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Friday, March 14, 2008

Are you getting "Computer Vision Syndrome"?

As computers become part of our everyday life, more and more people are experiencing a variety of ocular symptoms related to computer use. These include eyestrain, tired eyes, irritation, redness, blurred vision, and double vision, collectively referred to as computer vision syndrome.

According to a definition from Wikipedia:

"<"Computer vision syndrome"CVS) is a temporary condition resulting from focusing the eyes on a computer display for protracted, uninterrupted periods of time.
Some symptoms of CVS include headaches, blurred vision, neck pain, fatigue, eye strain, dry, irritated eyes, and difficulty refocusing the eyes. These symptoms can be further aggravated by improper lighting conditions (ie. bright overhead lighting or glare) or air moving past the eyes (e.g. overhead vents, direct air from a fan). CVS has not been proven to cause any permanent damage to the eye.

Why it happens?

CVS is caused by decreased blinking reflex while working long hours focusing on computer screens. The normal blink rate in human eyes is 16-20 per minute. Studies have shown the blink rate to decrease to as low as 6-8 blinks/minute for persons working on the computer screen. This leads to dry eyes. Additionally, the near focusing effort required for such long hours puts strain on ciliary muscles of the eye. This induces symptoms of asthenopia and leads to a feeling of tiredness in the eyes after long hours of work. Some patients present with inability to properly focus on near objects after a short duration. This can be seen in people aged around 30-40 yrs of age, leading to a decrease in the accommodative focusing mechanisms of the eye. This can be a setting for early presbyopia."


Link to the original article: Computer vision syndrome

Computer vision syndrome symptoms may be the cause of ocular (ocular-surface abnormalities or accommodative spasms) and/or extraocular (ergonomic) etiologies. However, the major contributor to computer vision syndrome symptoms by far appears to be dry eye. The visual effects of various display characteristics such as lighting, glare, display quality, refresh rates, and radiation are also discussed. Treatment requires a multidirectional approach combining ocular therapy with adjustment of the workstation. Proper lighting, anti-glare filters, ergonomic positioning of computer monitor and regular work breaks may help improve visual comfort. Lubricating eye drops and special computer glasses help relieve ocular surface–related symptoms.

How is Computer Vision Syndrome diagnosed?

Computer Vision Syndrome can be diagnosed through a comprehensive eye examination. Testing, with special emphasis on visual requirements at the computer working distance, may include:

Patient history to determine any symptoms the patient is experiencing and the presence of any general health problems, medications taken, or environmental factors that may be contributing to the symptoms related to computer use.

Visual acuity measurements to assess the extent to which vision may be affected.

A refraction to determine the appropriate lens power needed to compensate for any refractive errors (nearsightedness, farsightedness or astigmatism).

Testing how the eyes focus, move and work together. In order to obtain a clear, single image of what is being viewed, the eyes must effectively change focus, move and work in unison. This testing will look for problems that keep your eyes from focusing effectively or make it difficult to use both eyes together.
This testing may be done without the use of eye drops to determine how the eyes respond under normal seeing conditions. In some cases, such as when some of the eyes' focusing power may be hidden, eye drops may be used. They temporarily keep the eyes from changing focus while testing is done.

Using the information obtained from these tests, along with results of other tests, your optometrist can determine if you have Computer Vision Syndrome and advise you on treatment options.

Solutions to computer-related vision problems are varied. However, CVS can usually be alleviated by obtaining regular eye care and making changes in how you view the computer screen.

Eye Care:
In some cases, individuals who do not require the use of eyeglasses for other daily activities may benefit from glasses prescribed specifically for computer use. In addition, persons already wearing glasses may find their current prescription does not provide optimal vision for viewing a computer.

Eyeglasses or contact lenses prescribed for general use may not be adequate for computer work. Lenses prescribed to meet the unique visual demands of computer viewing may be needed. Special lens designs, lens powers or lens tints or coatings may help to maximize visual abilities and comfort.

Some computer users experience problems with eye focusing or eye coordination that can't be adequately corrected with eyeglasses or contact lenses. A program of vision therapy may be needed to treat these specific problems. Vision therapy, also called visual training, is a structured program of visual activities prescribed to improve visual abilities. It trains the eyes and brain to work together more effectively. These eye exercises help remediate deficiencies in eye movement, eye focusing and eye teaming and reinforce the eye-brain connection. Treatment may include office-based as well as home training procedures.

Viewing the Computer:
Proper body positioning for computer use.Some important factors in preventing or reducing the symptoms of CVS have to do with the computer and how it is used. This includes lighting conditions, chair comfort, location of reference materials, position of the monitor, and the use of rest breaks.

Location of computer screen: - Most people find it more comfortable to view a computer when the eyes are looking downward. Optimally, the computer screen should be 15 to 20 degrees below eye level (about 4 or 5 inches) as measured from the center of the screen and 20 to 28 inches from the eyes.

Reference materials :- These materials should be located above the keyboard and below the monitor. If this is not possible, a document holder can be used beside the monitor. The goal is to position the documents so you do not need to move your head to look from the document to the screen.

Lighting :- Position the computer screen to avoid glare, particularly from overhead lighting or windows. Use blinds or drapes on windows and replace the light bulbs in desk lamps with bulbs of lower wattage.

Anti-glare screens :- If there is no way to minimize glare from light sources, consider using a screen glare filter. These filters decrease the amount of light reflected from the screen.

Seating position :- Chairs should be comfortably padded and conform to the body. Chair height should be adjusted so your feet rest flat on the floor. If your chair has arms, they should be adjusted to provide arm support while you are typing. Your wrists shouldn't rest on the keyboard when typing.

Rest breaks :- To prevent eyestrain, try to rest your eyes when using the computer for long periods. Rest your eyes for 15 minutes after two hours of continuous computer use. Also, for every 20 minutes of computer viewing, look into the distance for 20 seconds to allow your eyes a chance to refocus.

Blinking :- To minimize your chances of developing dry eye when using a computer, make an effort to blink frequently. Blinking keeps the front surface of your eye moist.
Regular eye examinations and proper viewing habits can help to prevent or reduce the development of the symptoms associated with Computer Vision Syndrome.


* All about vision suggets Computer Glasses for Blurred Vision and Other CVS Symptoms. They say that 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.
How these glasses help us?

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.
For more details: Computer Glasses for Blurred Vision and Other CVS Symptoms

* "All about vision suggests 10 Steps for Relief for Computer Eye Strain.

1 comment:

  1. I loved your article – it was some great information. I think you and your readers might be interested in another article I found on Medical and Dry Eyes.

    www.whatistheeye.wordpress.com

    ReplyDelete

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