Identifying biomarkers of Alzheimer’s disease (AD) will accelerate the understanding of its pathophysiology, facilitate screening and risk stratification, and aid in developing new therapies. Developments in non-invasive retinal imaging technologies, including optical coherence tomography (OCT), OCT angiography and digital retinal photography, have provided a means to study neuronal and vascular structures in the retina in people with AD. Both qualitative and quantitative measurements from these retinal imaging technologies (eg, thinning of peripapillary retinal nerve fibre layer, inner retinal layer, and choroidal layer, reduced capillary density, abnormal vasodilatory response) have been shown to be associated with cognitive function impairment and risk of AD. The development of computer algorithms for respective retinal imaging methods has further enhanced the potential of retinal imaging as a viable tool for rapid, early detection and screening of AD. In this review, we present an update of current retinal imaging techniques and their potential applications in AD research. We also discuss the newer retinal imaging techniques and future directions in this expanding field.
- Alzheimer's disease
- image analysis
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Contributors CYC, CPLHC and TYW conceptualised and designed the article. CYC drafted the article. CYC, VM, PJF, ET, CPLHC, TYW and CPLHC were responsible for revising it critically for important intellectual content. All authors approved this version to be published.
Funding CYC has received grant funding from the Health and Medical Research Fund, Hong Kong (Grant Number: 04153506) and Bright Focus Foundation (Reference Number: A2018093S). VM has received grant funding from SEEDS Foundation. PJF has received grant support for this work from The Richard Desmond Charitable Foundation via Fight for Sight, London, UK (Grant code 1965), The International Glaucoma Association, Ashford, UK and The Alcon Research Institute, Fort Worth, Texas, USA. CPLHC has received grant funding from the National Medical Research Council Singapore (NMRC/CG/NUHS/2010 and NMRC/CG/013/2013). ET has received grant funding from the EPSRC (M005976/1) and the NIHR Global Health Research Unit “INSPIRED” (16/136/102). TYW has received grant funding from the National Medical Research Council Singapore (NMRC/STaR/016/2013 and NMRC/OFLCG/001 c/2017) and Duke-NUS Medical School (DUKE-NUS/RSF/2014/0001).
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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