From owner-i_see@indiana.edu Sat Dec 23 13:10:44 EST 1995 Date: Sat, 23 Dec 1995 12:59:29 -0500 (EST) From: Alex Eulenberg Subject: Myopia Prevention: theory and practice Status: RO X-Status: The following letter was sent to me by Denis Alarie, from Ontario. He originally sent it to Howard Howland, a vision researcher at Cornell who has done work on chicks, inducing myopia by applying minus lenses to their eyes. Denis found the I SEE home page, and sent a copy of the letter to me. I now pass it on to I SEE... ------------------------------------------------- Mr. Howard C. Howland W201 Seeley G Mudd Hall Cornell University Ithaca NY 14853 USA Via: Ethernet hch2@cornell.edu Dear Sir : About your ongoing research on the development of the eye. It was with a great deal of interest that I read an article in Discover magazine in the October 1995 Issue concerning your ongoing work on the development of the eye and its relation to bio feedback. I come from a family of 7 where both the parents are with normal vision and where all 5 of the children were nearsigthed and read a lot. I graduated from Queen's University in 1977 with a first class degree in Civil engineering and also graduated with courses in Genetics. This interestingly enough, gave me a background in evolution, genetics, mechanics and physics. I had believed since I was about 15 that their was a causal link between eye development and Myopia and indeed was immensely interested when I read an article supporting that position. At first ( around 1972) I had hopes that by carefully managing the use of my eyes I would be able to reverse the myopia about (- 1 dioptre ) . This I theorized would be done by using reading glasses to simulate an at rest condition. I experimented with various lenses used while reading and studying ranging from +1.5 dioptre to + 2.5 dioptre, all the while thinking of and studying the structure of the eye to see if I could gain a better understanding of the process. Although my eyes never improved they did not get any worse from a refractory point of view. It was relatively easy to experiment since my eyes did not have any astigmatism. I could therefore purchase glasses at the drug store for reading . I also talked my eye doctor into prescribing lglasses at -.75 dioptre that I would wear while attending classes. This did not do anything even though I played around with this concept for years. One thing that it did do was make me more aware of the minor changes which seemed to occur with my eyes due to atmospheric pressure, influence of alcohol and marijuana use, reading, driving, smoking. After I graduated 1977, I married in 1978 and had a family. My wife was a graduate nurse at University of Toronto and was mildly myopic with -.50 in the right eye and -.75 in the left eye. She did not wear her glasses which probably helped to prevent her vision from changing further. We have two daughters aged 15 and 11 both of whom have eyes that are almost perfect as far as spherical corrections are concerned they are both at 0 dioptre +/- .25. From the time that they were young I have encouraged good eye habits in both of them, ie don't sit too close to the TV , Head up when they walk Etc. When we moved to Timmins in 1987 we went to see an eye doctor by the name of Al MacIvor. He was talked into prescribing reading glasses for both of the kids . My reasoning was that since my eyes had stabilized at about -1.00 to -1.25 dioptre that reading glasses of +1.25 dioptre would probably be about the right level for them. A l said that both of the girls had very little reserve in their eyes and would both be myopic by the time they were 15. He looked at me with a bit of a glazed look in his eyes when I started talking to him about my ideas and probably thought I was talking about pyramid glasses etc. I insisted that the prescription not contain any cylindrical corrections. This now 1995 and the girls are fine. Their eyes basically have not changed in 8 years. They both are avid readers and computer users and they both wear their reading glasses. In a further elaboration to the above I have noticed that in the workplace where I work there is a very high incidence of occupational myopia in office workers. Truck drivers never develop myopia . Similar to your observations about the pilots who have good vision prior to their studies and poor vision after. I am not looking for anything from this. Just trying to help where I can and enjoying the chance to finally be able to transmit my information to someone who takes it seriously and has the professional credentials and interest in pursuing it further . I attach a brief synpsis of my ideas to you: A THEORY ABOUT EYE DEVELOPMENT When a child is born his eyes are not fully developed. In a complex interaction between the ocular structures the child inherited and the environment the eyes develop over time. At this point we may well ask ourselves why nature would not see fit to endow a child with a perfect eye . Would it not be easier to create a perfect eye and not one that requires and goes through all kinds of changes in refractive powers as it develops. The answer is not at all obvious but may be deduced using plain common sense combined with a bit of basic knowledge about biology, genetics and engineering. It is not clear that in an evolutionary sense it is important to have good vision either. According to biological laws a child inherits all of his physical traits from his parents. In the case of the eye these traits could be for instance lens power, eyeball size, elasticity and tendencies towards certain patterns of eye development which we will get into later. One can see that for instance the inherited/genetic coupling of a small eye with a large eye ( a genetic simplification) could lead to problems in the sense that a lens adapted to a small eye would focus improperly when placed in a large eye. However nature in her wisdom has evolved an eye that usually develops normally unless of course the usual pattern of development is interfered with as we shall see later. The easiest way for this mechanism to work would be to have the eye interact with the environment into which it sees. By a simple bio-feed back mechanism( which by the way does not always work perfectly) the eye strives to adjust its accommodative/resolving/brain matching powers to develop a normal seeing ability. In order to act properly this feedback system has to act slowly in order not to overreact to short-term situations. It acts in such a fashion as to create a normal eye not in our modern environment but in an environment as it existed years ago before the advent of modern television, newspapers, and the avalanche of printed materials which are before us to-day. The importance of good vision was a powerful evolutionary force in the days before corrective measures were common or even invented. Such a powerful force would have evolved systems which in some cases are not that beneficial in the different modern visual environment. And yet it is true that in many situations then as well as now it is a handicap in the Darwinian sense to be endowed with good vision. The biofeedback system would act more rapidly at birth and gradually slows down in later years. In fact if this feedback developmental system is so important to the proper development of the eye that should the eye not interact properly with its environment before the age of six adequate development may never occur. This is the predominant reason why eye specialists recommend patching the strong eye in cases of lazy eye- to force the lazy eye to interact with its environment. How does this interaction with the environment take place ? The answer relates to many things - nerves , receptors at the back of the eye, eye drainage/ elasticity/accommodative powers/size etc. We are concentrating this discussion on the aspect of development which relates to physical eye development in terms of focusing ability and size. Research needs to be done in order to quantitatively pin down all of the relevant parameters. One of the first thing the brain trains the eye to do after birth is to focus on things such that a clear image is developed by a proper focus on the retina. Basically when the eye sees something it tries to focus on it. If the object is out of range of the eyes focusing/acuity ability makes the person see only a blur as the brain can only make limited sense out of the nervous impulses sent back to the brain. In the normal eye the focusing muscles which act on the lens are at rest when the eye is focused on objects at infinity. Any objects which are looked at any closer than 20' involve the use of these focusing muscles and objects which are very close to the eye involve a greater use of these muscles. The physical act of focusing causes a change in the eye's internal drainage system. This is the system which balances incoming fluid with outgoing fluid. The greater the strain on the focusing muscles of the eye the greater the constriction on the canals of Schlemm which are located at the juncture of the iris and cornea. It is not clear if the constriction amount is related to the degree of focus required or in genral terms to the use or non use of the focusing muscles. It may take quite a period of time for pressure to build up or decrease. As the pressure builds up in an eye the natural elasticity of the eye allows the eye to stretch and actually expand like a balloon but on a small scale. Over time and with this constant interaction between internal eye pressure and elasticity of the eye the eye may/will undergo a permanent minute change in size and shape which is enough to alter the refraction distance from the retina to the lens. The eye can be compared to a kitchen sink : There is a faucet to allow water to run in and a drain to let the water run out. Unlike a sink there is no overflow and excessive pressures in the eye can build up. These effects are very gradual and are usually overlooked. In adults the effects are minimal because the eye loses its elasticity as we get older and because the demands of adult life may require a different useage pattern. In a young child the changes can be most pronounced. Some children are born with one normal eye and one eye in which the drainage system is blocked. In the abnormal eye extreme nearsightedness and blindness eventually result combined with an abnormal increase in eye size. Nature has created this system of natural feedback to allow the eye to develop normally in response to an environment. After children are born , over time their eyes develop normal vision. The responses to the natural feedback are slow in occurring and each person's response would vary minutely from everyone else's. In a normal eye, at rest the light rays would be focused perfectly at the retina when the light rays are coming in from a distance of over 20 feet. The important thing to note is that it does occur and the effects can best be understood by examining the two extreme scenarios which might develop. These scenarios would of course be important in the case of Spherical aberrations only. When a person starts to look at astigmatism and all of the complications that might occur from such a consideration the situation becomes much more complex. Scenario #1: A person's eye is always gazing off into the distance. Nature's feedback system will work towards the eye muscles being completely relaxed when the eye is looking off in the distance. In order to see close the eye will have to actively focus. Scenario # 2 A person's eye is always looking at a book 14 inches away . Nature's feedback system will work towards the eye muscles being completely relaxed when the eye is looking at a book 14 inches away. This will occur through actual structural changes of the eye. When the person involved tries to look farther away things will seem blurry. In young children some of these effects are temporary but as the children get older the effects become more and more permanent. Once the effects before more permanent the eyes will have to wear corrective lenses for myopia since the muscles would already be completely relaxed. A complete understanding of the biofeedback system as it applies to the focusing power of the eye and its variations among individual's would allow trained individuals to interfere with the process and steer the eye's development so that the focusing muscles are at rest when the eye is looking at something far away. The biofeedback system is most active in the young and has a minimal effect after the early twenties. It is not meant as a criticism but the present state of the art in eye care does not recognize this biofeedback mechanism and in instances creates a spiralling biofeedback effect leading to extremes in eye development. Nature's biofeedback system does not respond to corrective lenses it responds to the accommodative responses required to focus. Suppose a child likes to play Nintendo and holds his face away from the screen about two feet away. Say that child's eye has responded to this environment and developed a need for a corrective lenses of -1.00 Dioptres. The eye doctor comes along and prescribes a lens of -1.00 Dioptres. The child may goes back to this environment. . If the child plays nintendo but does not wear his glasses then no further harm may result. If the child however wears his glasses to play nintendo then Lo and behold the first thing you know the child's eye develops a need for another - 1 Dioptres in addition to his initial 1 Dioptres lenses and so the cycle continues. This cycle is slow and eventually may stop once the child gets a little older. Sometimes to halt this process doctors ( without any real concept of the underlying mechanism )prescribe bifocal lenses to ensure that when the eye is engaged in close activities the eye is at rest. This may apply particularly when the child does a lot of reading. This bypasses the biofeedback system and slows or prevents further adverse changes. Nature has evolved unorthodox ways ways to prevent the biofeedback system from running amuck in young children. Some of these are as follows: Short attention span, eyes get tired quickly, minor astigmatism, dyslexia or inability to read. All of these prevent children from becoming completely absorbed in activities which involve considerable focusing on close objects. The most dangerous activities for children are computer terminals, books, and watching TV from a close distance. These activities all have several things in common: They involve a good deal of strong focusing over extended periods of time and they are all relatively new activities in the evolutionary time scale. In other words eye development has evolved in response to a different set of environmental parameters. It would seem entirely reasonable that proper eye care should recognize nature's Biofeedback system and act accordingly to ensure proper eye development. Articles have been written to indicate that there is strong correlation between Intelligence and nearsightedness. It would be interesting to see what correlation there is between eye habits and nearsightedness taking into account the imposed environmental stresses. It is noted of course that persons with High IQ may have very different eye habits than people with low IQ. In fact the very environments themselves that contribute to high IQ may also contribute to nearsightedness. Such a study would filter out such important factors as: 1)Description of activity. 2) The intensity and duration of the activity. 3) The level of refractive accommodation required by the eye to focus on the surface. 4) The type of rest period and the duration of the rest periods for the eyes. 5) The time of day various activities are engaged in and what releases might occur. 6) Initial state of the eye. 7) Age. 8) The distance from the eye to the surface being focused on. Example # 1 Reading: Scenario #1: 1)Description of activity. Reading 2) The intensity and duration of the activity. 1/2 hour at a time 3) The level of accommodation required +1.25 Dioptres 4) The type of rest period and the duration. 10 hours of sleep 5) The time of day . before bed 6) Initial state of the eye. normal 0 Dioptres correction Left and right 7) Age. Ten years old 8) The distance from the eye to the surface. 14 inches. Scenario #2: 1)Description of activity. Reading 2) The intensity and duration of the activity. 1/2 hour at a time 3) The level of accommodation required 0 Dioptres no glasses 4) The type of rest period and the duration. 10 hours of sleep 5) The time of day . before bed 6) Initial state of the eye. nearsighted -1.25 Dioptres correction Left and right 7) Age. Ten years old 8) The distance from the eye to the surface. 14 inches. Note the difference in the two scenarios. In the first example the eye is normal. In the second example the eye is nearsighted but the child does not wear corrective lenses and so his eyes do not need to engage in any refractive corrections. Example # 2 watching TV: Scenario #1: 1)Description of activity. Watching TV 2) The intensity and duration of the activity. 2 hours at a time 3) The level of accommodation required +.10 Dioptres 4) The type of rest period and the duration. 10 hours of sleep 5) The time of day . before bed 6) Initial state of the eye. normal 0 Dioptres correction Left and right 7) Age. Ten years old 8) The distance from the eye to the surface. 16 feet. Scenario #2: 1)Description of activity. Watching TV 2) The intensity and duration of the activity. 2 hours at a time 3) The level of accommodation required +1.00 Dioptres 4) The type of rest period and the duration. 10 hours of sleep 5) The time of day . before bed 6) Initial state of the eye. normal 0 Dioptres correction Left and right 7) Age. Ten years old 8) The distance from the eye to the surface. 3 feet. Not the distinct difference in the refractive accommodation required between the two scenarios. In Scenario # 2 the child is more likely to develop nearsightedness than in scenario # 1. Example # 3 walking : Scenario #1: 1)Description of activity. Walking- eyes looking in the distance 2) The intensity and duration of the activity. 1 hours at a time 3) The level of accommodation required +0 Dioptres 4) The type of rest period and the duration. no rest period required eye is at rest 5) The time of day . evening 6) Initial state of the eye. normal 0 Dioptres correction Left and right 7) Age. Ten years old 8) The distance from the eye to the surface. 20+ Scenario #2: 1)Description of activity. Walking- eyes looking at the ground 2) The intensity and duration of the activity. 1 hours at a time 3) The level of accommodation required +.75 Dioptres 4) The type of rest period and the duration. brief rest periods upwards glances 5) The time of day . evening 6) Initial state of the eye. normal 0 Dioptres correction Left and right 7) Age. Ten years old 8) The distance from the eye to the surface. 4 to 5 feet Not the distinct difference in the refractive accommodation required between the two scenarios. In Scenario # 2 the child is more likely to develop nearsightedness than in scenario # 1. Exercise: Many practitioners believe that a person should exercise their eyes periodically to reduce the incidence of eye deterioration and so on that develops. I have never seen a mechanism explained for why this exercise may be beneficial. The Elasticity, fluid balance ideas would suggest that so called exercise of the eye would be important since it would prevent the fluid balances in the eye from being out of balance for extended periods of time. So would an attention deficit disorder be beneficial in the young to prevent the eye focusing too long at close things and adversely triggering the biofeedback mechanisms. Your patience in reading the above is appreciated. Should you wish to confirm receipt of this letter I would appreciate it . Sincerely Yours Denis Alarie , P. Eng. 229 Rosemary Crescent Timmins Ontario Canada, P4P-7C2 djalarie@vianet.on.ca =========================================================================