Neuroscience: Teaching old eyes new tricks

Visual performance in individuals with presbyopia, the degeneration of near vision with age, may be improved by the repeated practice of a demanding visual task. The findings, published in Scientific Reports, need to be confirmed with a large, randomized controlled clinical trial, the authors caution, because subjects were not randomly assigned to experimental and control groups and because of the small sample size. Presbyopia (from the Greek for “ageing eye”) causes near visual acuity to degrade with age and affects most people over the age of 50, one of the main problems being difficulty reading up close, especially in poor lighting. Currently available solutions, such as reading glasses or bifocals, are not ideal for all daily activities. Uri Polat and colleagues studied 30 presbyopic subjects and seven young individuals with normal or corrected-to-normal vision. Participants were asked to practice a perceptual training protocol, in the form of the repeated practice of a demanding visual task, at least three times per week for 30-minute sessions, over the course of three months. The results indicate that perceptual learning can improve visual acuity and contrast sensitivity in individuals with presbyopia and, in some cases, results in performance levels similar to the young control group. The improvements are not due to improved optical performance of the eye, the authors show, suggesting that the ageing brain may retain enough plasticity to overcome natural biological deterioration with age.