Age-Related Changes in Ocular Aberrations and the Yamagata Study (Funagata).

Human vision quality is influenced by ocular aberrations, including astigmatism and higher-order aberrations (HOAs), in combination with other optical factors. In this study, we introduce the results and perceptions of previous studies investigating these aberrations. We also introduce our results obtained as part of the Yamagata Study (Funagata), a population-based epidemiologic study. To investigate the astigmatic change with age, researchers have used the power vector analysis, allowing incorporation of the magnitude and axis of astigmatism into statistical analyses. It was found that the axes of refractive astigmatism shift from with-the-rule toward against-the-rule with aging. It was demonstrated that the change in corneal curvature causes this shift. It was further reported that HOA increase is associated with deterioration of visual function. Some authors described that HOA increases with age in adults and that aging disrupts compensation between corneal and internal aberrations. Our study confirmed these results after considering possible confounding factors. HOA decreased from childhood to early adulthood and then increased with age, as modeled by a second-order polynomial regression. It is possible that the reduction in HOA is involved in emmetropization. In addition to age, HOA is known to be influenced by several factors, including pupil diameter, accommodation, and pupil shift. Although HOA increases with aging, the increase may be compensated by decreasing the pupil diameter. Better understanding of the causes of optical alterations with aging will improve the maintenance of vision quality.