Prior to the introduction of HAART, CMV retinitis affected 30–40 % of HIV-infected individuals, with visual loss primarily due to CMV involvement of the posterior retina and retinal detachment; it has also been suggested that upon careful examination, 30 % of patients with CD4 + T lymphocytes counts below 50 cells/μL would be suffering from CMV retinitis [4]. This evidence concerns the gene CD4 and cytomegalovirus retinitis.