Predictors of recurrent herpes simplex virus keratitis

Purpose. Determinants of the natural history of recurrent herpes simplex vi rus (HSV) keratitis have not been consistently established, We assessed how previous HSV eye disease affects the risk of recurrent HSV keratitis and e valuated whether demographic and other variables play any predictive role. Methods. Three hundred forty-six patients in the placebo group of the Herpe tic Eye Disease Study's Acyclovir Prevention Trial who had experienced an e pisode of HSV eye disease in the previous year were followed up for 18 mont hs. Recurrences were categorized according to the type of involvement. Rela tive rates of recurrence were compared for categories of demographic variab les, types and number of previous ocular HSV episodes, previous nonocular H SV infection, and month of the year. Results. Fifty-eight (18%) of the 346 patients developed epithelial keratit is and 59 (18%) developed stromal keratitis during the 18 months of follow- up. Previous epithelial keratitis did not significantly affect the risk of epithelial keratitis (p = 0.84). In contrast, previous stromal keratitis in creased the risk of stromal keratitis 10-fold (p < 0.001), and the risk was strongly related to the number of previous episodes (p < 0.001). Age, gend er, ethnicity, and nonocular herpes were not significantly associated with recurrences, and no seasonal effects were observed. Conclusion. Among patients who experienced active ocular HSV disease in the previous year, a history of epithelial keratitis was not a risk factor for recurrent epithelial keratitis. In contrast, previous, especially multiple , episodes of stromal keratitis markedly increased the probability of subse quent stromal keratitis.