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Issue Date: August 2001

Computers - how do they affect your eyesight?

1 August 2001

So, you spend eight hours a day in front of your computer screen. Have you ever considered the effect it has on your eyes?
A study, which was conducted by leading optometrists in conjunction with a large South African corporation with over 500 computer users, revealed symptoms such as impaired visual performance, red or sore eyes, headaches, or behavioural changes.
"Normally, when we read or work close up we drop our eyes and they converge (change the angle that they are aiming at) so that we can focus close up. With computers we are still looking close up but our eyes are lifted to what is normally a distance viewing position, creating an effective tug of war between the muscles that control focus and those that control alignment. The result - visual fatigue with a range of symptoms," said Oliver Davies, Optometrist and a Director of Classic Eyes.
"Also, imagine if I were to ask you to read a book but whilst you were reading, placed a screen of glass between you and the book. How comfortable would your eyes feel? Yet this is what we have done with computers creating annoying reflections and visual disturbance that get in the way of clear comfortablevision. Also the letters and digits we view are not objects but rather light source/fluorescences, as comfortable as trying to focus on the filament of a low-powered light bulb," concluded Davies.
There is now medical evidence that using display screen equipment is not associated with damage to eyes or eyesight, nor makes existing defects worse. But some users may experience temporary visual fatigue, leading to a range of symptoms such as impaired visual performance, sore eyes, headaches, or behavioural changes (shielding devices, postural change).
These symptoms may be caused by:
* Staying in the same position and concentrating for a long time.

* Poor positioning of the display screen equipment.

* Poor legibility of the screen to source documents.

* Poor lighting, including glare and reflections.

* A drifting, flickering or jittering image on the screen.
One should consider the following guidelines if one is experiencing headaches, having focusing difficulties, eye discomfort, difficulties seeing or reading the screen or source documents:
* Is the display screen difficult to read?

* Is there a reflection or glare on the screen from windows and lights?

* When you look away from the screen does any part of the room seem too bright or too dark?

* Are brightness and contrast of screen satisfactory?

* Is information on screen fuzzy, too small or flickering?
Furthermore, postural problems may be overcome by simple adjustments to the workstation such as repositioning equipment or adjusting your chair. Visual problems may also be tackled by straightforward means such as repositioning the screen to avoid glare or to place it at a more comfortable viewing distance, or by ensuring the screen is kept clean. Less frequently, new equipment such as window blinds or more appropriate lighting may be needed.
One of the most effective ways to counteract visual discomfort is the use of anti-reflection coatings, which have rapid results. The coatings are applied to lenses to decrease the amount of visible light reflected off the surfaces of a lens. This helps to decrease any unwanted light such as glare, reflections from behind, and ghost images from entering the eye.
Classic Eyes
(021) 683 4546

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