This requires your eyes to maintain focus and converge closely for long periods without a rest, which can often lead to vision symptoms such as:

• Difficulty changing focus away from the screen, or even driving home after work
• Blurred vision on the screen or across the room
• Occasional doubling or ghosting of vision on the screen
• Sore and tired eyes
• Headaches
• Neck and shoulder pain
• Dry, gritty or watering eyes

Staring at a computer screen for long periods requires increasing effort to maintain clear focus, which can gradually lead to increasing focusing problems that interfere with your ability to easily and comfortably use your eyes for reading and computers.

Our eyes are not designed to stare at a computer screen all day, and it is common for people with a heavy computer workload to need mild reading glasses to maintain easy and comfortable focus, and prevent further deterioration.

When we look at a screen for hours on end we do not blink as often due to concentration, and it is common for people to experience dry eye symptoms such as grittiness, burning and watering eyes, especially in combination with air-conditioning or heaters or fans.

Visual Workstation Design

It is very important to ensure your computer workstation is set up to help your vision to work as easily as possible. For instance, we read naturally with a book in our hands looking down about 20°, and yet all too often computer screens are set too high, with the middle of the screen level with your eyes.

Ideal computer posture.

This results in people lifting their head and gradually leaning forward, resulting in increased neck and shoulder problems. Ideally, the computer screen should be set so that the top of the screen is no higher than your eye level, so you are naturally looking downwards about 20° at the centre of the screen; the screen should also be tilted with the top away from you and at a distance of 35 to 50 cms.

It is very important to have regular breaks from looking at your computer screen; look away from your screen every 10 minutes, and take a physical break from your computer every hour.

It is important for any computer user to have a comprehensive assessment of their focusing and eye coordination abilities for near visual tasks such as computer use. This is particularly true for teenagers who have a heavy visual workload using their eyes for computers at school and home, reading and homework, and other concentrated and prolonged near focusing tasks such as a DS and Gameboys.

Problems of focusing can interfere with concentration and comprehension, ability to read fluently and easily, and ease of copying from the board, and copying from book to book. Modern research has found that focusing problems can in some cases lead to development of shortsightedness (myopia), which eventually results in a need to wear glasses constantly to be able to see the board at school or to drive.