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Holistic Health Last Update: 12/6/1999

Your Vision And Your Video Display Terminal

By
Robert Rothbard, O.D.

My name is Robert Rothbard. I have practiced optometry for nearly eighteen years. I have examined many patients who spend part of their time in front of a computer screen. Some patients don't have any problems. However, there is a significant amount of patients who suffer from a variety of symptoms. They include:

1. Headaches
2. Blurred vision while viewing the monitor
3. Increased blur at distance, particularly at night
4. Problems focusing from distance to near or visa versa
5. Increased sensitivity to bright light or fluorescent light
6. Increased losing of one's place
7. Increased dry eye syndrome
8. Pains developing in the neck area

Another problem I find is with those patients who haven't had to do much close-up work over an extended period of time and now find themselves in front of a screen all day long. These patients appear to me the most at risk at developing any or all of the above symptoms. It reminds me of the individual who has lived a very sedentary life style and all of a sudden starts to work out. Think of all the problems this individual might develop.

What causes the above problems to occur?

Simply stated, there are two divisions where the problems lie. The first deals with the issue of ergonomics. Specifically, how do you improve the compatibility between the individual and computer by improving the lighting, the office furniture, the quality of the screen image and the basic comfort of the workstation? The second division deals with how do you improve the individual. This is the area I wish to discuss first.

The first area I want to look at is very straightforward. It deals with those patients who need to wear bifocals. Bifocals that are conventionally prescribed for normal reading activity many times do not work well while sitting in front of a screen. There are two reasons for this. The first deals with the fact the computer screen is usually at a different height than the normal reading level, usually significantly higher. The second deals with the distance of the screen from the individual. Usually the distance of the screen is further than normal reading distance.

Taking these two factors into account, if an individual were using bifocals prescribed for normal reading on a terminal, he/she would have to lean closer into the screen as well as tilt their head back to see through the bifocal. Think of the neck and back strain.

Another area that I feel is often overlooked deals with those individuals working on terminals under the age of forty. Conventional prescribing states that it is unusual for the prescription for distance to be different than the prescription for near.

The focusing system should still be strong enough for an individual to use his/her distance prescription for reading. I find this often not to be the case. I have found both kids and young adults who need to have a different prescription for reading than for distance. This is measured for during the examination. Some of the time, all that an individual has to do is take off their distant correction while he/she reads or performs on a terminal. Also, I have examined many young individuals who have 20/20 clear sight at distance and have been helped immeasurably by lenses prescribed for close-up. Here's a clue for those kids or young adults who have undiagnosed vision problems that could be interfering with your reading efficiency. If you see clearly at distance and have to hold your print very close or very far away to comfortably read, you could have a vision problem requiring a prescription for close-up.

Coordination of the two eyes together is extremely important in whether an individual will have problems working on a terminal. Basically there are two systems involved when viewing print close up. They are the focusing system, which allows you to see clearly, and the aiming system, which allows you to see items as single (as opposed to having double vision). These two systems work together in allowing us to perform all near tasks. In some individuals, however, they do not team together well. As discussed in the above paragraph, sometimes just prescribing the appropriate correction for near will help significantly. Sometimes we have to look at whether eye exercises or vision training will also help the situation. The goal of training is to help coordinate the aiming and the focusing system together to help achieve single, clear, comfortable vision.

Certain considerations should be taken into account when designing a workstation. The most important deals with the screen itself. The more one can minimize reflections, the easier time one will have viewing a screen. Being able to adjust the height and distance of the monitor to a user's liking also is a benefit. Also, one should minimize the difference in distance and direction between hard text and the monitor. This will help minimize fatigue from changing focus. Many times, the environment a worker performs in is dry. This and the fact that some individuals don't blink while viewing text, causes a dry eye syndrome. Be aware of your blink rate and possibly consider artificial tears occasionally. Discuss this first with your eye-care professional.