Recurrent HSV-1 corneal epithelial lesions induced by timolol iontophoresis in latently infected rabbits.

Herpes simplex virus type 1 (HSV-1) ocular shedding and recurrent corneal epithelial lesions were assessed following ocular iontophoresis of 0.01% timolol at 0.8 mAmp for 8 min for 3 consecutive days in 17 rabbits latently infected with HSV-1 strain McKrae. The collection of ocular tear film for the detection of HSV-1 ocular shedding and the slit lamp biomicroscopic evaluation for HSV-1 epithelial lesions began on day 4 after the first iontophoresis and continued for 7 consecutive days. The tear film was collected on a Dacron swab with care being taken to avoid swabbing the corneal epithelium. The observed HSV-1 lesions were characterized as deep punctate lesions, dendritic lesions and geographic epithelial defects. The ratio of total days of eyes exhibiting HSV-1 epithelial lesions to the total number of observation days was 113/235 (48%). There were 46 punctate lesions, 27 dendritic lesions and 40 geographic epithelial defects. The ratio of positive swabs to total swabs was 77/235 (33%). Of the 113 positive lesion days, 65 (58%) were associated with a positive swab. Of the 77 positive swabs, 65 (84%) were associated with an epithelial lesion. Of the 122 negative lesion days, 110 (90%) were associated with a negative swab. Of the 158 negative swabs, 110 (70%) were associated with no epithelial lesions. By chi-square analysis, there was a significant association between HSV-1 swabs and HSV-1 lesions (P less than 0.001). These results demonstrate that ocular iontophoresis of timolol induces both HSV-1 ocular shedding and recurrent HSV-1 corneal epithelial lesions in rabbits latently infected with HSV-1 strain McKraw.