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Keratitis Herpetic (Herpes Simplex Keratitis)

What is Keratitis Herpetic?

Keratitis herpetic, also called herpes simplex keratitis (HSK), is an infection of the cornea—the clear, dome‑shaped front surface of the eye—caused by the herpes simplex virus (HSV). The virus most often involved is HSV‑1, the same pathogen that produces cold sores around the mouth, although HSV‑2 (more commonly linked to genital infections) can also cause eye disease.

The infection can affect any layer of the cornea, leading to three main clinical patterns:

• Epithelial keratitis: the virus infects the outermost corneal cells.
• Stromal keratitis: inflammation spreads into the deeper stromal layer, potentially causing scarring.
• Endothelial (disciform) keratitis: the innermost corneal layer swells, often with a characteristic disc‑shaped opacity.

Because the cornea is essential for focusing light, any damage can impair vision and, if untreated, may lead to permanent blindness. The condition is one of the leading causes of corneal blindness worldwide.<sup>1</sup>

Common Causes

Herpetic keratitis does not arise from a single factor; several conditions or circumstances can trigger viral reactivation or increase susceptibility.

• Primary oral/genital HSV infection (most often HSV‑1 acquired in childhood).
• Reactivation of latent HSV in the trigeminal ganglion due to fever, stress, or hormonal changes.
• Immunosuppression – e.g., HIV infection, organ transplantation, long‑term corticosteroid use.
• Topical eye‑drop steroids without antiviral coverage.
• Traumatic injury to the cornea or ocular surface (e.g., contact‑lens abrasion).
• Dry eye disease or ocular surface disease that disrupts the corneal epithelium.
• Exposure to ultraviolet (UV) light – sunlight can trigger viral reactivation.
• Systemic illnesses that cause fever or malaise, such as influenza.
• Neurological disorders affecting the trigeminal nerve (e.g., trigeminal neuralgia).
• Use of certain antiviral medications that paradoxically suppress immunity when discontinued abruptly.

Associated Symptoms

Symptoms can vary depending on which corneal layer is involved, but common manifestations include:

• Redness of the eye (conjunctival injection)
• Eye pain or burning sensation
• Blurred or decreased vision
• Photophobia (sensitivity to light)
• Foreign‑body sensation (“gritty” feeling)
• Watery or mucous discharge
• Visible corneal ulcer or dendritic (branch‑like) lesions on slit‑lamp examination
• Recurrent episodes after the initial infection has healed

In stromal or endothelial disease, patients may notice a gradual decline in visual acuity and may develop corneal haze or scarring.

When to See a Doctor

Herpetic keratitis can progress quickly; early evaluation is crucial. Seek medical attention if you experience any of the following:

• Sudden onset of eye redness with pain, especially if accompanied by visual changes.
• Photophobia that prevents normal activities.
• Presence of a visible ulcer, white spot, or branching lesion on the cornea.
• Recurrent episodes of eye irritation after a prior episode of HSV eye disease.
• History of HSV infection (cold sores) combined with new eye symptoms.
• Any loss of vision, even if mild.

Diagnosis

Diagnosing herpetic keratitis involves a combination of patient history, clinical examination, and occasionally laboratory testing.

1. Clinical History

Physicians ask about prior cold sores, recent fevers, stress, steroid use, contact‑lens wear, and systemic illnesses that could lower immunity.

2. Slit‑Lamp Examination

The gold standard. Using a high‑intensity light and magnification, eye‑care professionals look for characteristic signs:

• Dendritic lesions: branching, brush‑stroke edges that stain with fluorescein dye (typical of epithelial disease).
• Geographic or branching ulcers: larger, irregular lesions suggesting advanced epithelial disease.
• Stromal infiltrates or haze: indicating deeper inflammation.
• Endothelial “bump” or disciform keratitis: a localized swelling with a distinct border.

3. Laboratory Tests (when needed)

• Polymerase chain reaction (PCR) of corneal scrapings – highly sensitive for HSV DNA.
• Viral culture – less common due to low yield.
• Serologic testing – can confirm prior exposure but does not indicate active infection.

4. Imaging

Anterior segment optical coherence tomography (AS‑OCT) or confocal microscopy can assess depth of stromal involvement and monitor scarring.

Treatment Options

Therapy aims to eradicate the virus, control inflammation, prevent scarring, and preserve vision. Management differs by disease stage.

1. Antiviral Medications

• Topical antivirals:
  • Trifluridine 1% eye drops – 5‑6 times daily for 7‑10 days (first‑line for epithelial keratitis).
  • Penciclovir 1% ophthalmic gel – 4 times daily; useful for mild disease.
• Oral antivirals (systemic therapy):
  • Acyclovir 400 mg five times daily, or 800 mg three times daily for stromal disease.
  • Valacyclovir 500 mg twice daily (better bioavailability).
  • Famciclovir 500 mg twice daily.
  • Systemic therapy is preferred for stromal, endothelial, or recurrent disease.

2. Anti‑Inflammatory Therapy

• Corticosteroid eye drops: Only after antiviral coverage is established. Low‑dose prednisolone acetate 1% may be tapered over weeks to control stromal inflammation.
• Long‑term steroid use without antivirals can worsen viral replication, so strict supervision is essential.

3. Supportive & Home Care

• Artificial tears (preservative‑free) to relieve dryness and discomfort.
• Cold compresses for pain relief.
• Avoid rubbing the eye; use clean hands.
• Stop contact‑lens wear until cleared by an eye‑care professional.
• Protect eyes from UV light with sunglasses that block 100% UVA/UVB.

4. Surgical Interventions (rare)

When scarring threatens vision, procedures such as penetrating keratoplasty (full‑thickness corneal transplant) or lamellar keratoplasty may be required. Post‑operative antiviral prophylaxis is usually continued for at least a year.

Prevention Tips

While one cannot eliminate HSV entirely, the risk of ocular involvement can be lowered:

• Promptly treat oral or genital HSV outbreaks with prescribed antivirals.
• If you have a history of herpetic eye disease, keep an antiviral prophylaxis plan (e.g., daily valacyclovir) as advised by your physician.
• Avoid unnecessary topical steroid eye drops; always use them under antiviral cover.
• Practice good hand hygiene—wash hands after touching cold sores.
• Minimize exposure to intense sunlight; wear UV‑blocking sunglasses outdoors.
• Maintain adequate ocular surface health: use lubricating drops if you have dry eye, and manage blepharitis or meibomian gland dysfunction.
• For contact‑lens wearers: follow proper cleaning regimens, replace lenses and cases as directed, and avoid sleeping in lenses unless approved.
• Control systemic risk factors: manage diabetes, maintain a healthy immune system through nutrition, exercise, and adequate sleep.

Emergency Warning Signs

Key Take‑aways

• Herpetic keratitis is a viral infection of the cornea that can cause scarring and vision loss if untreated.
• Reactivation of HSV—often triggered by stress, UV light, or immune suppression—is the primary cause.
• Typical symptoms include eye redness, pain, photophobia, and characteristic dendritic lesions.
• Early diagnosis with slit‑lamp examination and prompt antiviral therapy are essential.
• Never use steroid eye drops alone; they must be combined with antivirals.
• Long‑term antiviral prophylaxis can prevent recurrences in high‑risk individuals.
• Seek urgent care for rapid vision loss, severe pain, or signs of perforation.

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References:

1. Mayo Clinic. “Herpes simplex eye infection.” https://www.mayoclinic.org
2. American Academy of Ophthalmology. “Herpes Simplex Keratitis.” https://www.aao.org
3. Cleveland Clinic. “Herpes Simplex Keratitis.” https://my.clevelandclinic.org
4. World Health Organization. “WHO Fact Sheet: Herpes Simplex Virus.” https://www.who.int
5. National Institutes of Health. “Herpes Simplex Virus – Eye Disease.” https://www.niaid.nih.gov

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