Updated December 15, 2014.

Question: What are computer glasses?

I work at a computer for several hours each day. Lately, my eyes feel tired and it's often hard for me to focus. Could I need special glasses for the computer?

Answer: If you work at a computer for a significant amount of time each day, you may indeed benefit from a pair of special reading glasses known as computer glasses. Even though you wear glasses or contacts on a daily basis, they are probably not quite right for your work at the computer.

Computer glasses are special glasses prescribed to lessen the symptoms associated with computer vision syndrome (CVS). CVS describes a group of symptoms caused by prolonged computer use. Symptoms appear because the eyes and brain react differently to words on a computer screen than they do to printed text. Symptoms often include eyestrain, dry eyes, headaches and blurred vision. Many people try to compensate for these vision problems by leaning forward or by looking down to see through the bottom portion of their glasses, often resulting in back and shoulder pain.

Symptoms of CVS can also be caused by presbyopia, a vision disorder that develops as we age. Presbyopia is the loss of the eye's ability to change focus to see near objects, and usually becomes noticeable around the age of 40. If you think you might be feeling some of the symptoms of CVS, you may need to purchase a pair of computer glasses. Computer glasses are prescription glasses specially designed to allow patients to work comfortably at a computer.

Computer work involves focusing the eyes at a close distance. Because computer monitors are usually placed a little further away than a comfortable reading distance, standard reading glasses are usually not enough to alleviate symptoms of CVS. With computer glasses, the whole lens focuses at the same distance and does not require you to tilt your head back to see the computer screen.

An optometrist or ophthalmologist will be able to prescribe a pair of computer glasses that will help to relieve symptoms brought on by CVS. Before your appointment, however, take a good look at your work space. It is important to tell your doctor exactly how your work space is set up, including the distance between your monitor and your eyes, in order to prescribe the appropriate computer glasses. Also, pay attention to lighting. Bright lights are often a source of eyestrain in the office. Anti-reflective (AR) coatings may be applied to your lenses to reduce the amount of glare and reflected light that reach your eyes. The following lenses are designed specifically for computer use:

• Single Vision: Single vision lenses are the simplest type of computer glasses. The entire lens is designed for seeing the computer monitor, providing the largest field of view. Many people, adults as well as children, enjoy these lenses because the monitor appears clear without obstructions. However, distant objects as well as objects that are closer than the computer screen will appear blurry.
   
• Flat-top Bifocal: A flat-top bifocal lens looks just like a regular bifocal lens that some people wear for distance and near vision. These lenses are designed so the top half of the lens is set to focus on the computer monitor while the bottom segment is set to focus on closer reading material. These lenses have a visible line that divides the two focusing segments. Even though these lenses provide comfortable viewing of the computer, objects in the distance will appear blurry.
   
• Variable Focus: Some eye care specialists call this lens a "computer progressive" lens. Although similar to a traditional no-line invisible progressive multifocal lens in design, a variable focus lens is much more task specific. This lens has a small segment at the top part of the lens for viewing objects in the distance, a wide intermediate segment for viewing the computer monitor, and finally a small segment in the lower part of the lens for focusing on close objects. No visible lines or segments are in this type of lens, so it feels more like normal vision.

Computer glasses can benefit computer users as long as they are properly fitted and correctly prescribed. Optometrists and ophthalmologists are knowledgeable in problems resulting from computer vision syndrome and can help you find an appropriate pair.
_Source:

Watt, Wendy Strouse, OD. Computer Vision Syndrome and Computer Glasses. Macular Degeneration Support, MDSupport.org. Accessed 29 Apr 2009.