The lighting industry has responded to the challenge with some good alternatives. But new parabolic fixtures and lighting techniques address only part of the problem. Screen filters, eye drops, software programs, wall and window coverings and ergonomic furniture lessen CVS symptoms to some degree. However, none of these techniques or products change the lighting environment, so the number and frequency of CVS cases continues to grow. Washout or uniform glare is the ambient light that falls across the computer screens.
Light washes over the entire screen and lightens it, robbing the image of sharp contrast.
For example, black objects or letters become dark gray and closer in color value to the lighter objects or backgrounds on a screen. The eye must work harder to see the characters on the monitor. Examples are reflected documents, the user's clothing and silhouette, furniture, objects hanging on the wall, etc. Initially this multiple image is not a problem, but after two or more hours, it becomes very tiring as the eye is always filtering out the reflected image from the screen image. Brightness ratio is the difference in the overall brightness of the computer screen compared to the brightness of the surrounding surfaces in the work station.