More than 40 million people infected with H.I.V./AIDS worldwide. Loss of vision and ocular complications are among the most common complication of infection, affecting 50 to 75 per cent of all AIDS patients.

India, with 5.3 million H.I.V.-affected people, faces a potential epidemic of blindness.

Cytomegalovirus Retinitis (C.M.V.), from the herpes virus group, is by far the most common disease affecting vision in people with AIDS.

Without treatment, C.M.V. destroys the retina, a thin, light, sensitive tissue at the back of the eye. Once the disease affects the eye, it generally causes blindness in four to six months. People with C.M.V. also have a 25 to 40 per cent chance of developing retinal detachment, a condition where the retina separates from the nerves of the eye, often leading to complete loss of vision.

The symptoms of the disease depend on which part of the retina is affected by the virus. People with C.M.V. can experience temporary vision blackouts, foggy or blurred vision, loss of central or peripheral vision, or see floaters, which are small dark specks that move slowly through their visual field. An increase in the number of floaters is an important early warning sign of this disease.

Patients diagnosed with C.M.V. are generally treated with antiviral medications, administered intravenously. However, such drugs have high toxicity and may lead to serious side-effects such as kidney failure. Recently, a new procedure has been developed in which the drug, in pellet form, is implanted in the cavity of the eye allowing the slow release of the medicine over five to eight months. This results in fewer side effects and a better prognosis for people living with C.M.V.