Cytomegalovirus Retinitis Across the Immunosuppression Spectrum: A Contemporary Framework for Risk Stratification, Diagnosis, and Vision-Preserving Therapy

Cytomegalovirus retinitis (CMVR) causes irreversible visual loss in patients with severe cellular immunodeficiency. Among people living with human immunodeficiency virus (HIV), risk is the highest with profound CD4+ T-cell depletion and absent or ineffective antiretroviral therapy. Other susceptible groups include transplant recipients, patients receiving treatment for malignancy or targeted immunosuppression, and children with inborn errors of immunity. This narrative review connects risk assessment, diagnosis, antiviral selection, and follow-up. Dilated retinal examination and serial imaging establish lesion activity and vision threat. Ocular-fluid polymerase chain reaction supports uncertain diagnoses, but results require interpretation alongside retinal findings and prior treatment. Antiviral selection requires concurrent assessment of lesion location, diagnostic certainty, renal function, marrow reserve, and systemic cytomegalovirus (CMV) disease. Systemic valganciclovir or ganciclovir provides the treatment backbone when feasible; immediately sight-threatening lesions may require adjunctive intravitreal therapy. Resistance or toxicity can necessitate alternatives, while evidence for newer agents remains limited. Maintenance duration depends on retinal inactivity and sustained immune recovery, with less certain stopping criteria outside HIV. Surveillance should address recurrence, immune recovery uveitis, retinal detachment, macular and vascular injury, and visual dysfunction beyond central acuity. Geographically diverse studies illustrate detection gaps, although heterogeneous populations and methods limit direct comparisons of burden and treatment outcomes.