To demonstrate the efficacy of oral ganciclovir in preventing new cytomegalovirus (CMV) disease in AIDS patients with unilateral CMV retinitis treated with an intravitreal ganciclovir implant. To compare safety and tolerance, time to progression, quality of life, and survival among patients treated with an intravitreal ganciclovir implant, with and without oral ganciclovir, versus standard intravenous (IV) ganciclovir therapy.