CVS stands for Computer Vision Syndrome. This is a disorder that is caused by staring at a computer display or VDT (Video Display Terminal). This page will focus on the effect of CVS on eBook Readers.

[edit] American Optometric Association

This is an organization devoted to Optometry and associated vision issues. They have created several pages to explain CVS. These include:

http://www.aoa.org/x5253.xml Causes at work. Has links to:

• What causes Computer Vision Syndrome?
• How is Computer Vision Syndrome diagnosed?
• How is Computer Vision Syndrome treated?

http://www.aoa.org/x5374.xml Occupational Issues. Has links to:

• Computer Vision Syndrome Symptoms
• The Relationship of Computer Vision Syndrome to Musculoskeletal Disorders
• Impact of Computer Use on Children's Vision
• The Effects of Video Display Terminal Use on Eye Health and Vision
• Criteria for Determining Whether the Need for Eyeglasses or Other Treatment is Related to Computer Use.

[edit] Display Factors

Settings can be adjusted to combat contrast and glare issues, color choices can be adjusted. However some things are inherent in the display itself.

• a CRT generally has a thick glass in front, which forces the eye to refocus from the front to the back of the glass constantly, contributing to eyestrain.
• LCD monitors have less of a boundary between LCD pixels and the front of the screen, causing the eye to work less to focus.
• Both CRTs and LCDs have screen refresh - The can be a flickering effect that places undue strain on the eyes, causing fatigue. This can be exacerbated by florescent lights being used in a room where the display is being used.
• E-Ink generally is reported to have the least eye strain. Some attribute this to lack of refresh and others to lack of backlight.

[edit] Anecdotal Evidence

While scientific study does not prove many of the claims of users there are enough claims to provide a few tips to minimize the problems that some people experience.

• Decrease the backlight level to the minimum acceptable (This will also increase battery life on portable devices).
• Increase the Font size to reduce eye strain.
• Change the color choices to something that is pleasant to view. Experimentation is required.