What is CMV Retinitis?To understand what CMV retinitis is we first need to break down the term into its basic parts.
- Cytomegalovirus (CMV) – CMV is a very common virus. In fact, between 50 and 85 percent of the population will test positive for CMV by the time they are 40 years old. In people with healthy immune systems, CMV is controlled by the body's natural defenses. However, in people with weakened immune systems--those on immunosuppressive therapies for cancer or organ transplant, or who are living with advanced HIV/AIDS--the virus can cause infection throughout the body. The weakened immune system can’t keep the virus at bay, allowing it to attack areas throughout the body.
- Retinitis – The retina is the light sensitive nerve tissue at the back of the eyeball that converts the images you see to electrical impulses which get interpreted by the brain. Without healthy retina, vision is impaired. The term retinitis means an inflammation or swelling of the retina caused by a variety of things, but most often as a result of infection. An inflammation of the retina will severely impair vision.
- CMV Retinitis – When you put together the two terms you get CMV retinitis, an inflammation of the retina caused by a CMV infection.
What are the Symptoms of CMV Retinitis?Unfortunately, the early symptoms of CMV retinitis can be mistaken for other common problems, such as failing vision or tired eyes. Talk to your doctor immediately if you have HIV and are experiencing any changes in vision.
The symptoms of CMV Retinitis include:
- Blurred vision
- Black spots in your visual field ("floaters")
- Eye pain
- Eye redness
- Pain or an uncomfortable feeling when exposed to light ("photophobia")
- Loss of vision
Keep in mind that having these symptoms doesn't necessarily mean you have CMV retinitis. See your doctor to find out for sure.
Who's Most at Risk for CMV Retinitis?Anyone with a weakened immune system, such as those people living with cancer or HIV and AIDS, is susceptible. In the case of someone living with HIV, risk is highest when his or her CD4 cell (T-cell) count falls below 50, but can occur anytime it is less than 100.
How is CMV Retinitis Treated?Traditionally, CMV Retinitis was treated with strong antivirals given intravenously (in the vein.) Newer medications given via surgical implants in the eye have proven to be more effective. These implants deliver high concentrations of antivirals directly to the infected area. Although these drugs are available, they carry their own side effects and can be less effective in severely immunosuppressed patients. In addition to getting the proper antiviral drugs and implants to treat CMV, the most important step is getting on medications to treat the HIV and improve the immune system. After successful treatment of the acute infection, which can be difficult to achieve, the oral medication Valcyte (valganciclovir) is used on a daily basis to prevent the infection from recurring in the eye, or developing in the other eye.
Preventing CMV RetinitisThe best way to reduce the risk of CMV retinitis is to improve the health of the immune system. If you are HIV positive, this is best done by taking HIV medications on a regular basis. The risk of CMV retinitis will decrease as the CD4 count rises. Also, yearly eye exams from an ophthalmologist (eye specialist) should become part of your routine health maintenance plan.