Which virus is the leading cause of blindness in AIDS patients?

• A. HSV
• B. VZV
• C. HIV
• D. CMV

Answer: (D)

CMV retinitis stands out in AIDS because CMV, a herpesvirus that can persist in a latent state and reactivate when the immune system is severely compromised, is the most common cause of sight-threatening retinal infection in this setting. When CD4 counts fall, especially below about 50 cells/µL, CMV reactivation can invade the retina, causing necrotizing retinitis with hemorrhages along the retinal vessels. The resulting progressive retinal damage leads to vision loss and can progress to blindness if not treated. HSV and VZV can cause viral eye infections, but they are far less common causes of retinitis in AIDS. HIV itself weakens immune defenses but does not directly cause the retinal lesions seen with CMV; it’s the opportunistic CMV infection that drives this complication. Management targets both controlling CMV with antivirals (like ganciclovir or valganciclovir, with possible intravitreal therapy) and improving immune function with antiretroviral therapy to reduce recurrence risk.