Herpetic keratitis: persistence of viral particles despite topical and systemic antiviral therapy. Report of two cases and review of the literature

Abstract

Objective: First, to characterize the histologic features of corneal buttons taken from two patients with chronic active herpetic stromal keratitis. Both eyes had suffered frequent and prolonged viral epithelial recurrences despite topical and systemic antiviral therapy and developed uniquely rapid deposition of chalklike stromal deposits. Second, to determine the clinical outcome of surgical intervention in eyes with such a pattern of herpetic disease.

Design: Patients received topical antiviral medication and 200 to 400 mg of acyclovir five times daily for 2 or 5 months until penetrating keratoplasty. They received tapered doses of acyclovir after surgery. Corneal buttons were evaluated with light microscopy and electron microscopy.

Results: Light microscopy of the specimens revealed calcium in the area of the chalklike deposits and a few cocci in the deep stroma. Electron microscopy showed numerous herpetic viral particles at various stages of maturity, including completely enveloped organisms, in the basal cells and keratocytes, and a few cocci in basal cells. Apart from one minor recurrence of a dendritic ulcer, both patients were free of herpetic disease at 13 and 22 months, required little to no medication, and had clear grafts.

Conclusions: Rapid calcium deposition in herpetic corneas may indicate disease of sufficient severity to warrant surgical intervention for removal of a stromal viral reservoir. Such intervention can stop further recurrences of keratitis that is poorly controlled by antiviral therapy. Such chronically diseased eyes may also harbor unsuspected bacterial infection.