Human immunodeficiency virus or HIV is a virus that damages the immune system by destroying white blood cells called CD4+ helper cells. This leaves people at risk for infections, especially weak infections that do not pose a threat to healthy people. When patients develop these infections, it is called acquired immune deficiency syndrome or AIDS. Many of these infections can destroy the retina, resulting in permanent blindness. These infections include: cytomegalovirus (CMV), varicella-zoster virus (chickenpox), herpes simplex virus 1 and 2, toxoplasmosis, pneumocystis choroiditis, and candida (yeast). HIV can also cause a background retinopathy that is similar in appearance to diabetic retinopathy with retinal hemorrhages (small bleeds), cotton wool spots, microaneurysms, and other vascular changes. Treatment for HIV/AIDS associated infections consists of systemic and intraocular appropriate antiviral, antibiotics or antifungal drugs, or vitrectomy surgery. Many of these infections can be asymptomatic and patients may be unaware until vision is suddenly lost. Early diagnosis and treatment are critical to maintain vision.
When a patient suffering from AIDS develops a CMV infection in the retina, there is little or no inflammation in the eye since the immune system is not functioning. Later the patient may start anti-viral medication, restoring the immune function. This is a good thing, but the newly active immune system can discover the CMV infection, resulting in an increase in inflammation in the eye called immune recovery uveitis, or IRU. IRU is treated with steroids until the CMV infection is controlled. IRU is best treated by a physician familiar with this condition.