Many people consider the eyes to be the window to the soul, but Professor Pankaj Kapahi from the Buck Institute sees them as a window to aging. His lab has demonstrated that imaging the fundus (blood vessel-rich tissue in the retina) can help physicians monitor human aging in a non-invasive, cost-effective, and highly accurate manner compared to existing aging clocks.
The research team, in collaboration with Google Health and Zuckerberg San Francisco General Hospital, also conducted a genome-wide association study (GWAS) to establish the genetic foundation for this “clock,” which they named eyeAge. Prof. Kapahi, a senior co-author of the study, believes this imaging technique could be invaluable in evaluating the effectiveness of interventions targeting the aging process. According to the results, within a year, it should be possible to determine aging trajectories with 71% accuracy by observing discernable changes in the eyes, providing a practical assessment of gero-protective therapeutics.
Retinal scans are likely more reliable due to the stability of eye changes compared to the dynamic nature of other blood-based biomarkers. The microvasculature in the retina is increasingly considered a reliable indicator of the overall health of the body’s circulatory system and brain, as changes in the eye are associated with aging and various age-related diseases.
Ophthalmologists often detect early symptoms of diseases such as AIDS, chronic high blood pressure, and tumors in the eyes. Researchers believe subtle changes in the vascular system first appear in the smallest blood vessels, with retinal capillaries being among the smallest in the body. Deep learning, spearheaded by Google Research, is necessary to identify these subtle changes that often go unnoticed even by advanced modern instruments.
Google researchers and others developed models for predicting diabetic retinopathy from retinal images and have since used retinal images to identify at least 39 eye and non-eye diseases. They trained and fine-tuned the eyeAge model using the EyePACS data set, which involved over 100,000 patients, and then applied it to more than 64,000 patients from the UK Biobank.
The genome study was conducted at the Buck Institute using biological samples from the UK Biobank. Postdoc Kenneth Wilson validated some genes identified in the analysis, building on previous research that found a connection between diet, eye health, and lifespan in fruit flies. Wilson identified nearly 30 genes in patient samples associated with various diseases, including visual decline, diabetes, hearing loss, Alzheimer’s disease, cardiovascular disease, and stroke. In particular, one gene, ALKAL2, has been shown to extend lifespan in fruit flies.
In conclusion, Prof. Kapahi believes the findings from this research pave the way for further studies. He emphasizes that the ability to track the efficacy of potential treatments for age-related diseases through a low-cost, non-invasive method is a significant advantage.
