Cytomegalovirus (CMV) retinitis

Cytomegalovirus is a double-stranded DNA herpes virus to which most individuals are exposed by early adulthood. It seldom produces clinical illness in healthy individuals.
Patients with poor immune function, however, are liable to reactivation of CMV virus in multiple organs including the retina. CMV retinitis occurs almost exclusively in immunocompromised patients, such as those with HIV/AIDS. The typical presentation is with a slowly-progressive, haemorrhagic necrotising retinitis in patients with CD4+ lymphocyte counts below 50 cells mm-3.

Symptoms

The most common symptoms are progressive, painless blurring or loss of vision with floaters in one or both eyes. A minority of patients – particularly with peripheral retinal involvement – are asymptomatic.