What is Cytomegalovirus Retinitis?
Cytomegalovirus (CMV) retinitis is a serious eye infection caused by the
cytomegalovirus, a member of the herpesvirus family. It primarily affects the retina, the light-sensitive layer of tissue at the back of the eye. CMV retinitis is most commonly seen in individuals with weakened immune systems, such as those with
HIV/AIDS or those who have undergone organ transplants.
Who is at Risk?
The risk of developing CMV retinitis is significantly higher in individuals with compromised immune systems. This includes patients with
AIDS who have a CD4 count of less than 50 cells/mm³. Additionally, individuals on immunosuppressive therapy, such as organ transplant recipients, and those receiving chemotherapy are at increased risk. CMV retinitis is less common in healthy individuals due to their robust immune response.
What are the Symptoms?
Symptoms of CMV retinitis can vary but often include visual disturbances such as blurred vision, floaters, loss of peripheral vision, and in severe cases, sudden vision loss. These symptoms are indicative of the virus damaging the
retina, which can lead to blindness if not promptly treated. Patients may also experience a sensation of flashing lights, known as photopsia.
How is CMV Retinitis Diagnosed?
Diagnosis of CMV retinitis is primarily made through a
comprehensive eye examination by an ophthalmologist. This includes a dilated fundus examination to directly visualize the retina. The presence of characteristic lesions, including areas of retinal whitening and hemorrhages, can confirm the diagnosis. Additionally, polymerase chain reaction (PCR) testing of the aqueous or vitreous humor can detect CMV DNA, providing further confirmation.
What are the Treatment Options?
Treatment of CMV retinitis involves antiviral medications to control the infection and prevent further damage to the retina. The most common antivirals used are
ganciclovir,
foscarnet, and
cidofovir. These can be administered intravenously, orally, or via intraocular injections. The choice of drug and administration route depends on the severity of the disease, the patient's overall health, and potential drug side effects. Maintenance therapy is often required to prevent recurrence, especially in individuals with persistently low CD4 counts.
Can CMV Retinitis be Prevented?
Prevention of CMV retinitis focuses on maintaining a robust immune system and monitoring high-risk individuals closely. In patients with HIV/AIDS,
antiretroviral therapy (ART) can significantly reduce the incidence of CMV retinitis by improving immune function. For transplant recipients and other immunocompromised individuals, prophylactic antiviral therapy and regular ophthalmological examinations can aid in early detection and prevention of the disease.
What are the Complications?
If left untreated, CMV retinitis can lead to retinal detachment, a condition where the retina peels away from its underlying support tissue, leading to permanent vision loss. Even with treatment, some degree of vision loss may occur due to irreversible retinal damage. In addition, prolonged use of antiviral medications can result in drug toxicity and other complications, such as kidney damage, necessitating careful monitoring by healthcare providers.
How is CMV Retinitis Managed in the Long Term?
Long-term management of CMV retinitis involves regular follow-up appointments with an ophthalmologist to monitor the condition and adjust treatment as needed. Patients with HIV/AIDS should continue antiretroviral therapy to maintain immune function. Those on antiviral maintenance therapy may require adjustments based on their response to treatment and any adverse effects experienced. It's essential for patients to report any changes in vision promptly to their healthcare provider.
