Herpes Keratitis – Comprehensive Medical Guide

Overview

Herpes keratitis is an infection of the cornea (the clear front surface of the eye) caused primarily by the herpes simplex virus type 1 (HSV‑1). It is the leading cause of infectious blindness in the United States and many industrialized nations. The virus can remain dormant in the trigeminal ganglion and reactivate, leading to recurrent episodes that may scar the cornea and impair vision.

There are several clinical forms, the most common being:

• Epithelial keratitis – ulceration of the corneal epithelium.
• Stromal keratitis – inflammation of the deeper corneal stroma, often immune‑mediated.
• Endothelial (disciform) keratitis – inflammation of the innermost corneal layer.

Understanding the disease’s natural history helps guide treatment and prevention strategies.

Symptoms Checklist

• Redness of the eye
• Eye pain or a gritty sensation
• Blurred or decreased vision
• Photophobia (sensitivity to light)
• Watery or mucous discharge
• Foreign‑body sensation
• Recurrent episodes of the above symptoms, often after a cold sore outbreak
• Visible corneal ulcer or dendritic (branch‑like) lesions on slit‑lamp examination

Risk Factors

• Prior infection with HSV‑1 (most people acquire it in childhood as oral cold sores)
• Immunosuppression – HIV infection, organ transplantation, systemic steroids, chemotherapy
• Frequent ocular trauma or surgery (e.g., cataract extraction, LASIK)
• Contact lens wear, especially extended‑wear lenses
• Stress, fever, or ultraviolet (UV) light exposure that can trigger viral reactivation
• Age – incidence peaks in adults 20‑50 years old, but can occur at any age

Diagnosis

Diagnosis is primarily clinical, performed by an eye‑care professional (ophthalmologist or optometrist) using the following tools:

• Slit‑lamp examination – reveals characteristic dendritic or geographic epithelial lesions, stromal infiltrates, or disciform edema.
• Fluorescein staining – highlights epithelial defects; dendritic lesions fluoresce bright green.
• Corneal scraping for viral culture or PCR – reserved for atypical cases or when the diagnosis is uncertain.
• Serologic testing – not routinely required but may be used to confirm HSV exposure.

Because untreated stromal disease can lead to permanent scarring, early recognition is essential.

Treatment Options

Medical Therapy

• Topical antiviral agents – Trifluridine 1% drops (five times daily) or Ganciclovir 0.15% gel (five times daily) for epithelial disease.
• Oral antivirals – Acyclovir 400 mg five times daily, Valacyclovir 500 mg three times daily, or Famciclovir 250 mg three times daily for 7‑10 days. Oral therapy is preferred for stromal or recurrent disease.
• Corticosteroid eye drops – Low‑dose prednisolone acetate 1% (or equivalent) may be added for stromal keratitis to control immune inflammation, but only under close supervision because steroids can worsen active viral replication.
• Pain control – Oral analgesics (acetaminophen or ibuprofen) and cycloplegic drops (e.g., homatropine) to relieve ciliary spasm.

Adjunctive / Home Care

• Artificial tears (preservative‑free) to maintain ocular surface lubrication.
• Cold compresses for comfort if there is significant redness or swelling.
• Strict hand hygiene and avoiding touching the eyes.
• Temporary discontinuation of contact lens wear until the infection resolves.

Prevention

• Prompt treatment of oral HSV‑1 outbreaks to reduce viral load.
• Prophylactic oral antivirals (e.g., Valacyclovir 500 mg daily) for patients with frequent recurrences or after corneal surgery.
• Use of UV‑blocking sunglasses outdoors to limit UV‑induced reactivation.
• Good contact‑lens hygiene: replace lenses as recommended, clean cases regularly, and avoid overnight wear unless approved.
• Manage systemic risk factors – control diabetes, avoid unnecessary systemic steroids, and maintain a healthy immune system.

Living With Herpes Keratitis

• Regular ophthalmology follow‑up – at least every 3‑6 months, or sooner if symptoms change.
• Medication adherence – complete the full antiviral course even if symptoms improve.
• Vision protection – wear sunglasses with 100 % UV protection; consider tinted lenses if photophobia persists.
• Monitor for scarring – any new visual distortion, halos, or decreased acuity warrants prompt evaluation.
• Stress management – adequate sleep, balanced diet, and stress‑reduction techniques may lower reactivation risk.
• Educate family and caregivers about the contagious nature of oral HSV during active lesions.

When to Seek Emergency Care

Immediate medical attention is required if you experience any of the following:

• Sudden, severe eye pain or a feeling of a foreign body that does not improve.
• Rapid loss of vision or a noticeable “shadow”/dark spot in the visual field.
• Marked increase in redness, swelling, or pus discharge.
• Sensitivity to light that becomes intolerable.
• Signs of corneal ulcer perforation (e.g., sudden decrease in eye pressure, watery discharge, or a visible defect).

Medical Disclaimer: This guide is for informational purposes only and does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified health‑care provider for personalized care. The content herein reflects current knowledge as of 2026 and may not include the latest research.

References

1. Mayo Clinic. “Herpes simplex eye infection (herpes keratitis).” https://www.mayoclinic.org/diseases‑conditions/herpes‑simplex‑eye‑infection
2. Centers for Disease Control and Prevention (CDC). “Herpes Simplex Virus (HSV) – Ocular Infection.” https://www.cdc.gov/herpes/
3. National Institutes of Health (NIH) – National Eye Institute. “Herpes Keratitis.” https://www.nei.nih.gov/learn‑about‑eye‑health/eye‑conditions/herpes‑keratitis
4. Cleveland Clinic. “Herpes Keratitis: Symptoms, Diagnosis, and Treatment.” https://my.clevelandclinic.org/health/diseases/21571-herpes‑keratitis
5. Johns Hopkins Medicine. “Herpes Simplex Virus Eye Infection.” https://www.hopkinsmedicine.org/health/conditions‑and‑diseases/herpes‑simplex‑virus‑eye‑infection