary spasm and prevent synechiae. Topical corticosteroids to reduce inflammation. Systemic steroids may be needed for severe cases or underlying systemic disease.

   • MRCP Tip: Always look for systemic links. Photophobia is a strong indicator.

5. Corneal Ulcer/Keratitis:

   • Features: Moderate-to-severe pain, foreign body sensation, photophobia, blurred vision, ciliary flush. Often history of contact lens use, trauma, or foreign body. Fluorescein staining will show a defect (often with surrounding infiltrate).

   • Management: Urgent ophthalmology referral. Do not delay. Broad-spectrum topical antibiotics (e.g., levofloxacin, fortified cefazolin/gentamicin) are often initiated after cultures, but best guided by ophthalmology.

   • MRCP Tip: Always ask about contact lens use or trauma. Fluorescein is your friend.

When to Refer?

• Immediate/Same Day Referral: Any red flag condition (severe pain, vision loss, ciliary flush, corneal opacity, fixed pupil, high IOP, hypopyon/hyphaema, proptosis). This often means calling the on-call ophthalmologist directly.

• Urgent Referral (within 24 hours): Conditions that require specialist management but are not immediately sight-threatening (e.g., episcleritis with uncertain diagnosis, persistent conjunctivitis not responding to initial treatment).

• Routine Referral: For follow-up or conditions requiring non-urgent specialist opinion.

MRCP Hot Tips for Acute Red Eye Questions

• Part 1/2 Written: Expect multiple-choice questions on differentiating causes, identifying red flags, and initial management steps. Focus on systemic associations for uveitis and scleritis.

• PACES Stations: While a full ophthalmology station is unlikely, you might encounter an acute red eye scenario in an acute medical take station or a communication skills station (explaining findings, management, and referral to a patient). Be ready to elicit key history, identify red flags, and articulate your initial plan.

• Investigations: For conditions like uveitis or scleritis with systemic associations, remember to consider relevant blood tests (e.g., ANA, RF, ESR, CRP, HLA-B27) as part of your overall management plan.

Mastering acute red eye management is a critical skill for any physician, and certainly for those aspiring to MRCP. By adopting a structured approach, prioritising red flags, and understanding the nuances of each condition, you'll be well-equipped to ace your exams and, more importantly, provide excellent patient care.