Retinal Asymmetry as a Potential Early Marker for Cognitive Frailty

A recent study conducted by researchers at National Taiwan University (NTU) has highlighted the significance of subtle differences in retinal thickness between the eyes—referred to as inter-eye retinal asymmetry—as a promising, noninvasive biomarker for early detection of cognitive frailty. Cognitive frailty is a condition that combines mild cognitive impairment with physical weakness, placing individuals at elevated risk for dementia, disability, and mortality.

The study found that uneven accumulation of amyloid beta, a key protein associated with Alzheimer’s disease, may lead to differences in retinal thinning that appear early during cognitive decline. These changes in retinal structure can be detected through optical coherence tomography (OCT), a quick and painless imaging technique that allows precise measurement of retinal layers like the ganglion cell–inner plexiform layer (GC-IPL). Notably, greater asymmetry in GC-IPL thickness at baseline was significantly linked to worsening cognitive function over four years, particularly in memory-related decline, while physical frailty alone did not show this association.

This discovery underscores the retina’s potential as a ‘window to the brain,’ providing insights into neurodegenerative processes through eye-based assessments. The research, published in Alzheimer’s & Dementia, attracted attention at the 19th International Congress of the Asian Society Against Dementia in Seoul (May 2025). Unlike more costly or invasive methods like brain scans or blood tests, OCT offers a widely accessible and noninvasive screening approach suitable for screening older adults.

The study, part of the long-term Taiwan Initiative for Geriatric Epidemiological Research (TIGER), involved 222 community-dwelling seniors with an average age of 75, followed over four years. It demonstrated that increased GC-IPL asymmetry correlates with the risk of developing cognitive frailty, suggesting that this structural marker could be crucial for early intervention. Age-related structural changes like retinal nerve fiber layer (RNFL) asymmetry show limitations, especially in populations with high myopia, making GC-IPL measurements a preferred indicator for Asians.

This research highlights the importance of early screening tools in preserving cognitive health. Professor Yen-Ching Karen Chen and Dr. Jen-Hau Chen emphasized that retinal imaging could be instrumental in routine assessments, enabling earlier detection and management of at-risk individuals. The findings are a step forward in preventive medicine, integrating ophthalmic imaging into comprehensive aging and dementia care strategies.

Source: https://medicalxpress.com/news/2025-06-retinal-asymmetry-eyes-early-indicator.html