Cytomegalovirus Keratouveitis: Charted and Uncharted Territory

Abstract

This report provides an overview of the current understanding of cytomegalovirus (CMV) keratouveitis: pathophysiology, clinical features, management, and gaps in knowledge. The wide availability of polymerase chain reaction (PCR) testing of ocular fluid has demonstrated that CMV is an important cause of keratouveitis. PCR has more recently been used to offer a microbiologic indicator (viral load), which has the potential to be correlated to clinical severity and corneal endothelial cell density. This knowledge may be used to help guide management of this chronic disease. Overlapping clinical features of viral keratouveitis, such as ocular hypertension and keratic precipitates, present a challenge in distinguishing CMV from other viral etiologies. Important findings suggestive of CMV include “coin-shaped” precipitates and diffuse iris atrophy. Definitive diagnosis requires identifying CMV using molecular testing. While multiple treatment options appear effective in controlling flares, one challenge is preventing long-term morbidity associated with recurrent inflammation. Thus, further studies on CMV keratouveitis are warranted to understand the relationship between viral burden, clinical features, and the most appropriate antiviral therapy.