AIDS patients can contract infections from several opportunistic viruses, bacteria, fungi, protozoa which would not usually cause infection otherwise in healthy persons. The cytomegalovirus (CMV) is the kingpin of all these infectious agents. CMV retinopathy develops 0in 15 to 25 percent of patients with AIDS. It is an ubiquitous virus. While CMV does not cause disease in healthy people throughout their lives, it can “reactivate” especially in people whose immune systems cannot fight back. CMV can infect any part of the body. When it infects the retina, it causes CMV retinitis.
The retina is a thin, light-sensitive tissue at the back of the eye. Like a film in a camera, the retina reacts to light that has been focused by the lens. Nerve endings in the retina send signals to the brain along with the optic nerve, and the brain changes the signals into the pictures that one see. CMV reaches different part of the retina through the blood vessels and can permanently destroy retinal cells through inflammation and other harmful effects of the virus.Floaters may be the earliest warning sign of CMV retinitis. They appear as small dark specks that move slowly throughout the visual field and are best seen against a blue or white background. An increase in the number of floaters is an important early warning sign. Brief flashes of light that vary in shape occur less frequently in the early stages of CMV retinitis and may not appear until after the diagnosis has been made. Distortions and blind spots may occur in any part of the field of vision. CMV retinitis can usually easily be diagnosed by ophthalmic examination by the characteristic features of white necrotizing lesions associated with hemorrhage often with what is called “ a pizza-pie” or cottage cheese with tomato ketchup” appearance.Prior to 1981, no effective treatment for CMV retinitis existed. Currently, several drugs are available which can arrest such retinal infection. But these drugs cannot kill the CMV. They prevent proliferation of the virus within the cell The choice of initial therapy for CMV retinitis should be individualised. For the majority of patients oral Valganciclovir is recommended over the ganciclovir implant, intravenous ganciclovir due to its ease of administration and reduced risk of complications or toxicity as recommended by Infectious Diseases Society Of America. Other effective treatments include intravenous Ganciclovir, Foscarnet and Cidofovir.