Background: Alterations to the retina manifest in patients diagnosed with neurodegenerative diseases such as Alzheimer's disease (AD). Retinal imaging techniques open the possibility for non-invasive evaluation of AD pathology. Clinically AD diagnosed patients exhibit retinal amyloid deposits. Few studies monitoring preclinical individuals exist, limiting the assessment of the feasibility of retinal imaging as a biomarker for early-stage AD risk detection.
Method: We compared retinal and cerebral amyloid in clinically normal individuals who screened positive for amyloid through positron emission tomography (PET) from the Anti-Amyloid Treatment in Asymptomatic Alzheimer Disease (A4) as well as a companion cohort of individuals who were negative on amyloid by amyloid PET in the Longitudinal Evaluation of Amyloid Risk and Neurodegeneration (LEARN) study. We quantified the number of curcumin-positive fluorescent retinal spots from a small subset of participants from both studies to determine retinal amyloid deposition at baseline.
Result: Participants from the A4 trial exhibited a greater number of retinal spots compared to those from the LEARN study. We report a positive correlation between retinal spots and brain amyloid, as measured by the standardized uptake value ratio (SUVr).
Conclusion: The results of this small pilot study support the use of retinal fundus imaging for detecting amyloid deposition that is correlated with brain amyloid PET SUVr. A larger sample set is under analysis currently to fully ascertain the relationship between amyloid PET and retinal amyloid both cross-sectionally and longitudinally.
© 2024 The Alzheimer's Association. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.