The problem is international: "Computer vision syndrome, also known as digital eye strain, describes a group of eye and vision problems caused by prolonged use of computers, tablets, e-readers and cell phones," says the American Optometric Association, for example.
"Studies indicate that one in two people who use computers and smartphones intensively suffers from CVS," said Wolf Lagreze from the German Ophthalmological Society (DOG), who is head of the Department of Neuroophthalmology, Pediatric Ophthalmology and Strabismus Treatment at the University Eye Clinic in Freiburg.
The leading symptoms of CVS include headaches and burning eyes caused by chronic poor posture and irritated eyes. The American Society of Optometry lists these leading symptoms of CVS: Eye strain, headaches, blurred vision, dry eyes, and neck and shoulder pain.
Screens strain the eyes
According to the expert from the German Society of Ophthalmologists, part of the problem is due to the computer technology itself. "We control the cursor on the computer with the mouse," explained the Freiburg ophthalmologist. "So that we can coordinate our movements well, we unconsciously reduce our blinking frequency."
The result: the eyes are no longer well moistened with tear fluid by the blinking, the tear film becomes unstable and the eyes begin to burn.
"Over time, it sometimes becomes a pain in the direction of the head," said Lagreze. In a DOG statement, he recommended taking frequent breaks at the computer, looking into the distance every few minutes and consciously blinking or even closing your eyes for a few seconds. "It is also beneficial for the eyes to heat less and ventilate regularly to keep the air more humid," advised the DOG expert.
Near glasses can provide a remedy
Varifocal glasses can also be a problem. Anyone approaching the age of 50 who notices that they are getting headaches in front of the computer should first think about presbyopia, which makes it difficult to see at close range and leads to fatigue and a feeling of pressure in the head.
"Close-up glasses can help, but this step is often delayed," said Lagreze. Varifocal glasses with a near part also help against presbyopia, but can also trigger headaches again. "This is because we then sit as if frozen and no longer move our head and spine to get the best focus on the screen with varifocals," explained the expert.
This leads to incorrect posture, which promotes headaches. "The solution is to have extra computer glasses made, such as monofocal glasses for a viewing distance of around 80 centimeters," said the DOG expert.
Recommendation: 20 second break every 20 minutes
In general, defective vision is a common cause of eye-related headaches. "If short-sightedness or long-sightedness is not recognized or corrected, we strain our eyes," explained the expert. "The reaction is a headache in the evening."
This also applies if glasses or contact lenses are not the right strength or if there is a "hidden" squint that is compensated for by increased eye muscle work. "We use eye tests and eye examinations to find the cause and adjust the visual aids correctly," says Lagreze. The headaches then usually disappear.
The US Society of Optometry offers the following advice on the CVS problem: "To alleviate digital eye strain, follow the 20-20-20 rule: take a 20-second break every 20 minutes to look at something 20 feet [six and a half meters] away." In the United States, it's estimated that the average worker spends about seven hours a day in front of a screen."