Abstract
Alzheimer’s disease (AD) is the most prevalent form of dementia, yet its early detection remains challenging due to the invasiveness, cost, and limited accessibility of current diagnostics. Increasing evidence suggests that retinal changes mirror cerebral pathology in AD, making the eye a promising site for non-invasive biomarker discovery. Here, we present a technique employing a custom-built tri-spectral retinal imaging module, designed to be integrated with existing fundus imaging systems, that captures retinal reflectance across three optimized spectral bands to quantify spectral alterations linked to AD. We validate the system in a case-control study of 38 mild AD patients and 28 age-matched controls, revealing spatially resolved differences in a fundus map derived from the blue-to-green ratiometric channel (p < 0.001). Our analysis identifies specifically the fovea-to-optic disc region as the most discriminative for AD, with an AUC of 0.74. Building on this, we developed a biologically informed machine-learning classification model incorporating spectral, clinical, and demographic data. On an independent validation test, the model achieved an AUC of 0.91, matching or slightly outperforming the most advanced spectral retinal measurements, yet using a simpler, more stable, and cost-effective setup that further facilitates clinical translation. The demonstrated technology, thanks to its non-invasiveness and its integrability with both existing medical technologies and advanced quantitative statistical methods, holds the potential to drive a significant leap forward in the early detection of AD, opening a window for timely intervention and thus profoundly impacting patient care.
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Data availability
De-identified participant data (including age, sex, ocular history, and spectral imaging values) and MATLAB/R analysis code are available from the corresponding author upon reasonable request. Due to privacy and ethical restrictions, raw retinal images cannot be publicly shared but may be provided in anonymized form for academic collaborations.
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The authors declare no competing financial or non-financial interests related to this work.
Funding
This work was supported by MUR PRIN 2022 (CUP: 2022CFP7RF, to M.L.). This research was also funded by the D-Tails-IIT Joint Lab, GR is supported by Project “National Center for Gene Therapy and Drugs based on RNA Technology” (CN00000041) financed by NextGenerationEU PNRR MUR— M4C2—Action 1.4-Call “Potenziamento strutture di ricerca e creazione di “campioni nazionali di R\&S” (CUP J33C22001130001)”. The research leading to these results was also supported by European Research Council through its Synergy grant program, project ASTRA (grant agreement No. 855923) and by European Innovation Council through its Pathfinder Open Program, project ivBM-4PAP (grant agreement No. 101098989). The authors acknowledge the support of the Italian Fund for Applied Sciences (FISA), project "ROAD- Retina Observation for Alzheimer Diagnostic", funded by the Italian Ministry of University and Research (MUR), under Call No. 1233 of 01/08/2023.
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Conceptualization: ZS, ML, VR, GR Methodology: ZS, MLInvestigation: ZS, GC, MsGVisualization: ZSFunding acquisition: GR, VRProject administration: ZSSupervision: ZS, MLWriting – original draft: ZS, GCWriting – review & editing: FDL, RR, ML, MsG, MgG, JZ, YZ.
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Salajková, Z., Ciasca, G., Di Lorenzo, F. et al. Non-invasive screening of alzheimer’s disease via label-free tri-spectral retinal imaging. Sci Rep (2026). https://doi.org/10.1038/s41598-026-35383-y
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DOI: https://doi.org/10.1038/s41598-026-35383-y


