Atlas of Ophthalmology

HIV-induced Bilateral Optic Neuropathy (Colour Photography, VEP, OCT)

Optic Nerve -> Optic Neuropathies
Patient: 47 years of age, male, BCVA 0.8 at OD, o.8 at OS, General medical history: HIV since 10 years, systemic therapy with truvada and isentress. Ocular medical history: visual acuity not constant, varied within months from 0.4 to 0.8. Main Complaints: varying visual acuity. Methods: Colour Photography, VEP, OCT. Findings: Colour Photography: pale optic nerve head. OCT: diminuished retinal nerve fiber thickness. VEP: prolonged latencies, regular amplitude. Discussion: Optic neuropathies in HIV patients are caused by a variety of pathologies including infectious, compressive and inflammatory processes. There is evidence that the optic nerves of HIV infected patients can undergo chronic degeneration resulting in axonal loss. The current widely accepted theory emphasises the key role of tumour necrosis factor alpha (TNF-α) in the genesis of primary HIV optic neuropathy. The pathogenesis of neuronal damage has been ascribed to the combined effect of neurotoxic agents including viral proteins and neurotoxic factors released from activated microglia and macrophages. Mwanza et al. (1) found, that VEPs were abnormal in 57% and 42% of HIV infected patients with and without neurological symptoms. HIV positive patients with neurological symptoms are not at higher risk for optic nerve damage than those without neurological manifestations. This support the hypothesis according to which axonal loss of the optic nerve is a common process occurring in all HIV infected subjects. There is evidence suggesting that, despite normal visual acuity, HIV infected subjects may have subclinical dysfunction of the optic nerves/retrochiasmal visual pathways that can be detected using electrophysiological methods. A loss of cortical neurons has been found in asymptomatic HIV positive subjects in early stages of the infection. These lesions as well as others affecting the retrogeniculate part of the visual pathways, especially the primary visual cortex, may result in delay in both cortical processing and signal generation and thus in VEP abnormalities. Literature: (1) J-C Mwanza,L K Nyamabo, T Tylleskär, G T Plant. Neuro-ophthalmological disorders in HIV infected subjects with neurological manifestations. Br J Ophthalmol 2004;88:1455-1459

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