Ocular herpes simplex - Symptoms, Causes, Treatment & Prevention

Overview

Ocular herpes simplex (HSV keratitis, conjunctivitis, or uveitis) is an infection of the eye caused by the herpes simplex virus, most commonly HSV‑1 and, less often, HSV‑2. The virus can affect any surface of the eye—including the eyelid, conjunctiva, cornea, and deeper structures such as the iris and retina.

While anyone can contract ocular HSV, it is most prevalent in adults aged 20‑50 years. The World Health Organization estimates that approximately 67% of the global population is infected with HSV‑1, and up to 20% of those individuals will develop an eye infection at some point in their lives. In the United States, the Centers for Disease Control and Prevention (CDC) reports ~1.6 million new cases of HSV ocular disease each year, making it a leading cause of infectious corneal blindness worldwide.¹

Symptoms

Ocular HSV can present in several patterns, depending on the ocular structure involved. Common symptoms include:

• Redness: Persistent or episodic redness of the conjunctiva or cornea.
• Eye pain or burning: Ranges from mild irritation to sharp, gnawing pain, especially with corneal involvement.
• Blurred vision: Frequently worsens during active lesions.
• Tearing or watery discharge: Excess lacrimation is typical.
• Photophobia (light sensitivity): Discomfort in bright environments.
• Foreign‑body sensation: Feeling of grit or sand in the eye.
• Swelling of the eyelids (blepharitis): Often accompanies conjunctival infection.
• Visible lesions: Dendritic (branch‑like) ulcers on the cornea, vesicles on the eyelid margin, or raised papillae on the conjunctiva.
• Decreased visual acuity: May be temporary or permanent if scarring occurs.
• Recurrent episodes: After the initial outbreak, the virus can reactivate, causing milder but recurring symptoms.

Causes and Risk Factors

What causes ocular HSV?

The virus enters the eye through direct contact with infected secretions (e.g., saliva, tears) or by self‑inoculation from a cold sore. Once in the ocular tissues, HSV replicates, causing inflammation and cell death. After the acute phase, the virus becomes latent in the trigeminal ganglion and can reactivate later.

Key risk factors

• Previous oral or genital HSV infection: Most ocular cases arise from reactivation of a prior oral HSV‑1 infection.
• Immune suppression: HIV/AIDS, organ transplantation, chemotherapy, or long‑term corticosteroid use increase reactivation risk.
• Eye trauma or surgery: Corneal abrasions, LASIK, or cataract surgery can trigger viral reactivation.
• Stress, fever, or UV light exposure: These can precipitate outbreaks.
• Contact lens wear: Especially if lenses are cleaned improperly, they can harbor HSV.
• Age: Peak incidence in 20‑50‑year‑old adults, but children and elderly can be affected.

Diagnosis

Accurate diagnosis combines a detailed history, visual examination, and sometimes laboratory testing.

Clinical examination

• Slit‑lamp biomicroscopy: Allows the clinician to see characteristic dendritic or geographic ulcers on the cornea.
• Fluorescein staining: Highlights epithelial defects; dendritic lesions fluoresce bright green with branching patterns.
• Fundoscopy: Used if posterior segment involvement (e.g., retinitis) is suspected.

Laboratory tests

• Polymerase chain reaction (PCR): The most sensitive test; detects HSV DNA from tear fluid or corneal scrapings.
• Viral culture: Less commonly used because it is slower and less sensitive.
• Serology: Detects HSV antibodies but cannot differentiate ocular infection from prior exposure.

When to refer

If a primary care provider suspects HSV keratitis, an urgent referral to an ophthalmologist is warranted because delayed treatment can lead to permanent scarring.

Treatment Options

Therapy aims to eradicate active virus, control inflammation, and prevent recurrences.

Antiviral medications

• Topical antiviral ointments: Trifluridine 1% drops (5‑times daily) are effective for mild epithelial keratitis but can cause toxicity with prolonged use.
• Topical corticosteroid + antiviral: For stromal keratitis, a steroid (e.g., prednisolone acetate 1%) is combined with oral antivirals to reduce inflammation while preventing viral replication.
• Oral antivirals (first‑line):
  • Acyclovir 400 mg five times daily
  • Valacyclovir 500 mg three times daily
  • Famciclovir 250 mg three times daily
  Treatment usually lasts 7‑10 days for an acute episode; longer suppressive therapy (e.g., valacyclovir 500 mg daily) may be prescribed for frequent recurrences.

Procedural interventions

• Debridement: Gentle removal of the necrotic epithelium under a slit lamp can improve drug penetration.
• Therapeutic corneal transplant (penetrating keratoplasty): Considered for severe scarring causing vision loss.

Lifestyle and supportive care

• Artificial tears to relieve dryness.
• Pain control with acetaminophen or ibuprofen (avoid NSAIDs if corneal ulceration is deep).
• Close eye hygiene—avoid rubbing.

Living with Ocular Herpes Simplex

Chronic management focuses on minimizing recurrences and protecting vision.

Daily management tips

1. Adhere to antiviral regimen: Even if symptoms improve, complete the prescribed course.
2. Use sunscreen on eyelids: UV exposure can trigger reactivation.
3. Practice hand hygiene: Wash hands frequently, especially after touching the face.
4. Avoid eye makeup during outbreaks: Discard used mascara or eyeliner to prevent reinoculation.
5. Regular ophthalmologic follow‑up: At least once a year, or sooner if symptoms recur.
6. Manage systemic triggers: Reduce stress, maintain a healthy sleep schedule, and treat concurrent illnesses promptly.

Emotional wellbeing

Recurrent eye disease can cause anxiety about vision loss. Counseling, support groups, or talking with a mental‑health professional can be beneficial. The American Academy of Ophthalmology notes that patients with frequent HSV recurrences often benefit from structured education and reassurance.

Prevention

• Suppressive antiviral therapy: For individuals with ≥4 episodes per year, daily valacyclovir (500 mg) reduces recurrence risk by up to 80% (NEJM, 2015).²
• Avoid direct contact with active oral lesions: Do not touch a cold sore and then your eyes.
• Proper contact‑lens care: Use recommended cleaning solutions; replace lenses as directed.
• UV protection: Wear wide‑brimmed hats and UV‑blocking sunglasses.
• Vaccination research: A prophylactic HSV vaccine is under investigation; stay informed about clinical trial results.

Complications

If untreated or inadequately treated, ocular HSV can lead to serious outcomes:

• Corneal scarring: Permanent opacity causing vision loss.
• Stromal keratitis: Immune‑mediated inflammation that can progress to ulceration.
• Endothelial decompensation: Leads to corneal edema.
• Recurrent epithelial keratitis: Increases risk of stromal disease.
• Herpes zoster ophthalmicus (if HSV‑2 co‑infected): Can affect the optic nerve.
• Vision‑threatening complications: Including glaucoma, cataract formation (from steroid use), and, rarely, retinal necrosis.

When to Seek Emergency Care

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Sources:

1. Centers for Disease Control and Prevention. “Herpes Simplex Virus – Ocular Infection.” CDC, 2023. https://www.cdc.gov/herpes/index.html
2. Shah SU et al. “Long‑term Suppressive Therapy with Valacyclovir for Recurrent Herpetic Keratitis.” New England Journal of Medicine, 2015; 373:2095‑2103.
3. Mayo Clinic. “Herpes eye infection (herpes keratitis).” 2022. https://www.mayoclinic.org
4. American Academy of Ophthalmology. “Herpes Simplex Virus Keratitis.” 2021. https://www.aao.org
5. World Health Organization. “Herpes Simplex Virus.” Fact sheet, 2022. https://www.who.int