CVS, or Computer Vision Syndrome, is a repetitive strain syndrome caused by prolonged computer usage. It affects 90% of workers who are on the computer for more than three hours a day, and can cause long term damage to one’s eyes if they are not looked after properly. Whilst it is similar to visual stress, and some of the symptoms do overlap, they are not the same thing.
What is it and what causes it?
CVS is visual strain that is caused by long periods of computer usage, and a lack of eye care. It is caused by extended short distance focussing, such as when we are focused on a computer screen for long periods of time. Often when we focus on something intently for a long period of time our average blinking time is reduced. This, combined with poor lighting, poor posture and excessive glare can all contribute to the problem.
However the main cause of CVS is a biological one, and is linked to how our eyes and brain react to characters on a computer screen. The characters on a computer screen don’t have the same definition as printed text. On a computer screen they are made up of combinations of lots of tiny points of light known as pixels, which are brightest at the centre, and less so towards the edges. This inconsistency makes it harder for the human eye to stay focused on them. Our eyes tend to drift involuntary to a reduced level of focus, known as “resting point of accommodation”, and then strain to regain focus on the screen.
The continuous flexing of the eye’s focusing muscles creates the fatigue and eye strain often felt after long periods of computer use. The human eye is at it’s most relaxed state when we use it for distance viewing, meaning that working at a computer for long periods of time without breaks cause cause cumulative negative effects.
Symptoms of CVS
The symptoms of CVS are similar, though not entirely the same, as eye strain. Blurred vision, difficulty concentrating and headaches are all common in those who are suffering from CVS. It can also cause red, dry or burning eyes, an increase in nearsightedness, slow refocusing, excessive fatigue, neck back and shoulder pain.
How does one mitigate the symptoms?
Taking breaks for your eyes is important, as it allows them to rest and focus naturally, rather than constantly re-strain to focus on something that is very close. Every twenty minutes, you should take a break to look into the distance for at least twenty seconds to give your eyes a micro break, and every two hours take a fifteen minute break to properly rest your eyes and let them relax.
Adjust your lighting and glare.
If possible, using natural light is the best way to work. It is gentler on the eyes, and less likely to cause eye strain. If possible, set your computer up away from any glaring lights that may be too bright for your eyes. If the glare on your computer screen is a problem, you could try using an anti-glare filter to cover your screen, reduce the intensity of the light coming from it, and of the glare off of the screen.
Keep your distance
If your computer screen is too close to your face it can make it even more straining on your eyes to use. Keeping your computer between 20 and 28 inches away from your eyes is approximately the recommended distance for working, especially for long periods of time. Any closer than this and it may be time to get your eyes tested. Whilst not many people carry around a ruler in their bag, their is a simple way to measure this. If you place your first under your chin, the distance from knuckles to your elbow is the approximate distance that your eyes should be from your work material.