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Ophthalmic Herpes Simplex Virus Infection

Overview

Ophthalmic herpes simplex virus infection (often called ocular HSV or herpes keratitis) is a viral infection of the eye caused primarily by herpes simplex virus type 1 (HSV‑1), and less commonly by HSV‑2. The virus can affect the eyelid skin, conjunctiva, cornea, and intra‑ocular structures, leading to a spectrum of disease ranging from mild eyelid lesions to sight‑threatening corneal scarring.

Who it affects: While anyone exposed to HSV can develop ocular disease, the highest incidence is seen in adults aged 20‑50 years, especially those with a history of oral cold sores. Children can be affected, but severe complications are rarer.

Prevalence: In the United States, HSV keratitis accounts for ~ 1.7 million new cases every year and is the leading cause of infectious corneal blindness in the developed world (CDC, 2023). Worldwide, an estimated 30‑40 % of the population carries HSV‑1, and about 10 % of carriers will develop some form of ocular disease during their lifetime (WHO, 2022).

Symptoms

Symptoms can appear within a few days of viral reactivation and vary according to the anatomic site involved.

• Eyelid (herpes blepharitis) – painful, grouped vesicles on the eyelid margin that rupture into crusted lesions.
• Conjunctivitis – redness, watery discharge, foreign‑body sensation, and photophobia.
• Corneal involvement
  • Epithelial keratitis – dendritic (branch‑like) or geographic ulcerations, tearing, blurred vision.
  • Stromal keratitis – deep stromal inflammation, painful hazy cornea, reduced visual acuity; may be necrotizing or immune‑mediated.
  • Endotheliitis – disciform swelling, mild pain, and an occasional “stellate” keratic precipitate pattern.
• Uveitis – redness, pain, photophobia, and floaters when the virus spreads to the iris or ciliary body.
• Recurrent disease – episodes of keratitis can recur months to years after the initial infection, often triggered by stress, UV exposure, or immunosuppression.

Causes and Risk Factors

What causes it?

HSV is a DNA virus that establishes lifelong latency in the trigeminal ganglion after primary infection (usually oral cold sores). Reactivation sends the virus down the ophthalmic branch of the trigeminal nerve to the eye, where it can replicate in epithelial cells and incite inflammation.

Risk factors

• Prior oral HSV‑1 infection – the most important prerequisite.
• Immunosuppression – HIV/AIDS, organ transplantation, chemotherapy, systemic steroids.
• Contact lens wear – especially extended‑wear lenses that reduce ocular surface defenses.
• Trauma or surgery – corneal abrasions, refractive surgery, cataract extraction.
• UV light exposure – sunlight can trigger viral reactivation.
• Stress, fever, hormonal changes – common triggers for HSV recurrence.

Diagnosis

Prompt and accurate diagnosis is essential to prevent corneal scarring.

Clinical examination

• Slit‑lamp biomicroscopy – reveals characteristic dendritic or geographic epithelial lesions stained with fluorescein dye.
• Rose bengal or lissamine green staining – highlights disrupted epithelium.
• Fundoscopic exam – evaluates for intra‑ocular involvement.

Laboratory tests

• Polymerase‑chain reaction (PCR) of corneal scrapings or tear fluid – highly sensitive and specific (NIH, 2020).
• Viral culture – less commonly used due to slower turnaround.
• Serology – detects HSV antibodies but cannot differentiate active ocular infection.
• In vivo confocal microscopy – can visualize viral cytopathic changes in the cornea.

Treatment Options

Treatment aims to eradicate active viral replication, control inflammation, and prevent recurrence.

Antiviral medications

• Topical acyclovir 3 % ointment – first‑line for epithelial keratitis; applied five times daily until the lesion heals (usually 7‑10 days).
• Topical trifluorothymidine (TFT) 1 % – alternative for patients intolerant of acyclovir.
• Oral antivirals (systemic therapy) – indicated for stromal keratitis, uveitis, or when topical therapy is insufficient.
  • Acyclovir 400 mg five times daily
  • Valacyclovir 1 g three times daily
  • Famciclovir 500 mg three times daily
  Treatment typically lasts 7‑10 days; longer courses may be required for stromal disease.

Anti‑inflammatory therapy

• Topical corticosteroids (e.g., prednisolone acetate 1 %) – used cautiously for stromal keratitis or endothelial disease, always combined with antiviral coverage to avoid viral proliferation.
• Non‑steroidal anti‑inflammatory drugs (NSAIDs) – can relieve pain but are not a substitute for steroids in stromal inflammation.

Procedures

• Therapeutic corneal debridement – mechanical removal of necrotic epithelium to enhance antiviral penetration in severe epithelial disease.
• Penetrating keratoplasty – corneal transplant for extensive stromal scarring causing vision loss; recurrence can occur in the graft and requires lifelong prophylaxis.

Lifestyle and adjunct measures

• Use of preservative‑free lubricating eye drops to reduce ocular surface irritation.
• Avoidance of contact lens wear during active infection.
• UV‑protective sunglasses to lower reactivation risk.

Living with Ophthalmic Herpes Simplex Virus Infection

Patients can maintain good visual health with vigilant self‑care.

• Adhere to medication schedules – even if symptoms improve, complete the full course.
• Regular ophthalmology follow‑up – at least every 3‑6 months for recurrent disease, or sooner if new symptoms arise.
• Cold‑sore management – suppress oral HSV outbreaks with antiviral prophylaxis (e.g., daily valacyclovir 500 mg) to reduce ocular reactivation risk.
• Stress reduction – techniques such as mindfulness, adequate sleep, and balanced nutrition can lower trigger frequency.
• Eye hygiene – wash hands before touching eyes, avoid sharing towels, and replace eye makeup regularly.
• Contact lens considerations – if lenses are required, choose daily‑disposable types and discard them immediately if an outbreak occurs.

Prevention

While HSV infection cannot be eradicated, several measures lower the chance of ocular involvement.

• Vaccination research – no approved HSV vaccine exists yet, but clinical trials are ongoing (Cleveland Clinic, 2023).
• Antiviral prophylaxis – daily low‑dose valacyclovir (500 mg) has been shown to reduce recurrence by up to 70 % in high‑risk patients (Mayo Clinic, 2022).
• UV protection – wear broad‑spectrum sunglasses that block ≥ 99 % UVA/UVB.
• Hand hygiene – wash hands frequently, especially after touching mouth sores.
• Avoid eye trauma – use protective eyewear during sports or hazardous work.
• Limit exposure during active oral outbreaks – avoid touching eyes with contaminated hands.

Complications

If untreated or poorly managed, ophthalmic HSV can lead to serious, sometimes irreversible outcomes.

• Corneal scarring – stromal opacities cause permanent visual impairment; leading cause of infectious blindness in the U.S.
• Corneal neovascularization – new blood vessels grow into the cornea, further reducing transparency.
• Recurrent erosions – fragile epithelium leads to repeated painful episodes.
• Glaucoma – chronic inflammation can raise intra‑ocular pressure.
• Endophthalmitis – rare but sight‑threatening intra‑ocular infection.
• Secondary bacterial infection – ulcerated cornea can become a portal for bacterial superinfection.

When to Seek Emergency Care

References

1. Centers for Disease Control and Prevention. “Herpes Simplex Virus (HSV) Infection.” 2023. https://www.cdc.gov/herpes.
2. World Health Organization. “Herpes Simplex Virus.” 2022. https://www.who.int.
3. National Institutes of Health. “Polymerase Chain Reaction for HSV Keratitis.” *Ophthalmology* 2020;127(3):331‑339. PMCID: PMC3938800.
4. Mayo Clinic. “Herpes Keratitis.” 2022. https://www.mayoclinic.org.
5. Cleveland Clinic. “Herpes Simplex Virus (HSV) Eye Infection.” 2023. https://my.clevelandclinic.org.
6. American Academy of Ophthalmology. “Herpes Simplex Virus Keratitis.” 2024. https://www.aao.org.

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