AIDS is caused by the human immunodeficiency virus (HIV), formerly known as HTLV-111, LAV, and ARV It belongs to the family of retroviruses and may have originated from a strain usually found in the African green monkey. When the HIV virus infects human cells, it may lay dormant (inactive) for many years. For unknown reasons, the virus may become active, causing AIDS or an AIDS-related illness. Therefore, people with HIV infection may be symptomless or may have symptoms ranging from mild to severe. People at particular risk of contracting AIDS include homosexual or bisexual men, intravenous drug abusers, prostitutes and hemophiliacs. There is growing concern about the spread of AIDS in the heterosexual population.

AIDS is not particularly contagious. It cannot be spread by casual contact. It is passed through contact with infected blood or semen. Blood banks now screen donors for HIV infection so transmission of the virus through blood transfusions has become rare.

How Does AIDS Affect The Eye?
About 75% of AIDS patients develop eye involvement of some sort. The retina (the light-sensitive membrane at the back of the eye) is most commonly affected. Tiny retinal hemorrhages and cotton-wool spots are early signs of infection and are often detected during an eye exam. A cotton-wool spot, which looks white and fluffy, is caused by a circulatory disturbance in a tiny area of the retina. This disturbance may also cause small blood spots or hemorrhages. Since other diseases can produce the same endings, cotton-wool spots and tiny retinal hemorrhages are not diagnostic of AIDS.

Infection of the retina with the cytomegalovirus (CMV) is more serious. CMV is known as an opportunistic infection because it rarely causes disease except in people whose immune system is damaged. CW kills retinal cells by moving from one cell to another. The entire retina may become involved within a period of two to three months. If the infection does not respond to treatment and is present in both eyes, it can lead to blindness. Other infections of the retina, including infections with the herpes virus, the parasite toxoplasma, and the fungus candida, can also occur in AIDS patients.

Kaposi's sarcoma is a rare form of cancer that occurs in AIDS patients. It may involve the eyelids, where it appears as a non-tender purple nodule. If it affects the conjunctiva, the mucus membrane that covers the white of the eye, it appears as a bright red fleshy mass. Kaposi's sarcoma lesions of skin and mucus membrane tend to grow slowly.

In the final stages of the disease, the brain is frequently involved, either with direct infection by HIV or with opportunistic infections. Because over 50% of the human brain is concerned in some way with the act of seeing, the eyes may show signs of brain involvement. Blurred vision, problems with eye movement, or double vision may result.

What Treatment Is Available?
No treatment is necessary for retinal cotton-wool spots or hemorrhage because they do not affect vision. A new experimental drug, DHPG (ganciclovir), appears to stop the progression of CW retinal infection. However it is not curative and may be toxic. The growth of Kaposi's sarcoma spots may be slowed by radiation treatment or surgical excision. Treatments for HIV infection are being investigated but the hope is that effective treatment can be found for the basic disease.

What About The AIDS Virus In Tears?
The HIV virus has rarely been found in tears of AIDS patients and no known case of AIDS has ever occurred because of tear contact. However, ophthalmologists are being especially careful in cleaning contact lenses and instruments which come in contact with the tears. It is reassuring to know that all commercially available contact lens cleaning solutions tested in a recent study were found to disinfect contact lenses which had been exposed to the HII-V virus.

Why Are Eye Examinations Important?
Ophthalmologists are frequent consultants in the care of AIDS patients. Detection of retinal cotton-wool spots and hemorrhage can be useful in detecting and diagnosing AIDS. Discovering CMV retinal infection before vision is lost may allow DHPG or other treatments to be helpful. AIDS patients also need regular eye examinations to discover and treat glaucoma, inflammation, cataract, and other diseases.

References: American Academy of Ophthalmology