computer vision syndrome

Why do we blink?

In my first year of optometry school, as part of the practical portion of our studies, we used to do vision screenings on kids in elementary schools around Boston. So picture me, the tall optometric freshman, kneeling down to examine the eyes of this adorable little 6 year old girl when she steps back and asks out loud "Harbir, why do we blink?". The whole classroom stopped and looked up at me...

I paused for a second, gathered as much information as I could from my 3 months of eye-related education, and began to answer. Well, cute little blonde-haired girl whose name I don't remember, there are 3 main reasons for blinking:

Number 1 is protection. Our eyelids and eyelashes provide a protective barrier against foreign objects such as dust, rocks, bits of metal, fruit flies, etc...

The second reason is lubrication. Every time we blink, our eyelids squeeze out small amounts of oil, water, and mucus to line the surface of the eye. Studies have shown that when we are engaged in activities that require more attention, we tend to blink less. That is why spending a lot of time on the computer can lead to dry eyes. So as soon as you're done reading this blog, get off the computer! Then come back and share it with all your friends :)

And last, but not least, the third reason for blinking is irrigation or removal of tears and waste. Our eyelids act similar to squeegees, the wonderful onomatopoeically named tool that helps smoothly remove water from car windows and such. Each time we blink, the lids pull tight and sweep tears and debris off the surface of the eye and towards the drainage duct which is located at the inner corner of the eye.

And that's why we blink.

Computer Vision Syndrome

I have a lot of patients who come in with complaints of eye strain while on the computer, while at work and home.

This is a condition referred to as Computer Vision Syndrome (CVS).

What causes CVS?

1) Need glasses? Uncorrected refractive error (see: All Kinds of Blurry) can make viewing the computer monitor very uncomfortable.

2) Looking at a computer monitor requires the focusing system inside our eyes to work constantly. Essentially fatiguing the tiny muscles inside our eyes.

3) Reflections from the screen can make it difficult for our eyes to focus accurately, thus causing our eyes to work harder.

4) Incorrect viewing angle can force the muscles on the outside of our eyes to work harder and fatigue.

5) People tend to blink less when at the computer. This leads to dry eyes.

What can be done?

1) First and foremost, get an eye exam. Even if you don't need glasses for other things in life, a simple pair of computer glasses may cure all woes.

2) Take breaks!! Remember 20/20/20. Every 20 minutes, look into the distance (at least 20 feet away) for at least 20 seconds. This will help relax your eyes.

3) Screen protectors are useful. Also, anti-reflective coatings on glasses are very helpful.

4) Ergonomics! Our eyes are most comfortable when looking slightly downward. There are very detailed workplace guidlines available for positioning and posture at the computer.  The American Optometric Association recommends that the center of the monitor should be approximately 15-20 degrees below eye level.

5) Blink more. Make a conscious effort. Also, using artificial tears can help moisturize your eyes. Remember our last discussion on Visine. Always best to ask your eye care professional which drops are best for you.