OPHTHALMIC EDUCATION (23) Your Eyes and Computers (VDUs) – Part 1 [Archives:2001/05/Health]

Mahfouth A Bamashmus
FRCSEd, FRCOphth
Consultant Ophthalmic Surgeon
Ibn-Al-Haitham Clinic
University of Science & Technology, Sana’a

There is disagreement about whether computer screens (VDUs) can cause damage to your eyes but we do know that environmental factors affect visual comfort and performance. This article is intended to help you to have a more pleasant and less fatiguing work environment.
Computer (VDU) users complain about their eyes about twice as often as other people at work. If you are about to start work with a VDU, you should have an eye examination. The optician can then see if there are any problems which could give you trouble and advise you how to avoid them.
Eyestrain:
Even though you can see clearly, it is still possible to have tired eyes. If your eyes are having to take in a large amount of detail over a long period of time, eyestrain is more likely.
Eyestrain is the term used to describe a wide range of problems including tiredness, irritation, soreness and sensitivity to light.
Computer (VDU) users are more prone to eyestrain than the average worker. The most common causes are: –
1.A fault in the focusing of the eye;
2.The eyes not working “as a team”;
3.Incorrect positioning of documents;
4.Unsuitable lighting;
5.Poorly designed work areas;
6.Lack of adequate maintenance and poor placing of the VDU and keyboard.
All of which can be corrected by attention to the work environment and regular visits to an eye doctor.
CONTACT LENSES
Contact lenses are suitable for use with VDUs as they give less distortion and reflection than glasses. However, when first used with VDUs, problems may arise if the lenses start to dry. This problem usually disappears once the wearer has got used to the lenses. It is also important to blink normally and to keep contact lenses clean and free from scratches to achieve the best possible vision in all circumstances.
Older VDU users who have contact lenses for an existing eye problem may need additional reading glasses.
EYE CO-ORDINATION
Each eye is moved by six muscles; but if these, or the nerves controlling them, do not work properly, it makes it difficult for both eyes to work together. This may make your eyes tired and sore, and you may get headaches or blurred or double vision. It is a simple matter for your optician to find this during an eye examination.
EYE EXERCISES
After an eye examination, if your optician finds that your eyes do not work together properly, eye exercises can sometimes solve the problem. During treatment, you may have to spend a short time each day on the exercises. It might also be necessary to wear glasses.
MEDICAL HISTORY
If you have headaches, or marked discomfort from “flicker”, or problems with VDUs, televisions or fluorescent lighting, you should be sure to mention this when you have your eyes examined.
WHICH SCREEN?
VDUs with “non-reflective” screens and clearer letters have improved working conditions for users. Unfortunately, models with highly reflective screens and poor letter definition are still marketed. You should not be able to see reflections when sitting infront of an unlit screen.
VDUs come in a variety of screen and character colors and increasingly, with multicolor displays. The legibility and suitability of the display are affected by the contrast between the screen and the characters as well as the general office lighting. It is not primarily a question of the colour. Brightness and contrast controls should be handy. Most VDU screens can be adjusted to suit your requirements.
Regular maintenance of VDUs is essential. The screen should be kept clean and any flicker or unwanted movement of the letters should be corrected as soon as possible.
POSITIONING OF EQUIPMENT
Incorrect siting of equipment may cause strain. Frequently, a VDU is positioned where a typewriter was originally, but good positioning for typing is often very poor for VDU work.
Keyboards need to be movable and should be positioned to ensure maximum comfort for the user. The position of documents should also be variable. The overall work range is normally between 33 Ð 100 cm. There should be sufficient space behind your VDU for you to be able to look past the screen so that your eyes can relax.
PSYCHOLOGICAL CONSIDERATIONS
Some tasks are tiring, because they are physically or mentally demanding or monotonous. Complains of eyestrain can be caused by psychological facts such as stress, repetition and lack of interest. Users should have a different task for short periods every hour or so to help reduce tiredness.
During training, mental concentration and unfamiliar visual tasks can be expected to cause eyestrain. Usually this doesn’t last long. If it does, have your eyes examined!
Routine eye exam by an eye specialist is very important. It is your sight and your eyes need all the care they can get.
Reference: Eyecare information Service, London.

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