Changes in Retinal Multilayer Thickness and Vascular Network of Patients With Alzheimer’s Disease

Abstract

Background: Retinal biomarkers of Alzheimer’s disease (AD) were largely investigated during last decades. Brain conditions could be reflected by retinal nervous and vascular parameters. It can be used to enhance the accuracy of early diagnosis of AD.Objective: Our study aimed to evaluate the difference of retinal neuro-layer thickness and vascular parameters between AD patients and health control (HC) subjects.Methods: Non-invasive technology of optical coherence tomography angiography (OCTA) were adopted to acquire the combination thickness of retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL), as well as the full retinal thickness (FRT). Vascular branch (VB), vascular curvature (VC), and vascular density (VD) were also collected in AD and HC groups. Mini-mental state examination (MMSE) was adopted to evaluate the cognitive levels of all subjects. After obtaining all the parameters, we used Mann-Whitney U test to compare the mean values of all retinal regions parameters between ADs and HCs. Pearson's correlation was used to test the association between retinal parameters and MMSE score, and vascular parameters.Results: Compared with HCs, the RNFL+GCL thickness of inferior quadrant, FRT of inferior and temporal quadrant, and retinal VD of patients with AD were significantly reduced (p < 0.05). The retinal thickness had significant correlations with MMSE scores (p < 0.05). Meanwhile, the retinal VD was significantly correlated with the average RNFL+GCL thickness (p < 0.05, r = 0.5956).Conclusion: In conclusion, our study suggested that AD patients had significant reduced RNFL+GCL thickness and vascular density compared with the age-matched HCs. Meanwhile, these reductions correlated with the cognitive level of the subjects. Trial registration number: ChiCTR2000035243Date of registration: Aug., 5, 2020URL of trial registry record: http://www.chictr.org.cn/index.aspx