After being stratified by the clinic and by stage of disease, patients are randomized to 1 of 2 treatment arms: intravenous (IV) cidofovir (Group I) or intraocular ganciclovir device plus oral ganciclovir (Group II). Group I: Cidofovir is administered IV once weekly for 2 consecutive weeks, then every 2 weeks thereafter. If progression occurs, oral ganciclovir is added to treatment or if this regimen is not tolerated, patients are treated according to the best medical judgment. Concurrent oral probenecid and intravenous hydration are administered with each cidofovir infusion. Group II: An intraocular ganciclovir device is surgically implanted at baseline and then every 6 to 8 months and ganciclovir is administered orally. If more than 1 progression or unacceptable toxicity occurs, patients are treated according to the best medical judgment.