Correlation between inner retinal layer thickness and cognitive function in HIV: new insights from an exploratory study

OBJECTIVE:to compare retinal layer thickness in human immunodeficiency virus (HIV) infected subjects with (CI-HIV) and without (NCI-HIV) cognitive impairment, with a control population and to correlate it with the cognitive status of the patient and other clinical parameters. DESIGN:single center cross-sectional study METHODS:Subjects with controlled HIV infection aged between 40 and 70 years and sex and age matched controls were enrolled. Retinal nerve fiber layer (RNFL), ganglion cell layer (GCL) and inner plexiform layer (IPL) thickness were assessed using optical coherence tomography. These measurements in HIV subjects were compared to those in controls. Age and gender related changes were compared in both groups. Other variables studied in HIV subjects includedduration of HIV infection, CD4+ cell count nadir, antiretroviral therapy regimen and cognitive status using the Montreal Cognitive Assessment (MoCA)Test. RESULTS:69 subjects, 34 with and 35 without cognitive impairment, and 70 controls were enrolled. GCL was significantly thinner in CI-HIV subjects compared to NCI-HIV subjects and controls (p = 0.01 and p = 0.02 respectively). GCL and IPL thickness significantly decreased with age in subjects with HIV (p = 0.0003, p = 0.02 respectively for the entire cohort). This change was not seen in controls. MoCA Test score significantly decreased with age in HIV subjects and controls. GCL thickness positively correlated with cognitive function across the entire HIV cohort (p = 0.02). CONCLUSIONS:GCL was thinner in HIV subjects with cognitive impairment. GCL thickness correlated positively with cognitive function and negatively with age in HIV subjects. GCL thickness may reflect accelerated cognitive aging in HIV.