Herpes keratitis

Abstract

Herpes simplex virus-1 (HSV-1) infects the majority of the world's population. These infections are often asymptomatic, but ocular HSV-1 infections cause multiple pathologies with perhaps the most destructive being herpes stromal keratitis (HSK). HSK lesions, which are immunoinflammatory in nature, can recur throughout life and often cause progressive corneal scaring resulting in visual impairment. Current treatment involves broad local immunosuppression with topical steroids along with antiviral coverage. Unfortunately, the immunopathologic mechanisms defined in animal models of HSK have not yet translated into improved therapy. Herein, we review the clinical epidemiology and pathology of the disease and summarize the large amount of basic research regarding the immunopathology of HSK. We examine the role of the innate and adaptive immune system in the clearance of virus and the destruction of the normal corneal architecture that is typical of HSK. Our goal is to define current knowledge of the pathogenic mechanisms and recurrent nature of HSK and identify areas that require further study.

Figure 1

A) Slit lamp photograph of a patient with herpes stromal keratitis demonstrating opacity and neovascularization of the cornea.

Figure 2

A) Slit lamp photograph of a patient with HSK demonstrating central stromal opacity causing significant visual impairment. B) Slit lamp photograph of the same patient approximately two years after undergoing deep anterior lamellar keratoplasty demonstrating recurrence of HSV with large geographic ulcer stained with fluorescein dye and deep stromal vessels. Of note, the patient was noncompliant with post-operative medications and stopped all topical steroids and systemic antiviral therapy against medical advice