CD4 and cytomegalovirus retinitis: Notably, the introduction of anti-HIV therapy (i.e., ART) has increased CD4+ T-cell counts and reduced the proportion of the population with CD4+ T-cell counts below 50 cells/μL, thus reducing the incidence of CMV retinitis [102,103,117,119,120,121]; however, it has not yet been eradicated [117].