Age has no significant influence on visual acuity in the presence of defocus and astigmatic blur, reports a study published in the March 2015 Optometry and Vision Science.1

Researchers dilated the right eyes of 22 participants—12 young adults and 10 older adults—using cyclopentolate 1.0%, then provided each with artificial pupils mounted on the back of a trial lens. To evaluate visual acuity, researchers simulated 13 blur conditions using five spherical lens conditions and two cross-spherical lenses at four negative cylinder axes. In each instance, participants were asked to read lines of decreasing size of high-contrast letters based on the Bailey-Lovie chart through the center of the artificial pupil. Following visual acuity measurements, aberrations were also measured.

Researchers found no significant differences in visual acuity between the two age groups, disproving their hypothesis regarding the older group experiencing less decrease in visual acuity with blur; accordingly, they reported no need to test their second hypothesis that variations between the two age groups is explained by differences in higher-order aberrations. However, they suggested further study with more participants may yield a different outcome. 

1. Mathur A, Suheimat M, Atchison DA. Pilot Study: Effect of Age on Visual Acuity with Defocus and Astigmatism. Optom Vis Sci. 2015 Mar;92(3):267-71.