Ocular Herpes Infection (Herpes Simplex Keratitis)

Yes, herpes can affect the eyes, a condition known as ocular herpes or herpes simplex keratitis (HSK).

HSV-1 is mainly associated with oral and eye infections, while HSV-2 is more commonly linked to genital infections.
The incidence of ocular herpes is approximately 150 cases per 100,000 people in developed countries.
HSV is transmitted through direct contact and saliva, initially infecting the mouth and later residing in the trigeminal nerve root, where it can reactivate and cause eye infections.

Stress, trauma, surgery, menstruation
Nutritional deficiencies (e.g., vitamin A deficiency, more common in developing countries)
Ultraviolet (UV) exposure (e.g., excimer laser treatments, sunlight)
Immunosuppressive conditions (e.g., AIDS, weakened immune system)

Clinical Manifestations

Caused by HSV-2, transmitted from the mother’s birth canal in 80% of cases.
Can be limited to the eye or spread to other organs, requiring systemic acyclovir treatment.
May lead to keratitis, cataracts, uveitis, chorioretinitis, optic neuritis, or even cortical blindness.

Newborns are protected for the first six months by maternal antibodies.
Afterward, HSV is transmitted through saliva or direct contact, with an incubation period of 3-12 days.
Symptoms include:
- Fluid-filled vesicles on the eyelids
- Conjunctivitis and keratitis
- Systemic symptoms (fever, fatigue, swollen lymph nodes)
Typically, eyelid vesicles and conjunctivitis resolve within two weeks, but corneal infections persist longer.

Primarily affects the cornea rather than the eyelids and conjunctiva.
Classic “dendritic” (branch-like) epithelial lesions appear, which stain brightly with fluorescein dye.
Larger geographic ulcers may develop, which heal more slowly.
Reduced corneal sensitivity is common.
Metaherpetic ulcers can occur after the active virus clears, distinguished by their raised ulcer edges.
Deep corneal (stromal) involvement can lead to:
- Disciform edema (localized corneal swelling with mild inflammation)
- Necrotizing stromal keratitis (severe inflammation with corneal necrosis, similar to fungal or Acanthamoeba infections)
- Immune ring formation, which can increase intraocular pressure and cause glaucoma.

Patient history is essential.
Clinical examination includes:
- Corneal sensitivity testing
- Fluorescein and Rose Bengal staining
Laboratory tests:
- Papanicolaou stain for detecting Lipschütz bodies
- Viral culture (gold standard if active virus is present)
- ELISA (detects viral antigens or immune response)
- Polymerase Chain Reaction (PCR) (detects viral DNA fragments)

Acyclovir (oral and topical) is the most effective treatment due to its high corneal penetration and antiviral activity.
Oral acyclovir (400 mg, five times daily) reaches high levels in tear fluid, making it effective for recurrent keratitis.

Dendritic epithelial keratitis:
- Topical antiviral agents (e.g., trifluridine, ganciclovir)
- Artificial tears to prevent dryness
- Antibiotic drops to prevent secondary bacterial infections
Caution: Long-term topical antiviral use can cause epithelial toxicity, requiring switching to oral antiviralswhen necessary.

Once the epithelial defects heal, steroid eye drops (e.g., prednisolone) can be added to reduce inflammation.
Antiviral coverage must continue alongside steroid use to prevent viral reactivation.

Do NOT respond to antivirals.
Treatment includes:
- Artificial tears for lubrication
- Surgical interventions, such as:
  - Conjunctival flap surgery to cover the ulcer
  - Tarsorrhaphy (partial eyelid closure)

Oral acyclovir (400 mg twice daily) for 9-12 months significantly reduces recurrence risk.