Retinal Imaging Shows Promise for Earlier Alzheimer’s Detection

Retinal structural and microvascular abnormalities are promising, non-invasive biomarkers for early detection and monitoring of Alzheimer’s disease, according to Ahmed Abdalla MD.

A systematic review carried out by Dr Abdalla and colleagues found consistent associations between retinal changes and both mild cognitive impairment (MCI) and Alzheimer’s disease (AD). Using retinal imaging modalities to detect these abnormalities could help identify Alzheimer’s disease at an earlier stage.

The findings are particularly relevant given the growing global burden of AD and the challenges associated with early diagnosis, Dr Abdalla said. Alzheimer’s disease is often diagnosed relatively late in its course, after significant neurodegeneration has already occurred. Current diagnostic biomarkers, including cerebrospinal fluid analysis and advanced neuroimaging, can be invasive and costly or have limited availability.

Retina potential

Dr Abdalla noted that the retina is an embryological extension of the central nervous system, making it an attractive target for non-invasive assessment of neurodegenerative disease.

Dr Abdalla and colleagues conducted a narrow systematic review to evaluate whether structural and microvascular retinal changes could serve as biomarkers for Alzheimer’s disease and MCI. The review identified studies published between 2016 and 2026 that assessed the diagnostic and prognostic value of different retinal imaging modalities, optical coherence tomography (OCT) and OCT angiography (OCTA), and measurement techniques on cognitive outcomes.

Twenty studies from Europe, Asia, and North America met the inclusion criteria.

Key findings

Across the studies, significant thinning of the macular ganglion cell-inner plexiform layer (GC-IPL) and retinal nerve fibre layer (RNFL) was consistently observed in patients with MCI and Alzheimer’s disease compared with cognitively normal controls. Reduced retinal microvascular density was also reported.

Importantly, these associations remained significant after adjustment for age, sex, APOE genotype, and vascular comorbidities, Dr Abdalla reported. Greater retinal thinning was also associated with increasing disease severity and established Alzheimer’s biomarkers, including amyloid and tau pathology.

The review found that combining structural OCT measures with OCTA vascular metrics improved diagnostic performance compared with individual measurements alone.

Variations in imaging protocols, study populations, and analytical methods contributed to moderate heterogeneity across studies, he noted.

Scalable technology

Dr Abdalla said the findings support the potential role of retinal imaging as a non-invasive, accessible biomarker for early detection and monitoring of Alzheimer’s disease. Such approaches could also potentially aid risk stratification and disease progression and facilitate earlier intervention in patients at risk of cognitive decline.

“OCT is a very scalable technology and is more available in a primary care setting compared to other diagnostic modalities for Alzheimer’s disease, which are quite expensive and invasive,” Dr Abdalla told EuroTimes.

However, he cautioned that further work is needed before retinal biomarkers can be incorporated into routine clinical practice. The review concluded that standardised retinal imaging protocols and large-scale longitudinal studies will be required to determine whether OCT and OCTA can be integrated into future population screening and diagnostic pathways for Alzheimer’s disease.

Dr Abdalla spoke at the Irish College of Ophthalmologists 2026 Annual Conference in Galway.

Ahmed Abdalla MD practices at Cavan General Hospital, Ireland. Ahmedhsn9696@gmail.com