Vision problems, prolonged computer work

What do we most often complain about when working with a computer?

I feel my eyes tired.

  • When I work for a long time, the text gets blurry, sometimes I get double images.
  • My head hurts.
  • I feel dryness in my eyes. My eyes often get red, itchy.
  • My neck and back hurt after working with a computer.

The computer is often blamed for causing vision problems. It is established that this is not due to harmful radiation from the video terminals. When ergonomic conditions of computer work are observed, complaints are most often due to previously unnoticed refractive anomalies or an imbalance between the two eyes.

What happens in front of the computer?

There have been no significant evolutionary changes in the human eye, but over the past 100 years the nature of our work has changed radically. Today we use our eyes disproportionately more when working up close.

The images on the computer screen are not as contrasty as those printed on a piece of paper and the eye is constantly trying to focus them well. There is also an effort to obtain a clear image in the periodic shift of the gaze  from screen to printed text and vice versa. Excessively low or high screen placement puts the eyes in forced fatigue situation. Glare from the screen makes it difficult to contrast the image. In front of the computer man Blink much less often than in your everyday life, and blinking is necessary to maintain image clarity. Fatigue when working with a computer depends on the duration, respectively on the ergonomic conditions, the user’s refraction and good muscle balance

What is refraction and accommodation?

Receptors in the retina perceive and transform light energy into a nerve impulse in order for the information to reach the brain. The perception of visual information depends on the eye’s ability to refract and focus light rays onto the retina, and this property is denoted as refraction.

The refraction depends on the refractive media of the eye (cornea, anterior chamber fluid, lens, vitreous) and the length of the eyeball. With accurate focusing of the image on the retina, a person has no refractive error, and the condition is denoted as emmetropia. In a refractive error (due to different eye length or refractive power), light rays fall in front of or behind the retina and an unclear image is produced.

The ability of the eye to see objects clearly at different distances is called accommodation. It is accomplished by changes in lens thickness. The changes depend on the elastic forces in the lens and the contraction/relaxation of the ciliary muscle. When we read and write, the muscle shortens, the lens bulges and the image of nearby objects is focused on the retina.

Thanks to accommodation, people without refractive errors up to about 40 years of age work nearby without problems.

How do the two eyes work together?

Eye movements in different directions are performed by the external eye muscles (6 for each eye). They move the eyes synchronously so that the images that are produced on the retinas are symmetrical and when superimposed in the cerebral cortex merge into one clear and three-dimensional image. When working up close to focus on the subject, the eyes slightly converge.

In the absence of a good balance between the eye muscles and prolonged computer work, fatigue easily occurs from straining them. Many of these problems can be identified in an eye examination and a functional solution found with the appropriate eyewear.

What are refractive anomalies?

The most common is hypermetropia (hyperopia, farsightedness), followed by myopia (myopia, nearsightedness) and astigmatism.

About 50% of people are farsighted. With this refractive error, the image of an object would be obtained behind the retina.

To get a clear image people with this anomaly continuously acclimate:

  • when looking away, the ciliary muscle is only strained enough to compensate for the “optical insufficiency” (in healthy individuals in such a situation the muscle is not strained);
  • the load on the ciliary muscle is greater than in the case of emmetropes.

With low farsightedness and working without prolonged visual strain, hypermetropes manage to see clearly at various distances with the help of accommodation until about 35-40 years of age.

With prolonged computer work, ciliary muscle fatigue occurs and images become blurred. In these people, an accurate refraction examination is necessary, very often with drops (to relax the ciliary muscle) and correction of hyperopia with glasses(plus lenses).

Why do people after 40 use glasses for close work?

Over the years, the eye’s ability to accommodate (ciliary muscle function weakens) gradually decreases and replacement with plus lenses is necessary. Close-fitting glasses are replaced every 5 years between the ages of 40-45 and 60 in the absence of other eye diseases.

What are the other refractive anomalies?

In myopia, the image of an object is obtained in front of the retina.

In order to see well into the distance people with myopia need to wear minus glasses.

Nearby they manage without correction and make little or no use of their accommodation. After 40, they usually work without close-up glasses or with ones with a smaller diopter (according to their age and distance correction).

In people with hyperopia and myopia the refractive power of the eye is almost the same in its different planes and after passing the image through the optical system it remains undeformed.

In astigmatism, the refractive power of the eye is not uniform in its different planes, resulting in distorted images on the retina .

Like hyperopia to a mild degree, small values of astigmatism are usually compensated for in everyday life. But not in front of the computer. To have no complaints, an accurate correction with glasses is necessary after examination with drops. The correction of this refractive error is with cylindrical lenses.

Are eyes spoiled by glasses with a diopter at an early age?

Each person’s refraction is inherited just like height, eye and hair color and other features. Its precise examination and adjustment puts the eyes in optimal conditions for work, much like tailored clothing. Wide or tight clothes create some discomfort and even complexes. The choice of many modern professions would be impossible without the use of accurate glasses with dioter or contact lenses. Not only are the eyes not spoiled, they are spared from additional strain. Modern technology allows for a variety of functional and aesthetic solutions to computer eye problems.

What problems do people with contact lenses have in front of the computer?

Most often dryness, redness and irritation in the eyes.

When working with a computer, blinking is reduced by about 70% of the normal frequency. With monitors positioned above eye level, the view is greater and the eyes are wider open. All this leads to faster drying of the tear filmwhich is extremely important for clear vision and comfort when wearing contact lenses. This requires more frequent voluntary blinking or the use of additional artificial tears.Caution: it is not desirable to use eye drops with a vasoconstrictor – the constriction of the vessels further aggravates the dryness in the eye.) Air-conditioning also contributes to faster drying of the tear film.

What can we do to reduce computer complaints?

  1. Monitors should be positioned 50-60 cm from the eyes and about 20° below eye level.
  2. Glare from the screen can be reduced by anti-reflective screens or glasses with such a coating.
  3. During computer work it is necessary to take a visual break – averting the gaze into the distance at half-hourly intervals for 30-60 seconds to relax the accommodation. Alternating different activities in the office is a good solution to reduce visual fatigue.
  4. It is desirable to blink more often, and for more serious problems, after consulting an eye doctor, use artificial tears.

Refractive anomalies and imbalance between the two eyes can be corrected after an eye examination. It also excludes the presence of other eye diseases, the symptoms of which we can attribute to computer work.

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