Abstract
Physiological changes associated with aging increase the risk for the development of age-related diseases. This increase is nonspecific to the type of age-related disease, although each desease develops through a unique pathophysiologic mechanism. People who age at a faster rate develop age-related diseases earlier in their life. They have an older “biological age” compared to their “chronological age”. Early detection of individuals with accelerated aging would allow timely intervention to postpone the onset of age-related diseases. This would not only increase their life expectancy, but would also increase their length of good quality life. The goal of this study was to investigate whether retinal microvascular complexity could be used as a biomarker of biological age. To test this, retinal images of 68 participants ages ranging from 19 to 82 years were collected in an observational cross-sectional study. Twenty of the old participants had age-related diseases such as hypertension, type 2 diabetes, and/or Alzheimer’s dementia, while the rest of the participants were healthy. Retinal images were captured by a hand-held, non-mydriatic fundus camera and quantification of the microvascular complexity was performed by using Sholl’s, box-counting fractal, and lacunarity analysis. In healthy subjects, increasing chronological age was associated with lower retinal microvascular complexity measured by Sholl’s analysis (young healthy vs. old healthy mean=716.1 vs. 637.6, p=0.010). Decreased box-counting fractal dimension was present in old patients with age-related diseases (old healthy vs. old with age-related diseases mean=1.358 vs. 1.324, p=0.031). Retinal microvascular complexity could be a promising new biomarker of biological age.
