Family medicine
Red Eye
Red eye is a common clinical sign characterized by hyperemia of the conjunctival, episcleral, or ciliary vessels due to a wide range of conditions including infection, inflammation, allergy, trauma, or elevated intraocular pressure.
Murtagh Diagnostic Strategy
| Category | Diagnosis | Key Discriminator | Cantonese Question / Finding |
|---|---|---|---|
| Probability Diagnosis | Viral conjunctivitis [1] | Bilateral, watery discharge, follicles, preauricular LN, recent URTI | 「兩隻眼都紅？有冇水汪汪？最近有冇傷風？」 |
| Bacterial conjunctivitis [1] | Unilateral → bilateral, mucopurulent discharge, morning crusting | 「朝早起身隻眼有冇實埋？有冇黃綠色嘢流出嚟？」 | |
| Allergic conjunctivitis [1] | Bilateral, intense itch, watery/stringy discharge, seasonal, hx of atopy | 「隻眼痕唔痕？轉季會唔會特別差？有冇鼻敏感？」 | |
| Dry eye syndrome | Gritty/sandy sensation, worse with screen use, no discharge | 「有冇覺得隻眼好乾、好似有沙入咗？」 | |
| Subconjunctival haemorrhage | Painless, bright red patch, no vision change, self-limiting [1] | 「隻眼一撻紅色但係唔痛唔矇？」 | |
| Serious Not To Miss | Acute angle-closure glaucoma (AACG) [1][2] | Severe pain, ↓VA, haloes, semi-dilated fixed pupil, hard eye, N/V | 「隻眼好脹好痛？睇嘢好矇？見到彩虹圈？有冇作嘔？」 |
| Anterior uveitis / iritis [1][4] | Pain, photophobia, ciliary flush, miotic pupil, cells/flare in AC | 「怕唔怕光？有冇關節痛？」(A/w HLA-B27, AS) | |
| Corneal ulcer / infective keratitis [1][2] | Contact lens wearer, pain, photophobia, white corneal infiltrate, ↓VA | 「有冇戴con？隻眼好痛、怕光、睇嘢矇？」 | |
| Scleritis [1] | Severe boring pain (wakes from sleep), violaceous hue, tender globe | 「隻眼半夜痛醒？隻眼摸落去痛？」(A/w RA, vasculitis) | |
| Gonococcal conjunctivitis | Hyperacute, copious purulent discharge, can perforate cornea rapidly | 「有冇大量黃膿流出嚟？有冇新嘅性伴侶？」 | |
| Orbital / pre-septal cellulitis [1] | Lid swelling, proptosis, pain on eye movement, fever | 「隻眼腫唔腫？有冇發燒？郁隻眼痛唔痛？」 | |
| Pitfalls | Episcleritis | Sectoral redness, mild discomfort (not severe pain), blanches with phenylephrine | 「隻眼一個位紅，少少唔舒服但唔係好痛？」 |
| Herpes simplex keratitis | Dendritic ulcer on fluorescein, unilateral, hx of cold sores, ↓corneal sensation | 「之前有冇生過唇瘡？」Fluorescein: dendritic ulcer | |
| Herpes zoster ophthalmicus | Vesicular rash V1 dermatome, Hutchinson's sign (nose tip) | 「額頭或者鼻尖有冇出水泡？」 | |
| Foreign body (subtarsal) | Persisting FB sensation after apparent removal, must evert upper lid | 「有冇覺得仲有嘢喺入面？」→ Evert lid | |
| Masquerades | Drugs (topical) | Preservative toxicity, self-medication with steroid drops | 「有冇自己買眼藥水用？」 |
| Diabetes | Immunocompromised → atypical infections; diabetic rubeosis iridis | 「有冇糖尿？」 | |
| Trying to Tell Me Something? | Anxiety about blindness / cancer | Fear of serious disease, need reassurance | 「你最擔心係咩？」「有冇擔心係嚴重嘅病？」 |
| Cosmetic / work concern | Red eye affecting social or work function | 「隻眼紅有冇影響你返工或者見人？」 |
| Time | Task | Cantonese Key Phrases | Why It Scores Marks |
|---|---|---|---|
| 0:00–0:30 | Greeting, rapport, open question | 「你好呀，我係X醫生，今日由我幫你睇。請問你點稱呼呀？」「今日咩嘢唔舒服呀？」 | Friendly opening, patient-centred start, interpersonal marks |
| 0:30–1:30 | HPI: characterise the red eye – onset, duration, uni/bilateral, pain, discharge, vision change, photophobia, trauma, contact lens | 「隻眼紅咗幾耐呀？」「一隻定兩隻？」「有冇眼痛呀？」「睇嘢有冇矇咗？」「有冇怕光？」「有冇嘢篤到隻眼？」「有冇戴con呀？」「有冇嘢流出嚟？」 | Systematically covers key discriminators for the major DDx |
| 1:30–2:30 | Red flags + targeted ROS – severity of vision loss, headache, N/V, haloes, recent URTI, joint pain, autoimmune Hx, STI exposure | 「有冇突然間睇唔到嘢？」「有冇頭痛、作嘔？」「睇燈有冇彩虹圈？」「最近有冇傷風感冒？」「有冇關節痛？」 | Screens acute glaucoma, iritis/uveitis, GCA, systemic associations |
| 2:30–3:30 | PMH, DHx, Allergy, FHx, Social Hx – DM, HTN, autoimmune, glaucoma FHx, eye drops, smoking, occupation, screen time | 「你有冇長期病㗎？」「食緊咩藥？」「有冇藥物敏感？」「屋企人有冇青光眼？」「你做咩工作㗎？」 | Completeness marks; identifies risk factors |
| 3:30–4:30 | ICE (Ideas, Concerns, Expectations) – uncover hidden agenda | 「你自己覺得點解隻眼會紅？」(Idea) 「你最擔心啲咩？」(Concern) 「你今日嚟最想我點樣幫你？」(Expectation) 「點解揀今日嚟睇呀？」(hidden agenda / trigger) | Core interpersonal marks; reveals RFC |
| 4:30–5:15 | Signpost → focused physical exam offer | 「我想幫你檢查下隻眼，可以嗎？」「我會睇下你隻眼紅嘅位置，瞳孔大細，同埋視力。」 | Shows structured approach; permission = interpersonal marks |
| 5:15–6:00 | Summarise, safety-net, close | 「總結返，你隻右眼紅咗三日，有少少痛同分泌物…我覺得最有可能係…不過我想排除幾個可能。」「如果隻眼突然間睇唔到嘢、好痛、或者怕光嚴重咗，一定要即刻去急症。」「你有冇其他嘢想問？」 | Summarising + safety-net + checking understanding = high marks |
Uncovering the hidden agenda: Ask 「點解揀今日嚟睇呀？」 or 「有冇咩特別嘢令你擔心？」. The symptom "red eye" may mask fear of blindness, worry about infection spreading to family, cosmetic concern before an event, or a contact-lens-related issue they feel guilty about.
| Domain | English Question | Cantonese Question | Why It Matters | If Positive, Think Of |
|---|---|---|---|---|
| Onset/Duration | When did it start? Sudden or gradual? | 「幾時開始紅㗎？突然定慢慢嚟？」 | Acute = infection/trauma/glaucoma; subacute = uveitis | Acute angle-closure glaucoma (AACG) if hyperacute |
| Laterality | One eye or both? | 「一隻定兩隻眼？」 | Bilateral → viral/allergic conjunctivitis; Unilateral → keratitis, uveitis, AACG | Bilateral + itch → allergic; bilateral + discharge → viral/bacterial |
| Pain character | Is it painful? Dull ache or sharp? Worse with eye movement? | 「痛唔痛？係脹痛定刺痛？郁隻眼痛唔痛？」 | Painful red eye = serious until proven otherwise [1] | Deep ache → AACG/uveitis; foreign-body sensation → corneal pathology; pain on movement → scleritis/optic neuritis |
| Vision change | Any blurred vision? | 「睇嘢有冇矇咗？」 | Reduced VA + red eye = must refer [1][2] | AACG, corneal ulcer, uveitis, endophthalmitis |
| Photophobia | Sensitive to light? | 「有冇怕光？」 | Key sign of anterior uveitis / keratitis [1] | Anterior uveitis, keratitis, corneal ulcer |
| Discharge type | Any discharge? What colour? Sticky? | 「有冇嘢流出嚟？咩色？實唔實？」 | Purulent → bacterial; watery → viral/allergic; stringy mucoid → allergic | Hyperacute purulent → gonococcal (emergency) |
| Haloes around lights | See rainbow rings around lights? | 「睇燈有冇見到彩虹圈？」 | Corneal oedema from ↑IOP | AACG |
| Headache / N&V | Headache? Nausea/vomiting? | 「有冇頭痛？有冇作嘔作悶？」 | Autonomic response to ↑IOP | AACG |
| Contact lens use | Do you wear contact lenses? Overnight? | 「有冇戴con？有冇戴住瞓？」 | Major RF for infective keratitis / corneal ulcer [1][2] | Pseudomonas keratitis, Acanthamoeba keratitis |
| Trauma / FB | Any injury or foreign body? Welding/grinding? | 「有冇嘢篤到？有冇做燒焊或者打磨？」 | Foreign body, corneal abrasion, penetrating injury [3] | Corneal FB, open globe injury, UV keratitis |
| Recent URTI | Recent cold or sore throat? | 「最近有冇傷風感冒？」 | Preceding URTI common in viral conjunctivitis and EKC | Adenoviral keratoconjunctivitis |
| Autoimmune / joint pain | Any joint pain? Back stiffness? Skin rash? Mouth ulcers? | 「有冇關節痛？腰骨僵硬？口瘡？皮膚出疹？」 | Screens for uveitis associated with AS, Behçet's, SLE, reactive arthritis [1][4] | Anterior uveitis (HLA-B27), Behçet's |
| STI exposure | (If appropriate) Any new sexual partner? Urethral discharge? | 「有冇新嘅性伴侶？有冇尿道分泌物？」 | Gonococcal/chlamydial conjunctivitis; reactive arthritis | Hyperacute purulent conjunctivitis; Reiter's syndrome |
| PMH | Diabetes? Autoimmune disease? Previous eye problems? Glaucoma? | 「有冇糖尿、免疫病？之前隻眼有冇問題？有冇青光眼？」 | DM → immunocompromised; prior uveitis → recurrence | Recurrent anterior uveitis |
| DHx | Any eye drops? Oral medications? Steroids? | 「有冇用眼藥水？食緊咩藥？有冇食類固醇？」 | Steroid eye drops → ↑IOP, infection; anticoagulants → subconjunctival haemorrhage | Drug-induced glaucoma |
| Allergy | Any allergies? Seasonal? Itchy? | 「有冇敏感？轉季會唔會痕？」 | Allergic conjunctivitis very common in HK | Allergic conjunctivitis, vernal keratoconjunctivitis |
| Occupation / hobbies | What is your job? Computer use? Outdoor? | 「你做咩工㗎？成日對住電腦？」 | Screen time → dry eye; outdoor/welding → UV keratitis, FB | Dry eye syndrome |
| Functional impact | Does it affect your work or daily life? | 「影唔影響你返工同日常生活？」 | Psychosocial and functional assessment for case report | Biopsychosocial problem |
Case Report Form Answer Builder
Write: "Red eye × [duration]"
High-yield HPI points to capture:
- Onset, duration, laterality
- Pain (character, severity), vision change, photophobia, discharge (type, colour)
- Trauma / contact lens / foreign body
- Associated symptoms: headache, N/V, haloes, URTI, joint pain
- Eye drops used / prior episodes
- Impact on vision and daily function
| Likely RFC Examples | How to Phrase |
|---|---|
| Worried about vision loss | "Patient concerned about decreasing vision in the affected eye" |
| Wants diagnosis | "Patient wants to know the cause of the red eye" |
| Wants treatment | "Patient wants eye drops / treatment for the red eye" |
| Fear of infection spreading | "Worried about spreading infection to family / other eye" |
| Cosmetic concern | "Patient embarrassed by red eye appearance before upcoming event" |
| Triggered by worsening | "Red eye not improving despite self-treatment, came today because of worsening" |
Best single answer: Use the patient's own words. E.g., "The patient is concerned that the persistent red eye may indicate a serious eye condition and wants a diagnosis and treatment."
| Component | Likely Content | Example Wording |
|---|---|---|
| Ideas | Thinks it is "heat" (熱氣), infection, allergy, or something serious | "Patient thinks the red eye is caused by an eye infection." |
| Concerns | Worried about blindness, cancer, spreading to children, needing surgery | "Patient is worried that the red eye may affect her vision permanently." |
| Expectations | Wants eye drops, referral to eye specialist, or reassurance | "Patient expects to receive eye drops and know if specialist referral is needed." |
For the typical FM exam station, the most likely diagnosis is usually one of:
- Viral conjunctivitis (if bilateral, watery discharge, recent URTI, preauricular LN)
- Bacterial conjunctivitis (if mucopurulent discharge, morning crusting)
- Allergic conjunctivitis (if bilateral itch, seasonal, atopy)
- Subconjunctival haemorrhage (if painless bright red patch, no discharge, no vision change)
Minimum supporting evidence: laterality + discharge type + pain/vision/photophobia status + relevant history.
High Yield from GC Lecture: The lecture distinguishes red eye by: painless vs painful, vision affected vs not affected, and pattern of injection (diffuse conjunctival vs ciliary flush). Use these three discriminators to choose your most likely diagnosis. [1]
| DDx | One Key Discriminator |
|---|---|
| Acute angle-closure glaucoma | Semi-dilated fixed pupil + raised IOP + haloes + severe pain + N/V [1][2] |
| Anterior uveitis (iritis) | Ciliary flush + miotic pupil + photophobia + cells/flare in anterior chamber [1][4] |
| Corneal ulcer / infective keratitis | Contact lens wearer + white corneal opacity + pain + photophobia + ↓VA [1][2] |
(Adjust to match the specific scenario presented — these are the three "must not miss" serious DDx for a painful red eye.)
| Domain | Example Problem |
|---|---|
| Biological | Painful red eye with risk of vision-threatening cause requiring urgent assessment |
| Psychological | Anxiety about possible permanent vision loss / fear of blindness |
| Social / Functional | Unable to work (e.g., screen-based occupation) or care for children due to eye symptoms; concern about infecting household contacts |
| Diagnosis / DDx | Best Supporting Physical Sign | How to Elicit | Why It Supports This Diagnosis |
|---|---|---|---|
| Viral conjunctivitis (most likely) | Follicles on inferior tarsal conjunctiva + preauricular lymphadenopathy [1] | Evert lower lid → look for small elevations; palpate preauricular LN | Follicular reaction + LN = viral aetiology; bacterial has papillae not follicles |
| Bacterial conjunctivitis | Mucopurulent discharge with papillary conjunctival reaction | Inspect discharge on lids/lashes; evert lower lid for papillae | Purulent discharge distinguishes from viral (watery) |
| Allergic conjunctivitis | Papillae on upper tarsal conjunctiva (cobblestone appearance in severe vernal) [1] | Evert upper lid → giant papillae | Papillae + chemosis + itch = allergic |
| AACG | Semi-dilated, fixed, non-reactive pupil + hard globe on palpation [1][2] | Compare pupil size and reactivity bilaterally; gently palpate globe through closed lid | Fixed mid-dilated pupil + stony hard eye = raised IOP = AACG |
| Anterior uveitis | Ciliary flush (circumcorneal injection) + miotic pupil [1][4] | Inspect injection pattern (perilimbal > peripheral); check pupil size | Ciliary flush = deep vessel involvement; small irregular pupil = posterior synechiae |
| Corneal ulcer | White corneal infiltrate / opacity visible on penlight; fluorescein uptake [1][5] | Penlight oblique illumination → white spot on cornea; fluorescein + blue light → green staining | Corneal staining confirms epithelial defect; white infiltrate = active infection |
| Scleritis | Violaceous (bluish-red) hue that does not blanch with 2.5% phenylephrine [1] | Apply topical phenylephrine → episcleritis blanches, scleritis does not | Distinguishes scleritis (serious, a/w systemic disease) from benign episcleritis |
| Subconjunctival haemorrhage | Sharply demarcated bright red area, no other signs | Inspect — flat, blood-red patch with clear borders | Benign; no pain, no discharge, no vision change = reassurance |
Must-Not-Miss Red Flags – Refer Urgently
- Reduced visual acuity in the red eye [1][2]
- Severe eye pain (especially deep/boring)
- Photophobia (suggests corneal or uveal involvement)
- Fixed semi-dilated pupil (AACG until proven otherwise)
- Corneal opacity / white spot (corneal ulcer – same-day ophthalmology)
- Hypopyon (pus level in anterior chamber – endophthalmitis / severe uveitis)
- Proptosis + restricted eye movements (orbital cellulitis – admit)
- History of penetrating trauma or high-velocity injury (open globe – do NOT press on eye)
- Hyperacute purulent discharge (gonococcal – can perforate cornea in 24h)
- Vesicular rash on nose tip (Hutchinson's sign) → HZO – urgent antiviral + ophthalmology [3]
Top traps that lose marks:
| Trap | How to Avoid |
|---|---|
| Assuming all red eyes are conjunctivitis | Always check VA, pupil, and pain character |
| Forgetting to ask about contact lens use | Contact lens + red eye = keratitis until proven otherwise [1][2] |
| Missing AACG because patient reports "headache and nausea" instead of "eye pain" | Always ask about haloes and check pupil |
| Not asking about trauma or foreign body | Subtarsal FB is a classic pitfall — must evert lid |
| Prescribing steroid drops without ophthalmology review | Steroids contraindicated in herpes simplex keratitis and infective keratitis — can cause perforation |
| Forgetting to elicit ICE | Core marks in both consultation and case report |
| Writing "eye infection" as diagnosis instead of specific entity | Write "acute bacterial conjunctivitis" or "viral conjunctivitis" — be specific |
Safety-net closing line (Cantonese): 「如果隻眼突然間睇唔到嘢、好痛、好怕光、或者越嚟越腫，你要即刻去急症室。」
High Yield Summary
What to ASK: Pain? Vision change? Photophobia? Discharge type? Contact lens? Trauma? Haloes/N&V? URTI? Joint pain? ICE + hidden agenda.
What to WRITE on the Case Report:
- Chief complaint: "Red eye × [duration]" with key HPI features
- RFC: Use patient's own words — usually fear of vision loss or wanting treatment
- ICE: Specific ideas (infection? allergy?), concern (blindness?), expectation (eye drops? referral?)
- Most likely Dx: Usually conjunctivitis (viral/bacterial/allergic) or subconjunctival haemorrhage in FM
- 3 DDx: AACG, anterior uveitis, corneal ulcer (for painful) OR episcleritis, dry eye, allergic (for painless)
- 3 biopsychosocial: Bio (eye pathology + risk), Psych (anxiety re vision), Social (work/function/infection spread)
- Physical sign: Pattern of injection + pupil + discharge type + VA
What NOT to MISS: Any red eye with reduced VA, severe pain, or photophobia = urgent ophthalmology referral same day. [1][2]
Active Recall - Family Medicine Clinical Test
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