OTHER LINKS
WEBSITES BY MYOPIA PREVENTION ACTIVISTS
EYEGLASSES AND CONTACT LENS SUPPLIERS
A DEPENDABLE SOURCE FOR CONTACT LENSES IS www.1800contacts.com.
OTHER MYOPIA PREVENTION INFORMATION
LETTER TO THE NATIONAL INSTITUTE OF MEDICINE
Dr. Elena Nightingale
Director, Preventive Medicine
National Institute of Medicine
2101 Constitution Avenue
Washington, DC 20418
November 9, 1977
Dear Dr. Nightingale:
The enclosed two reports are a statement concerning the prevention of myopia - the one within the profession by Francis Young ("The Development and Control of Myopia in Human and Subhuman Primates", Contacto 19, p.16) and the other a discussion at an elementary level by myself, a physicist.
The point is that myopia can be prevented in essentially all cases by appropriate management of the focal environment. It requires measuring each year the mean relaxed-state focal length of the eye during child development. When this refractive error is zero, one then uses any of the proven methods of preventing or inhibiting the progression of myopia. If the child does not progress beyond refractive error of zero, the child retains a refractive error of zero. This is called 20/20 vision. The simplest, easiest and least drastic means of inhibiting further progression of myopia is the use of positive lens glasses, +1.5 to +2 diopters for all reading and protracted close work.
The eye progressively adapts to its mean focal environment starting from the focal properties of all new-born babies, +4 to +6 diopters, to progressively more near-sighted each year, usually -1/2 to -1 diopters per year. Then at the age of 6 to 10 years the mean relaxed state focus, refractive error, passes through zero. The normal environment of distance and no reading means that when the refractive error becomes zero, the time average contraction of the ciliary muscle becomes small and further adaptation to the focal environment ceases. This way the normal development leads to and maintains zero refractive error. The unnatural environment of reading causes myopia by extending the progressive adaptation to the unnatural near point focal environment of the book. The logical and least disruptive action is to change the effective focal properties of the book to infinity. Elementary optics indicates the use of a positive lens to accomplish this.
Conventional ophthalmology has traditionally treated the symptoms, not the cause. We wait until the individual has adapted to the near-point focal environment. This adaptation is called myopia. We then fit the person with a negative lens which endows the distant object with the focal properties of a close-by one. If the individual then uses the negative lens glasses for reading, a further adaptation to a still closer point focus is made and the grotesque result is called progressive myopia. The optometry profession has traditionally defended itself on the basis that all focal properties of the eye are predetermined genetically. One can equally well explain the observed very large genetic correlation function and myopia with a variable genetic endowment affecting the focal adaptation mechanism.
Francis Young has, in my opinion, demonstrated conclusive scientific evidence for the existence and for the mechanism of this adaptive mechanism - namely the small, progressive and irreversible lengthening of the eyeball in response to the fluid pressure increase caused by a contraction of the ciliary muscle.
On very general grounds (information theory) one can argue that there has to exist some such mechanism: Genetic endowment generally encompasses a physiological dispersion of roughly 10 percent limited by cellular growth dispersion, i.e., cell growth is a noisy system. 20/20 vision on the other hand requires an accuracy of the composite structure of the normal eye of 1 in 5000, i.e., 2 x 10(-4). The progression from a genetic noise figure of 10% to a functional accuracy of less than 1/10% requires a developmental feed-back mechanism. This mechanism is well documented by the work of Francis Young.
The alleviation of myopia is a worthwhile goal. At the very least, an open choice and recognized knowledge of the causes and prevention would seem to me to be an outstanding objective in preventive medicine.
Stirling A. Colgate, Ph.D.
Theoretical Physics Division
MS-210, Los Alamos Scientific Laboratory
Los Alamos, New Mexico 87545
Editor's Note: Stirling Colgate is an internationally-known physicist. Other than send him a courtesy reply, nothing was ever done about his request by the NIM.