Red Eye Algorithm · Reasoning GP

1

Safety

Exclude Sight-Threatening & Systemic Emergencies First

Done

Ask about pain, vision change, and onset before anything else. Any red flag = act immediately — do not delay for examination.

Acute Angle-Closure Glaucoma Severe unilateral pain, halos around lights, rock-hard globe, nausea/vomiting, mid-dilated non-reactive pupil → 999 / same-day emergency ophthalmology

Corneal Ulcer / Keratitis Significant pain, photophobia, contact lens wearer, visible white corneal opacity, reduced vision → Same-day emergency ophthalmology

Anterior Uveitis (Iritis) Deep aching pain, photophobia, perilimbal (ciliary) flush, small/irregular/sluggish pupil, blurred vision → Same-day ophthalmology

Chemical Injury Any history of chemical splash (acid or alkali) → 999 / immediate copious irrigation — do not wait; alkali injuries penetrate rapidly

Hyphaema Blunt trauma + blood layering in anterior chamber (red fluid level visible) → Same-day emergency ophthalmology — risk of raised IOP and rebleed

Penetrating Eye Injury Mechanism of high-velocity foreign body (grinding, hammering), teardrop pupil, visible uveal prolapse → 999 — do NOT pressure or patch tightly

Gonococcal Conjunctivitis Hyper-purulent copious discharge, rapidly progressive, sexually active adult or neonate → Same-day GUM / emergency ophthalmology — can perforate cornea within hours

Sudden Vision Loss with Red Eye Any acute reduction in visual acuity accompanying red eye → Same-day emergency ophthalmology — assume serious until proven otherwise

Red eye is one of the most common acute presentations in UK general practice, accounting for approximately 1–2% of all GP consultations. The vast majority are benign (conjunctivitis, blepharitis, dry eye), but a small minority represent genuine ophthalmic emergencies where delayed treatment leads to permanent visual impairment or blindness. Acute angle-closure glaucoma causes irreversible optic nerve damage within hours if IOP is not lowered urgently. Corneal ulcers, especially in contact lens wearers, can progress to corneal perforation within 24–48 hours without appropriate antifungal or antibacterial treatment. The "pain + photophobia + perilimbal flush" triad reliably identifies anterior uveitis, which requires same-day slit-lamp examination. Chemical injuries — particularly alkali (cement, oven cleaner) — penetrate the anterior chamber within minutes; immediate and prolonged irrigation is the single most important intervention before any other assessment.

2

Diagnose

Key Diagnostic Questions — Narrow the Differential

Done

Use targeted history to separate the 4 key diagnostic groups before examining. The answers to these questions direct your examination and management.

Pain or irritation?

Pain (deep aching) → uveitis, keratitis, glaucoma | Gritty/foreign body sensation → conjunctivitis, dry eye, foreign body | Painless → subconjunctival haemorrhage, episcleritis (usually mild)

Vision change?

Reduced VA → urgent referral regardless of other features | Blurred then clears on blinking → dry eye, mucus discharge | Halos around lights → angle-closure glaucoma until proven otherwise

Discharge character?

Watery / serous → viral conjunctivitis, allergy | Mucopurulent → bacterial conjunctivitis | Profuse purulent → gonococcal (emergency) | Stringy/mucoid → allergic or dry eye

Unilateral or bilateral?

Unilateral → more likely serious (glaucoma, uveitis, keratitis, episcleritis) | Bilateral from outset → more likely viral/allergic conjunctivitis | Started unilateral, spread → viral conjunctivitis

Contact lens use?

Any contact lens wearer with red eye, pain, or discharge → High risk bacterial/acanthamoeba keratitis — refer same day to ophthalmology, advise stop lens wear immediately

Recent URTI / sick contacts?

Adenoviral conjunctivitis often follows URTI, highly contagious — advise strict hygiene, no sharing towels, no swimming pools for 2 weeks

Atopy / hay fever?

Known hay fever or eczema + bilateral itchy watery eyes → allergic conjunctivitis. Seasonal or perennial?

Systemic symptoms?

Arthritis / back pain / skin rash / urethritis → consider reactive arthritis (HLA-B27 associated). Rosacea → consider ocular rosacea / blepharitis.

A targeted history is more valuable than examination alone in differentiating red eye causes. The presence of pain is the single most discriminating feature — painless red eye is rarely serious, whereas painful red eye demands examination and often urgent referral. Visual acuity change is the second most important screening feature and should prompt same-day ophthalmology review. Studies show that experienced GPs use pain, vision change, and discharge character as the core diagnostic triad — CKS (NICE) and College of Optometrists guidance align on these as the primary discriminators. Contact lens wear increases risk of Pseudomonas and Acanthamoeba keratitis by 10–80 fold compared to non-wearers; any contact lens wearer with a painful red eye should be treated as keratitis until proven otherwise.

3

Diagnose

Classification — Identify the Likely Diagnosis

Done

Map the clinical picture to the most probable diagnostic category. Most GP red eye presentations fall into one of the groups below.

Bacterial Conjunctivitis

Mucopurulent discharge, lids stuck in morning, gritty, unilateral or bilateral, painless, VA normal. Most common bacterial pathogens: S. aureus, H. influenzae. Usually self-limiting 7–10 days

Viral Conjunctivitis

Watery/serous discharge, follicles on palpebral conjunctiva, pre-auricular lymphadenopathy, often recent URTI, highly contagious. Adenovirus most common. Lasts 2–3 weeks — no antiviral treatment

Allergic Conjunctivitis

Bilateral itching (hallmark symptom), watery/stringy discharge, conjunctival chemosis, papillae on tarsal conjunctiva, seasonal or perennial trigger. Responds to antihistamine drops

Subconjunctival Haemorrhage

Bright red patch, sharply demarcated, painless, VA normal, no discharge. Often after coughing/straining/Valsalva. Alarming appearance but usually benign. Check BP if recurrent

Episcleritis

Sectoral or diffuse redness, mild ache or tenderness on palpation, no discharge, VA normal. Young adults, may be recurrent. Blanches with phenylephrine 2.5%. If painful and does not blanch — consider scleritis

Blepharitis

Lid margin crusting/redness/scaling, gritty or burning bilateral symptoms, worse in morning, may have meibomian gland dysfunction (MGD). Chronic, recurrent. Often associated with rosacea or seborrhoeic dermatitis.

Dry Eye Disease

Gritty/burning bilateral symptoms, worse in afternoon/evening, worse in dry environments, improves on blinking. Schirmer test if uncertain. Common in older adults, screen users, post-menopausal women.

Anterior Uveitis Refer

Perilimbal (ciliary) flush, photophobia, deep aching pain, small irregular pupil (posterior synechiae), reduced VA. Screen for HLA-B27 associations: AS, IBD, psoriasis, reactive arthritis

Keratitis Refer

Pain (often severe), photophobia, reduced VA, white corneal opacity (fluorescein staining positive in epithelial defects). Contact lens use, foreign body, or herpes simplex (dendritic ulcer). Same-day ophthalmology

Acute Angle-Closure Emergency

Unilateral severe pain, halos, nausea, semi-dilated fixed pupil, hard globe, reduced VA. IOP typically >40 mmHg. 999 — irreversible damage within hours

Classification drives treatment. The most common GP pitfall is treating all red eyes as bacterial conjunctivitis — studies show that up to 50% of presumed bacterial conjunctivitis in primary care is actually viral, for which antibiotics provide no benefit and can drive resistance. Accurate phenotyping also ensures serious diagnoses like uveitis are not missed: anterior uveitis has a prevalence of approximately 8–15 per 100,000 population per year and frequently presents to GP first. Missing this diagnosis risks cataract, glaucoma, and visual loss from posterior synechiae. Subconjunctival haemorrhage, while alarming in appearance, is almost always benign — unnecessary urgent referrals cause system strain. Classification allows confident reassurance of benign conditions and rapid escalation of dangerous ones.

4

Diagnose

Targeted Examination — What to Look for and Why

Done

A structured examination takes under 3 minutes. Use a bright pen torch. Fluorescein strips and a Wood's lamp or cobalt blue light significantly improve corneal assessment.

Visual Acuity

Check FIRST in all red eye presentations. Use Snellen chart — record each eye separately with correction (specs/lenses). Any reduction from baseline = same-day ophthalmology. Normal VA is reassuring but does not exclude uveitis or early keratitis.

Pupil Assessment

Normal, equal, reactive → reassuring | Mid-dilated, fixed, oval → angle-closure glaucoma | Small, irregular, sluggish → anterior uveitis (posterior synechiae) | RAPD present → optic nerve or retinal pathology — urgent

Conjunctival Pattern

Diffuse injection → conjunctivitis | Perilimbal/ciliary flush (ring of redness around cornea) → uveitis, keratitis, angle-closure | Sectoral redness → episcleritis | Discrete red patch → subconjunctival haemorrhage

Discharge

Mucopurulent → bacterial | Watery → viral/allergic | Profuse purulent → gonorrhoea emergency | Stringy mucoid → allergic or dry eye. Evert upper lid to inspect tarsal conjunctiva for papillae (allergy) or follicles (viral)

Corneal Clarity

With pen torch: cornea should be clear/bright. Any haziness, white opacity, or dendrites → same-day ophthalmology. Use fluorescein drop + cobalt blue light: green staining = epithelial defect (corneal ulcer, abrasion, herpes dendrite)

Globe Palpation

Gently palpate closed eyelids. Rock-hard globe → angle-closure glaucoma (IOP >40 mmHg). Normal soft globe is reassuring. Do not palpate if penetrating injury suspected.

Lid Margins

Crusting, scaling, meibomian gland plugging → blepharitis/MGD. Hordeolum (stye) = acute follicular infection. Chalazion = chronic meibomian cyst. Trichiasis (inturned lashes) → corneal abrasion.

Pre-auricular Nodes

Tender pre-auricular lymphadenopathy → strongly supports viral (adenoviral) conjunctivitis. Also consider EBV, HSV. Absent in bacterial conjunctivitis.

Blood Pressure

Check in all subconjunctival haemorrhages — hypertension is a precipitant. Also check if recurrent or no clear cause.

Visual acuity is the most important single examination finding in red eye — it is the "sixth vital sign" of ophthalmology. Any unexplained reduction should trigger same-day review. The ciliary flush (perilimbal injection) is a clinically crucial sign differentiating conjunctivitis (peripheral redness) from uveitis/keratitis/glaucoma (central redness at the limbus) — it requires a good light source and recognition. Fluorescein staining detects corneal epithelial defects not visible on naked-eye examination; herpes simplex dendritic ulcers (branching pattern) are a classic missed diagnosis when fluorescein is not used. Studies show that fluorescein is used in fewer than 20% of appropriate GP red eye consultations, leading to missed corneal pathology. Pupil examination takes 10 seconds and rules out the two most dangerous diagnoses: angle-closure (mid-dilated fixed) and uveitis (small irregular).

5

Diagnose

Investigations — When and What to Request

Done

Most acute red eye does NOT require investigations in primary care. Investigate only when results will change management. Over-investigating simple conjunctivitis is common and unhelpful.

Conjunctival Swab Targeted

When to swab: suspected gonococcal conjunctivitis (profuse purulent discharge — send for NAAT + MC&S), treatment-resistant bacterial conjunctivitis after 7 days, neonatal conjunctivitis (ophthalmia neonatorum — send urgently), immunocompromised patients. Do NOT swab routine mild conjunctivitis — will not change empiric treatment.

STI Screen

If gonococcal conjunctivitis suspected: refer to GUM for full STI screen (gonorrhoea, chlamydia). Same-day referral. Chlamydial inclusion conjunctivitis (chronic, non-purulent) → chlamydia NAAT from eye swab or genital swab.

IOP Measurement

Arrange same-day tonometry (ophthalmology or optometrist) if angle-closure glaucoma suspected. Not available in GP surgery — do not delay referral waiting for this. Normal IOP: 10–21 mmHg. Angle-closure typically >40 mmHg.

Blood Pressure

Check in all subconjunctival haemorrhages, especially recurrent or unprovoked. Target <140/90 mmHg (or <130/80 if diabetic/CKD). Investigate secondary causes if severely elevated.

HLA-B27 / Bloods

If first presentation of anterior uveitis confirmed by ophthalmology: HLA-B27, CRP/ESR, ANA, ACE level (sarcoidosis), VDRL/TPHA (syphilis). Arrange after ophthalmology review, not in acute presentation.

Fluorescein Staining

In-consultation investigation. Fluorescein strip + cobalt blue/Wood's lamp — screens for corneal epithelial defects. Should be used whenever keratitis, abrasion, or foreign body is suspected. If positive, same-day ophthalmology referral.

NOT Routine

Do not routinely request: FBC, cultures, allergy testing, or imaging for standard conjunctivitis presentations. Tear osmolarity / Schirmer testing is for specialist dry eye assessment, not primary care.

Routine conjunctival swabbing in uncomplicated bacterial conjunctivitis adds cost and delay without improving outcomes — NICE CKS guidance states that swabs are not required for typical presentations. The key investigations that change acute management are: (1) fluorescein staining for corneal pathology, (2) IOP measurement for angle-closure, and (3) gonococcal swabs / STI screen for hyperacute purulent conjunctivitis. Chlamydial conjunctivitis is frequently missed in primary care — it presents as a chronic red eye with minimal discharge in sexually active adults. A careful sexual history followed by chlamydia NAAT from an eye swab makes this diagnosis. HLA-B27 testing for uveitis is a secondary care investigation — ordering it in primary care before specialist review is premature and unhelpful in acute management.

6

Refer

Referral Criteria — Who, When, and Where

Done

Use the urgency grading below. When in doubt about severity, refer — ophthalmologists can always downgrade, but delayed referral of serious pathology risks blindness.

999 / A&E

• Acute angle-closure glaucoma (severe pain, fixed mid-dilated pupil, hard globe, nausea)
• Chemical eye injury — irrigate first (1–2 litres saline), then 999
• Penetrating eye injury (do NOT patch tightly, do NOT apply pressure)
• Hyphaema with significant vision loss or suspected arterial bleed

Same-Day Emergency Ophthalmology

• Anterior uveitis (ciliary flush + photophobia + pain)
• Corneal ulcer / keratitis (opacity visible, fluorescein positive, painful)
• Contact lens wearer with any significant pain or reduced VA
• Gonococcal conjunctivitis (hyper-purulent) — also refer GUM
• Suspected herpes simplex keratitis (dendritic ulcer)
• Hyphaema post-trauma
• Any red eye with unexplained reduced visual acuity

Urgent (within 1–2 weeks)

• Recurrent anterior uveitis (established diagnosis, second episode)
• Scleritis (severe pain, does not blanch, scleral thinning)
• Herpes zoster ophthalmicus — Hutchinson's sign (tip of nose vesicles) → urgent ophthalmology within 24h
• Ophthalmia neonatorum — same-day to paediatric ophthalmology

Routine Ophthalmology

• Recurrent or chronic episcleritis (exclude systemic disease)
• Chronic blepharitis not responding to lid hygiene after 3 months
• Dry eye disease not responding to lubricants after 3 months
• Suspected chlamydial conjunctivitis (after GUM referral)

Primary Care Management

• Uncomplicated bacterial conjunctivitis (mild, VA normal, no corneal involvement)
• Allergic conjunctivitis (VA normal, no corneal involvement)
• Viral conjunctivitis (self-limiting, reassure, hygiene advice)
• Subconjunctival haemorrhage (painless, VA normal, no trauma)
• Mild blepharitis — lid hygiene programme

Where to Refer

Emergency: A&E with ophthalmology on-call (most DGHs) or dedicated eye casualty department
Urgent/routine: Community optometry (can assess IOP, VA, anterior chamber) or hospital ophthalmology outpatients
GUM: Suspected gonorrhoea or chlamydia

The threshold for same-day ophthalmology referral should be low in general practice. A 2019 NHS England audit found that significant proportions of avoidable visual loss cases involved delayed GP referral of anterior uveitis, keratitis, and undiagnosed angle-closure glaucoma. GPs are not expected to manage these conditions independently — the role is accurate recognition and timely escalation. Community optometrists are a valuable intermediate resource: they can measure IOP, assess anterior segment with a slit lamp, and perform fundoscopy, and many practices offer direct GP referral schemes. For herpes zoster ophthalmicus (shingles affecting V1 dermatome), the key clinical sign is Hutchinson's sign — vesicles on the tip of the nose (nasociliary nerve) — which predicts a 76% chance of ocular involvement. All such patients require urgent same-day ophthalmology review.

7

Treat

Treatment — Diagnosis-Specific Pharmacological Management

Done

Match treatment to the confirmed diagnosis. Do not prescribe topical antibiotics for all red eyes — this drives resistance and delays diagnosis of non-bacterial conditions.

Bacterial Conjunctivitis

Chloramphenicol First-line

0.5% drops every 2h while awake for 2 days, then 4× daily for 5 days. Or 1% ointment at night. OTC available — consider delayed prescription approach (advise self-resolves in 7–10 days without treatment). If treatment failure at 7 days → swab and switch to fusidic acid 1% gel BD or refer.

Allergic Conjunctivitis

Sodium cromoglicate First-line

2% drops 4× daily — mast cell stabiliser, most effective if started before allergen exposure. If inadequate: switch to Olopatadine 0.1% drops BD (antihistamine + mast cell stabiliser). Add oral antihistamine (cetirizine 10mg OD) for systemic symptoms. Cold compresses and allergen avoidance.

Viral Conjunctivitis

Supportive only No antiviral

No proven effective antiviral for adenoviral conjunctivitis. Lubricant drops (e.g., hypromellose 0.3%) for comfort. Cold compresses. Strict hygiene counselling (own towels, no school/work until discharge resolves — typically 7–10 days). Resolves spontaneously in 2–3 weeks.

Blepharitis / MGD

Lid hygiene First-line

Warm compresses 5–10 min BD → massage lid margins → clean with dilute baby shampoo or proprietary lid wipes (Blephaclean). If insufficient: chloramphenicol ointment applied to lid margin at night for 2–4 weeks. For MGD / rosacea: oral doxycycline 100mg OD for 6–12 weeks (reduces meibomian gland inflammation).

Dry Eye Disease

Lubricant drops First-line

Preservative-free lubricants preferred for regular use (>4× daily): e.g., Hylo-Tear, Carbomer 0.2% gel. Hypromellose 0.3% drops QDS for mild symptoms. Warn that improvement takes 4–6 weeks. Add omega-3 supplements if MGD present. Screen triggers: screen time, air conditioning, medications (antihistamines, beta-blockers, antidepressants).

Subconjunctival Haemorrhage

Reassure — no treatment Self-limiting

Resolves in 2–3 weeks without treatment. Lubricant drops for comfort if irritated. Treat hypertension if identified. If on anticoagulation — check INR, review anticoagulant management. If recurrent or bilateral → investigate coagulation screen, platelet count, BP.

Conditions requiring SPECIALIST-INITIATED treatment (prescribe only after ophthalmology diagnosis):

Uveitis Prednisolone acetate 1% drops (or dexamethasone 0.1%) — started by ophthalmology only. Cyclopentolate 1% for cycloplegia. Never start steroids without slit-lamp confirmation — can worsen keratitis/glaucoma

HSV Keratitis Aciclovir 3% eye ointment 5× daily for 10 days — epithelial dendrites. Initiated by ophthalmology. Do NOT use topical steroids in epithelial disease — will worsen. Stromal disease: specialist management only

HZV Ophthalmicus Oral aciclovir 800mg 5× daily for 7 days — start within 72h of rash onset (GP can prescribe this). Refer urgently to ophthalmology regardless of eye symptoms — may have iritis or keratitis without symptoms

Gonococcal IM ceftriaxone 1g stat (GUM/hospital) + topical irrigation. Systemic treatment essential — topical alone insufficient. Partner notification required.

Episcleritis NSAID drops (ketorolac 0.5% QDS) or oral ibuprofen 400mg TDS for symptomatic relief if mild. Most resolve spontaneously. Exclude systemic inflammatory disease if recurrent.

Chloramphenicol is first-line for bacterial conjunctivitis in UK primary care per NICE CKS — it covers the key pathogens (S. aureus, H. influenzae, Streptococcus pneumoniae) and is available OTC. However, a Cochrane review (2012) found that bacterial conjunctivitis resolves spontaneously in 64% of patients within 5 days without antibiotics; a delayed prescribing strategy reduces antibiotic use by 53% without affecting patient-reported outcomes. Olopatadine outperforms cromoglicate in head-to-head trials for allergic conjunctivitis — consider it first-line in moderate-to-severe cases. Topical corticosteroids must never be prescribed in primary care without slit-lamp examination confirmation: they are contraindicated in HSV keratitis (cause corneal perforation), bacterial ulcers, and can dangerously raise IOP in steroid responders (~35% of the population). The clinical rule: no steroids for the red eye without a slit lamp.

8

Lifestyle

Non-Pharmacological Interventions — Essential, Not Optional

Done

Lifestyle measures are disease-modifying for blepharitis, dry eye, and allergic conjunctivitis — provide written information or signpost to NHS resources.

Infection Control (Viral/Bacterial) Wash hands before and after eye drops. Own towel and pillowcase — wash at 60°C. No school/nursery until discharge resolves (school guidance varies — check local policy). No swimming for 2 weeks with viral conjunctivitis. Do not share eye makeup — discard current makeup.

Contact Lens Management Stop contact lens wear immediately with any red eye until fully resolved and reviewed. Do not return to lens wear until asymptomatic + 24h after completing antibiotic course. Replace current lens case and lens solution. Review wear schedule — max 8–10h/day. Consider switch to daily disposables if recurrent infections.

Lid Hygiene (Blepharitis) Twice-daily routine: warm compress (microwaveable eye mask or face cloth) for 5–10 min → massage lid margins in circular motion → clean with proprietary lid wipes or dilute baby shampoo on cotton bud. Must be long-term — 3–4 months to see benefit. Do not stop when symptoms improve.

Screen Use / Eye Rest (Dry Eye) Apply 20-20-20 rule: every 20 minutes, look 20 feet away for 20 seconds. Reduce screen brightness and glare. Use anti-reflective coating glasses. Blink consciously (blink rate reduces by 66% during screen use). Humidifier in dry environments. Avoid air conditioning directed at face.

Allergen Avoidance Seasonal allergy: keep windows closed in high pollen times, wear wraparound sunglasses outdoors, shower after being outside. Perennial allergy (house dust mite): mattress and pillow covers, damp dusting, reduce soft furnishings. Pet allergy: avoid touching face, change clothes after exposure.

Nutrition (Dry Eye / MGD) Omega-3 fatty acids (oily fish 2–3×/week or 1g omega-3 supplement OD) reduce meibomian gland inflammation and improve tear film stability — evidence base: Cochrane review 2019 (modest benefit). Adequate hydration: 6–8 glasses water daily.

Makeup & Hygiene Waterproof mascara blocks meibomian glands — switch to water-soluble. Remove all eye makeup before bed. Replace eye makeup every 3 months (mascara every 6 weeks). Wash face and eye area gently before bed to remove lid margin debris.

Environmental Modification Reduce exposure to smoke, dusty environments, chlorinated pools. Use protective eyewear for hazardous work (grinding, woodwork). Safety glasses mandatory for DIY — refer to NHS Better Health campaign. UV-blocking sunglasses reduce actinic exposure and may slow pterygium progression.

Lid hygiene is the cornerstone of blepharitis management and is as effective as antibiotics for mild-to-moderate disease — it must be presented to patients as a long-term daily commitment, not a temporary measure. Studies show that consistent twice-daily lid hygiene for 12 weeks significantly reduces symptoms and bacterial load compared to controls. Contact lens misuse is the biggest modifiable risk factor for microbial keratitis — extended wear increases risk by 10-fold compared to daily wear. The 20-20-20 rule for screen use has limited RCT evidence but is endorsed by the College of Optometrists and has good face validity for reducing accommodative fatigue and improving blink rate. Infection control measures for viral conjunctivitis are critical in preventing household and workplace spread — adenovirus can survive on surfaces for up to 30 days; the advice to use separate towels is evidence-based and important.

9

Safety

Follow-Up, Monitoring & Safety-Netting

Done

Most uncomplicated red eye resolves in 1–2 weeks. Clear safety-netting is essential — patients must know exactly when to seek urgent review. Document safety-netting advice given.

Bacterial Conjunctivitis

Review at 7 days if not improving (or if worsening before). Most resolve in 5–7 days with treatment. If persistent at 7 days → swab → review antibiotic. If worsening despite treatment at 48h → same-day ophthalmology.

Viral Conjunctivitis

Reassure: resolves in 2–3 weeks naturally. No review needed unless worsening or new symptoms. Advise: if severe pain, significant photophobia, or vision change → same-day review.

Allergic Conjunctivitis

Review at 4 weeks if treatment not working — consider step up to olopatadine or add oral antihistamine. Seasonal: annual review to adjust treatment plan pre-season. If perennial: consider allergen testing.

Blepharitis

Review at 6–8 weeks — lid hygiene must be established as routine. If no improvement with lid hygiene + chloramphenicol ointment after 3 months → routine ophthalmology referral. Review for rosacea association.

Dry Eye

Review at 6–8 weeks — lubricant drops take 4–6 weeks to show benefit. If not improving → consider referral to ophthalmology or community optometry for tear film assessment, punctal plug consideration.

Subconjunctival Haemorrhage

No review required if uncomplicated. Reassure resolves in 2–3 weeks. If recurrent (2+ episodes in 6 months) → FBC, coagulation screen, platelet count, BP. Review antiplatelet/anticoagulant medications.

Post-Ophthalmology Uveitis

Follow ophthalmology discharge plan strictly — typically review in 1–2 weeks after initiating topical steroids. GP role: support medication compliance, screen for systemic associations (HLA-B27, IBD, psoriasis), refer if new systemic symptoms.

Safety-net: 999

• Sudden severe eye pain with halos/nausea (angle-closure)
• Sudden complete vision loss
• Chemical splash — irrigate and call 999
• Penetrating injury / foreign body at speed

Safety-net: Same-Day GP/Eye Emergency

• Any reduction in visual acuity at any stage
• Increasing pain (any red eye that was mild becoming painful)
• New photophobia
• Corneal cloudiness or visible white spot
• Worsening despite 48h antibiotic treatment
• Rash on forehead/nose tip with red eye (HZV ophthalmicus)

Monitoring Parameters

On topical antibiotics: no routine monitoring required
On oral doxycycline (blepharitis): review at 6 weeks — photosensitivity, GI side effects, contraception (reduces OCP efficacy)
On oral antihistamines: drowsiness, dry mouth — use non-sedating (cetirizine, loratadine)
On topical NSAIDs (episcleritis): ophthalmology to monitor for corneal complications

Explicit safety-netting for red eye is critical because the clinical picture can change rapidly — bacterial conjunctivitis can precede or mask developing keratitis, and patients often initially present with mild symptoms that escalate. The RCGP guidance on safety-netting (2021) recommends the "diagnosis, management, and reconsideration" framework — patients should know what the expected course is, what symptoms should prompt return, and by what route. Documenting safety-netting advice is medico-legally important; a red eye that progresses to blindness after GP consultation without documented safety-netting represents a significant clinical governance concern. Follow-up intervals for blepharitis and dry eye are longer because both conditions require behaviour change (lid hygiene, lubricants) that takes weeks to show effect — premature escalation to specialist referral without adequate trial of conservative measures is a common SCA exam pitfall.