Vision improvement in pilots with presbyopia

Abstract

Purpose: Our earlier studies have shown significant improvement in near visual acuity (VA) in presbyopes following training protocol based on perceptual learning, with consequent improvement in higher visual functions, such as reading, and with persistence of up to 6.2 years. It has also been shown to improve distance VA in young subjects, supported by neurophysiological measurements. Our hypothesis is that both improvements in contrast sensitivity and processing speed underlie the observed gains in visual functions. Israeli Air Force pilots continue flying combat missions past the age of onset of presbyopia. Any optical correction for presbyopia limits their flying capabilities. Therefore, there is an operational need for delaying the onset of presbyopia or improving their near VA in order to avoid the use of optical corrections. Here we aimed 1) to test whether the temporal processing of pilots that is commonly assumed superior compared to age-matched controls, leads to an advantage in visual functions and 2) to improve pilots' near VA using our training method.

Methods: 30 pilots with both early and advanced presbyopia completed the training protocol for presbyopia (GlassesOff mobile application for iOS devices), consisting of a 12-15 minute session, 3 times a week for 3 months. Processing speed was measured using a discrimination paradigm with briefly presented stimuli (ranging from 30, 40, 60, 90 and 130 milliseconds). Aerial photography interpretation was tested using an object detection paradigm using natural scene images with low contrast (2, 4, 6 and 8%).

Results: 1) Pilots showed a significant advantage in the processing speed measurements compared to controls before training. 2) Despite this initial advantage, pilots showed a significant improvement following the training protocol in several basic visual functions, such as contrast sensitivity, contrast discrimination and temporal processing. These training gains were also generalized to higher visual functions, such as reading and low-contrast aerial photography interpretation.

Conclusions: 1) Pilots demonstrate a superior visual performance compared to controls in tasks relying on temporal processing. 2) Despite this initial temporal processing advantage, training protocol for presbyopia is effective for overcoming the blurred vision in presbyopic pilots, with real operational benefits.

Keywords: 579 learning • 653 presbyopia • 641 perception