Corneal transplantation for herpes simplex keratitis
While episodes of herpes simplex virus (HSV) epithelial keratitis can be treated effectively, recurrences may lead to corneal stromal scarring and decreased visual acuity. Consequently, herpetic stromal keratitis is a common indication for corneal transplantation in many published reports. However, there is a relatively high risk of graft failure in this patient group. The published literature on the management of herpetic keratitis by keratoplasty is difficult to interpret because diagnostic criteria are not standardised, duration of follow up is variable, and recipients of repeat grafts are included in many series. A rational basis for management of patients with visually significant herpetic keratitis awaits the resolution of certain key questions.
What is the comparative contribution of viral recurrence and allograft rejection to graft failure?
HSV has a natural ability to establish life long latency, a state in which the viral genome is not integrated, lytic viral genes are quiescent, and the metabolic functioning of the host cell is apparently undisturbed (reviewed by Cook and Hill1). Reactivation of latent infection in the trigeminal ganglion and/or the cornea itself leads to recurrent disease. In one retrospective study of 72 first penetrating keratoplasties for herpetic keratitis, in the absence of any antiviral prophylaxis, the rate of recurrence following transplantation was 44% at 2 years.2 However, graft failure in herpetic keratitis is most commonly attributed to allograft rejection. Cobo et al reported rejection to be the principal cause of graft failure in 64% and epithelial viral recurrence …
