Abstract
Previous studies have demonstrated that Alzheimer's disease (AD) it is not limited to the brain but also affects the retina. We investigated the correlation between the retinal vascular complexity and neurodegenerative changes in patients with mild cognitive impairment (MCI). Quantification of the retinal structure and function using advanced retinal imaging and full-field electroretinogram (ERG) was performed. Also, visual performance exams were conducted using the Rabin cone contrast test (CCT). Retinal images and ERGs from each subject were obtained. Retinal vascular parameters were calculated using the Singapore Institute Vessel Assessment (SIVA) software which was also used to calculate the fractal dimension (FD) of the retinal vasculature network and retinal vascular caliber, summarized as central retinal artery equivalent (CRAE) and central retinal vein equivalent (CRVE). The Montreal Cognitive Assessment (MoCA) was used to assess cognitive dysfunction. Spearman's linear correlation was performed between variables, the level of significance was set at 5%. For the analysis, Statistics 7.0 software was used (Statsoft Inc., Tulsa, OK). Of the 55 participants, 21 had cognitive impairment (38%), 34 served as healthy controls. We found that the complexity of the branching pattern and caliber of retinal vessels were lower in patients with MCI (FD (mean±SE): 1.310±0.020; CRVE (92.65±1.60; age range [76-86]) in comparison to healthy controls (FD: 1.382±0.002; CRVE: 202.15±0.76; age range [76-86]). Also, drusen and retinal pigment mottling were noted in some elderly MCI subjects. For all full-field ERG measurements, smaller amplitudes and larger peak times were observed in the MCI subjects. The visual performance test with the computerized Rabin CCT revealed functional loss in color vision. Interestingly, FD significantly correlated with CRVE (p=0.0212, r=-0.4628) and with the ERG's implicit time (p=0.0240, r=0.4910) in MCI individuals. To our knowledge, this is the first study to examine the association between FD and full field ERG implicit time in patients with MCI. Our preliminary findings also show that our approach to evaluating visual capacities in elderly individuals may add predictive value of early visual pathway injury associated with MCI and facilitate the introduction of a novel multimodal eye biomarker for the early detection of AD.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Alzheimer's & Dementia: The Journal of the Alzheimer's Association
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
