August 3, 2021

How to reduce sight fatigue after many hours in front of a screen | Technology

How to reduce sight fatigue after many hours in front of a screen | Technology

Have you ever felt exhaustion, dryness and itchy eyes, blurred vision or even headache after using a computer, mobile or tablet for many hours at a time? These are the typical symptoms of visual fatigue caused by the prolonged use of these devices, as ophthalmologists and opticians warn. These specialists claim that there is no scientific evidence that the light from the screens causes direct damage to the visual organ. But they warn that excessive eye strain can negatively impact our well-being, as well as doing them a disservice in the eyes of those suffering from problems such as myopia, hyperopia or astigmatism. Some precautions can help mitigate these symptoms, especially when the need prevents to reduce the hours of digital activity, experts say.

Ricardo Casaroli, professor of ophthalmology at the University of Barcelona, ​​points out that by focusing on the screens "at a short distance" the effort to read is activated. This intellectual activity can cause eyestrain – in medical terms, asthenopia – if it lasts a long time, he says. The other factor that influences to cause ocular fatigue, according to this doctor, is the degree of attention that is placed on the use of the devices. "It is proven that the more we pay attention to one thing we are doing, the lower the frequency of blinking. And if we blink less we are more predisposed to have the symptoms of ocular dryness, "he says.

Visual fatigue can also increase due to environmental factors, adds the ophthalmologist from the University of Valencia Manuel Díaz. One of them is insufficient exposure to natural light, important to protect the health of the eyes and prevent more serious problems such as myopia, he explains. They can also influence the presence of fluorescent lights or the high intensity of air conditioning or heating in certain work environments, adds this specialist. A too high or too low position of the computer screens with respect to the height of the eyes and the excessive closeness of tablets and smartphones can increase fatigue, detail this and other specialists. "It is a multifactorial intellectual exhaustion," says Díaz.


Experts offer different tips to mitigate the most annoying effects of eye fatigue. But they also warn that the study of the impact of exposure to screens is still evolving. Below are some of the precautions on which the sources consulted by this newspaper are most in agreement.

A properly lit work environment. Ophthalmologists and opticians consider it important to avoid an excessive contrast effect of the screens in the eyes. That's why they recommend using electronic devices in places with good ambient lighting, for example that produced by desk lamps or bedside tables. "A warm light placed in the office, which indirectly reaches the eyes and somehow illuminates the screen and keyboard, is the most comfortable," says Diaz. The optometrist of the Universidad Complutense de Madrid Beatriz Antona discourages the use of mobile devices in the dark. "In that situation the eyes are adapted to a night vision according to the environment, but they find the bright screen that generates glare and creates visual fatigue," he explains. It is also advisable to "avoid that the light sources generate reflections on the screen", considers this specialist. For people who wear glasses, "it is good that the crystals include a good multi-layer antireflective that contributes to a good image sharpness," he adds.

Small periodic breaks. Another common recommendation is to fragment the work with fixed eyes on a screen through small breaks. According to Casaroli, this precaution allows the habitual blinking rhythm to be retaken from time to time, fixed at 15 or 20 blinks per minute, and to prevent ocular dryness. Antona recommends "looking far away every 15 minutes, better through a window", before returning to the task. If you go to work many hours in a row, a good measure of rest to "break that tension" is to take a break of five or ten minutes every "hour, hour and a half", says Casaroli.

The use of artificial tears in case of dry eyes. Also lubricate the eyes regularly is important not to reduce excessively the rate of blinking, ophthalmologists and ophthalmologists coincide. To achieve this, apply artificial tears when you begin to notice symptoms of visual fatigue is a good precaution, they say. The recommendation is especially true for people with dry eyes, says Antona. Artificial tears can be especially useful when working in offices with a lot of air conditioning or heating, adds Casaroli. Diaz suggests that putting on the drops can even represent a good opportunity to take a break.

Care of the position in which you work. Avoiding visual fatigue is also a matter of ergonomics. Díaz explains that not respecting the natural tendencies of the ocular musculature increases the effects of fatigue. That's why he considers that staring for hours at a screen placed "on top of a tower that sits on a table" does not help keep his eyes relaxed. This doctor believes that it is best to place the computer in a position similar to "as if it were a lectern" and think about the naturalness of the position in which a book is read. Casaroli fixes as a reference a height that corresponds "to that of the gaze in the direction of the horizon". The ophthalmologist at the University of Barcelona and the optometrist Beatriz Antona advise a minimum distance of 50 centimeters with respect to computer screens and 30 centimeters for tablets and mobile phones. Antona adds that adopting a good position of the whole body with respect to the screen helps to avoid "neck and spine pain".

Proper correction of the lenses if glasses are worn. The specialists do not get tired of remembering the importance that people with glasses have controlled the correction of the lenses to not strain the eyesight when they use electronic devices. "This prevents the visual system from having to make continuous readjustments to try to correctly focus the image," says Antona. Casaroli stresses the need to go regularly to medical checkups to "take preventive measures" and find out if it is necessary to wear glasses to facilitate the exercise of reading. Ramón García, optometrist and author of the blog, recommends in his free guide 7 ways to avoid visual fatigue, go to a control at least once a year.

This optometrist advises the use of an e-reader before other devices if the intention is to read, especially at night. Casaroli states that he usually advises e-books in particular "to patients who have low vision", because the fact of being able to expand the letter of the texts "facilitates reading". However, he explains that neither for this type of devices are there specific studies that demonstrate their impact on vision. The most advisable, in his opinion, is to apply to the use of books on paper or digital "the same eye health rules that serve for a computer screen".

Glasses with blue light filters and brightness and contrast adjustments

The scientific community investigates the effectiveness of some tools available in the market for its possible use in reducing visual fatigue. Among them, the specialists make reference to the blue light filters applied to the glasses and to some adjustments of the luminosity incorporated to the most recent versions of the electronic devices. However, not all of them express the same security about the benefits they could bring. Manuel Diaz says he often advises patients to wear glasses with blue light filters. This ophthalmologist, who is also representative of the Spanish Society of Myopia, considers that it is an easy option to find at reasonable prices and useful to mitigate eye fatigue. Blue light filters can be applied to both custom glasses and standard use to work in front of screens, he explains.

Ricardo Casaroli believes that it is still unclear if the blue light of electronic devices causes damage to the retina. This aspect is currently the subject of different investigations, he says. For that reason, both he and Diaz doubt the medical efficacy of the applicable filters in common settings on many devices. The ophthalmologist at the University of Barcelona believes that "they can facilitate reading a little, improve the contrast, and allow the use is not unpleasant in relation to brightness and brilliance", but believes that it is not possible to give generalized instructions for the use of these options. In his guide, Ramón García recommends "adjust the brightness to the minimum necessary to see well at all times," which "varies depending on the light conditions of the work environment." Also remember that in many phones you can invert the color of the letter and the background (from black to white and vice versa) and thus reduce the light received in the eyes


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