AIDS and the eye
The HIV virus is a retrovirus, which causes AIDS. It is a chronic infection which can take around 8-10 years before the infected patient will develop AIDS with its symptoms. It targets the CD4+ T lymphocyte cells. As these cells start to deplete the person becomes much more susceptible to opportunistic infections and tumours. Around 40 million people are infected with HIV worldwide, where most are from developing countries.
For more information on HIV/AIDS, click here to visit a SSC website created by Damali Harris.
For more information on HIV/AIDS, click here to visit a SSC website created by Damali Harris.
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Ocular manifestations of AIDS:
Main eye complications caused by AIDS:
Main eye complications caused by AIDS:
- Cotton wool spots – caused by bleeding and white spots in the retina, which result from inflammation of the blood vessels in the retina. These are often not dangerous and disappear in a couple of weeks. Large cotton-wool spots at the macula can cause scotoma.
- Red eye – because the infection lasts for a long time, it causes reddening of the eyes.
- Kaposi's sarcoma – A noncancerous tumour, which can appear on the eyelid or sclera. It can look like a purple-red bump or spot that can appear on any part of the body, including the eyes. In the eye, a Kaposi's sarcoma appears as a purple-red bump on the eyelid or a spot on the sclera.
- Herpes, Toxoplasmosis, and Zoster - These eye infections are common in AIDS patients
- CMV retinitis – This is an infection caused by the cytomegalovirus and is probably the most serious and commonest AIDS-related eye condition. CMV Retinitis becomes more prevalent as AIDS progresses and the numbers of CD4+ cells are being depleted. Patients experience floaters, flashing lights, blurred vision and blind spots. There may be a full thickness necrosis of the retina. The lesions seen can be described as granular with irregular borders and opacification of a yellow-white colour. There may be haemorrhage present. However, CMV Retinitis can also occur without these eye symptoms. CMV Retinitis occurs in about 25% of AIDS patients and those who have an absolute CD4+ level of <50 cells/mm3.
- Uveitis – inflammation of the uveal tract due to infection. The uveal tract consists of the Choroid, Ciliary body and Iris.
- Molluscum Contagiosum - This is the most common ocular adnexal manifestation in patients with HIV as it is very frequent and severe in patients who are HIV positive. It is caused by the DNA poxvirus and is a highly contagious dermatitis, which affects the skin or mucous membranes. It can spread by direct contact between HIV positive people or by fomites. There are small lesions which contain poxvirus particles and these are released into tears with associated toxic keratoconjunctivitis.
The ocular manifestations can be grouped into 4 categories:
HIV related vasculopathy, Oppurtunistic infections, Neoplasms and Neuroopthalmic complications.
1. HIV related vasculopathy – This is the most common manifestation of AIDS. It is characterised by swollen endothelial cells, loss of pericytes, basal lamina thickening, and narrowing of capillary lumens. Cotton-wool spots are the most common presentation whereas intraretinal haemorrhages and microaneurysms are also seen.
2. Opportunistic infections
3. Neoplasms
4. Neuroopthalmic manifestations – These are uncommon and occur in 6% of AIDS patients.
HIV related vasculopathy, Oppurtunistic infections, Neoplasms and Neuroopthalmic complications.
1. HIV related vasculopathy – This is the most common manifestation of AIDS. It is characterised by swollen endothelial cells, loss of pericytes, basal lamina thickening, and narrowing of capillary lumens. Cotton-wool spots are the most common presentation whereas intraretinal haemorrhages and microaneurysms are also seen.
- Conjunctival Microvasculopathy – In HIV positive patients, there are many conjunctival microvascular changes which include segmental vascular dilation and narrowing, microaneurysms, comma-shaped vascular fragments. The aetiology of these changes are not fully known, but it is known that the increased plasma viscosity and immune-complex deposition are involved. Direct infection of the conjunctival vessels may also be a possible cause. These microvascular changes are very common and occur in 70-80% of patients with HIV.
2. Opportunistic infections
- CMV Retinitis – see above
- Varicella – Zoster virus retinitis – This can lead to retinal necrosis and full retinal thickness necrosis. Progression of this infection can lead to blindness.
- Taxoplasmic retinochoroiditis – This is more common in countries where there is a high rate of toxoplasma gondii infection. This causes anterior uveitis, vitritis and neuro-taxoplasmosis. This always requires treatment, as without it, the lesions will enlarge.
- Other opportunistic infections – These include: Pneumocystis carinii choroiditis, cryptococcal chorioretinitis and papillitis, histoplasmic chorioretinitis, syphilitic chorioretinitis and papillitis, Herpes Zoster Opthalmicus, Herpes simplex virus retinitis, keratitis.
- Pneumocystis carinii choroiditis – This is quite uncommon. When it does occur, it is often bilateral and has yellow choroidal patches around the posterior pole, with some vitritis.
- Herpes Zoster Opthalmicus – This occurs due to a reactivation of latent VZV from a previous primary infection. This could be caused by the loss of T-cells in HIV. The infection travels down the nerve; most commonly the trigeminal nerve CN V. HZO affects 5-15% of patients who have HIV.
3. Neoplasms
- Kaposi’s sarcoma – See above.
- Non – Hodgkins Lymphoma – This arises from B Lymphocytes and can occur alongside CNS (Central Nervous system) disease, visceral disease or an isolated ocular disease. With CNS disease, the retina is most likely to be affected whereas with visceral disease, the uveal tract is most likely to be affected.
4. Neuroopthalmic manifestations – These are uncommon and occur in 6% of AIDS patients.
- Orbital or intracranial neoplasms and infections - The neoplasms are mainly lymphomas - These can cause papilloedema, optic atrophy, visual field defects, cranial nerve palsies, eye movement disorders and cortical blindness.
- Cryptococcal meningitis – This is a very common cause of neuroopthalmic complications, and is seen in more than 50% of people. It is also a common cause of papilloedema.
- Other infectious causes of intracranial disease – Taxoplasmosis, CMV encephalitis, Varicella- zoster virus encephalitis or cerebritis and progressive multifocal leukoencephalopathy.