Abstract
Purpose: :
People with HIV disease have an increased prevalence of psychophysical losses (reduced contrast sensitivity [CS]; abnormal color vision), which has been attributed to "neuroretinal disorder" (NRD), although a relationship between visual dysfunction and structural changes in the retina has not been shown directly. NRD has been associated with certain mitochondrial haplogroups and autopsy studies suggest that an HIV-related primary optic neuropathy is common. We compared retinal nerve fiber layer (RNFL) thickness to CS and color vision in HIV-infected individuals.
Methods: :
We evaluated 43 eyes of 22 HIV-infected individuals without ocular opportunistic infections. Average peripapillary RNFL thickness was determined with spectral-domain optical coherence tomography (OCT), based on values from 4 quadrants. CS was measured with the Pelli-Robson technique and expressed as logCS. Color vision was evaluated with the Lanthony desaturated 15-hue technique and expressed as a color confusion score (CCS); higher scores indicate worse color vision. Correlations among various measures were assessed using Pearson correlation coefficients.
Results: :
Median average RNFL thickness was 105.0 um (range 81.7-123.3 um). Median logCS score was 1.65 (range 1.35-1.95). Median CCS was 1.62 (range 0.96-2.97). Median average RNFL thickness was inversely correlated with CS (r=-0.34, p=0.026) and there was a weakly positive correlation with CCS (r=0.30, p=0.053).
Conclusions: :
The relationship between increased RNFL thickness and worse visual function in this population suggests that axoplasmic stasis may be the basis for psychophysical losses. These changes could lead to ganglion cell death with RNFL atrophy, resulting in the optic neuropathy seen in autopsy studies. Mitochondrial dysfunction, caused by HIV or its treatment or both, in susceptible individuals, is a potential disease mechanism.
Keywords: AIDS/HIV • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • contrast sensitivity