Cytomegalovirus Retinitis (CMV Retinitis)

What Is Cytomegalovirus Retinitis (CMV Retinitis)?

Cytomegalovirus (CMV) Retinitis is a virus that may infect the retina and potentially cause irreversible vision loss due to retinal detachment or destruction. It is most often diagnosed in patients with a severely compromised immune system, including those with AIDS or those on chronic immunosuppressive therapy following organ transplantation. Although a large percentage of the human population is infected with the virus, only those with significant compromise of the immune system develop retinitis. During the height of the AIDS epidemic, nearly 30 percent of AIDS patients developed CMV retinitis. Those at highest risk have a CD4+ T-lymphocyte count less than 50 cells/mm3 (normal >500 cells/mm3). With the advent of HIV-fighting antiretroviral therapy in the late 1990s, the incidence of CMV retinitis declined dramatically. 


  • Blurry vision
  • Floaters
  • Increased sensitivity to light
  • Loss of peripheral vision

The symptoms described above may not necessarily mean that you have CMV retinitis. However, if you experience one or more of these symptoms, contact your ophthalmologist for a complete exam.


CMV retinitis is caused by retinal infection with cytomegalovirus in patients with moderate to severe immune compromise.

Risk Factors

  • Immunosuppressive therapy (eg. after organ transplantation)
  • Cancer chemotherapy
  • Advanced age

Tests and Diagnosis

CMV retinitis is usually diagnosed based on the findings of a complete eye examination. In atypical or unusual cases, a small specimen of fluid may be withdrawn from the eye for laboratory testing. 

Treatment and Drugs

Recent advances in oral medications have allowed us to treat CMV retinitis with high-dose oral valganciclovir with or without direct injection of antiviral drugs into the eye. It is important for the patient’s physician to monitor blood work during the treatment course. Treatment of the underlying systemic disease (AIDS, leukemia, etc.) is of great importance for reducing severity of retinitis and preventing recurrence. The goal of treatment is to retain present vision and to limit retinal damage. Unfortunately, individuals who do not receive or respond to treatment may progress to retinal detachment, severely limiting visual potential.

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Reviewed by Mark W. Johnson, M.D.