Do your eyes hurt from so much computer? We tell you how we can avoid eye fatigue
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By Shutterstock / fizkes Juana Gallar Martínez , Miguel Hernández University and María del Carmen Acosta Boj , Miguel Hernández University
During the COVID-19 pandemic, work and family and social relationships have become fundamentally remote. We often use devices such as the computer or mobile. Since these electronic devices are understood to cause “eye strain”, we can feel that this problem has increased in recent months.
Eye fatigue manifests as a feeling of discomfort, dryness, or itching of the eyes. In addition, it leads to blurred vision and can cause severe headaches.
But do our eyes really "tire"? What do we call eye strain? Currently, there is already talk of the "visual computer syndrome" . This last term seems to be more appropriate to the problem that we will talk about in this article, since it is not really fatigue that occurs in our eyes. It is a sum of different eye and vision problems.
What part of the eye is fatigued?
The muscles responsible for moving our eyes are some of the fastest in our body. Your shape and metabolism are poised to continually contract and relax. The eyes move so that we focus the objects of our interest in the area of the retina that best sees, the fovea.
Unlike other muscles in our body, these are endowed with certain mechanisms that allow us to continuously carry out this task. They have abundant mitochondria, the intracellular organelles where the energy necessary to carry out contraction is produced. Precisely because of this high metabolic capacity, these muscles do not fatigue or cause stiffness.
Nor does fatigue occur in our retina, a structure capable of constantly performing the process of sensory transduction (the transformation of light into electrical signals) for hours and hours, day after day. To do this, it is equipped with mechanisms that regenerate the molecules that are "consumed" during the process that starts vision.
Lack of blinking can damage the eye
While we pay attention to a visual task (working with electronic devices or reading a book), our blink rate decreases so that we do not lose sight of anything.
The function of blinking is to protect the eye, but also to renew and distribute the tear film that hydrates and nourishes the ocular surface. Therefore, if our blink frequency decreases, our eyes dry out, causing irritation and in some extreme cases, pain .
If, in addition, we have low tear production (general or ocular diseases that cause dry eye, menopause, etc.) or we work in a dry environment (with air conditioning), the problem worsens. Of course, the use of contact lenses complicates this situation, since they hinder the passage of oxygen and the distribution of the tear film on the ocular surface.
As a consequence of the dryness of the surface of our eyes, the outermost cells are poorly protected and can be injured . This would cause a slight local inflammation that causes the eyes to redden and the sensations of discomfort appear. Sometimes these symptoms are accompanied by pain in the eyes or headache.
This problem could be avoided, if necessary, by voluntarily increasing our blinking frequency or by using artificial tears to compensate for dry eyes.
Position the screen properly
Another factor to consider is the height and distance at which we place the screen we use. The higher it is, the more open our eyes will have, which will help to evaporate that film of tears that covers the surface of the eye, increasing the problem.
Therefore, we must always regulate the height of the screen so that it is not high but not so low that it forces us to flex the neck too much. In general, it will be enough for the upper frame of the screen to be at the level of our eyes or our nose. As for the distance between our eyes and the screen, it is recommended that it be between 50 and 60 cm.
Close focus: accommodation
Our eyes are prepared to see objects from near and far, changing the focus continuously. However, when we are working with screens, we spend many hours at a time focusing only on a nearby object (less than 60 cm).
This will also cause that when we change from a close plane to a distant one, we have focus problems and blurred vision that can lead to headaches . This phenomenon can be seen even more after the age of 45 , with the appearance of “tired” eyesight or presbyopia. In this sense, it is very important that if we wear corrective lenses, they are well graduated.
Screen lighting: the "blue light" problem
It is widely believed that blue light from device screens causes "fatigue" and even eye damage. However, our eye is prepared to "work" with this and other wavelengths (the so-called visible spectrum, the small band of wavelengths of the electromagnetic spectrum that the human eye is capable of perceiving).
Those of blue light (between 400 and 500 nm approximately) are part of the white light with which the sun illuminates us during the day. If really blue light were harmful to our eyes, it would also be, for example, contemplating the sea, whose color we perceive because it sends precisely those wavelengths towards our eyes.
However, the use of this "blue light" at night would activate a series of neurons in our retina that connect directly with the centers of the brain that regulate circadian rhythms , marking the time to sleep and the time to activate to begin activity. daily.
If we use screens at night, the light they emit will trick our brain. He perceives that it is still daylight and does not start the mechanisms that help us to get the restful sleep that we all need at the end of a long day at work.
Many electronic devices make it possible to reduce the level of luminosity and even make the tone of light they emit at night more yellow. This helps us reduce the intensity of the light that falls on our retina. However, we should minimize its use in the twilight hours, in order to help our body fall asleep.
In short, what we commonly call “eye fatigue” is a sum of feelings of discomfort and irritation derived from dry eyes (which is produced by keeping the eyes open for a long time) and a slightly blurred vision due, in part, to dryness and focus problems.
To avoid it, we must therefore increase our blink frequency (and, eventually, use artificial tears). In addition, it is important to take breaks in which we carry out activities that do not require continuous attention and allow changes in focus (look into the distance). Finally, we have to make sure that the air conditioning, lighting and both our position and that of the screens (ergonomics) are appropriate.
Juana Gallar Martínez , Professor of Physiology at the Institute of Neurosciences, Miguel Hernández University and María del Carmen Acosta Boj , Professor of Physiology, at the Institute of Neurosciences, Miguel Hernández University