Improve Your Eyesight Naturally

by Leo Anghart

  Normal visual acuity with age

  after Elliot et al., 1995

  Detecting small changes in visual acuity

  When you want to detect small changes in vision, credit is given to each letter identified correctly. Research conducted by Baily and associates (1991) has shown that people with normal eyesight identify letters with a 95 percent confidence for changes at ± 5 letters on the eye-chart. If visual acuity is scored row by row, the 95 percent confidence limit for change is determined to be ± 2 rows, because the 95 percent discrepancy lies in the next smallest category, which is ± 1 row. This means that when visual acuity is scored by row, at least two rows of change must occur before a clinician can determine that there has been any real change. Therefore, testing by letter appears to be a more accurate method of measurement.

  Decimal acuity

  The image of a 20/20 letter E as relayed to the central fovea where you have absolutely clear vision.

  With a decimal visual acuity of 1, you can see letters that are 8.7 mm high at a distance of 6 meters. Decimal value decreases with increasing letter size. For visual acuity to be half as good as 1, the letter size would have to be twice as large. For example, for visual acuity to be 0.5, the letter size of the smallest readable letter would be 17.45 mm.

  The formula for constructing a decimal acuity chart is as follows. The height of a letter for any given decimal acuity value can be determined by a simple relationship: height of letter = 8.726 mm/decimal acuity. For a letter of a given height, therefore, decimal acuity = 8.726 mm/height of letter. Decimal acuity is used when comparing visual acuity with other variables.

  Percentage acuity

  Multiplying decimal acuity by 100 results in percentage acuity. Thus the decimal acuity of 1 becomes 100 percent. Percentage acuity can mislead you since it sounds very scary. For example, someone who can only read the top letter “E” of the eye-chart will be told that he or she has only 5 percent vision. Hearing this you think you are going blind!

  Letter height Percentage acuity Decimal acuity Metric English Snellen

  4.4 mm 200% 2.0 6/3 20/10

  6.5 mm 133% 1.33 6/4.5 20/15

  8.7 mm 100% 1.0 6/6 20/20

  13.1 mm 67% 0.67 6/7.5 20/30

  17.5 mm 50% 0.5 6/12 20/40

  21.8 mm 40% 0.4 6/15 20/50

  43.5 mm 20% 0.2 6/30 20/100

  87.3 mm 10% 0.1 6/60 20/200

  174.5 mm 5% 0.05 6/120 20/400

  Snellen acuity

  The common eye-chart is a visual acuity testing system devised by Dutch ophthalmologist Hermann Snellen in 1862, on the basis of what is now known as the Snellen fraction, which is defined as follows:

  Snellen acuity can be stated in either metric or imperial units. The first numbers refer to the testing distance, which is usually 20 feet (6 meters). The second number refers to the distance from which someone with normal eyesight would be able to see this line of letters. So, a reading of 20/40 tells us that a person with normal eyesight could see these letters at 40 feet (12 meters). In other words visual acuity is about half of normal. 20/40 (or 6/12) is also the legal limit for driving without optic correction.

  Illumination and contrast

  The standard illumination for visual acuity tests is a minimum of 10 foot-lamberts. If you are reading this in daylight the illumination is probably 40 or 50 foot-lamberts in a room with windows. Large windows, on a sunny day, will bring the illumination level up to 100 foot-lamberts. Increasing the illumination does not improve vision, but reducing illumination causes considerable loss of visual acuity. You might have experienced this when trying to read a menu in a dimly lit restaurant.

  Contrast is also an important factor. Visual acuity suffers when the contrast goes below 90 percent. One hundred percent contrast is defined as black letters on white background, while 0 percent contrast would be gray letters on an equally gray background – the letters would of course be invisible. Eye-charts for testing contrast are made by altering the gray tones of both background and letters.

  Near-vision acuity

  This is commonly referred to as reading ability. Near-vision test charts are designed using the same principles that are used for distance vision tests. This text is printed using a 10-point font which makes reading comfortable under most lighting conditions. Normal reading acuity in daylight is 3-point text. The following is printed in a 3-point font:

  Doctor: Good morning, Albert … what seems to be the problem today?

  Patient: Well, when I look in the mirror I see sagging jowls, red blotches, thinning hair … why do I look so awful?

  Doctor: I don’t know Albert … but you have excellent eyesight.

  Your reading ability is greatly affected by quality of light. Fluorescent light is the least effective while sunlight is the best reading light. Try reading the above story in different light conditions and you will immediately experience the effect.

  Presbyopia is a condition affecting your ability to read because your near point of focus has drifted out. Vision Training is highly effective for presbyopia especially if you start exercising your eyes when you become aware of your reading difficulty or before you find that your arm is not long enough to hold a book to read comfortably.

  Night vision

  At night we rely exclusively on the highly sensitive rod cells. These cells take about 35 minutes to fully adapt to the dark. After about half an hour in darkness your eyes have become 100,000 times more sensitive to light. At night a lighted cigarette can be seen several kilometers away. The military is very aware of this fact, thus the need for total black-out in war situations.

  As twilight gradually fades into night, your light sensitive cells also hand over operation from the cone cells used during the day to the rod cells used at night in low light conditions. However, in today’s world we seldom experience total darkness. Modern cities have street lights so the total transfer to absolute night vision is seldom completed.

  Have you ever had the experience of waking up at night and wondering where the light is coming from? Most likely you realize that the room is illuminated by the digital clock display on your VCR. This is an example of the power of your night vision. It is amazing how much you can actually see with so little light.

  Research shows a direct link between night vision and vitamin A. If you have problems driving at night try taking about 5,000–10,000 IU of vitamin A per day.

  This is

  100%

  Contrast

  Contrast

  The difference between the intensity of the object you look at and the background is referred to as contrast. Amazingly, our ability to detect contrast does not vary with lighting conditions. Looking at a black print on a white shirt does not vary significantly between indoors in dim light or outdoors in bright sunlight. This consistency in contrast is obtained at the loss of sensitivity. You have probably experienced this whilst reading. The level of black and white contrast is maintained in all lighting conditions. However, it becomes more difficult to read small print in poor light. Your visual system looks for the difference in contrast between the objects you want to see and the background around them. Part of this is also related to vergence. In low light your depth of field – the area where you can see clearly – becomes much smaller. The same phenomenon is well known in photography. With a large aperture opening you get a picture where the background is out of focus. The object therefore stands out against a soft background. Portrait photographers often use this technique to emphasize the face.

  To maintain your low light reading ability, try reading small print in dim conditions. I know your mother probably told you not to read in poor light. She was right when it comes to reading a novel with a penlight under your bedcovers. However, it’s a good idea to maintain your ability to read small print in varying light conditions. As you begin to experience what small print looks like under different kinds of light, you should notice how the contrast seems to remain the same, even while your ability to read the text varie
s.

  Loss of contrast after laser surgery

  One of the unfortunate consequences of laser surgery is the loss of contrast. After surgery many people find it impossible to distinguish details in an object that is brightly lit from behind. They see something similar to a picture taken of a person against a sunset. Either you can see the sunset and the person is only a shadow, or you can see the person and the sunset is over-exposed. The photographer overcomes this by using artificial light on the person. While driving you often come across situations where your ability to recognize contrast is called for. For example, if you are driving behind a truck with cars coming towards you in the opposite lane, your aptitude with contrast allows you to see both the bicycle between you and the dark outline of the truck ahead. In the pre-surgery consultation the possibility of a significant loss of contrast sensitivity in low light conditions is frequently not mentioned. A little known fact is that many people have to give up driving at night following laser surgery. This is why legislation is under way in the United States and Canada to make it unlawful to drive at night if you have had laser surgery on your eyes.

  In Germany, testing for contrast sensitivity is required before you can get a driver’s license. Many people who have undergone laser surgery fail this test and consequently cannot get a license.

  What is a diopter?

  The measurement used to describe lens power is a diopter of the focal length of a lens. If your far point of clear vision is 20 cm, then you will need a 5 diopter lens to correct your vision to normal. The formula is as follows:

  The farthest you can see in an absolutely crystal clear manner can easily be converted into diopters using the above formula. Here is an example.

  If you can clearly see up to a distance of 20 cm from your eyes, then the above calculation is as follows:

  1 over 20 = 0.05. This is multiplied by 100 to equal 5 diopters.

  Using the string exercise described on page 83 you can accurately determine your diopter prescription.

  Plus and minus lenses

  Plus lenses are magnifying and bring the near point closer. Reading glasses are plus lenses. These lenses are also used for hyperopia to relieve eyestrain.

  A lens with a minus reading of diopters, which is used for correcting myopia, does not have a true focal point because it causes light rays to diverge. The strength in diopters of a minus lens is determined by measuring the distance from that lens to the point where the diverging rays would converge if their path was reversed.

  7. Vision: The Mind Side

  Vision takes place mostly in the mind. The physical side of seeing is only about 10 percent of what takes place when you are reading this. The optical structures of your eyes – the cornea, lens and the fluid that fills the eye – combine to focus an image on your retina. This is very similar to a camera. The optical part of the camera is your eyes. The film in the camera is your retina.

  Conversion of light into nerve energy takes place in the retina. The retina is a very important part of seeing. Color is perceived through three types of photosensitive light cells and, like color film, there are three layers, each sensitive to one of the primary colors. In the retina we have cone cells that are sensitive to red, green and blue light. Yellow is the result of blending red and green; the same subtractive color principle is used in video and television.

  The image is now converted into energy flowing through millions of nerve fibers packed together into the optic nerve, which leads to the geniculate body located in the middle of the brain. Here the nerves branch out. Seeing involves about two thirds of the brain. Many parts of the brain receive input from visual perception. For example, there are parts of the brain that recognize shape, another part perceives color and yet another is in charge of determining where objects are in space. Your peripheral vision is especially sensitive to motion. In prehistoric times, when people lived in the wilderness, it was very important to be aware of danger approaching. Today we use this ability to navigate our way through traffic or down a crowded street.

  In Vision Training we involve both the physical part of seeing and the mental and psychological sides. The physical side involves practicing exercises which are designed to relax the eye muscles and affect the shape of the eyeball. This is equivalent to moving the lens back and forth until the image is sharp. With eyesight this is a dynamic process that constantly works to keep objects in focus. Your eyes are far superior to any video camera ever developed. Anyone with normal eyesight can focus on something very close and just an instant later adjust to focus on something far away. Your image is always in focus and crystal clear. A video camera is too slow to make that kind of shift without a cut.

  It’s a wonderful world out there

  All five senses are involved in creating our experience of the world around us. Vision is perhaps the most important of our senses because it serves as the interface between our internal world and the physical reality around us. Your work is likely to involve a significant visual component – seeing what you do, seeing where you drive, seeing a client and so on. This does not mean that you can’t function without sight; you can, but it means a significant loss of connection.

  For some people, sight is the most important sense. They like to see something before they believe it is possible. In learning, the visually inclined person prefers to see something demonstrated before they can understand and learn. The majority of people in the world belong to that group. Others prefer to hear someone talk about a topic of interest. This is the lecture format used in most of higher education. For these people, the auditory is an important sensory input. Finally, there is the last group of people who need to try something out physically before they really understand it. The kinesthetics are often great craftspeople since they have a feel for the material with which they work. The sense of touch is exceptionally sensitive as well.

  Sometimes the senses connect, so that an input of one sense leads to an experience of another. For example, for some people the smell of freshly baked bread triggers memories of childhood. Newly cut grass is another common smell that evokes such recollections. Sometimes a perfume worn by mother or grandmother provides a direct link to memories of days gone by. On other occasions it can be the sense of taste that evokes recollections. Many people tend to order the same dish in a favorite restaurant as the flavor conjures up pleasant scenes from the past.

  Certain locations may also bring up memories or feelings. For example, if you go back to the place where you went to school, it is bound to stir up memories. I remember returning to Copenhagen, a city I lived in during the 1960s. Returning 20 years later everything seemed smaller than I remembered. Experiences and states of being can be anchored to specific locations. If you have a negative experience in a certain establishment it is likely that you will choose not to return. If the first impression of a person is less than positive, this tends to color your perception of that individual. Appearances are extremely important. Great chefs spend almost as much time decorating their dishes as they do cooking the food.

  Appearance is, of course, the driving force behind fashion. There is no practical reason why we need to change our wardrobe every year. There is no logic that dictates why certain colors are no longer desirable. Fashion goes through cycles. Years go by, and the same patterns and styles come back in some form or other. Shoes cycle through round, square and pointed toe shapes, whilst fabric patterns shift constantly through dots, stripes, flowers and geometrics.

  Physical appearance determines how you are perceived. If you are tall, well dressed and young then you are more likely to get the job. The visual aspects of people and objects are of vital importance.

  Designers make a healthy living from figuring out what will appeal to your esthetic sense in any given situation. The layout of this book went through several stages of development before we felt that it had the right appeal. The typeface was chosen for its clean appearance and the line spacing to make it easy to read. The illustrations were designed to be vis
ually pleasing. Most attention of all went into the title and cover design. Most likely you bought this book either because of the title or because the cover attracted your attention. After all, vision is the most important sense that we possess.

  Where does your attention go?

  Your eyesight is directed by your attention. Are you the kind of person who is curious about the world or are you more interested in reading books and minding your own business? If you want to regain your eyesight it is important that you begin to pay attention to what is out there in your environment. Energy follows attention, so if you believe that you can’t see, your attention will not reach out very far. The ancient Greeks thought that near-sight was caused by a weak spirit, which did not have the energy to venture out very far. To regain your eyesight you need to consistently direct your attention further and further out into the world. One of the concepts that took me a long time to grasp is the fact that the world only responds to us in relation to how far we throw out our attention. The energy we put out brings back the information we seek. For example, you want to know the time so you look at the clock tower. Your intention shifts out to the clock tower and the energy then comes back to you with the information you seek – the time.