To evaluate the safety and efficacy of foscarnet induction treatment of cytomegalovirus (CMV) retinitis in AIDS patients who have previously suffered severe dose-limiting ganciclovir-related myelosuppression, who are ineligible for ganciclovir treatment due to myelosuppression or who have clearly failed to have a therapeutic response to ganciclovir therapy. To assess the duration of clinical response. To evaluate the effect on quantitative CMV cultures of blood and urine. To determine the effect on recovery of HIV p24 antigen capture direct from plasma.