Clinical features:

Ø  Herpes simplex keratitis occurs in two forms – primary and recurrent.

Ø  Primary infection of any of the 3 branches (ophthalmic, maxillary, mandibular) of cranial nerve V leads to latent infection of nerve cells in trigeminal ganglion.

Ø  Interneuronal spread of HSV within ganglion allows patients to develop ocular disease without ever having had primary ocular HSV infection.

Ø  Recurrent infection has been thought of as reactivation of virus in the sensory ganglion.

Ø  The disease manifests as vesicular blepharoconjunctivitis occasionally with corneal involvement as punctate keratitis.

Ø  The patient presents with irritation, photophobia, reduction in vision (when central cornea is affected) and corneal anaesthesia.

Ø  Corneal ulceration and scarring can occasionally be the only sign of recurrent herpetic infections. Typical branching, linear pattern with feathery edges and terminal bulbs at ends are visualized by fluorescein staining.

Pharmacological treatment:

1.  Antiviral drugs

-  Trifluridine and acyclovir are much more effective in epithelial disease than others.

-  Idoxuridine and trifluridine are frequently associated with toxic reactions.

-  Oral acyclovir may be useful in treatment of severe herpetic eye disease particularly in atopic individuals.

-  For active treatment 400 mg five times daily in non immunocompromised patients.

-  800 mg five times daily in compromised and atopic patients.

-  Prophylactic dosage in recurrent disease is 400 mg twice daily.

-  Famciclovir or valacyclovir may also be used.

2.  Topical corticosteroids accelerate corneal thinning, increasing risk of corneal perforation

3.  Epithelial debridement is an effective way to treat dendritic keratitis before acyclovir. Infected epithelium is easy to remove with tightly wound cotton tip applicator.

4.  Adjunctive therapy with topical antiviral accelerates epithelial healing

5.  Surgical management like penetrating keratoplasty is indicated for visual rehabilitation in patients with severe corneal scarring. It should not be undertaken until herpetic disease

has been inactive for many months.