Eyesight and Computers

Do computers affect our vision?

Problems caused by computers are the second most frequent reason for young healthy people to visit their ophthalmologist. What happens to people that use computers for long hours during the day is basically what is called “asthenopia”, that is difficulties in vision. The second problem is of course problems caused by repetitive movements of the fingers and of the muscles of the arm.

The consequences of computers on vision and the eyes are still under general observation, but any kind of permanent damage hasn't yet been verified.

More than 50% of computer users suffer from eye fatigue, headaches and blurry vision. These symptoms sometimes affect the person's general health, creating a sense of fatigue, which leads to decreased work performance.

There are also some indications that, in rare cases, people working long hours in front of a computer, face an increased risk for glaucoma.


How do computers affect our vision?

When we are viewing a computer screen, what happens is that we lose depth perception, i.e. stereopsis, and our focus is always on a single point. Also, our eye convergence (what happens when we're looking at something really close) is continuously hyperactive and the frequency of blinking is decreased. This is completely different from reading a printed page, since most computer monitors, especially those with a CRT, do not emit a single image, but an image that passes frame by frame and our brain connects it so we can see a continuous image; it is an image with diffused light and has very different contrast and clarity. After using a computer for many hours, what happens is that the cones, the cells we use to perceive colors, are always hyperactive and the image from the cones' hyperactivity stays in our brain, despite the change of image on the computer screen. This is called “after effect” or McCollough effect and sometimes color perception is reversed.

Things that worry us with computer use is if we are exposed to radiation and UV radiation and how much, and if this can potentially lead to cataract. It should be noted that there is proof that the radiation we receive, especially when it comes to UV radiation, is less than that of a fluorescent bulb, so there is no dangerous radiation for the eye and no proof that this can lead to cataract.


Ophthalmological symptoms caused by PC use

Headache during and after PC use
Pain between the eyes
Dry and/or irritated eyes
Blurry vision
Slow focus during screen use
After long hours of PC use there is difficulty in viewing distant objects

Occasional diplopia
Poor color perception

General physical symptoms caused by PC use

Pain in the neck and the shoulders
Back pain
Fatigue, maybe even pain, of the hands and wrists
Decreased work performance, frequent mistakes, fatigue

Ways to avoid such symptoms

The computer monitor should be on a lower level than the eyes.
The keyboard should be in such a position that the bottom of our arms and wrists is parallel to the ground.
The seat should be adjustable, so it can cater to the user's needs.
The thighs, like the arms, should be parallel to the ground.

Contrast and brightness of the screen should be adjusted to the desired setting, so that the user feels comfortable and doesn't tire his eyes.
The lighting in the room must be three times brighter than the monitor.
A screen filter should be used

It is important to work on a big screen, so it isn't tiring to read or write a text
The screen shouldn't reflect light from a window or another light source
It is necessary to clean your screen regularly.
Adjust the font size on your screen, choosing a setting which is comfortable, if the software gives you that choice.
Adjust brightness and contrast on your screen.
People who use computers all the time may experience some refractive anomalies, like slight myopia, slight astigmatism, slight hyperopia; if this is corrected with the use of glasses or contact lenses, it will help them use these devices easier.
Use of artificial tears may help with xerophthalmia that long hours in front of the PC might cause, due to the decrease in blinking speed and frequency; proper moisturizing of the atmosphere, in which the person works and uses the PC, may also help.
The most important thing of all is to have short and frequent breaks of 2-3 minutes every 15-20 minutes of work or 5 minutes for every 30 minutes or 10 minutes for every hour.


What problems can excessive PC use cause during childhood?

The past few years in America, Europe, even in Greece, children spend 1 to 3 hours daily in front of a computer screen, either for their school work or to play. Many times, it is the parents who encourage their children from an early age of 2 or 3 to access the PC at home or at school.

Many pediatric optometrists believe that excessive use of PC during childhood can increase the risk of myopia. They refer to studies that have been done and which show that computers have a negative impact on a child's vision.

Particularly, various studies claim that:

25% of the children that use computers need corrective glasses in order to work on the computer with comfort and without danger at home or at school.
The percentage of children in the first stage of myopia has increased from 12% to 20% from 1995 until today.
The percentage of children between 7 and 9 years of age with myopia has doubled the past three years, reaching 34%.

Twenty years ago, most children played in open spaces and their distant vision was more important. Today, most children work in front of the PC either at home or at school. Sitting in front of the PC, looking intently at the screen creates problems that weren't known a few years ago. With PC use, the child's visual system is more focused and more pressured than with other activities. PC use requires high-level skills from the eyes of small children, whose visual system has not yet been fully developed. Only when it is mature enough, can the child manage the pressure and stress caused by PC use.

According to the American Academy of Ophthalmology, the impact of PC use in childhood includes the following factors:

Children have a diminished degree of self-protection. They can work in front of the PC for hours with little to no breaks. This extended activity can cause focusing and attention problems.
Children are especially adaptive. They believe what they see and the way they see things is always the norm for them, even if they have eyesight problems. That's why it's important for the parents to monitor the time their children spend in front of a PC.
Children are by definition smaller than adults. Most of the times, the work space in front of the PC is designed to be used by adults. This may change the children's visual angle. PC users should keep the monitor at a lower lever than their eyes, by about 15 degrees. Also, as a result of the difficulty with which the children reach the keyboard or touch their feet on the ground, they may feel pain in the neck, the shoulders or the back.


Advice to avoid problems from PC use in childhood
Many pediatric optometrists claim that children who use a computer long before their visual system is fully developed are at the heart of the problem known as “computer vision syndrome”, which is a visual syndrome caused by excessive PC use.

In order to protect your children from this syndrome, you should follow the following advice:

Before school starts, every child should have already had a full ophthalmological examination, including tests for distant and close vision.
Work space for the computer should be adjusted for a child, not for an adult.
Suggested distance between the monitor and the child's eyes is 50-60 cm. Looking at the computer screen from a closer distance endangers their vision due to excessive visual adjustments.
The time children work in front of the PC should always be monitored and, if possible, discontinuous, so that there are breaks when the visual and the musculosceletal system may rest.
Parents and teachers should recognize every behavior that shows possible problems such as: red eyes, frequent eye rubbing, head leaning or other unusual body stances and, finally, complaints about blurry vision or tired eyes. If any of this is observed they should immediately visit their ophthalmologist.


Remember:Your ophthalmologist is the best source for responsible answers on issues related to your eyes and their health. Under no circumstances is information taken from our website intended to replace him. Seek your doctor for complete information.





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