A Randomized, Controlled Study of the Safety and Preventive Efficacy of Oral Ganciclovir When Used in Conjunction With An Intravitreal Ganciclovir Implant in the Treatment of Cytomegalovirus Retinitis

Inclusion Criteria Concurrent Medication: Allowed: * Topical drugs and ophthalmics. Patients must have: * AIDS. * Unilateral CMV retinitis. Exclusion Criteria Co-existing Condition: Patients with the following symptoms or conditions are excluded: * Chronic, clinically significant diarrhea, nausea, abdominal pain,or other symptoms of uncontrolled gastrointestinal disease. * Ocular opacities (corneal, aqueous, lens, or vitreous) preventing ophthalmologic retinal assessment of fundus photography. * Acute retinal necrosis or any other intraocular condition that might preclude study completion. * Ocular condition requiring immediate surgery. * Unable to have long-term IV catheter placement. Concurrent Medication: Excluded: * Vidarabine. * Amantadine hydrochloride. * Cytarabine. * FIAC or FIAU. * Idoxuridine. * Ribavirin. * Valacyclovir. * Foscarnet. * CMV hyperimmune globulin. * Soluble CD4. * Trichosanthin. * Imipenem-cilastatin. * Isoprinosine. * Levamisole. * Interferon. * Other investigational drugs. Patients with the following prior conditions are excluded: * History of previous invasive intraocular surgery of any kind in the involved eye or any condition for which ocular surgery is contraindicated. * History of hypersensitivity to acyclovir or ganciclovir. Prior Medication: Excluded: * Any prior oral ganciclovir in a CMV retinitis treatment protocol OR more than 4 months of prior oral ganciclovir in a prophylaxis study (per amendment). * Prior intravitreal ganciclovir implant. * More than two prior induction dose courses of IV anti-CMV therapy (per amendment). * Intravitreal injection of any antiviral medication within the past 4 weeks (per amendment).