Ocular Physiology Research Articles

Physiologie oculaire clinique.

The author has been interested for the last quarter of a century in ocular physiology, particularly in the field of ocular tension and in the retina and iris. He retired in 1940 from active duty in the Lariboisiere Hospital, of Paris, where he had succeeded Victor Morax and Poulard, and was able to devote the next four or five years to collecting his papers and writing this excellent book. There was a distinct need for it, since no similar textbook was available in French except Nicati's, which is both out of print and out of date. This book is written by and for the practicing ophthalmologist, and physiology is approached with a constant view to the explanation of clinical facts. Reversely, clinical facts are used to support and enlighten physiologic theories. If the book had been written by a pure physiologist, and not by a practicing ophthalmologist interested in physiology,

MECHANISM OF ACCOMMODATION

The Helmholtz 1 theory of accommodation appeared in 1855, and since that time the refutation or substantiation of this hypothesis has concerned students of ocular physiology. The difficulty of observing the interior of the anterior segment without mutilating the eye has permitted the theory to persist in explanations of this ocular function. There are two firmly entrenched schools of thought on the mechanism of accommodation: One supports Helmholtz, and the other favors the Tscherning 2 theory. The two agree that the fundamentals of accommodation are contraction of the ciliary muscle and increased convexity of the crystalline lens but differ on the method by which the former accomplishes the latter. The followers of Helmholtz believe that contraction of the ciliary muscle reduces zonular tension, permitting the elastic capsule of the lens to shape the lens. In opposition, Tscherning's disciples think the force of the ciliary muscle acting through the zonule and

MECHANISM OF ACCOMMODATION

The Helmholtz 1 theory of accommodation appeared in 1855, and since that time the refutation or substantiation of this hypothesis has concerned students of ocular physiology. The difficulty of observing the interior of the anterior segment without mutilating the eye has permitted the theory to persist in explanations of this ocular function. There are two firmly entrenched schools of thought on the mechanism of accommodation: One supports Helmholtz, and the other favors the Tscherning 2 theory. The two agree that the fundamentals of accommodation are contraction of the ciliary muscle and increased convexity of the crystalline lens but differ on the method by which the former accomplishes the latter. The followers of Helmholtz believe that contraction of the ciliary muscle reduces zonular tension, permitting the elastic capsule of the lens to shape the lens. In opposition, Tscherning's disciples think the force of the ciliary muscle acting through the zonule and

Outline of Ocular Refraction.

This is an exceptionally interesting and valuable book, written by one who has evidently had considerable experience in all the practical details of prescribing glasses, from the initial refraction done in the office to the grinding of the lenses and the fitting of frames. The chapter on applied optics deals chiefly with the theory of glasses and contains many tables which are of value and are not often found in less practical books, such as the table giving the values of decentration of cylinders at different axes and that giving the effective powers of different types of lenses. The most stimulating chapter is that on ocular physiology, which is chiefly concerned with the relation of the muscle balance to the static and dynamic refraction. The main thesis of this is that the tonic innervation of the ocular muscles, determined by dissociation tests such as the Maddox rod, is not the

THE PHYSIOLOGY OF CERTAIN OCULOMOTOR PHENOMENA WITH RESPECT TO SOME RECENT THEORIES OF ASTHENOPIA.Read in the Section on Ophthalmology, at the Forty-fifth Annual Meeting of the American Medical Association, held at San Francisco, June 5-8, 1894.

That physiology is the basis of scientific medicine is generally recognized. Medical students are taught that physiologic processes and the known laws governing them, form the foundation of our knowledge of the pathologic conditions with which we have to deal,—a criterion of the value of clinical observation; the base-line from which we are to estimate every real or apparent deviation from the normal functions of the human body. More especially is this true as regards ophthalmology, in many respects the most scientific department of medicine. Nevertheless, there have appeared in our ophthalmic literature, during the past five years, a number of theories which, when critically analyzed have little or no substantial scientific foundation. While it is true that our knowledge of ocular physiology is incomplete, yet those physicians whose educational training has disciplined their minds to act logically; to habitually analyze the evidence presented; to refer phenomena if possible to