The relationship between retinal structure and visual function in non-immuno-compromised people living with HIV without retinitis on antiretroviral therapy

Abstract

Background: This study sought to establish the association between retinal morphology, visual function and linear parameters of cerebral atrophy in non-immunocompromised people living with HIV (NIPLHIV).

Methods: Sixty participants (30 NIPLHIV, 30 controls), aged 18-45 years, were sourced from an outpatient clinic in South Africa. NIPLHIV on antiretroviral therapy (ART) had elevated CD4 counts and low viral loads. Macula thickness and volume measurements were obtained using the Spectralis optical coherence tomographer. Contrast sensitivity (CS), colour vision and visual-evoked potentials (VEP) were also obtained. Linear parameters of cerebral atrophy (Sylvian fissure ratio, SFR) and bicaudate nucleus ratio (BCR) were all acquired from computed tomography (CT) scans. Associations between retinal thickness and volume and visual function were established by principal component factor analysis.

Results: CS scores were indirectly associated with the Inner Nuclear Layer (INL)-ETDRS thickness and volume subfields (co-efficient = -0.07; p = 0.02 and -0.11; p = 0.001), respectively. F100 total error scores (TES) were directly associated with the thicknesses of Ganglion Cell Layer-ETDRS subfields (co-efficient = 6.06; p = 0.04) but indirectly associated with INL-ETDRS subfields (co-efficient = -5.49; p = 0.04). F100-TES were indirectly associated with volumes of RNFL (Retinal Nerve Fibre Layer)-ETDRS subfields (co-efficient = -5.54; p = 0.02) and inner retina -ETDRS subfields (co-efficient = -6.70; p = 0.02). P100 latency was directly associated with RNFL-ETDRS subfield thickness (co-efficient = 2.90; p = 0.02) and volumes of outer retina subfields (co-efficient = 2.72; p = 0.04). CS scores were directly associated with SFR (co-efficient = -0.04; p = 0.01). F100-TES were directly associated with BCR (co-efficient = 0.003; p = 0.004) and SFR (co-efficient = 0.002; p = 0.02). P100 latency was indirectly associated with BCR (co-efficient = -0.001; p = 0.03).

Conclusion: The recognition of associations may be the first step in the proposal to develop a framework for the surveillance of vision in patients with NIPLHIV. We recommend a study of the sample population to track the stability of these observations before general recommendations for clinical care.

Keywords: CT scans; HIV; OCT; VEP; colour vision; contrast sensitivity; retina; vision.