Millions of people around the world currently spend a
few hours a day sitting in front of computer screens, whether desktop, laptop,
tablet, or even smartphones, reading references, study materials, or websites,
or doing their work that has become highly dependent on the use of these
devices in various companies and institutions. and universities, or even engage
in some recreational activities and use video games.
On the other hand, many people suffer as a result of
these long hours of use from many physical problems, especially back and neck
pain, in addition to eye pain, which may become tired and dehydrated when
sitting too close or too far from the computer screen. In the following, we
will discuss the negative physical impact of sitting in front of computer and
laptop screens uncomfortably, and what is the optimal distance that separates
us on the computer screen during use in order to maintain the safety and comfort
of our eyes.
Why should we sit at an appropriate distance from the screen?
Many people think that the danger of sitting in front
of a computer screen for a long time lies only in sitting very close to the
device screen and that the farther our eyes are from the computer screen, the
more we keep our eyes safe, but in fact, this is not exactly true, whether the
user approaches his eyes Stay away from the computer screen too much or stay
away from it too much, both of which can harm the safety of the eyes.
If we sit too far from a computer screen, we will see
things too small and we won't be able to see details clearly, for example, if
we try to read a written text our eyes will suffer as a result. If we sit too
close to the screen, the brightness of the screen and the sharpness of its
details will become too big and bloated for our eyes, causing them to be tired
as well.
The dangers of eye strain
Red and dry eyes, headache, blurred vision, eye pain,
and other changes that occur to the user's eyes when sitting in front of the
computer screen or the laptop in an incorrect position are the main signs that
the user's eyes are tired and need some rest. Eyestrain may also cause the eyes
to stay open for long periods of time without blinking, which is called squint.
Eye blinking or eyelid movement at intervals to close
and open the eye involuntarily helps to moisten the eye using tears, mucus, and
eye fluids, and to get rid of foreign bodies by expelling them, which protects
the eyeball from drying out.
Exposing the eye to dehydration as a result of this
lack of hydration poses a threat to the integrity of the cornea, which is the
outer layer that protects the eye, and then dehydration may cause it to be
scratched, and since this layer contains many nerve endings, this will be very
painful. If these symptoms appear, the user should immediately stop looking at
the computer screen, and get some rest by lying on the back and closing the
eyes to rest them for some time, or going out to an open place to breathe some
fresh air.
What is the best distance to sit away from the computer screen?
It is difficult to answer this question, as it is not
possible to determine the exact distance that should separate the user from the
screen of his desktop, laptop, or tablet device, as this distance depends on
several factors such as visual strength, which varies from one user to another,
and the type and size of the screen The device, which is measured in inches,
the resolution and quality of the screen display, which is measured in pixels,
as well as the type of activity that the user engages in while using the
device. Watching a movie or browsing websites, for example, does not require
getting close to the screen as much as writing a text, or playing a video game.
But let's say we have a standard 16:9 screen, not an
HD screen like 32-inch gaming monitors, and let's also say we have a standard
user with perfect visual acuity i.e. 6/6, now we can find A standard answer is
also to this question, that is, it does not apply to all users of desktop and
laptop computers, but only applies to some.
First, in the case of desktop computers
while sitting to engage in various activities and uses
in front of desktop computer screens; It is preferable that the user’s eyes
remain at a distance from the computer screen approximately equal to the length
of the arm, that is, between 50-70 centimeters, even if more than one device or
screen is used at the same time, the user must maintain the same distance
between his eyes and between each device with Ensure that all devices are
placed in one horizontal level as much as possible so that the user does not
have to constantly raise and lower his eyes while moving his eyes from one
screen or monitor to another.
If not all of these screens or beams are of equal
heights, it is best for the user to place the lower screens on flat surfaces of
paper or cardboard to raise them and align them with the higher screens, and
they can also be placed on special stands, which can provide other additional
advantages besides Height control.
When using two devices at the same time, it is
preferable for the user to sit exactly in the middle between the screens of
both devices, with a distance of 50-70 centimeters from each of them so that he
does not have to constantly move his neck for large distances. This position
will allow him to turn frequently at slight side angles to keep his neck safe.
In the case of using three devices at the same time, it is preferable for the
user to sit at a distance of 50-70 centimeters from each of the three screens
separately so that he is facing one of them directly and in the middle of the
two screens or the other two screens exactly in order to facilitate viewing all
the screens smoothly without causing bone pain the neck.
There is another solution in the case of using more
than one computer screen or a monitor at the same time, which is to sit on a
movable seat or rotate around a fixed axis so that the user moves with his
whole body to face the desired screen when needed instead of repeatedly turning
the neck.
It is also recommended to avoid staring at the
computer screen. If you find your eyes staring at the screen of the device, and
not blinking enough, try moving the upper eyelid to close and open your eyes
frequently to moisturize and protect them from drying out. Also, make sure to
keep the computer screen at a slightly lower level and not exactly at eye
level, which increases the field of vision, relaxes the eyes, and reduces the
feeling of squinting and opening your eyes wide.
But take care that the screen does not become so low
that it forces you to bend forward so that you can read and see, as this may
cause you a pain in the neck, but the level of the first line of text displayed
on the screen should be approximately at the level of your eyes.
Second, in the case of the laptop
The situation for laptops or laptops is different from
the previous situation. In the case of the laptop, the keyboard is connected to
the screen of the device so that the user has to stay close to the screen of
the device in order to be able to use the keyboard and the tactile device
indicator, and this mode does not allow the previous distance to be adhered to,
But there is an alternative solution so that the user can sit 50-70 centimeters
away from the screen.
This alternative solution is to connect an external
keyboard and an external mouse to the laptop using USB cables and control the
device from an appropriate distance, which is the arm distance as previously
while maintaining a safe distance that protects the safety of the user's eyes
without having to approach the device screen too much.
Summary | It is difficult to accurately determine the optimal distance that should separate the user from his desktop, laptop, or tablet screen, as this distance depends on several factors such as visual strength, which varies from one user to another, the type and size of the device screen in inches, the resolution and quality of the screen display in pixels, as well as The type of activity the user engages in while using the device.
However, if we assume a conventional standard desktop
computer screen with a 16:9 height-to-width ratio, which is not
ultra-high-resolution, and we assume a standard user whose visual acuity is an
ideal 6/6, then in this case we can assume that the ideal distance that the
user must be away from the screen in order to keep his eyes safe and
comfortable is the arm distance, i.e. between 50-70 centimeters, and this does
not apply, of course, to laptops where the keyboard is not separated from the
screen of the device.
Therefore, in the event of observance of the aforementioned safe distance, it should be taken into account to connect the device to an external keyboard and mouse through USB cables so that the user can control the device while maintaining a safe and comfortable distance between the user’s eyes and the device screen.