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FAQ – Computer Vision Syndrome

Can A Computer Screen Damage My Eye?

Twenty years ago, few offices workers used computers, let alone had computers. However with the dramatic increase in home and office computer use, complaints of eye fatigue and discomfort are commonplace. Many people assume increased computer use is the source of these complaints. But extensive testing in government and private laboratories has not produced scientific evidence that computer monitors will harm your eyes. Research has established that computer monitors emit little or no hazardous radiation, such as x-ray, or non-ionizing radiation, such as ultraviolet rays.

While computers have no known harmful effects on eyesight, computer users do often complain of eye related symptoms such as eyestrain, headaches, fatigue, dry eyes, and difficulty focusing, These symptoms (Computer Vision Syndrome – CVS) however are caused not by the computer screen itself but rather by the conditions surrounding the computer screen, such as poor lighting or improper placement of computer equipment and computer furniture. In some instances, a pre-existing eye problem may be the cause.

Why Do We Get Eyestrain?

There are several different things that can lead to eyestrain symptoms. When the muscle inside of the eye that controls focusing is overworked, symptoms can occur. In many cases, these symptoms will not start immediately, but only after several hours of work. When the muscle in the eye becomes fatigued, the eyes may feel uncomfortable or ache. The vision may blur off and on. A mild headache can occur if the eyes continue to work. In some cases, the muscle within the eye can become so fatigued that it cannot fully un-focus, leading to blurred distance vision.

The following things can contribute to eyestrain:

  • Having to read or use a computer at a fixed, set distance for a long continuous
    period of time. Even if a person has more than adequate focusing ability, focusing at a set distance continuously can fatigue the lens.
  • Having to read or work at very close distances. This requires much more focusing and leads to more rapid fatigue.
    Using inadequately powered reading glasses, or using an outdated glasses prescription.
  • Working in situations with inadequate lighting, or with glare from overhead lighting. Having other underlying eye problems, such as ocular allergy or dry eye. Having an imbalance in eye muscle alignment, so that the eyes have to fight to stay fixated on a near object.

What Can We Do About Eyestrain?

Eyestrain will not permanently damage the eyes or cause a loss of vision. However, it can be very uncomfortable and lead to a loss of productivity. Anyone who uses a computer can take measures to reduce eye discomfort.

Get An Eye Exam

The American Academy of Ophthalmology suggests that you start with a comprehensive eye exam. This is always a good staring point anytime you experience symptoms like headaches, eye strain, blurred vision, eye irritation, double vision, excessive tears, dry eyes, pain in the eyes, excessive blinking or squinting. The exam will help rule out any ocular conditions that may exist that are causing eye symptoms.

Vision Correction

Getting an eye exam is especially important if you wear glasses or contact lenses. Let the ophthalmologist know how often you are in front of a computer screen. Since most glasses are made to correct for a reading distance of 16 inches, it is important that they are adjusted for your particular work environment. It is recommended that the computer screen should be 20 to 26 inches from your eyes, and your glasses can be made to accommodate this distance. Your glasses can also receive special anti-reflective coatings and tints to help reduce eyestrain. If you are over forty, you may require one pair of glasses that corrects for your “normal” prescription and another pair that corrects your vision when in front of a computer screen. If you are over forty and require reading glasses or wear bifocals (with lines or without), the need for two separate pairs of glasses may be even more necessary.

If you do not normally require a vision correction, computer eyeglasses with low power plus lenses and sometimes a light tint is often helpful. The color of the tint depends upon the screen background color, ambient room lighting, and your prescription. This should be discussed with the optician.

Adjust the Equipment

Set the monitor, desk, and chair at comfortable distances and heights. Some of these figures may be obtained in the documentation that came with the computer products. Most users prefer a viewing distance of 20 to 26 inches, but this distance should be between 18 and 28 inches; a little farther away than for reading printed text. The computer screen should be placed slightly below eye level. A good rule of thumb is that the center of the computer screen should be 4 to 9 inches below your eyes, enabling you to look down slightly at your work. Adjust the brightness of the monitor to an intensity that is comfortable to your eyes; not to bright and not to dim. Then adjust the contrast control so that the characters on the monitor and the background so the letters are easily read.

Create Good Lighting and Reduce Glare

Try to modify the lighting eliminating glare and harsh reflections. If reading, having the light source coming from behind, over your shoulder, helps to prevent glare problems. If using a computer, dark print on a white or light gray background is less fatiguing to the eyes than multicolored print. Sometimes a plastic or glass filter over a computer screen with an anti-reflective coating can help with computer glare. These can be purchased from any office supply store.

Rest Your Eyes Periodically
Take frequent, short breaks from near work by focusing on a distance object for a few seconds. Every twenty minutes, get up, stretch your back and neck and look around. Move your eyes and move your body, change your position.
Change the distance that you work frequently. If the eyes are feeling increasingly fatigued, hold things further away rather than closer to you. Avoid getting very close to what you are reading.

Avoid Dry Eyes

Blink! Studies have shown that when you look at the computer monitor, there is a natural tendency toward a reduced blink rate. The less you blink, the more likely you are to experience dry eye symptoms of burning, sand-in-the-eye, heavy lids, etc.
The normal blink rate is averages 12 times per minute. Computer users usually blink 5 times per minute. The longer the eye remains open between blinks, the more likely the cornea is to dehydrate, burn or ache. Then, finally, you blink. But the damage, although minor and easily repaired, is already done. Your eyes sting, burn, sting and otherwise feel miserable. You tear, feel better, then start the process all over again. Eventually, the disruption to the corneal tissue causes a blurred image to go along with the other symptoms. You stop work, fall asleep and your body heals itself until the next time.

There is plenty of non-prescription tear replacement or re-wetting drops available at your local drug store but being aware of the need to blink is the real fix, especially if you wear contact lenses.