Red Eye Algorithm

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, headache, halos around lights, blurred vision, nausea/vomiting, cloudy cornea, fixed mid-dilated pupil → 999 / immediate emergency ophthalmology — do not delay for tonometry

Corneal Ulcer / Keratitis Significant pain, photophobia, contact lens wearer, visible white corneal opacity, reduced vision → Same-day emergency ophthalmology — remove the lens, do not patch

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) → immediate copious irrigation (saline, water or other isotonic fluid) continued until ocular-surface pH is approximately neutral — remove contact lenses and particulate matter; do not delay for history, VA or referral; alkali injuries penetrate rapidly → then emergency ophthalmology (999 if severe)

Hyphaema Blunt trauma + blood layering in anterior chamber (red fluid level visible) → Same-day emergency ophthalmology — risk of raised IOP and rebleed; emergency transfer if visual compromise, high IOP, open-globe concern or major trauma

Penetrating Eye Injury High-velocity metal-on-metal mechanism (grinding, hammering), irregular/teardrop pupil, uveal prolapse, shallow or abnormally deep anterior chamber, full-thickness injury, severe visual loss after trauma → 999 — rigid shield without pressure; do NOT apply pressure, palpate the globe, patch tightly, remove an embedded foreign body or instil drops unnecessarily

Gonococcal Conjunctivitis Hyper-purulent copious discharge, marked chemosis, severe eyelid swelling, rapidly progressive, sexually active adult or neonate → Same-day ophthalmology + sexual-health/GUM assessment — corneal perforation can occur; systemic treatment required

Sudden Vision Loss with Red Eye Any acute reduction in visual acuity accompanying red eye, unexplained by discharge or refractive blur → Same-day eye casualty / emergency ophthalmology / commissioned urgent eye service; sudden severe or complete visual loss → emergency transfer

Orbital Cellulitis Suspected orbital cellulitis with systemic illness, proptosis, ophthalmoplegia or neurological features → 999 / emergency transfer. Severe sepsis or anaphylaxis with ocular symptoms → 999

Herpes Zoster Ophthalmicus / HSV V1 vesicles (forehead, nose, eyelids), with or without ocular symptoms, or suspected herpes simplex keratitis (dendrite) → Same-day ophthalmology

Recent Intraocular Surgery Recent eye surgery or intravitreal injection with pain, redness or reduced vision → Same-day ophthalmology (possible endophthalmitis)

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 suggests anterior uveitis (or keratitis), which requires same-day slit-lamp examination. Conjunctivitis usually causes diffuse redness, discharge and normal vision; pain, photophobia, visual change, ciliary flush, corneal opacity or a fixed pupil suggest a deeper or more serious diagnosis. Chemical injuries — particularly alkali (cement, oven cleaner) — penetrate the anterior chamber within minutes; immediate irrigation continued until the ocular-surface pH is neutral (volume is not the endpoint) is the single most important intervention before any other assessment.

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 (unexplained by discharge or refractive blur) → same-day referral regardless of other features | Diplopia → urgent assessment (orbital/neurological cause) | 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?

Ask lens type and hygiene, and sleeping, swimming or showering in lenses. Painful red eye, photophobia, reduced vision, corneal opacity or significant unilateral redness → High risk presume bacterial/acanthamoeba keratitis — same-day ophthalmology. Mild, painless irritation does not necessarily need an ambulance but needs prompt clinical assessment. Remove lenses immediately in all cases.

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?

Inflammatory arthritis / back pain / IBD / psoriasis / urethritis → consider HLA-B27-associated uveitis or reactive arthritis. Rosacea → consider ocular rosacea / blepharitis.

Trauma, chemical or surgery?

Grinding, hammering or chemical exposure → injury pathway. Recent eye surgery or intraocular injection → same-day ophthalmology if painful, red or vision reduced.

Sexual history?

Genital discharge, dysuria or sexual exposure → consider chlamydia/gonorrhoea conjunctivitis.

Past history & medication?

Previous herpes simplex or zoster · anticoagulants, antiplatelets · immunosuppression.

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 — College of Optometrists guidance 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.

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, mild irritation rather than deep pain, unilateral or bilateral, VA usually normal, no corneal opacity or significant photophobia. Most common bacterial pathogens: S. aureus, H. influenzae. Many resolve spontaneously within 5–14 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, associated rhinitis, asthma or eczema. 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%. Usually resolves spontaneously. If painful and does not blanch — consider scleritis

Scleritis Refer

Severe, deep boring pain, may radiate to the face or jaw, may be associated with systemic inflammatory disease. Same-day ophthalmology — do not treat from primary care with ketorolac drops or oral NSAIDs while assuming the diagnosis is secure.

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 or sluggish pupil (posterior synechiae), reduced or blurred VA. Same-day ophthalmology — do not commence steroid eye drops before specialist assessment. Ask about 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). A painful red eye in a contact-lens wearer is presumed keratitis until excluded — remove the lens, do not patch. Same-day ophthalmology

Acute Angle-Closure Emergency

Unilateral severe pain, headache, halos, blurred/reduced VA, nausea/vomiting, cloudy cornea, fixed mid-dilated pupil. 999 / immediate ophthalmology — irreversible damage within hours Do not delay referral for tonometry or give IV acetazolamide from routine primary care.

Gonococcal Conjunctivitis Emergency

Hyperpurulent discharge, marked chemosis, severe eyelid swelling or rapid progression — corneal perforation can occur. Same-day ophthalmology + sexual-health/GUM assessment. Systemic therapy required; topical treatment alone is inadequate.

Herpes Zoster Ophthalmicus Refer

V1 vesicles, especially nose, forehead or eyelids → same-day ophthalmology assessment. Start systemic antiviral promptly per current local guidance when indicated, but do not let prescribing delay ophthalmology referral where ocular involvement is possible.

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.

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. If a slit lamp, fluorescein or appropriate VA testing is unavailable and there is diagnostic uncertainty, use community optometry, eye casualty or ophthalmology rather than managing an undiagnosed red eye remotely.

Visual Acuity

Check FIRST in all red eye presentations. Use Snellen chart — record each eye separately with correction (specs/lenses). Any unexplained reduction = same-day assessment (eye casualty, emergency ophthalmology or a commissioned urgent eye service). Normal VA is reassuring but does not exclude uveitis or early keratitis, and absence of discharge does not exclude serious eye disease.

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)

Ocular Movements

Check ocular movements — painful or restricted movement, proptosis → consider orbital cellulitis. Do not palpate the globe to estimate IOP — it is unreliable; if angle closure is suspected arrange emergency ophthalmology without delaying for tonometry. Never palpate if penetrating injury is 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 helps identify two of the most dangerous diagnoses: angle-closure (mid-dilated fixed) and uveitis (small irregular).

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 or chlamydial conjunctivitis suspected: refer to GUM for full STI screen and partner management. Same-day referral for gonococcal disease. Chronic follicular conjunctivitis or relevant sexual exposure → chlamydia NAAT from eye swab or genital swab.

IOP Measurement

Suspected acute angle closure → immediate ophthalmology, where IOP is measured — do not delay referral for tonometry. Where other glaucoma is suspected, arrange IOP measurement through optometry or ophthalmology. Normal IOP: 10–21 mmHg.

Blood Pressure

Check in all subconjunctival haemorrhages, especially recurrent or unprovoked. Clinic target <140/90 mmHg under age 80 (NICE NG136); <130/80 in CKD with ACR 70 mg/mmol or more (NICE NG203). Investigate secondary causes if severely elevated.

HLA-B27 / Bloods

Only after ophthalmology confirms uveitis, and based on the clinical phenotype, consider inflammatory or infectious investigations: HLA-B27, CRP/ESR, ANA, ACE level (sarcoidosis), VDRL/TPHA (syphilis). Do not request during the acute red-eye consultation.

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: conjunctival swabs for uncomplicated mild conjunctivitis, FBC, CRP, cultures, allergy testing, imaging, or HLA-B27, ANA, ACE or syphilis serology during the acute red-eye consultation. 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 — swabs are not required for typical presentations in routine practice. 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.

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, visual loss, haloes, nausea/vomiting, fixed mid-dilated pupil)
• Severe chemical eye injury — irrigate immediately and continuously until ocular-surface pH is neutral (volume is not the endpoint), then 999 / emergency ophthalmology
• Penetrating / open-globe injury (rigid shield without pressure; do NOT patch tightly, apply pressure or remove an embedded foreign body)
• Hyphaema with visual compromise, high IOP, open-globe concern or major trauma
• Sudden severe or complete visual loss
• Suspected orbital cellulitis with systemic illness, proptosis, ophthalmoplegia or neurological features
• Severe sepsis or anaphylaxis associated with ocular symptoms

Same-Day Emergency Ophthalmology

• Anterior uveitis (ciliary flush + photophobia + pain)
• Corneal ulcer / keratitis (opacity visible, fluorescein positive, painful)
• Contact lens wearer with painful red eye, photophobia, reduced vision, corneal opacity or significant unilateral redness (remove lenses in all cases)
• Painful red eye with photophobia · ciliary/perilimbal injection · corneal haze, opacity, infiltrate or ulcer
• Gonococcal conjunctivitis (hyper-purulent) — also refer GUM
• Suspected herpes simplex keratitis (dendritic ulcer)
• Hyphaema post-trauma
• Any red eye with reduced visual acuity unexplained by discharge or refractive blur (eye casualty, emergency ophthalmology or commissioned urgent eye service)
• Suspected scleritis (severe deep boring pain, does not blanch, scleral thinning)
• Herpes zoster ophthalmicus (V1 involvement), with or without ocular symptoms; Hutchinson's sign (tip of nose vesicles) raises risk of eye involvement
• Recent intraocular surgery or injection with pain, redness or reduced vision
• Superficial foreign body that cannot be removed easily, rust ring, contact-lens involvement, corneal infiltrate or persistent pain

Urgent (same day to within 24 hours)

• Recurrent anterior uveitis (established diagnosis, second episode)
• Ophthalmia neonatorum — same-day to paediatric ophthalmology

Routine Ophthalmology

• Recurrent or painful episcleritis — seek ophthalmology advice; consider scleritis and 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 (STI screen and partner management)
No slit lamp/fluorescein and uncertain: community optometry, eye casualty or ophthalmology — do not manage an undiagnosed red eye remotely

The threshold for same-day ophthalmology referral should be low in general practice. Avoidable visual loss from anterior uveitis, keratitis and angle-closure glaucoma is linked to delayed recognition and referral. 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.

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. Do not initiate topical ocular steroids in primary care for an undiagnosed red eye. Align all antibiotic, antiviral, NSAID and steroid regimens with current product information, the local formulary and the local eye/emergency pathway.

Bacterial Conjunctivitis

Hygiene ± topical antibiotic per local formulary If appropriate

Many cases resolve spontaneously within 5–14 days. Mild disease: cleaning, hygiene and a delayed or no-antibiotic approach, depending on local policy. If treatment is appropriate, use the current local formulation and licensed dosing (e.g. chloramphenicol drops or ointment; OTC available). Review if symptoms worsen, vision changes or there is no improvement within the expected period; swab if treatment-resistant.

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). Use a locally approved topical antihistamine or mast-cell stabiliser. Add oral non-sedating antihistamine (e.g. cetirizine) if rhinitis or systemic allergy coexists; intranasal steroid where allergic rhinitis is clinically significant. Cool compresses, preservative-free lubricants 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 and cosmetics; follow current UKHSA/local public-health advice on exclusion — outbreak or institutional policy may differ). Avoid contact lenses until resolved. Avoid topical steroids unless initiated by ophthalmology. Safety-net for pain, photophobia or visual change. 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). Lubricants where dry eye coexists; treat associated rosacea or seborrhoeic dermatitis. If insufficient: topical antibiotic to the lid margin per local formulary. Oral doxycycline is not routine for blepharitis — consider only for significant rosacea-associated or meibomian-gland disease after assessment, per local prescribing guidance; avoid in pregnancy, observe age restrictions in children, and warn about photosensitivity and GI adverse effects.

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. Omega-3 supplements are not standard treatment — evidence is mixed and they are not required for routine care. 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 anticoagulant or antiplatelet — check INR where relevant and review, without stopping essential medication reflexively. 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 Topical antiviral (ganciclovir 0.15% eye gel; aciclovir 3% eye ointment has been discontinued in the UK; oral aciclovir is an alternative) per current product information and local eye pathway — epithelial dendrites. Initiated by ophthalmology. Do NOT use topical steroids in epithelial disease — will worsen. Stromal disease: specialist management only

HZV Ophthalmicus Systemic antiviral promptly when clinically indicated, per current product information/local guidance (GP can prescribe) — but do not let prescribing delay urgent eye assessment where ocular involvement is possible. Refer urgently to ophthalmology — may have iritis or keratitis without symptoms

Gonococcal GUM/hospital-led systemic regimen per current BASHH/local antimicrobial guidance, with renal, pregnancy and age considerations + topical irrigation. Systemic treatment essential — topical alone insufficient. Partner notification required.

Episcleritis Reassurance ± lubricants — most resolve spontaneously. Topical (ketorolac) or oral NSAIDs are not routine primary-care treatment. Recurrent or painful episcleritis → consider scleritis/systemic disease and seek ophthalmology advice.

Topical steroids Ophthalmology-led only — uveitis, severe allergic keratoconjunctivitis, selected episcleritis/scleritis, significant ocular-surface inflammation. Require corneal examination and consideration of infection and IOP. Can worsen HSV, bacterial, fungal or acanthamoeba keratitis and may cause glaucoma or cataract.

Next steps: see Uveitis · Glaucoma · Blepharitis · Dry eye disease · Subconjunctival haemorrhage · Allergic conjunctivitis

Where an antibiotic is appropriate, follow the local antimicrobial formulary; chloramphenicol is commonly used for bacterial conjunctivitis in UK primary care (College of Optometrists Clinical Management Guidelines) — 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 can worsen HSV, bacterial, fungal or acanthamoeba keratitis (risk of corneal perforation), may cause cataract, 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.

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. Follow current UKHSA/local public-health advice on exclusion from school, nursery or work — outbreak or institutional policy may differ. No swimming for 2 weeks with viral conjunctivitis. Do not share eye makeup — discard current makeup.

Contact Lens Management Remove lenses and stop contact lens wear immediately with any red eye until fully resolved and reviewed; painful red eye, photophobia or visual change → same-day assessment. Never sleep, swim or shower in lenses. 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 supplements are not standard first-line therapy for dry eye — the evidence is mixed and they are not required for routine care. A balanced diet including oily fish is reasonable. 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.

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 if worsening, atypical or not improving as expected — persistent redness for several days is not by itself "treatment failure". Swab if treatment-resistant. Same-day ophthalmology for pain, photophobia, visual change, corneal findings or clinical deterioration.

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: identify triggers clinically — allergy testing is not routine.

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 immediately and continuously, then call 999 / emergency eye care
• Symptoms of acute glaucoma or significant eye trauma
• 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
• Increasing redness or clinical worsening despite treatment
• Painful red eye in a contact-lens wearer
• Hyperpurulent discharge
• HZO rash involving the forehead, nose or eyelids

Monitoring Parameters

On topical antibiotics: no routine monitoring required
On oral doxycycline (selected rosacea/MGD only): review at 6 weeks — photosensitivity, GI side effects, contraception: no additional precautions with hormonal contraception (CoSRH CEU guidance on drug interactions — non-enzyme-inducing antibiotics); avoid in pregnancy
On oral antihistamines: drowsiness, dry mouth — use non-sedating (cetirizine, loratadine)
On ophthalmology-initiated topical NSAIDs or steroids: ophthalmology to monitor for corneal complications and IOP

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.