Visual function, digital behavior and the vision performance index

Abstract

Historically, visual acuity has been the benchmark for visual function. It is used to measure therapeutic outcomes for vision-related services, products and interventions. Quantitative measurement of suboptimal visual acuity can potentially be corrected optically with proper refraction in some cases, but in many cases of reduced vision there is something else more serious that can potentially impact other aspects of visual function such as contrast sensitivity, color discrimination, peripheral field of view and higher-order visual processing. The measurement of visual acuity typically requires stimuli subject to some degree of standardization or calibration and has thus often been limited to clinical settings. However, we are spending increasing amounts of time interacting with devices that present high-resolution, full color images and video (hereafter, digital media) and can record our responses. Most of these devices can be used to measure visual acuity and other aspects of visual function, not just with targeted testing experiences but from typical device interactions. There is growing evidence that prolonged exposure to digital media can lead to various vision-related issues (eg, computer vision syndrome, dry eye, etc.). Our regular, daily interactions (digital behavior) can also be used to assess our visual function, passively and continuously. This allows us to expand vision health assessment beyond the clinic, to collect vision-related data in the whole range of settings for typical digital behavior from practically any population(s) of interest and to further explore just how our increasingly virtual interactions are affecting our vision. We present a tool that can be easily integrated into digital media to provide insights into our digital behavior.

The negative effects of dry eye disease on quality of life and visual function

“…Functional visual acuity is a contrast measurement of visual acuity during and after sustained visual activity, which is argued to be more accurately representative of visual function in real-life situations like reading, computer work, and driving [9]. In fact, dry eye disease has been found in multiple studies to degrade visual function with sustained visual tasks like reading [8,44,45], digital device use (computer vision syndrome) [46], and driving [47]. Furthermore, studies support that dry eye disease negatively affects contrast sensitivity [48] and is associated with irregular astigmatism and higher order optical aberrations [49].…”

Visual Sequelae of Computer Vision Syndrome: A Cross-Sectional Case-Control Study

“…Digital technologies are now universal and have spread worldwide; thus, digital behaviour has dramatically changed peoples' lifestyles. Previous studies have reported that individuals interact with digital screens for up to 12 hours daily [ 1 , 2 ], and the American Optometric Association defined a combination of ocular and extraocular symptoms that affects the screen users as computer vision syndrome (CVS) [ 3 ]. However, our current understanding of digital technologies and their harmful impact on the eye and public health [ 1 , 4 , 5 ], visual performance [ 6 – 8 ], sleep patterns [ 7 , 8 ], circadian rhythms [ 5 , 8 ], musculoskeletal system activities [ 3 , 4 ], and underlying physiological mechanisms [ 9 ] remains incomplete and replete with misconceptions [ 1 ].…”

“…CVS ocular symptoms include visual blur with an underlying mechanism that is not fully understood [ 10 ], dry eye disease (DED) [ 3 , 14 , 15 ], eye redness and irritation, eyestrain, fatigue, discomfort [ 14 , 16 ], difficulty in refocusing the eyes, and diplopia [ 3 , 4 ]. CVS extraocular symptoms include headache; sleep disturbances; depression [ 7 , 8 ]; musculoskeletal aches, such as neck/shoulder/back pain [ 2 – 17 ]; difficulty in writing or holding objects; and pain in thumbs, fingers, or wrists because of tendonitis and/or arthritis [ 18 – 20 ].…”

“…Smartphones are used extensively worldwide by people of all ages [ 21 – 23 ] and are characterised by a close viewing distance [ 24 ], related high-definition resolution [ 14 ], thousands of time-consuming applications and games in stores, and 24/7 Internet connectivity [ 2 , 22 ]. Smartphone usage is thought to be responsible for the sharp rise in CVS prevalence and severity among users, including paediatric populations [ 25 ].…”

Two-Photon Microperimetry: A Media Opacity-Independent Retinal Function Assay

“…The fovea is densely populated with three types of cones that are responsible for central visual function. Cone function is evaluated subjectively with visual acuity (VA) testing, 1 , 2 color and contrast testing, 3 , 4 and microperimetry. 5 All conventional tests of visual function use visible light, and their results are altered by ocular media opacities such as cataracts, corneal scars, and dense vitreous debris.…”