Posters
Presenting Author Academic/Professional Position
MS2
Academic Level (Author 1)
Medical Student
Academic Level (Author 2)
Medical Student
Academic Level (Author 3)
Medical Student
Academic Level (Author 4)
Faculty
Discipline/Specialty (Author 4)
Neuroscience
Academic Level (Author 5)
Faculty
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Neuroscience
Discipline Track
Clinical Science
Abstract Type
Research/Clinical
Abstract
Background: Alzheimer’s disease (AD) is characterized by cerebral microvascular dysfunction, which may be mirrored in the retina due to shared embryological origins and common risk factors such as hypertension.1 Optical coherence tomography angiography (OCTA) offers a noninvasive approach to quantify retinal microvascular changes associated with AD.2 This systematic review evaluated retinal vessel density and diameter changes in relation to AD and related disorders, including mild cognitive impairment.
Methods: A systematic search of PubMed and Scopus was conducted following PRISMA guidelines.3 Eligible studies included peer-reviewed human research using OCTA to assess retinal vessel density and/or diameter in mild cognitive impairment, AD, and control groups. After screening 1,606 abstracts and removing duplicates, 26 studies met inclusion criteria. Data on sample size, imaging protocols, and vascular measurements were extracted from these studies and qualitatively analyzed.
Results: Across the 26 included studies, sample sizes ranged from 32 to 222 participants, with a median of 78. Participants were primarily older adults, with reported mean ages typically spanning the mid-60s to mid-70s. Seventeen studies assessed superficial capillary plexus (SCP) vessel density, with 11 (64.7%) reporting significant reductions in AD. Of 13 studies evaluating deep capillary plexus (DCP), 8 (61.5%) found similar decreases. Parafoveal SCP loss was the most consistent finding. Some studies observed reduced vessel diameter, though variable definitions and imaging techniques limited comparability. Six studies reported no significant differences, often citing small samples or methodological variability. Several studies identified correlations between vessel density and cognitive performance or neuroimaging markers such as hippocampal atrophy. A subset applied novel image features or machine learning algorithms to classify AD with high accuracy. Two studies confirmed strong repeatability of OCTA parameters. Variability in scan size, segmentation, and projection correction contributed to inter-study heterogeneity.
Conclusion: Decreased vessel density in the SCP and DCP is frequently observed in AD and, when measured via OCTA and analyzed using novel machine learning algorithms, may serve as a promising noninvasive biomarker for early detection. However, the variability across the studies highlights the need for standardized OCTA protocols and longitudinal studies to validate the clinical application of retinal vascular metrics in AD.
Presentation Type
Poster
Recommended Citation
Nichols, Alexa E.; Sayers, Tori; Ibrahim, Amin; Zwir, Jorge; Tsin, Andrew; Flores-Hernandez, Lorena; Maestre, Gladys; and Melgarejo, Jesus, "Retinal Vessel Density and Diameter Changes in Alzheimer’s Disease: A Systematic Review" (2025). Research Colloquium. 3.
https://scholarworks.utrgv.edu/colloquium/2025/posters/3
Included in
Retinal Vessel Density and Diameter Changes in Alzheimer’s Disease: A Systematic Review
Background: Alzheimer’s disease (AD) is characterized by cerebral microvascular dysfunction, which may be mirrored in the retina due to shared embryological origins and common risk factors such as hypertension.1 Optical coherence tomography angiography (OCTA) offers a noninvasive approach to quantify retinal microvascular changes associated with AD.2 This systematic review evaluated retinal vessel density and diameter changes in relation to AD and related disorders, including mild cognitive impairment.
Methods: A systematic search of PubMed and Scopus was conducted following PRISMA guidelines.3 Eligible studies included peer-reviewed human research using OCTA to assess retinal vessel density and/or diameter in mild cognitive impairment, AD, and control groups. After screening 1,606 abstracts and removing duplicates, 26 studies met inclusion criteria. Data on sample size, imaging protocols, and vascular measurements were extracted from these studies and qualitatively analyzed.
Results: Across the 26 included studies, sample sizes ranged from 32 to 222 participants, with a median of 78. Participants were primarily older adults, with reported mean ages typically spanning the mid-60s to mid-70s. Seventeen studies assessed superficial capillary plexus (SCP) vessel density, with 11 (64.7%) reporting significant reductions in AD. Of 13 studies evaluating deep capillary plexus (DCP), 8 (61.5%) found similar decreases. Parafoveal SCP loss was the most consistent finding. Some studies observed reduced vessel diameter, though variable definitions and imaging techniques limited comparability. Six studies reported no significant differences, often citing small samples or methodological variability. Several studies identified correlations between vessel density and cognitive performance or neuroimaging markers such as hippocampal atrophy. A subset applied novel image features or machine learning algorithms to classify AD with high accuracy. Two studies confirmed strong repeatability of OCTA parameters. Variability in scan size, segmentation, and projection correction contributed to inter-study heterogeneity.
Conclusion: Decreased vessel density in the SCP and DCP is frequently observed in AD and, when measured via OCTA and analyzed using novel machine learning algorithms, may serve as a promising noninvasive biomarker for early detection. However, the variability across the studies highlights the need for standardized OCTA protocols and longitudinal studies to validate the clinical application of retinal vascular metrics in AD.
