Retinal structure and vasculature changes and their relationship with mild cognitive impairment in type 2 diabetes

BackgroundMild cognitive impairment (MCI) is an intermediate stage between normal aging and Alzheimer's disease (AD). Diabetes mellitus (DM) increases the risk of cognitive decline and may accelerate progression to AD. Retinal changes observed through non-invasive imaging techniques could reflect early neurodegenerative processes.ObjectiveTo compare the influence of DM on cognitive impairment and its possible association with AD-related changes by evaluating retinal structural and vascular alterations in MCI patients, and their relationship with neuropsychological performance.MethodsA cross-sectional study of association between neuropsychological and ophthalmological variables was carried out on a sample of 40 patients divided into two groups: 20 MCI patients and 20 DM-MCI patients.ResultsA decrease in the ganglion cell layer (GCL) and foveal avascular zone (FAZ) with increased arteriolar thickness at the papilla exit and superficial capillary plexus (SCP) has been demonstrated in DM-MCI patients compared to those with MCI. In the DM-MCI group, decreased GCL thickness and increased arteriolar thickness correlate with memory impairment. On the other hand, in the MCI group an increase in FAZ area and SCP show greater memory impairment, while an increase in arteriolar thickness correlates with greater executive function impairment.ConclusionsDM and MCI influence the development of retinal damage that could predict the development of AD as they maintain correlation with the impairment of cognitive domains assessed by different neuropsychological tests. Retinal neurovascular changes assessed by optical coherence tomography angiography may be informative of early cerebral alterations in MCI.