Working on a computer can cause eye strain, blurred vision, and symptoms of Computer Vision Syndrome. Studies show that between 50 and 90 percent of people who use computers at work have CVS.
Common causes of eye strain
For people who are under 40 years old, the most common cause of eye strain when working on computers is problems focusing. The eye functions by automatically changing focus when we look from one object to another. This is called “accommodation”. But your eyes may have trouble focusing back and forth repeatedly from the keyboard to the computer screen or from paperwork by the screen. The longer you spend on the computer, the more difficulty with accommodation your eyes may have. Another problem can be difficulty remaining focused on the computer screen for long periods of time. Looking across the room or down a hallway can help give your eyes a break from up-close focusing.
For people who are over 40, presbyopia can result in problems seeing the computer screen clearly. Presbyopia is the normal, age-related change in vision that makes it harder to see up close. It’s the condition that may cause you to hold a newspaper farther away to read it, and may require “reading glasses” for up-close work.
Why regular glasses don’t work
It may seem logical that if you need to wear glasses to read printed material, those same glasses can help you see the computer. In general, this is not the case. A computer screen is typically located about twice the distance as you would hold normal reading material. So glasses that help you read a book won’t help you focus at the correct distance to see the computer. At the same time, distance glasses are designed to help you focus farther away than the computer screen. These glasses are the kind most often needed by younger people and may be required for safe driving.
Even progressive trifocals that have prescriptions for reading, distance, and in-between are not a good choice for computer use.