Cytomegalovirus (CMV) retinitis is a viral inflammation of the retina of the eye.

CMV retinitis is caused by a member of a group of herpes-type viruses. CMV is very common. Most adults have antibodies to CMV in their blood (indicating they have been infected) by age 40. Usually, CMV produces no symptoms. However, serious CMV infections can occur in people weakened immune systems due to:

• AIDS
• Chemotherapy
• Drugs that suppress the immune system for bone marrow or organ transplants

Note: Many patients with CMV retinitis have no symptoms.

Symptoms include:

• Blind spots
• Blurred vision
• Decreased visual acuity
• Floaters
• Loss of peripheral vision

Retinitis usually begins in one eye, but often progresses to the other eye. Without treatment, progressive damage to the retina can lead to blindness in 4 - 6 months.

Even with regular treatment, the disease can worsen to blindness. This may be because the virus becomes resistant to the drugs so that the drugs are no longer effective, or because the patient's immune system has deteriorated further.

Patients with CMV retinitis also have a chance of developing retinal detachment, in which the retina detaches from the nerves of the eye, causing blindness. Systemic CMV infection also can occur.

CMV retinitis is diagnosed through a standard ophthalmologic exam. Dilation of the pupils and indirect ophthalmoscopy will show signs of CMV retinitis.

CMV infection can be diagnosed with blood or urine tests that look for substances specific to the infection. A tissue biopsy can detect the viral infection and presence of CMV virus particles.