Purpose: To compare the rate of retinal detachment in a group of patients treated with intravitreal ganciclovir to the rate of retinal detachment in a group of patients treated with systemic ganciclovir.
Methods: A retrospective non-randomized comparative case series was conducted. The participants were 186 consecutive patients with cytomegalovirus (CMV) retinitis treated at two centres over the period from June 1990 to May 1997. Of the 186, 133 patients had systemic therapy of whom 113 had intravenous ganciclovir or foscarnet and 20 had oral ganciclovir, and 53 patients had intravitreal induction and maintenance therapy. The main outcome measure was the rate of retinal detachment, which was calculated using person-months-at-risk denominators. The effect measure used in the main comparative analysis was the hazard ratio obtained from multiple regression using the Cox proportional hazards model.
Results: Retinal detachment occurred in three of 53 patients in the intravitreal therapy group, one of 20 patients receiving oral maintenance therapy and 21 of 113 patients receiving intravenous maintenance therapy. The risk of retinal detachment with systemic therapy was 14-fold higher than with intravitreal therapy (P < 0.001)and up to fourfold higher with oral maintenance therapy.
Conclusions: Intravitreal therapy offers a significant advantage over systemic therapy in the treatment of CMV retinitis by substantially reducing the risk of CMV-related retinal detachment.