|
AIDS-Related Visual Impairment
AIDS and Vision Loss
Dr. Dorothy Friedberg, a leading ophthalmologist who specializes in ocular complications of HIV, answers some of the most frequently asked questions about vision loss and AIDS.
Q: What are the most common causes of vision loss affecting patients with AIDS?
A: Cytomegalovirus (CMV) retinitis, a member of the herpes virus family, produces an infection of the retina in immunocompromised individuals. CMV causes visual loss in several ways:
- It attacks the retinal tissue directly, destroying the cells necessary for responding to visual stimuli.
- Patients with CMV infection are more prone to complicated retinal detachments, which are often difficult to repair.
- After retinal detachment repair, cataracts can develop, another cause of vision loss in patients with CMV.
Infections in the brains of patients with AIDS, such as toxoplasmosis and progressive multifocal leukoencephalopathy (PML), can cause disruption of central nervous system visual pathways and can produce abnormalities in the visual field. Patients with these problems often complain of bumping into things or unexplained difficulty reading.
Q: Do all patients with AIDS experience vision loss?
A: No. In the early 1980s there were no effective treatments for CMV retinitis, and these individuals often became blind prior to death. Currently there are several effective medications available for CMV disease, as well as other treatments under development. However, the available medications do not work in all cases and some patients do lose vision. Since the advent of HAART (Highly Active Antiretroviral Therapy) the number of new cases of CMV retinitis has decreased.
Q: When does vision loss occur?
A: Most patients with AIDS develop ocular opportunistic infections late in the course of their disease. This is when the body's natural defense (immune system) loses its significant disease in people with normal immunity.
Cytomegalovirus (CMV) Retinitis
What is Cytomegalovirus (CMV) Retinitis?
Cytomegalovirus (CMV) Retinitis is the most common cause of vision loss affecting patients with AIDS. It is a member of the herpes virus family and it produces an infection of the retina in immunocompromised individuals.
CMV causes vision loss in several ways:
- It attacks the retinal tissue directly, destroying the cells necessary for responding to visual stimuli.
- Patients with CMV infection are more prone to complicated retinal detachments, which are often difficult to repair.
- After retinal detachment repair, cataracts can develop, another cause of vision loss in patients with CMV.
Symptoms
- Floating spots
- Flashing lights
- Blind spots
- Blurred vision
Diagnosis
CMV is a complication of AIDS -- Acquired Immunodeficiency Syndrome. AIDS, a disease which affects the body's ability to fight illness, is caused by the Human Immunodeficiency Virus (HIV). The HIV attacks lymphocytes - white blood cells. T-cells are a kind of lymphocyte, and when the number of T-cells in the body drops below 200 per milliliter, a person is considered to have AIDS.
A person can be infected with HIV but not get the disease until many years later.
Because HIV attacks the body's immune system, eye infections are common in people with the virus. Incidence of eye infection is high in people with T-cell counts of less than 250. Cytomegalovirus is found in 20 - 30% of people with AIDS and causes a serious infection of the retina. Most CMV infections occur in people whose T-cell counts is dangerously low, usually under 40.
Risk Factors
If a person has been diagnosed with AIDS, he or she may be at risk for developing an infection from CMV.
Treatment
CMV can harm vision permanently and as yet, there is no cure, just treatment with medication. Currently, there are several effective medications available for CMV disease, as well as other treatments under development. However, the available medications do not work in all cases and some patients do lose vision. Since the advent of HAART (Highly Active Antiretroviral Therapy) the number of new cases of CMV has decreased.
An ophthalmologist should be contacted immediately if a person notices: floating spots, flashing lights, blind spots or blurred vision. CMV can also cause the retina to separate from the back of the eye. A detached retina will cause serious vision loss. The only method of attachment is surgery.
Source: The Canadian National Institute for the Blind (CNIB) and Lighthouse International