Tired eyes need a break

How to beat computer vision syndrome
By Dr. Melanie Amarasooriya, Pic by M.A. Pushpa Kumara

Are you one of those who spend hours in front of your computer trying to get through your work and meet your deadlines? At the end of the day, do you find yourself with an aching head and tired eyes, having difficulty in seeing. If so, beware, you may be suffering from ‘Computer vision syndrome’.

It is not very complicated, and indeed quite common. A large percentage of computer users have eye symptoms and seek eye examinations. The prevalence of ocular symptoms in computer users as part of Computer vision syndrome, in fact, ranges from 25-93%.

This week Dr. Madhuwanthi Dissanayake, Consultant Ophthalmologist and senior lecturer in the Faculty of Medicine, University of Colombo speaks to MediScene about ‘Computer vision syndrome’.

Computer vision syndrome is the name given to a collection of signs and symptoms related to eyes and vision that occur due to use of computers. This is commonly found among those who use computers more than two hours per day. Statistics in the U.S. suggest that 1 out of every 6 people needing eye examinations have symptoms of Computer vision syndrome.

Symptoms of Computer vision syndrome:

1. Eye strain
2. Blurring of vision
3. Double vision
4. Difficulty looking at light
5. Burning sensation and irritation of eye
6. Headache (This could also be associated with neck pain, back pain and shoulder pain)

There are many factors that contribute to Computer vision syndrome. “It may it be environmental factors, computer design and software or personal characteristics- but it is important to be aware of it,” says Dr. Dissanayake, stressing that most of the factors can be modified if we know about the problems they cause.

One major factor is reduced blinking, when our attention is concentrated on the computer monitor. The natural blinking frequency is about 18 times per minute. Blinking helps the spreading of the tear film across the eye ball lubricating its surface. It has been found that when using the computer the blinking frequency can reduce even up to 4 times per minute. This results in inadequate spread of tears and leads to dryness. Reduced humidity in an air-conditioned environment and fans directly in front add to the problem causing more dryness.

Illumination is also an important factor. The contrast issues also play a major part in setting off an otherwise irreversible process. Unlike the printed letters, the letters on a computer screen lack contrast to a great extent. The margins of the letters are not as defined as in print. Therefore focusing is more difficult on the screen and causes eye strain. Also harmful lighting conditions such as very bright overhead lamps add to the problem.

Our angle of gaze is also important.

That is the angle that the direction of gaze makes with the centre of the computer screen. The angle can be large, meaning your eyes are wide open, when looking at the computer, for instance when the computer screen is at a higher level than the eyes. When the computer screen is at a lower level the angle of gaze is small and your eyelids cover a significant portion of your eye ball. This reduces the chance of dry eyes. Dryness is more when the eyes are exposed more.

Moreover focusing on something close by for a long time is strenuous for the eye muscles. This leads to eye strain and double vision. People with undiagnosed refractive errors do find it more difficult to tolerate problems related to computer use.

Some useful tips

If you have been having Computer vision syndrome for many years, it can lead to difficulty in focusing and other visual problems. This does not mean you need to quit your job, not use the internet nor play any computer games. As in any problem prevention is the key word here too.

There are few steps and a few modifications that should be made. You may find these difficult to initiate, but they are sure to help you in preventing long term problems. One of the most important steps is to “correct your existing visual problems”, says Dr. Dissanayake, as undiagnosed and untreated visual problems can be aggravated by use of computers for a long time.

1. 20-20-20 rule
Every 20 minutes you need to look at an object at least 20 feet away for 20 seconds.Looking at distant objects is more relaxing to the eye.

2. Blink voluntarily
When using the computer you forget to blink. Think and blink. At least at the end of every sentence you read, think and blink completely.

3. Avoid bright light, and fans directed to face.

4. Reduce the angle of gaze
Reducing the angle by 14 0 will reduce eye symptoms. That means keeping your computer screen at a slightly lower level than your eyes. But remember, not to a level that you need to bend your neck. Or else your eyes will be relieved at the expense of your neck

5. Get your eyes checked.

6. The chances of developing these symptoms are high if you already have even a minor refractive error (lack of focusing). If you are prescribed glasses wear it all the time you use the computer. Even if you had no refractive error to begin with, the chances are that you may benefit from glasses with an anti-reflective coating; But do not use glasses without medical advice. They can do more harm.

7. Wear proper correction for near vision if you are presbiopic-6++
Using the computer involves focusing for near and intermediate distance. Towards the age of 40 years our ability to focus near (accommodation) wears off. Most of us need additional help with reading glasses.

But normal reading glasses with bifocal lenses could give problems when used for computer work because the lower segment of the lens which is for near vision is set too low. By trying to use this your neck has to extend and this bad posture will lead to neck pain.

To avoid this you can obtain varifocal /progressive glasses; These are specially designed glasses for computer use.

8. If your doctor has prescribed artificial tears using it regularly is important.

9. Keep yourself well hydrated.

Drinking adequate amount of water is important. You can also apply clean cool water to your closed eyes with the aid of a handkerchief or a face towel.

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