HIV infection does not change the basic structure of the eye, but the resulting immune system compromise allows eye issues to manifest visually. The virus attacks and depletes CD4+ T-cells, the primary orchestrators of the body’s immune response. This immune suppression allows diseases to occur in the eye that typically would not affect a person with a healthy immune system. The extent of these problems is closely linked to the severity of the immunodeficiency, often appearing when the disease is advanced.
Subtle Internal Changes
The most common internal ocular finding associated with HIV is HIV Retinopathy, a microvascular complication rather than an infection. This condition is caused by damage to the small blood vessels within the retina, the light-sensitive tissue at the back of the eye. The characteristic signs are often seen only during a specialized eye examination because they rarely cause symptoms in early stages.
Cotton Wool Spots
HIV Retinopathy involves small areas of retinal damage, including “cotton wool spots” and tiny hemorrhages. Cotton wool spots appear as puffy, white, irregularly shaped patches on the retina. They represent micro-infarcts, or areas where nerve fibers have swollen due to a blockage in the blood vessels supplying them. These non-infectious changes are generally a sign of systemic vascular disease related to HIV, similar to what is seen in severe diabetes or hypertension.
External and Surface Manifestations
Changes visible on the exterior of the eye and surrounding tissues are typically a result of secondary infections or specific cancers related to immune suppression. One such manifestation is Kaposi’s Sarcoma (KS), a cancer caused by Human Herpesvirus 8 (HHV-8). Ocular KS lesions may appear on the eyelids or the conjunctiva, the clear membrane covering the white of the eye.
Kaposi’s Sarcoma and Dry Eye
On the eyelids, KS lesions can look like purplish, blue, or red-to-pink bumps or patches. If KS affects the conjunctiva, it often presents as a red, fleshy mass that can resemble a subconjunctival hemorrhage. Another common surface issue is severe dry eye syndrome, known as keratoconjunctivitis sicca. This condition makes the eyes appear chronically red, irritated, or dull due to inadequate tear production.
Vision-Threatening Opportunistic Infections
The most serious and visually destructive complication of advanced immune suppression is Cytomegalovirus (CMV) Retinitis, an opportunistic infection. This infection is the leading cause of blindness in individuals with advanced HIV. CMV Retinitis occurs when the virus, which is common and usually harmless, attacks the retina due to a severely weakened immune system.
The appearance of CMV Retinitis is often described as a “cottage cheese and ketchup” or “pizza pie” retinopathy. This refers to confluent areas of white, necrotic (dead) retinal tissue mixed with significant retinal hemorrhages. The lesions typically start in the periphery and rapidly spread, causing irreversible full-thickness retinal damage. Untreated, the infection progresses to severe vision loss or blindness within a few months, often accompanied by symptoms like floaters, flashing lights, or blind spots.
Importance of Clinical Examination and Timing
The timing of these ocular conditions is highly correlated with the CD4+ T-cell count, a measure of immune function. Most severe opportunistic infections, including CMV Retinitis, occur when the CD4 count drops below 100 cells/µL, indicating advanced immune suppression. HIV Retinopathy is significantly more prevalent in patients with CD4 counts below 200 cells/µL.
Self-diagnosis based on external appearance is unreliable, as many early changes are only visible with specialized equipment. A comprehensive clinical examination, specifically a dilated fundus examination, is necessary to detect subtle internal changes like cotton wool spots or the early stages of CMV Retinitis. Regular screening is recommended for all individuals with HIV to allow for early detection and treatment, since conditions like CMV Retinitis can progress rapidly before symptoms appear.