# Computer vision syndrome

Computer vision syndrome (CVS) is a condition resulting from focusing the eyes on a computer or other display device for protracted, uninterrupted periods of time and the eye's muscles being unable to recover from the constant tension required to maintain focus on a close object. Some symptoms of CVS include headaches, blurred vision, neck pain, fatigue, eye strain, dry eyes, irritated eyes, double vision, vertigo/dizziness, polyopia, and difficulty refocusing the eyes.

## Quotes

* There isn't a name for it and few eye doctors test for it. But many people are having trouble seeing in the middle distance that demands so much of our focus. Some 80% of us use computers, staring intently on screens set well between typical distance and reading range, often for many hours each day. Add in laptops, pagers, e-readers, smartphones, personal-digital assistants and hand-held video games, each with its own optimum...
** Melinda Beck, “Becoming a Squinter Nation” Archived 2017-04-05 at the Wayback Machine, Wall St. Journal, August 17, 2010 (Updated Aug. 17, 2010)
* With the increased use of electronic devices with visual displays, computer vision syndrome is becoming a major public health issue. Improving the visual status of workers using computers results in greater productivity in the workplace and improved visual comfort.
** Randolph, SA (July 2017). "Computer Vision Syndrome". Workplace Health & Safety. 65 (7): 328. doi:10.1177/2165079917712727. PMID 28628753. S2CID 206831504.
* Many ophthalmic lens manufacturers are currently marketing blue-blocking filters, which they claim will reduce symptoms of Digital Eye Strain (DES). However, there is limited evidence to support the proposal that DES results from the blue light emitted by electronic screens.
** M, Rosenfield; RT, Li; NT, Kirsch (2020). "A double-blind test of blue-blocking filters on symptoms of digital eye strain". Work (Reading, Mass.). 65 (2): 343–348. doi:10.3233/WOR-203086. PMID 32007978. S2CID 211012744.
* Prior to the advent of artificial lighting, the sun was the primary source of light. When the sun sets today, however, one is hard-pressed to find darkness—illumination from light-emitting diodes (LEDs), and incandescent, fluorescent, and xenon-arc sources (among others) provide indoor and outdoor illumination. The effects of exposure to this seemingly unnatural technological adaptation are starting to become evident, with several studies indicating undesirable associations between exposure to artificial light at night and both reduced sleep quality and diminished alertness during the day. A relatively recent concern is the excessive near-field exposure to handheld and other electronic light-emitting devices. Estimates from large population surveys in developed countries indicate that 35% of people born between the years of 1965 and 1996 spend at least 9 h/day on digital devices, such as smartphones, tablets, or computers, and a recent report indicates that the average American spends 10 h and 39 min viewing screens. Such intense use of these devices has been found to have undesirable effects not only on sleep quality and alertness during waking hours, but also on parameters of physical health (e.g., neck and eye strain, eye fatigue, headache;) and cognitive performance (e.g., poor inhibitory control;). The prevalence of complaints associated with excessive use of computers and other digital devices is so great that the common ocular and physical effects have been collectively termed “Computer Vision Syndrome” (CVS).
** Stringham, James; Stringham, Nicole; O’Brien, Kevin (2017). "Macular Carotenoid Supplementation Improves Visual Performance, Sleep Quality, and Adverse Physical Symptoms in Those with High Screen Time Exposure". Foods. 6 (7): 47. doi:10.3390/foods6070047. ISSN 2304-8158. PMC 5532554. PMID 28661438.

### "Computer Vision Syndrome (CVS)" (2017)

"Computer Vision Syndrome (CVS)". 'American Optometric Association. 2017.
* Many individuals experience eye discomfort and vision problems when viewing digital screens for extended periods. The level of discomfort appears to increase with the amount of digital screen use. The average American worker spends seven hours a day on the computer either in the office or working from home. To help alleviate digital eyestrain, follow the 20-20-20 rule; take a 20-second break to view something 20 feet away every 20 minutes.
* Viewing a computer or digital screen often makes the eyes work harder. As a result, the unique characteristics and high visual demands of computer and digital screen viewing make many individuals susceptible to the development of vision-related symptoms. Uncorrected vision problems can increase the severity of computer vision syndrome (CVS) or digital eyestrain symptoms. Viewing a computer or digital screen is different than reading a printed page. Often the letters on the computer or handheld device are not as precise or sharply defined, the level of contrast of the letters to the background is reduced, and the presence of glare and reflections on the screen may make viewing difficult.
* If nothing is done to address the cause of the problem, the symptoms will continue to recur and perhaps worsen with future digital screen use.
* CVS, or digital eyestrain, can be diagnosed through a comprehensive eye examination. Testing, with special emphasis on visual requirements at the computer or digital device working distance, may include:
* Solutions to digital screen-related vision problems are varied. However, they can usually be alleviated by obtaining regular eye care and making changes in how the screen is viewed.

### "Computer Vision Syndrome Affects Millions" (2016-05-30)

Jane E. Brody, "Computer Vision Syndrome Affects Millions". The New York Times, (2016-05-30). Archived from the original on 2018-02-10. Retrieved 2018-04-09.
* Worldwide, up to 70 million workers are at risk for computer vision syndrome, and those numbers are only likely to grow. In a report about the condition written by eye care specialists in Nigeria and Botswana and published in Medical Practice and Reviews, the authors detail an expanding list of professionals at risk — accountants, architects, bankers, engineers, flight controllers, graphic artists, journalists, academicians, secretaries and students — all of whom “cannot work without the help of computer.” And that’s not counting the millions of children and adolescents who spend many hours a day playing computer games.
* Studies have indicated 70 percent to 90 percent of people who use computers extensively, whether for work or play, have one or more symptoms of computer vision syndrome. The effects of prolonged computer use are not just vision-related. Complaints include neurological symptoms like chronic headaches and musculoskeletal problems like neck and back pain. The report’s authors, Tope Raymond Akinbinu of Nigeria and Y. J. Mashalla of Botswana, cited four studies demonstrating that use of a computer for even three hours a day is likely to result in eye symptoms, low back pain, tension headache and psychosocial stress. Still, the most common computer-related complaint involves the eyes, which can develop blurred or double vision as well as burning, itching, dryness and redness, all of which can interfere with work performance.
* One reason the problem is so pervasive: Unlike words printed on a page that have sharply defined edges, electronic characters, which are made up of pixels, have blurred edges, making it more difficult for eyes to maintain focus. Unconsciously, the eyes repeatedly attempt to rest by shifting their focus to an area behind the screen, and this constant switch between screen and relaxation point creates eyestrain and fatigue. Another unconscious effect is a greatly reduced frequency of blinking, which can result in dry, irritated eyes. Instead of a normal blink rate of 17 or more blinks a minute, while working on a computer the blink rate is often reduced to only about 12 to 15 blinks. But there are additional problems. The head’s distance from the screen and position in relation to it are also important risk factors. To give the eyes a comfortable focusing distance, the screen should be about 20 to 26 inches away from the face. The closer the eyes are to the monitor, the harder they have to work to accommodate to it.