Author: Yana Nencheva, Biochemist, PhD candidate in biophysics

For many of us, everyday life passes in front of the computer screen and other screens. There are very few people who have no vision problem at the end of the working day. Often the discomfort is evident after a busier day, when we play a movie with subtitles and it turns out that we see the text slightly blurry. We instinctively close our eyes just a bit and things generally return to normal. We may feel the new tension in the eyelids, of course, but then we get sleepy quite fast. At first we think we should go to an ophthalmologist, but in the morning the problem is gone, and with a clear conscience we postpone the examination. During the pandemic, however, those who can work from home may have noticed that discomfort has increased and it is increasingly difficult to focus small and more distant objects at the end of the day.

What is the structure of the eye

I'm going to describe the structure of the eye in general, so that we can imagine its mechanics.

Behind the pupil there's a biconvex spherical lens ( imagine the shape of the glass of an ordinary magnifying glass). This information, passing through the lens, is broken and refracted in such a way that the information falls directly into the retina. The retina can be imagined as the back of the eye that perceives the information that came into it and transmits it to the brain. From there, the brain analyzes this information and tells us what we actually see.

What is accommodation

But in order to "project" the information in the same place in the eye (retina),the lens through which the information passes must be able to refract it with different force (optical force) according to the remoteness of the objects. Therefore, the thickness is regulated by the contraction and relaxation of small eye muscles that are attached to the periphery of the lens. When they shrink, the lens is "stretched" and becomes thinner, and when the muscles relax, "relax" the edges of the lens and it becomes thicker. Thus, the image focuses on the retina using the change in the optical strength of thelens. So (ideally)we can focus objectsboth 20 cmfrom our eyes (near point) and at an infinitedistance (distantpoint)from them.

How our eyes get tired in front of the computer

Most likely, you know how, if for a long time you carried something in your hands in the same pose, then your hands are stiff and you experience discomfort when you change their position. Well, something similar is happening here. After all day the muscles have maintained the same thickness of the lens constantly in front of the computer, attempts to focus small objects (such as subtitles) lead to discomfort. It takes more time for the eye to amod. If we were at work in the office (as before the isolation), by the time we get home, there is some kind of "movement" of focus along the way: we walk, drive, look out the window. In general, we observe large objects, and by the time we get home, the problem has passed imperceptibly. But if we work from home, we do not have the opportunity to walk, and the discomfort increases.

Eye exercise with a change of focus

A very easy exercise that would help is changing the focal length. Go to the window and first focus some nearby non-irritating object (e.g. window frame or pot) for 7-8 seconds. Then find the furthest point that can be seen from your window and monitor it again for 7-8 seconds. So repeat 5-6 times the exercise - focusing a close and distant object. You can do it every two hours. This will move the small muscles responsible for the amodation and relieve eye strain at the end of the working day.

 

Note that the cause of discomfort in the eyes may also be due to illness. For this, it is important that even if a person does not have complaints, a full preventive ophthalmic examination is conducted every year.

 

Source:

Optical optical instruments - magnifying glass, microscope, telescope

 

The author:

👩 🔬 Yana Nencheva is a molecular biologist, Master of Biochemistry and Master of Optometry, PhD candidate in Biophysics. She has been an active organizer of a number of events since 2015, including "PhD tea" and "Eye Health Seminar", which aim to promote science in the public space. She has been the manager and co-founder of the Center for Career Guidance in Natural Sciences ScienceUp since 2019.