Cytomegalovirus (CMV) Retinitis

Serious Eye Complication Associated with Advanced HIV Disease

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Image Credit: Bruce Blausen

Eye problems are not uncommon in people with HIV, the complications of which can occur at any stage of infection but most predominantly when the immune system has been significantly suppressed.

One of the most common eye disorders is cytomegalovirus (CMV) retinitis, which typically occurs with advanced HIV infection and, if left untreated, can cause blindness—often within 2-6 months of initial diagnosis.

What is CMV Retinitis?

Cytomegalovirus (CMV) is a very common viral pathogen that rarely causes serious disease in those with intact immune systems. The virus is so prevalent, in fact, that between 50-80% percent of the world's population will test positive for CMV by the time they are 40 years of age.

In people with healthy immune systems, CMV is controlled by the body's natural defenses. In those with compromised immune systems—such as individuals on immunosuppressive therapies for cancer or organ transplant, as well as those with late-stage HIV—the virus can cause infection throughout the entire body.

When CMV presents in the eye, it can cause retinitis, a condition which can inflame and damage the nerve tissue on the back of the eyeball. This section of the eye, called the retina, is where light-sensitive nerves emit electrical impulses to the brain, which the brain then interprets as vision.

The progressive swelling and inflammation can profoundly and permanently damage retinal nerve cells, resulting in visual impairment and, in many cases, blindness in one or both of the eyes.

Symptoms of CMV Retinitis

The early symptoms of CMV retinitis can often be mistaken for other common problems. Most usually they develop when a person's CD4 count (the measure of immune function) is below 50 cells/mL but can also occur when it is under 100 cells/mL.

(AIDS is defined by, among other things, a CD4 count of under 200 cells/mL.)

Symptoms can include:

  • Blurred vision
  • Black spots in your visual field ("floaters")
  • Eye pain
  • Eye redness
  • Pain or discomfort when exposed to light (photophobia)
  • Loss of vision

Treating CMV Retinitis

Traditionally, CMV retinitis is treated with strong antivirals given intravenously, sometimes with a combination of drugs. In some cases, doctors may opt to deliver medications through a surgical implant of the drug ganciclovir, which is inserted directly into the eye. This is most frequently done when a patient has resistance to intravenously delivered ganciclovir.

After treatment of acute CMV infection, patients will most commonly be put on a daily oral antiviral treatment, which can reduce the risk of disease recurrence. Patients untreated for HIV will also be prescribed antiretroviral therapy (ART) to assist with reconstitution of immune function and reduce the risk of HIV-associated opportunistic infections (OIs).

Preventing CMV Retinitis

The best way to reduce the risk of CMV retinitis is to prevent the deterioration of your immune system. It is why current treatment guidance strongly supports the implementation of ART at the time of diagnosis.

Unlike previous treatment recommendations, in which ART was initiated based on CD4 count, HIV therapy today is indicated for all people diagnosed with HIV, irrespective of age, income, ethnicity, geographic location, or immune status.

For people with marked immune suppression, it is advised that a yearly eye exam be performed by a qualified ophthalmologist (not an optician) to proactively assess any changes that may occur on or within the eye.

Learn more about HIV-related eye disorders, which includes a complete list of HIV-associated complications of the eye.


Varani, S. and Landini, M. "Cytomegalovirus-induced immunopathology and its clinical consequences." Herpesviridae. 2011; 2(6):6.

Hodge, W.; Boivin, J.; Shapiro, S.;et al. "Iatrogenic risk factors for cytomegalovirus retinitis." Canadian Journal of Ophthalmology. December 2005; 40(6): 701-710.