Computer Glasses for Blurred Vision
and Other CVS Symptoms

When you work at a computer for any length of time, it's common to experience blurred vision and other symptoms of computer vision syndrome (CVS). You're more likely to experience eyestrain and eye fatigue while sitting at the computer, because of unique visual demands that are unlike those associated with most other activities.

If you're under age 40, blurred vision may be due to an inability of your eyes to remain accurately focused on your computer screen for a sustained time period. Or eye fatigue and blurriness may be related to problems with quickly and accurately changing focus, such as when you shift your gaze from your monitor to your keyboard and back again. This lag of accommodation can be associated with CVS.

If you're over age 40, the problem may be due to the onset of presbyopia — the normal age-related loss of near focusing ability. This, too, can cause CVS symptoms.

What can you do? For one thing, obtaining customized computer glasses can make a world of difference in your comfort level while you're using the computer. These special-purpose glasses are prescribed specifically to reduce eyestrain and to give you the most comfortable vision at your computer.

If you already wear regular eyeglasses or reading glasses, you may be tempted to just dismiss the idea of computer glasses outright. Unfortunately, your regular glasses are probably not quite right for computer work.

Why? Computer screens are usually positioned 20 to 26 inches from the user's eyes. This is considered the intermediate zone of vision — closer than driving ("distance") vision, but farther away than reading ("near") vision.

Most young people wear eyeglasses to correct their distance vision. Reading glasses are prescribed to correct near vision only. And bifocals prescribed for those over age 40 with presbyopia correct only near and far. Even trifocals and progressive lenses (which do have some lens power for intermediate vision) have only a small portion of the lens dedicated to this area, not nearly large enough for comfortable computer work.

Without appropriate eyeglasses, computer users can often end up with blurred vision, eyestrain, and headaches—the hallmark symptoms of computer vision syndrome. Worse still, many people try to compensate for their blurred vision by leaning forward, or by tipping their head to look through the bottom portion of their glasses. Both of these actions can result in a sore neck, sore shoulders and a sore back.

Research supports the notion that computer eyeglasses can increase worker productivity and that even a slightly inaccurate prescription can decrease it. A study conducted at the University of Alabama School of Optometry* examined the vision of computer users, ages 19 to 30, before and while performing tasks that required them to read fonts of various sizes on a computer screen. Participants in the study were randomly assigned to wear either computer glasses or non-corrective eyeglasses. Researchers timed the tests and recorded the number of errors the subjects made. The participants then answered questions about the vision problems they had experienced.

"Even when symptoms were not reported and the computer screen was seen clearly, we found differences in productivity and accuracy over time," said Kent Daum, OD, the lead investigator. "The greater the miscorrection, the greater the decrease in productivity. Even when the subject's vision was slightly off, productivity was significantly affected." A difference of just 0.5 diopters from the correct lens prescription resulted in an average 9 percent loss in productivity and a 38 percent decrease in accuracy.

Researchers calculated that an employee earning $60,000 a year would gain $5,400 worth of productivity for an employer who paid for his computer eyeglasses (minus the cost of the eye exam and about $300 for the eyewear), a benefit/cost ratio of $18 for every $1 spent. (Read more about how computer eyewear can significantly increase worker productivity.
 

There are a number of special purpose lens designs that work well for computer glasses. Because these lenses are prescribed specifically for computer use, they are not suitable for driving or general purpose wear.

The simplest computer glasses have single vision lenses with a modified lens power prescribed to give the most comfortable vision at the user's computer screen. This lens relaxes the amount of accommodation required to keep things in focus at the distance of the computer screen and provides the largest field of view, reducing the risk of eyestrain, blurred vision, and unnatural posture that can cause neck and back pain. These lenses can be used comfortably by younger and older computer users alike.

A popular type of computer eyeglass lenses for people with presbyopia is the occupational progressive lens — a no-line multifocal that corrects near, intermediate, and, up to a point, distance vision. It has a larger intermediate zone than regular progressive lenses for more comfortable vision at the computer. But this leaves less lens area for distance vision. So these lenses are not recommended for driving or other significant distance vision tasks.

Another option for presbyopic computer users is a lined trifocal, with a larger intermediate zone than regular trifocals.

Still another possibility is an occupational bifocal, with the top part of the lens for intermediate vision (computer screen) and the bottom portion for near vision (reading).

Computer lenses are also available in clip-ons that can be attached to regular eyeglasses.

Your eyecare professional can help you decide which lens design will best suit your needs.

In addition to fixing your blurry vision, computer glasses can help with another problem as well: eyestrain from bright office lighting. Getting anti-reflective (AR) coating on your lenses can significantly reduce the amount of glare and reflected light that reach your eyes. [Read more about Glare and Reflection.]

If your office has fluorescent lights, you might want to consider two other options as well. According to Cosmo Salibello, OD, fluorescent lights emit a great deal of blue light, which makes it "difficult for the human eye to focus due to (blue light's) scattering characteristics."** An ultraviolet (UV) absorbing coating can cut down on the amount of blue light that reaches your eyes, as can an amber tint, says Dr. Salibello.

Page 2 of 2: How prism in computer glasses can reduce eyestrain; what you need to know when you're shopping for computer glasses