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Vitamin A status in relation to electroretinographic and electrooculographic findings in HIV infection
P Bartel1, P Roux, M van Niekerk
1Department of Neurology, Pretoria Academic Hospital and University of Pretoria, Pretoria, South Africa. pbartel@medic.up.ac.za
Objectives:
To investigate the electrooculogram (EOG) and an expanded battery of electroretinograms (ERGs) in HIV-infected subjects without retinopathy at two different levels of immunosuppression. Consideration was given to the possible effects of serum levels of vitamin A.
Methods:
Two groups of neurologically normal HIV-positive subjects with CD4+ cell counts of <200 (n=17) or >400 (n=19) were contrasted with 20 HIV-negative controls. Rod ERGs, oscillatory potentials and cone ERGs were obtained using ganzfeld stimulation. A sequence of dark- and light-adapted EOG recordings was analyzed to obtain light/dark ratios. The HIV-positive subjects underwent a comprehensive ophthalmologic examination.
Results:
Intergroup comparisons failed to reveal any significant intergroup differences. Abnormal ERG findings, those exceeding the 98% confidence limits, occurred in 11% (4/36) of the HIV-positive subjects. One of these subjects was hyporetinemic and another had a subnormal retinol level. No subjects had abnormal EOGs.
Conclusions:
HIV infection influenced retinal function in 11% of a group of neurologically normal subjects without clinical signs of retinopathy. The profile of electrophysiological findings suggested predominant functional deficits involving middle or inner retinal layers. Vitamin A deficiency and possible vascular changes could account for the observed ERG abnormalities.
