Lockdowns and stay-home orders to minimize spread of the novel coronavirus consequently maximized digital device use as millions of Americans pivoted to remote work and schooling. Now, this always-on, work-from-home (WFH) mindset could sow not only mental but also visual fatigue.
In April, Gallup reported 83% of U.S. school-age children were learning remotely through school-sponsored online distance education as at least 43 states and Washington, D.C., ended in-person classes for the remainder of the academic year. As if children's screen habits weren't already a concern for parents, data suggest most children ages 6-12 say they're in front of a digital screen twice as much as before the pandemic-or for what feels like "most of the day."
In fact, metrics of children's screen habits are up across the board with traffic to kids' apps up nearly 70%, viewership of kids' TV programming up 58%, average weekly time spent in gaming or nongaming apps worldwide up 20%, a tripling in tablet traffic and doubling on phone traffic. And, that's not to mention circumstances where device use exponentially increases: children with no regular device use outside of school now spending hours more on loaned devices to facilitate distance learning.
"Here you have kids who don't use devices on a regular basis or maybe only at school and now they're using them pretty much full time for their education, their games and entertainment, and they're going to eventually come to us with all these eyestrain problems," says Karl Citek, O.D., Ph.D., Pacific University College of Optometry professor and member of the American National Standards Institute's Accredited Standards Committee for Ophthalmic Optics.
"Children will start talking about how print looks fuzzy after a while, or swims in and out, and this is going to uncover uncorrected astigmatism, uncorrected anisometropia, uncorrected eye movement problems-some things that might have been glossed over before or not as obvious will start coming out of the woodwork."
Likewise, adults can't escape the screen time proliferation either during the pandemic; 63% of U.S. employees reported working from home as of early May, up from 31% in mid-March. While many employees are used to hours spent in front of a computer, home workspaces may be less than ideal; ergonomic substitutes for the office for weeks on end and these circumstances may be taking their toll.
Tips for healthy device use
Prolonged viewing of a computer or digital screen often makes the eyes work harder, and as a result, these unique characteristics and high visual demands make many individuals susceptible to the development of vision-related problems. Factors, such as screen or font size, glare, definition, luminosity and contrast, viewing distance or angle, all can increase discomfort and exacerbate uncorrected vision problems.
In most cases, this digital eyestrain occurs because the visual demands of the task exceed the visual abilities of the individual to comfortably perform them, while those most at risk are people spending two or more continuous hours starting at a digital device. However, doctors can make patients aware of important considerations for any work location that can help mitigate digital eyestrain symptoms, including:
- Position your screen correctly. Computer screens should be 15-20 degrees below eye level (or about 4-5 inches) as measured from the center of the screen and 20-28 inches from your eyes.
- Think about lighting. Tilt or position the computer screen in a way that minimizes glare from overhead lighting or windows, and if there's no way to cut glare, consider using an anti-glare screen to decrease reflected light.
- Correct your posture. Adjust your chair height so that feet are resting flat on the floor, back is straight and wrists aren't resting on the keyboard when typing.
- Remember to blink. To minimize changes of dry or discomforted eyes when using your computer, be sure to blink frequently to keep the ocular surface moist.
- Take frequent breaks. Generally, it's good advice for every 20 minutes of computer viewing to look into the distance for at least 20 seconds to allow your eyes a chance to refocus. For every two hours of continuous computer use, consider resting your eyes for 15 minutes.
- Get ready for bed. Stop working on your computer, tablet, or smartphone at least 1 hour before bedtime. The mental and visual demands of answering emails, playing a video game, or even surfing the web can prevent you from falling asleep or sleeping soundly.
Additionally, Dr. Citek suggests device users take font size and distance into consideration. Ensure a screen large enough for the task at hand; i.e., opt for a tablet or desktop screen over a smartphone when accessing small font type, or consider a larger screen when viewing copious amounts of content. Also, maintain an appropriate working distance commensurate to the size of device; at least 13-20 inches for small to medium devices and greater than 20 inches for full-sized laptop or desktop screens.
Lastly, don't forget to take environmental and device lighting into consideration.
"You need to adjust your device light level so it's close to the light level in the environment," Dr. Citek says. "If you're in a bright office-type space, then turn your screen lighting up; if you're in a dark room then turn your screen lighting down."
What about blue light?
Blue light concerns originate from the wavelength's proximity to ultraviolet (UV) light on the electromagnetic spectrum; i.e., visible blue light (420-480 nm) stops just short of the invisible UV band (10-400 nm). While anterior structures of the eye block and absorb most UV rays from reaching the retina, visible blue light passes through the cornea and on to the light-sensitive tissue.
Long-term, overexposure to UV rays can cause serious problems that affect the eye, such as corneal damage, cataract, pterygium and increased risk of cancer, and may be a risk factor in development of age-related macular degeneration. Hence, concerns about the increased amount of artificial blue light people receive from the proliferation of digital device screens.
While some studies have shown blue light exposure may adversely affect ocular health, there remain numerous questions about the implications for blue light-emitting digital devices. For instance, the amount of blue light in sunlight is at least 100 times greater than what's produced from a typical smartphone; that means, Dr. Citek says, someone would have to stare at a smartphone screen for over 13 hours straight to get as much blue light as in only 8 minutes of sunlight.
Additionally, the light intensity of an everyday digital device screen is nowhere near that of some artificial sources, known for blue-light hazards. An LED dental curing light emits over 5,000 times as much blue light as a smartphone, Dr. Citek points out.
However, that's not to say there are no consequences of blue light. Evidence suggests excessive blue light exposure, including that from digital device screens, can affect melatonin release and affect normal sleep cycle. Artificial bright light stimulation of retinal cells at nighttime can disrupt sleep by as much as 14 minutes.
"Stimulation of these cells by blue-colored light (or from strong white light with a substantial blue component) can inhibit sleep and keep one alert," notes the AOA's Light and Eye Damage resource. "This can be beneficial to keep one alert during tedious activities but can be detrimental if one is stimulated right before bedtime."
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