What is the leading cause of blindness in a patient with AIDS?

• A. HIV
• B. HSV
• C. CMV
• D. VZV

Answer: (C)

In AIDS, the most common cause of blindness is CMV retinitis. When CMV reactivates in someone with a severely weakened immune system (often with CD4 counts below about 50 cells/µL), it invades the retina and causes necrotizing retinitis with hemorrhages along the retinal vessels. This progressive damage can lead to retinal detachment and irreversible vision loss if not treated. The classic fundoscopic look is a granular, hemorrhagic retina described as a “pizza pie” pattern because of the combination of retinal whitening and intraretinal hemorrhages. Diagnosis is made by seeing these changes on eye exam, with confirmation from CMV testing in blood or intraocular fluid. Treatment combines systemic antiviral therapy (such as ganciclovir or valganciclovir) with ART to restore immune function, and sometimes local intravitreal antiviral injections to control the infection quickly. HSV and VZV can also cause retinal infections, but they are less common causes of blindness in AIDS, and HIV itself predisposing to opportunistic infections does not directly cause the retinal damage.