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fatigue or irritation of the eyes, resulting from excessive use, as from prolonged reading of small print, or uncorrected defects of vision
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



or asthenopia, a state characterized by a feeling of heaviness in the eyes, a dull pain in the forehead and temples (sometimes expressed as a headache), difficulty in working, diffuseness and indistinctness of previously distinct contours of objects (for example, letters in a text), and a need to close the eyes and rest them.

There are two types of eyestrain: accommodative and muscular. Accommodative eyestrain (overstrain of the accommodation muscle) develops primarily in young people suffering from hyperopia when there is need to study an object at close range for a long time. To avoid eyestrain the hyperopia must be corrected with eyeglasses, and the person must take periodic breaks from work and look into the distance. Analogous phenomena of eyestrain may be observed with uncorrected astigmatism of the eye.

Muscular eyestrain develops predominantly with uncorrected myopia and is caused by a relative weakness of the interior straight muscles of the eye, which effect convergence of the visual lines of both eyes on an observed object; upon closing one eye, all unpleasant sensations disappear. To pre-vent this form of eyestrain the myopia must be corrected, sometimes with the use of prismatic glasses (spheroprismatic lenses), and the person must take periodic breaks from work.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

computer vision syndrome

A variety of problems related to prolonged viewing of a computer or mobile screen. Short term effects include dry eyes, blurred vision, mild headaches and eye fatigue. Long term effects include migraines and visual epilepsy. Some solutions are to keep reflections and glare to a minimum and to provide a non-fluorescent, uniform light source. Special lamps are available that maintain the proper light around the monitor and generate light at much higher frequencies than regular light bulbs.

The 20-20-20 Rule
A worthwhile rule of thumb is 20-20-20: look into the distance at least 20 feet for 20 seconds after every 20 minutes of computer, tablet or smartphone use. See medical conditions.
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References in periodicals archive ?
Poor workplace conditions such as ergonomically unsound computer tables and chairs and improper work habits can contribute to digital eyestrain, but the condition is primarily caused by the computer screen's stress on the eyes.
Digital eyestrain is irritating, painful and a productivity killer--no question.
Even the imperceptible flicker of the fluorescents can be a source of stress and eyestrain. Add a dimmer switch to control the luminance and try to match the brightness of the lighting with that of your monitors.
The main cause of eyestrain is thought to be fatigue of ciliary and extraocular muscle due to prolonged accommodation and vergence required by near vision work.
* Lighting: Reduce eyestrain by avoiding sun glare and providing adequate light at the workstation.
Therefore, with near vision demands or computer work, accommodation lags and fails to fully relax, thereby causing blurred vision and/ or eyestrain in the person.
The flicker-free light also helps reduce eyestrain, making it the perfect light for reading, needlework and long periods of studying.
The flicker–free light also helps reduce eyestrain, making it the perfect light for reading, needlework and long periods of studying.
To minimize eyestrain, the unit's micro-array lens evens out light refraction for more natural lighting and even distribution.
Extraneous light, otherwise known as glare, is the greatest source of eyestrain to computer users.
Kondrot practices both traditional and alternative therapies for the prevention and treatment of eye diseases, including macular degeneration, glaucoma, cataracts, eyestrain, and much more.