Herpes simplex - ocular
Exam Tips
- In an OSCE red-eye station, always document visual acuity first, then fluorescein findings and pupil pattern.
- Classic HSV epithelial lesion is a branching dendrite with terminal bulbs on fluorescein; reduced corneal sensation supports diagnosis.
- Do not start topical steroids in primary care for suspected epithelial HSV keratitis; this is a high-risk prescribing error.
- Contact lens wearer with dendritiform keratitis needs urgent same-day ophthalmology to exclude Acanthamoeba.
- Recurrent unilateral episodes plus stromal haze/uveitis suggest higher risk of scarring and need close specialist follow-up.
- Image reference: See Figure from page X showing fluorescein-stained dendritic ulcer and terminal bulbs; compare with pseudodendrites in zoster.
Definition
Ocular herpes simplex is infection and/or immune-mediated inflammation of ocular tissues caused predominantly by HSV-1, most often affecting the cornea (herpes simplex keratitis) but also the conjunctiva, eyelids, uvea, and rarely retina. It is usually recurrent disease due to viral latency in the trigeminal ganglion, and is a key cause of unilateral corneal visual loss if stromal involvement or repeated episodes lead to scarring.
Pathophysiology
After primary mucocutaneous HSV-1 acquisition (often in childhood), virus becomes latent in sensory neurons, especially the trigeminal ganglion, and may also persist in corneal tissue. Reactivation (for example after UV exposure, stress, trauma, fever, menstruation, or immunosuppression) causes viral shedding at the corneal surface. Epithelial keratitis reflects active viral replication and classically produces branching dendritic ulcers on fluorescein staining. Stromal keratitis is often driven by host immune response to viral antigens (with or without replicating virus), causing stromal oedema, neovascularization, uveitis, raised intraocular pressure, and scarring; necrotizing stromal disease can progress to thinning and perforation. Recurrent inflammation reduces corneal sensation and can cause trophic (metaherpetic) epithelial defects.
Risk Factors
- Previous ocular HSV episode (strongest predictor of recurrence)
- Immunosuppression (disease- or treatment-related, including corticosteroid exposure)
- Atopy
- Corneal trauma or surgery (including keratorefractive procedures)
- Contact lens use (also raises concern for Acanthamoeba in dendritiform keratitis)
- UV light exposure
- Physical or emotional stress, febrile illness, fatigue
- Menstruation
- Perioral HSV with possible autoinoculation
Clinical Features
Symptoms
- Usually unilateral red, painful, irritated eye (can be bilateral, especially in children or immunosuppressed people)
- Photophobia and watering (suggestive of keratitis)
- Blurred vision (more prominent in keratitis/stromal disease)
- History of recurrent similar episodes
- Malaise/fever more likely in primary infection
- Pain may be mild in recurrent disease due to reduced corneal sensation
Signs
- Conjunctival injection (acute red eye)
- Fluorescein-positive branching dendritic epithelial ulcer or amoeboid/geographic ulcer
- Periocular/lid vesicles, ulcers, or crusted lesions; possible blepharoconjunctivitis
- Reduced corneal sensitivity
- Hazy cornea or focal stromal creamy opacity/oedema (stromal keratitis)
- Limbal (ciliary) injection, irregular/fixed pupil, or signs of anterior uveitis
- Reduced visual acuity on Snellen testing
Investigations
Management
Lifestyle Modifications
- Same-day ophthalmology assessment for suspected keratitis, stromal disease, uveitis, reduced vision, severe pain, bilateral disease, immunosuppression, or contact lens wear
- Stop contact lens wear immediately; restart only after specialist advice
- Strict hand hygiene and avoid touching/rubbing eyes to reduce autoinoculation/transmission
- Avoid topical over-the-counter steroid eye drops unless explicitly prescribed by ophthalmology
- Avoid prolonged UV exposure; advise trigger management for recurrent disease
Pharmacological Treatment
Topical antiviral (first-line for epithelial keratitis)
- Aciclovir 3% eye ointment: apply 5 times daily, continue for at least 3 days after complete healing
- Ganciclovir 0.15% eye gel: 1 drop 5 times daily until healing, then 1 drop 3 times daily for 7 days (where locally used/licensed)
Usually specialist-guided in UK eye care pathways. Advise transient stinging/blurred vision after application.
Oral antiviral (alternative/add-on, recurrent or deeper disease under specialist care)
- Aciclovir 400 mg orally five times daily for 7-10 days
- Valaciclovir 500 mg orally three times daily for 7-10 days
Adjust dose in renal impairment; maintain hydration to reduce crystal nephropathy risk.
Recurrence prophylaxis (selected frequent/severe recurrences)
- Aciclovir 400 mg orally twice daily for up to 12 months
- Valaciclovir 500 mg orally once daily (alternative regimen in some specialist protocols)
Specialist decision based on relapse burden and stromal risk; review renal function and adherence.
Anti-inflammatory therapy for stromal keratitis/uveitis
- Prednisolone acetate 1% eye drops (specialist initiated/tapered) with concurrent antiviral cover
- Cyclopentolate 1% eye drops (cycloplegia for painful anterior uveitis, specialist use)
Safety critical: topical corticosteroid monotherapy can worsen active epithelial HSV and risk corneal melt/perforation; only use under ophthalmology supervision.
Analgesia/supportive
- Paracetamol 1 g orally every 4-6 hours as needed (max 4 g/day)
- Ibuprofen 400 mg orally three times daily with food if appropriate
Avoid dispensing topical anaesthetic drops for home use due to corneal toxicity and delayed healing.
Surgical / Interventional
- Corneal debridement in selected epithelial disease (specialist procedure)
- Tissue adhesive/bandage contact lens or urgent tectonic procedures for impending/perforated cornea
- Amniotic membrane graft for persistent epithelial defects
- Penetrating or lamellar keratoplasty for visually significant scarring or structural failure
Complications
- Corneal scarring with permanent visual impairment
- Corneal neovascularization and irregular astigmatism
- Necrotizing stromal keratitis with corneal thinning/perforation
- Secondary bacterial or fungal keratitis
- Secondary glaucoma/raised intraocular pressure
- Recurrent anterior uveitis
- Neurotrophic (metaherpetic) keratopathy with non-healing epithelial defects
- Rare systemic spread (for example encephalitis/hepatitis), especially in immunocompromised patients
Prognosis
Blepharoconjunctivitis and uncomplicated epithelial keratitis often settle within about 1-2 weeks, including some spontaneous resolution of epithelial disease. Prognosis worsens with stromal involvement, recurrent attacks, immunosuppression, and delayed treatment; recurrence is common over years and cumulative episodes increase risk of scarring and visual loss. Most eyes retain useful vision, but a minority develop significant long-term impairment.
Sources & References
🏥BMJ Best Practice(1)
💊BNF Drug References(4)
- Aciclovir[management.pharmacological]
- Dexamethasone[contraindications]
- Inosine pranobex[management.pharmacological]
- Valaciclovir[management.pharmacological]
✅NICE Guidelines(1)
- Herpes simplex - ocular[overview]
📖Textbook References(20)
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 661)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1660)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1605)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 982)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1822)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 874)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1605, 1606)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1833)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 732, 733)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 661, 662)[context]
- Emergencies in - Obstetrics and Gynaecology, Second Edition (Stergios K. Doumouchtsis, S. Arulkumaran) (Z-Library).pdf(pp. 104, 105)[context]
- Emergencies in - Obstetrics and Gynaecology, Second Edition (Stergios K. Doumouchtsis, S. Arulkumaran) (Z-Library).pdf(pp. 144, 145)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 104, 105)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 105)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 337, 338)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 471)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 801)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1037)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 597, 598)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1255, 1256)[context]