98CORNEAL INFECTIONS

30.What are the noninfectious manifestations of a herpetic keratitis?

Some ophthalmic findings of herpetic keratitis are not directly caused by the viral infection itself but instead relate to the immunologic response to the infection. Examples of this phenomenon include chronic keratouveitis (where large keratic precipitates are associated with corneal edema) and disciform and necrotizing keratitis (in which stromal infiltration with leukocytes and neovascularization can occur with an intact epithelium).

Corneal scarring and neurotrophic ulcers are signs of previous herpetic keratitis that can be visually debilitating and potentially necessitate surgical intervention with penetrating keratoplasty or tarsorrhaphy.

31.How should these infections be treated?

Herpes simplex epithelial keratitis and conjunctivitis should be treated with frequent topical trifluorothymidine (Viroptic) drops. Zovirax ointment can be added for skin involvement but cannot be used in or near the eye. Disciform stromal keratitis should be managed with topical corticosteroids and prophylactic antiviral agents.

All herpes zoster infections, regardless of ocular involvement, are treated primarily with oral acyclovir (800 mg PO five times/day for 7–10 days). Skin lesions should receive antibiotic ointment and warm compresses. Topical medications should be added as needed according to other ocular involvement (e.g., conjunctivitis, uveitis, glaucoma).

32.What is the role of topical corticosteroids in herpes simplex keratitis?

Although topical corticosteroids are contraindicated in the presence of active epithelial disease, such as in dendritic keratitis, their use in treating herpes simplex stromal keratitis

with an intact epithelium is beneficial. The Herpetic Eye Disease Study has documented that topical steroids and prophylactic antivirals are safe and effective in the treatment of stromal keratitis.

Wilhelmus KR, Gee L, Hauck WW, et al: Herpetic Eye Disease Study: A controlled trial of topical corticosteroids for herpes simplex stromal keratitis. Ophthalmology 101:1883–1895, 1994.

KEY POINTS: HERPETIC KERATITIS

1.Herpes simplex typically causes episodic keratitis.

2.Herpes zoster causes a dermatomal rash and chronic ulcers and pain.

3.Viroptic should be used for epithelial HSV keratitis.

4.Topical steroids are used for herpetic stromal keratitis.

5.All patients with VZV eye disease should receive oral acyclovir.

6.Oral acyclovir is beneficial only in certain types of HSV eye disease.

33.When should oral acyclovir be used in herpes simplex keratitis?

The Herpetic Eye Disease Study reported:

&Oral acyclovir (400 mg orally twice daily for 1 year) reduced the recurrence of ocular herpes simplex in patients who had one or more recurrent episodes.

&Oral acyclovir (400 mg orally five times/day for 10 weeks) may be helpful for treating herpes simplex iridocyclitis, but the results did not reach statistical significance.