Computer Vision Syndrome

Almost everyone these days is using a computer for work or play. We spend a lot of time staring at our computer screens and many people are experiencing vision related problems. The eyestrain, blurred vision and headaches that often come with computer use are called Computer Vision Syndrome (CVS). Studies indicate that up to 80% of computer users have vision related problems or CVS. Many computer users do not associate their symptoms with the time they spend on the computer. Some assume that their headaches or eyestrain are from job stress, or that their tired eyes are an expected part of their job. Computer glasses are special glasses designed for your computer environment. They will make your computer time more productive and comfortable. One of the causes of CVS is due to the nature of text and graphics on a computer screen. The image on a monitor is created with pixels of light, which are glowing dots that are brightest at their center, with their luminance falling to zero towards their edge in a bell-shaped fashion. Print on paper usually has sharp high-contrast edges.

The human visual cortex has special cells that are very good at recognizing high-contrast edges like print on paper. These cells are important to our basic visual perception system, because much of what we see as a “thing” in the natural world is shaped by high-contrast edges. Our eyes can lock onto sharp contrast edges but have a difficult time maintaining exact focus on a pixel-created edge. When we look at a computer screen, our eyes have to exert muscular effort to focus for that distance and must ideally maintain that effort as long as we are looking at the screen. In fact, what happens is that the focusing effort gradually relaxes and then must be re-focused to the plane of the screen. Over time the muscles fatigue and CVS symptoms become apparent.