This patient-education article is written by the cornea service at Suraj Eye Institute, Nagpur.

What is Viral Keratitis?

Viral keratitis is corneal infection by one of two herpes-family viruses:

  • Herpes simplex virus (HSV) — usually HSV-1. After childhood infection the virus lives latent in the trigeminal ganglion and reactivates from time to time, producing a corneal disease that is the commonest infectious cause of unilateral corneal blindness worldwide.
  • Varicella zoster virus (VZV) — the chickenpox virus, which reactivates in the ophthalmic branch of the trigeminal nerve as herpes zoster ophthalmicus (shingles affecting the eye) and can damage the cornea in several ways.

Both viruses cause not only direct epithelial infection but also longer-term stromal inflammation and reduced corneal sensation, which together account for most of the visual loss.

Viral Keratitis — Dendritic, Geographic and Zoster Pseudodendrite Patterns

HSV vs Zoster Epithelial Disease — Fluorescein Staining

HSV DENDRITIC ULCER

Branching ulcer with terminal bulbs (live virus)

HSV GEOGRAPHIC ULCER

Larger amoeboid — usually after inappropriate steroid drops

ZOSTER PSEUDODENDRITES

Raised mucous plaques — no terminal bulbs, stain less brightly

Reduced corneal sensation is a key shared feature of both viral keratitides.

Figure 1. Three classical fluorescein-staining patterns. HSV dendritic ulcer (left) is a fine branching epithelial ulcer with characteristic terminal bulbs at the tips. HSV geographic ulcer (centre) is a larger amoeboid epithelial defect, often seen after inappropriate steroid use on an early dendrite. Zoster pseudodendrites (right) are raised, mucoid epithelial plaques without terminal bulbs and stain less brightly than HSV dendrites.

The Spectrum of Disease

Both HSV and VZV cause more than one corneal pattern, often in the same eye over time:

  • Epithelial keratitis — the dendrite (HSV) or pseudodendrite (VZV) of acute live-virus infection
  • Stromal keratitis (disciform or interstitial) — immune-mediated inflammation of the corneal stroma, often weeks to months later, with risk of scarring and thinning
  • Endothelitis — inflammation of the endothelium with corneal oedema, sometimes mimicking a graft rejection
  • Neurotrophic keratitis — chronic non-healing epithelial defects due to reduced corneal nerve sensation, especially after zoster

Symptoms

Patients describe red, watery, photophobic eye with blurred vision; HSV dendritic disease often has surprisingly modest pain because the cornea is partially anaesthetic. In zoster, the eye disease is preceded or accompanied by the typical painful vesicular skin rash in the distribution of the ophthalmic nerve.

How Viral Keratitis is Diagnosed

Diagnosis is clinical. The fluorescein-staining pattern is usually distinctive. Reduced corneal sensation, measured with a wisp of cotton wool, is a key clue. PCR of the tear film or epithelial sample confirms the diagnosis in atypical cases.

Treatment

Treatment is tailored to the form of disease:

  • HSV epithelial keratitis — topical ganciclovir 0.15 % gel five times daily, or topical acyclovir 3 % ointment, for 1–2 weeks. Oral acyclovir or valacyclovir is an effective alternative.
  • HSV stromal / endothelial disease — topical corticosteroids carefully titrated, with concurrent oral antiviral cover (acyclovir 400 mg twice daily prophylaxis or higher dose during flares).
  • Zoster ophthalmicus — oral acyclovir 800 mg five times daily (or valacyclovir 1 g three times daily) for seven to ten days, started within 72 hours of the rash where possible. Topical lubricants and steroid drops for ocular involvement.
  • Long-term oral antiviral prophylaxis for patients with recurrent HSV disease, and for all patients undergoing corneal transplantation for HSV-related scarring (substantially reduces recurrence and rejection).
  • Neurotrophic keratitis — preservative-free lubricants, bandage contact lens, autologous serum drops, and amniotic membrane grafting for persistent defects.
Topical steroids must be used carefully in viral keratitis. Steroids worsen live epithelial infection (the dendrite) but are essential for stromal and endothelial disease. Their use should always be supervised by a cornea specialist and protected with oral antiviral cover.
✔ Viral Keratitis Care at Suraj Eye Institute

Our cornea service manages the full spectrum of HSV and zoster eye disease. We use topical ganciclovir or acyclovir for acute epithelial disease, structured topical steroid courses for stromal and disciform disease, and long-term oral antiviral prophylaxis to reduce recurrences and graft rejection in eyes that need keratoplasty.

Book a Cornea Consultation

Frequently Asked Questions

Will my dendrite come back?
Recurrence is possible — the virus lives permanently in the trigeminal ganglion and reactivates from time to time. Long-term oral acyclovir or valacyclovir prophylaxis substantially reduces the frequency of recurrences in patients who have had two or more episodes.

Is herpes simplex eye disease sexually transmitted?
No. HSV-1 ocular disease is almost always a reactivation of the childhood virus that most adults already carry. It is not transmitted to others through ordinary social contact. The acute open dendrite contains live virus and direct contact with the tears should be avoided, but the everyday risk to family members is very low.

Will I need a transplant?
Most HSV and zoster keratitis is controlled with topical and oral medication. Transplantation is reserved for eyes with significant central corneal scarring after the inflammation has been quiescent for at least a year and the patient is on oral antiviral prophylaxis to protect the graft.

My shingles rash has cleared but my eye still feels strange — why?
Herpes zoster damages the corneal nerves. The cornea may stay partly numb for months or permanently, which dries the surface and prevents the eye from registering normal sensations. Long-term lubrication, attention to lid closure and regular review are essential to prevent neurotrophic ulcers.

Can the zoster vaccine prevent this?
Yes — the recombinant zoster vaccine (Shingrix) substantially reduces the incidence of herpes zoster ophthalmicus in adults over 50, and is recommended for that age group where available.

← Back to All Cornea Topics