To evaluate the safety and tolerance of long-term ganciclovir (DHPG) therapy for newly diagnosed macular threatening Cytomegalovirus (CMV) retinitis in AIDS patients. To evaluate the clinical response to a 52 week course of intravenous DHPG therapy. To evaluate the safety and tolerance of long-term DHPG with concurrent treatment with zidovudine (AZT). (Patients utilizing treatment with other anti-retroviral drugs will be considered for study entry on a case by case basis.) To determine survival in this group of patients with AIDS and CMV retinitis.