27th June 2023

Ophthalmic complications of HIV/ AIDS

Cytomegalovirus (CMV) retinitis

Cytomegalovirus is a herpes virus which causes eye infection in HIV. It is considered an AIDS-defining illness when present in the context of HIV. It is ubiquitous (~80% of people are seropositive) and causes eye disease predominantly in immunosuppressed individuals. Causes of underlying immunosuppression for CMV retinitis include:

• HIV
• Haematological malignancy
• Iatrogenic immunosuppression
• Solid organ transplantation

CMV is a DNA virus which establishes latency and is reactivated when there is severe immunosuppression. CMV retinitis is usually seen with a CD4+ T-cell count <50/μL. Additionally, on restoration of immunity once antiretroviral therapy is started, uveitis may occur. Most patients with CMV retinitis are asymptomatic and are detected on screening of the retina, as the inflammation often begins on the outside of the retina. Symptoms include:

• Blurred vision (most common)
• Flashing lights
• Scotomas
• Vitreal floaters

Based on clinical course, CMV retinitis can be classified into different clinical variants:

• Indolent variant – usually affects the peripheral retina, with granular retinal opacification, white lesions, with no bleeding
• Fulminant variant – dense, yellow-white lesions with opacification and haemorrhage
• Perivascular variant

CMV retinitis is usually a clinical diagnosis made by fundoscopy. Characteristic features of the retina on fundoscopy:

• Dense retinal whitening
• Usually follows blood vessels
• Haemorrhage may be present

Management in HIV patients involves high dose antiviral medications, including:

• Ganciclovir (preferred initial treatment option)
• Valganciclovir
• Foscarnet
• Cidofovir

Induction therapy is followed by maintenance therapy. Patients should be started on antiretroviral therapy in addition.