Ординатура / Офтальмология / Английские материалы / Relearning To See_Quackenbush_2000

t

desire to see clearly without glasses can a reference to Sinbad be? In Arabian Nights tales, he occupies a prominent place. In his many voyages he described many extraordinary things which happened and which were very wonderful, although not always probable or true. Being a sailor, he used his eyes principally for distant vision. He had good eyesight, but after one of his numerous voyages he returned to his home in Baghdad and complained to his friends that his sight for distance had become poor, so poor that he was unable to recognize people ten feet away. An Egyptian astrologer sold him a pair of glasses for a price which made a big hole in his savings. For a time he was happy because his vision was decidedly improved by the glasses, but it was not long before his imperfect sight required stronger glasses, and the strength of his glasses was frequently increased. In a shipwreck he had difficulty in reaching the shore because the water clouded his glasses so that they became useless. Whenever it rained the glasses became too clouded to help him to see. In many emergencies, when he most needed his glasses, they failed him. When swimming he could not see any better than without his glasses. It embarrassed him very much when trying to reach land, because he was unable to locate it. Other sailors would throw water in his face, fog

his glasses, and tease the blind man without risk to themselves. With his glasses he suffered great pain and fatigue.

While visiting a city in a foreign land and walking the streets without seeing much, a stranger handed him a parchment on which was written:

"Go where all things are moving, Watch and think the livelong day; The truth is always proving

Your sight will return, I say."

The words gave him some hope and he believed that in one of his voyages he would find some land or country where all things would be moving and nothing immovable or stationary. In a voyage to India he felt that in this country he would find a land where all things were moving. After a long day of traveling he entered a temple where many worshippers on their knees were alternately raising their arms and faces on high and then bowing to the ground, saying:

"Allah is Allah, God is Allah."

To avoid attracting attention he imitated the others while remembering that the paper of instructions told him to watch and think. He noted that when he raised his head up that things in front of him and to one side seemed to move down or in the opposite direction, and that when he bowed his head down to the ground, things appeared to move up.

At last he believed that he had found a place were all tilings were moving. By going through the motions without prayer he found that it worked just the same. After he left the temple he was able to notice that when he walked straight ahead things to each side of him, and the ground in front of him appeared to move in the opposite

direction. He was able to demonstrate then, without any effort, that the place where all things are moving was wherever he happened to be, and since he was always moving his eyes during the day it was possible for him to see things moving opposite all day long.

"Watch and think" was ever in his mind. He became able to demonstrate that when he imagined the movement easily that all pain, discomfort or fatigue in his eyes and in other parts of his body were prevented or relieved. It was not long before he found that the light became brighter; and, with this increased illumination, his vision improved.

When the swing was practiced with an effort, very little or no benefit followed. He discovered that the swing was of great help to his vision when practiced at night, and brought him more comfort than the same time devoted to sleep. All this time he believed that he had discovered a truth; that the cause of his imperfect sight was a strain or an effort to see, and that he improved by rest and not by effort.

He returned to Baghdad overflowing with the wonderful news. He called on the Egyptian astrologer who had sold him his glasses, and with a happy smile on his face reported the facts.

The astrologer was furious and screamed in a loud voice:

"Out upon you, you lying knave. I believed your story of the mammoth bird, the rock, your experiences with mermaids and many other of your strange tales, but this is too much. To eliminate poor sight by rest is too absurd. You must be crazy." Then he drove Sinbad from his house, announcing to the mob of people outside to shun him for a liar, a cheat, and a fool.

For many years later Sinbad held his peace but did not neglect to help those with poor sight until their number became sufficiently great to overwhelm the ignorant astrologer and others like him.

More stories from the Better Eyesight magazines are located in Appendix G, "Additional Vision Stories."

C H A P T E R C O M M E N T S

Clara Hackett, in Relax and See, writes:

Overcoming the handicap of defective vision, important at any age, is especially rewarding for a child. For better vision can play an important role throughout his life- time—in personality and social development, in school work and, later in his whole career.

... Helping him to firmly establish sound habits of using his sight which will stand him in good stead all his life, are worthwhile goals....18

One of the most important assets you can endow your child with is an understanding of how to develop and maintain the good visual habits that will help to keep his sight perfect throughout his life.19

I am especially interested in training Natural Vision teachers who can teach children. (See Appendix E—Becoming a Natural Vision teacher.)

Ellen Raskin wrote a wonderful little children's book, called Nothing Ever Happens on My Block, which is all about interest. (See Bibliography.)

Js'OTES

i W.B.MacCrackcn, Use Your O w n Eyes (Berke­ ley. California: Published by the author, 1937), p. 232.

J Graphic and caption reprinted from Perfect

Sight Without Classes.

* Paul E. Dennison, "Reading and Vision," Brain Gym Magazine, Vol. II, No. 3 (Fall 1988), p. 1.

4 Clara A. Hackett and Lawrence Galton, Relax and See (London: Faber and Faber, Limited,

1957), p. 262.

5 T.Ribot, Иге Psychology of Attention (Chicago:

The Open Court Publishing Company, 1890), p. 2.

'Ibid., p. 6.

7 Ibid., p. 8. "> Ibid., p. 12.

9 Ibid., p. 15. w Ibid., p. 19.

11Ibid., p. 23.

12Ibid., pp. 29-32.

13Ibid., p. 34.

14Ibid., pp. 36-37.

15Ibid., pp. 59-60.

16Ibid., p. 66.

17Ibid., p. 105.

18Clara A. Hackett and Lawrence Galton, Relax and See, p. 254.

19Ibid., p. 261.

COMPUTERS

See Plate 59; "Evolution."

COMPUTERS AND NATURAL VISION

HABITS

The same principles—movement, centralization, and relaxation—and the same habits—sketch, breathe, and blink—are necessary during computer work and play.

Shift from one point to another with a head movement. Even a small head movement makes a big difference in releasing the neck. Do not lock your neck. This is probably the greatest problem. Move your body as you work. The human body is not designed to be stationary. Again, even a small movement is \aluable. Do not lock your body.

Centralize. Do not try to see the whole screen at once, i.e., do not diffuse.

Do not stare and "space out" when you are thinking of something else. Either continue to sketch and blink, or close your eyelids.

Blink frequently and softly. Many people have dry eyes when using a computer because of infrequent blinking.

Breathe abdominally. Yawn!

Computer screens, like books and TV screens, are relatively "flat" or two-dimen- sional. Vision needs to move from near to far and back. Shift your attention into the distance (at least twenty feet) periodically. If you are in a small room, close your eyelids and pretend you are shifting your attention to a far-away object. Never "stare into the distance" as one computer magazine incorrectly suggests

Take breaks. This is important. It is better to take a break before you feel uncomfortable. Stretch and yawn!

Note that computers and TVs did not exist when Bates taught his students in the 1920s It is easy to acquire incorrect vision habits while using a computer—especially if used for long periods of time, and if you are not aware of correct vision habits. Keep the neck and shoulders loose and flexible. Computers do not lower vision—incorrect vision habits do.

If your computer work is somewhat boring, the correct vision habits will create more interest automatically. Boredom often leads to the harmful staring habit.

Tip: If you have a programmable screen saver, type in "Sketch, Breathe, and Blink!"

COMPUTER POSTURE

See Figure 24-1: Computer Posture. The woman on the right has excellent posture. The wrist/forearm angle is straight, and the computer monitor is positioned at an excellent height.

All of the monitors on the left are too low— a very common mistake. A low monitor encourages poor posture. The body tends to bend over forward or even sideways. This puts a high strain on the neck and spinal column.

One of the simplest adjustments that can be made with a computer is to raise the mon-

itor to a comfortable level. A good rule of thumb is to position the top of the active part of the screen (not the top of the monitor) slightly above eye level.

Correct posture supports a released, mobile neck and abdominal breathing. Incorrect posture creates tension, shallow breathing, fatigue, and strain.

It is easy to understand how computer work can be a strain on the visual system. With a few ergonomic adjustments and the practice of correct vision habits, one can support normal sight.

ANNOYING MONITOR FLICKER

Almost all monitors have a vertical scan frequency of 60-75 Hz. Vertical scan frequency is also known as vertical refresh rate (VRR).

It is mainly the VRR which determines whether a monitor has annoying flicker. This flicker is similar to the annoying 60-Hz flicker in fluorescent light fixtures with magnetic ballasts. Since the horizontal scan frequency, or horizontal refresh rate (HRR), is usually many thousands of Hz, there is no noticeable flicker created by the HRR.

Monitors with VRRs of 65 Hz or less can have noticeable flicker. The lower the rate, the more noticeable the flicker.

This "flicker" is perceived mainly by the rods from the peripheral parts of the monitor (relative to where you are centralizing). The cones in the fovea do not pick up movement as well as the rods. So, the point at which you are centralizing often appears to be stable, while the periphery may nicker annoyingly.

VRRs of 70 Hz or higher produce an essentially "flicker-free" monitor. Many modem monitors have a VRR of 70 Hz or higher. Some VRRs go as high as 79 Hz. On multiresolution monitors, the VRR is often dependent upon the resolution selected. The manual or manufacturer should be able to provide this information.

Tom'S PERSONAL LOG: My monitor has a VRR of 75 Hz with a HRR of 60,000 Hz at 1024x768 resolution. This provides flickerfree viewing on a large screen.

CRT COMPUTER MONITOR

RADIATION CONCERNS

One of the biggest concerns regarding computers is the potentially harrnful effects of the

radiation emitted from monitors Many articles have been written in computer magazines and newspapers about the possible harmful biological effects of electromagnetic frequency (EMF) radiation from computer monitors, power lines, and other electrical devices. A computer monitor operates similar to a television. However, most people do not sit as close to a television1 as a CRT.

Since this "invisible" energy could be a potential source of strain, it could be prudent to minimize possible risks.

Radiation 101

There are two main types of electric and magnetic radiation emitted by CRTs: Very Low Frequency (VLF), 10,000-300 Hz; and Extremely Low Frequency (ELF), 300 Hz and lower. See Plate 22: Electromagnetic and

Visible Spectrums. Since VLF is not considered to be as potentially harmful as ELF, most research has been directed toward the ELF radiation.

Children who have prolonged exposure to low-level (2-3 milligauss), 60-Hz magnetic fields may have an increased risk of cancer. A gauss is a unit of measure of magnetic energy; a milligauss is i/ioooth of a gauss.

Brain chemistry of living cats has been changed by exposure to low-level EMF. Low-level EMF radiation, similar to the type found in CRTs, has produced malformations in developing chick embryos and mice. The development of cancer has been associated with workers, like some utility employees, in occupations in which they are frequently exposed to power lines. ELF has been identified as a possible cause of miscarriages, birth defects, and cancer.

The Environmental Protection Agency

issued a draft report in 1990 entitled "An Evaluation of the Potential Carcinogenicity of Electromagnetic Fields." In the summary of this report, the EPA states:

The human evidence, as described in the next section, suggests that magnetic fields rather than electric fields are associated with cancer incidence, and mechanisms have been sought to explain how weak currents induced by ELF magnetic fields could interact with cells and body tissue in such a way as to induce a carcinogenic response

.. .With our current understanding we can identify 60 Hz magnetic fields from power lines and perhaps other sources in the home as a possible, but not proven, cause of cancer in people.

Robert O. Becker, M.D., in his book Cross

Currents: The Perils of Electromagnetic Pollution, The Promise of Electromedicine, recommends "a maximum field strength of 1 milligauss for continuous exposure to 60-Hz fields."2

Most monitors appear to have maximum emissions at the top and sides. Some monitors have as high as 73 milligauss at a distance of four inches from the top. The front and back usually have less emissions.

Swedish MPR-II and TCO

Low-Emission Standards

Not surprisingly, many government agencies and computer companies claim there is no proof radiation from monitors has had any detrimental effects on our health. Yet many computer companies have gone to great lengths to comply with MPR-II and TCO radiation standards—even though there is no legal requirement for them to do so. Hmmm.

A standard for low electromagnetic radi-

ation from monitors, known as MPR-II, was set in 1990 by the Swedish Board for Measurements and Testing (MPR). The MPR-II guideline, which has gained international acceptance, Unfits ELF electromagnetic fields to 2.5 milligauss at 50 centimeters (approximately 20 inches) in all directions from the monitor. Many modern monitors meet the MPR-II standard, and they usually advertise this fact.

The Swedish Confederation of Professional Employees (TCO) determined that there was inadequate protection using the older MPR-II standard. So, in 1992, a stricter standard was set by the Swedes, called TCO. TCO limits ELF radiation to 2.5 milligauss at 30 centimeters from the front of the monitor, and (the same) 50 centimeters from other sides. Some monitors now meet the stricter TCO guidelines.

MPR-II and TCO guidelines set limits on VLF and electrical fields as well.

Radiation Solutions

Most ELF radiation does not come directly from the front of the monitor to the user, as one might guess. ELF radiation travels from the sides, top and bottom, around the front of the screen to the user sitting in front of the monitor. So, although radiation screens can dramatically reduce electric field emissions, they usually do little, or nothing, to block the magnetic VLF/ELF emissions in front of the monitor.

One way to lower ELF radiation is to add a special metal shield inside the monitor.

A large coil inside the monitor produces EMF radiation. Some computer companies and monitor manufacturers have taken steps to reduce this radiation by adding a second

•reversed" coil. The second coil creates another electromagnetic field which, theoretically, cancels out the electromagnetic field created by the CRT's primary coil. This is the method used in many monitors to meet the Swedish MPR-II and TCO standards for low emissions.

Tip: Sit back at least an arm's length from your CRT. As discussed in Chapter 16, "Light," radiation (from an ideal point source) diminishes exponentially with distance. A monitor that has 30 milligauss at 4 inches may have only 7 milligauss at 12 inches, 1 milligauss at 28 inches, and 0.5 milligauss at 36 inches. As you can see, a small increase in distance from the CRT reduces radiation exposure by a large amount. One computer magazine reports that all ten monitors they tested had less than 1 iriilligauss from the front at a distance of 28 inches.

Note: Contrary to common belief, dnmning the monitor's screen or using "screen saver" software does not reduce radiation from a monitor.

On toe Horizon

Perhaps the best solution to avoiding radiation from monitors will be the new "flat" LCD (Liquid Crystal Display) monitors which have negligible radiation. These monitors do not use a magnetic coil to create the images on the screen.

Unlike their predecessors, the very latest LCD monitors have excellent performance and quality. Unfortunately, they are too expensive for most computer users. But prices should drop as they are produced in larger quantities. (TV screens will be flat LCD monitors in the future also.)

Many problems attributed to radiation from monitors have also been attributed by Bates to incorrect vision habits. These problems include headaches, eyestrain, blurred vision, red eyes, irritated eyes, dry eyes, nausea, sleeplessness, fatigue, neck and shoulder pain, etc.

While CRT radiation may be, and probably is, harmful, incorrect vision habits are harmful. Minimize the former and eliminate the latter.

G L A RE

The easiest way to reduce glare on a computer monitor is to orient it so that bright lights are not in front of the screen. Placing a monitor perpendicular to a window reduces glare, and lets you enjoy the light and scenery outside!

Another way to reduce glare is to place an opaque visor on top and/or on the sides of the monitor.

Glare screens can be used as an option, but they tend to distort the image and usually reduce the amount of light from the screen. Glare screens that use optical glass tend to have less distortion than other types. If you use a glare screen, avoid the mesh type.

Many monitors have an "etched" glass surface, or sprayed-on coating, which helps reduce glare. Etched screens can produce some loss of detail, but they are usually better, overall, than glare screens.

Never strain to see the images on the screen. Vision is always best when relaxed.

SMALLER, NOT LARGER, PRINT , is THE SOLUTION

Many computer users and software designers have read or assumed that larger letters on the computer screen result in less eyestrain. This is incorrect.

Magnifiers that fit over the front of the monitor have been used to enlarge the entire screen. "Computer glasses" enlarge the print and even claim to "protect" you from UV light. (Oh, no. Here we go again.) No UV Ught emanates from CRTs.

Some computer users have enlarged the size of print on the screen with software.

These solutions could encourage diffusion. As mentioned in Chapter 22, "Reading—For All Ages," Bates objected to large type. Centralizing in a smaller area is what is needed— not greater diffusion. A person who wears corrective lenses already diffuses. Increasing the size of print, by any method, only encourages more diffusion and increases the strain.

TOM'S PERSONAL LOG: I set the type size to a small size (9 point is nice) on my monitor. This encourages centralization. (Now, if I can just convince my editor and designer to use smaUer type— )

Of course, one should never squint or strain to see. Remember to practice relaxed vision habits—especially when using a computer.

OTHER COMPUTER TIPS

If you use a computer for long periods of time, obtain a comfortable chair—preferably one that aUows sufficient mobility.

Adjust your monitor controls to provide maximum contrast. Vision functions by contrast and edges

Place paper holders on both sides of the monitor. Then, alternate your papers from left to right periodically. This helps keep the neck balanced.

Bifocals can create higher neck tension while using a computer. Often the head is forced unnaturally upward in order to look through the bottom part of the bifocal. Sin- gle-lense glasses (reduced) are the solution.

Palm occasionaUy to rest your eyes. Again, take breaks!

T E L E V I S I O N

As with computers, televisions were not available to the masses in Bates' day. We live in a very different era than the 1920s.

Many of the issues discussed above regarding computer monitors apply to watchmgTV. One major difference is posture. Most people do not sit upright in a chair when watching TV. Correct posture is important when watching TV.

Do not lock your neck while watching TV. Do not stare.

Dr. Thomas H. David, D.C., in his 1951 booklet, Improve Your Vision with Television!, wrote:

To STARE steadily at the television screen... can cause congestion which may result in eye-strain, headaches, a feeling of tiredness, or pressure behind the eyeballs, nerve tension ... and other discomforts resulting from looking at the television incorrectly. If these conditions are allowed to go on, they could lead to more serious complications.3

... Do not squint; do not open the eyes widely... Glance around the room from time to time for a few seconds....

Shift... from one part of the picture to another, and blink frequently....

...prevent stiffness and strain of neck muscles [by] turning the head—4

Sketch with a head movement; this keeps the neck released and mobile. Breathe abdominally. Yawn also.

Remember to blink frequently. Do not copy the incorrect habit of non-blinking taught to many actors and actresses! (See "TV and Movies—No Blinking Allowed," in Chapter 14, "The Third Habit—Blinking.")

Centralize. Do not diffuse over the whole TV screen. Shift from one point of the screen to another.

Notice that as the TV camera moves in one direction, all stationary objects move in the opposite direction—oppositional movement. The same is true at movie theaters.

There are some excellent programs on TV. Unfortunately, many programs and movies today do not support relaxation. Do not watch "negative, pessimum" programs. Perhaps the poor programs will encourage us to find other activities which include more movement. We live in a very sedentary (read: staring) society.

MOVIE THEATERS

Better Eyesight magazine, October 1920:

GO TO THE M O V I E S

Cinematograph pictures are commonly supposed to be very injurious to the eyes, and it is a fact that they often cause much discomfort and lowering of vision. They can,however, be made a means of improving the sight. When they hurt the eyes it

is because the subject strains to see them. If this tendency to strain can be overcome, the vision is always improved, and, if the practice of viewing the pictures is continued long enough, nearsight, astigmatism and other troubles are reversed.

If your sight is imperfect, therefore, you will find it an advantage to go to the movies frequently and learn to look at the pictures without strain. If they hurt your eyes, look away to the dark for a while, then look at a corner of the picture; look away again, and then look a little nearer to the center; and so on. In this way you may soon become able to look directly at the picture without discomfort. If this does not help, try palming for five minutes or longer. Dodge the pain, in short, and prevent the eyestrain by constant shifting, or by palming.

Movie theaters provide an excellent opportunity to practice correct vision habits. Notice how many people do not move their head while watching the movie!

C H A P T E R C O M M E N T S

There are people who read, use a computer, and watch TV and movies who have normal sight. It is not the activities of reading, doing computer work, and watching TV and movies which lower sight—it is the acquiring of incorrect vision habits.

Natural vision students can learn how to use their sight correctly—in all situations. Practice the correct habits and principles of eyesight more each day during all activities.