Abstract
BackgroundTo explore the retinal vascular density changes in Alzheimer’s disease (AD) and mild cognitive impairment (MCI) patients using optical coherence tomography angiography (OCTA).MethodsWe recruit 62 AD patients, 47 MCI patients, and 49 cognitively healthy controls (HC) in this study. All participants in the study received a comprehensive ophthalmological and neurological evaluation, including global cognitive screening, as well as the Mini-Mental State Examination (MMSE), and completed the following eye examinations: visual acuity (VA), intraocular pressure (IOP), examination with slit-lamp, fundus photography (Version 1.5.0.0, NIDEK CO, LTD) and Optical coherence tomography imaging (software ReVue version 2017.1.0.155, Optovue Inc., Fremont, CA, United States). The visual rating scales for atrophy and white matter lesion in MRI was evaluated for all the patients with AD and MCI.ResultsIn the AD patient group, the superficial vascular density in the superior, inferior and whole retina was 44.64 ± 3.34, 44.65 ± 3.55, and 44.66 ± 3.36, respectively. These values were 44.24 ± 3.15, 43.72 ± 3.16, and 44 ± 3.07, respectively, in the MCI patient group. After multivariate analysis of the generalized linear model, adjustments for the confounding factors of sex, age, hypertension, diabetes and the quality index of OCTA image, the superficial vascular density in the AD and MCI patient groups was significantly lower than that in the HC group (P < 0.05): 46.94 ± 2.04, 46.67 ± 2.26, and 46.82 ± 2.08, respectively. No difference in the area of the FAZ among the three groups was observed (AD group: 0.34 ± 0.11 mm2; MCI group: 0.36 ± 0.12 mm2; control group: 0.33 ± 0.12 mm2, p > 0.05). The ganglion cell complex (GCC) thickness, inner parafovea thickness, and peripapillary retinal nerve fiber layer (p-RNFL) thickness were associated with the superficial vascular density. We found no significant correlation between the global cognition (MMSE scores) or between the Fazekas score and retinal OCT angiogram flow density.ConclusionThe superficial vascular density in the AD and MCI patient groups was significantly lower than that in the HC group. Our findings suggest the retinal microvascular dysfunction occurred in MCI and AD.
Highlights
Approximately 47 million people suffer from dementia, and the number is expected to triple in 2050 (Livingston et al, 2017)
Alzheimer’s disease (AD) and Mild cognitive impairment (MCI) were diagnosed based on the clinical evaluation, neuropsychological assessment, neuroimaging, and laboratory tests according to the 2011 guidelines of the National Institute of Aging-Alzheimer’s Association workgroups (NIA/AA)
After meeting the inclusion criteria, retinal blood flow and thickness measurements were successfully obtained in 165 subjects
Summary
Approximately 47 million people suffer from dementia, and the number is expected to triple in 2050 (Livingston et al, 2017). Alzheimer’s disease (AD), as the most common type of dementia, is characterized by its continuous, irreversible pathological process, which initiates decades before overt cognitive impairment (Sperling et al, 2011). Mild cognitive impairment (MCI) is the prodromal stage of AD (Morris et al, 2001; Langa and Levine, 2014). Cerebrospinal fluid (CSF) analyses (amyloid and tau proteins) and positron emission tomography (PET) scans may help in the early identification of MCI (Albert et al, 2011; Ottoy et al, 2019), these methods have not been widely used in clinical practice due to their invasiveness and high cost (Handels et al, 2017). To explore the retinal vascular density changes in Alzheimer’s disease (AD) and mild cognitive impairment (MCI) patients using optical coherence tomography angiography (OCTA)
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