Schweigger on Squint A Monograph by Dr. C. Schweigger   By: C. Schweigger

A MONOGRAPH

BY

DR. C. SCHWEIGGER,

PROFESSOR OF OPHTHALMOLOGY AT THE UNIVERSITY OF BERLIN

TRANSLATED FROM THE GERMAN

BY

EMILY J. ROBINSON

EDITED BY

GUSTAVUS HARTRIDGE, F.R.C.S.

LONDON J. & A. CHURCHILL 11, NEW BURLINGTON STREET 1887

TRANSLATOR'S PREFACE

The subject of Squint is so interesting that we venture to think an English rendering of this exhaustive monograph will be acceptable to many ophthalmic surgeons and students.

While adhering as far as possible to the spirit and style of the original we have not hesitated here and there to give a somewhat free translation. This has been partly necessitated by the difficulty of finding an exact equivalent in English for all the terms used in the original text.

In the German Edition the old system of inches is used. We have (with the consent of the author) altered these to the dioptric system.

E. J. R. G. H.

PREFACE

Amicus Plato, amicus Socrates, magis amica veritas. May my friends and colleagues, whose views differ from mine, read the following observations without prejudice. A fact, which does not agree with the system, is generally worth more than theory, still it is very difficult for even the most important fact to find recognition if it contradicts received opinion. For theories and dogmas are narcotics, which are necessary to men; some flatter themselves by composing them, while others content themselves by satisfying their own craving for a creed. Reasonably applied, they may be useful, but the boundary line is only too easily over stepped. It is the task of science to observe also whether theories correspond with the progress of facts. The present reigning theory on strabismus will have to submit to various limitations; on the other hand, we are ready to leave to the scholastic science of medicine and its followers certain dogmas which remain unproved and which have nothing but the fact of their existence to recommend them.

The small compass of the following treatise proves that it was not intended to exhaust the rich literature on the subject; I have only referred to the same where it appeared to me necessary for the interest of the work in hand.

Above all, it has been my endeavour to treat the subject of this treatise (which occurs so frequently in practice) in a way intelligible to every physician, at the same time, however, to bring sufficiently into notice those facts and views which are of value to my special colleagues.

C. SCHWEIGGER.

BERLIN.

INDEX TO CONTENTS.

INTRODUCTION. PAGES

Ordinary use of the word squint and its meaning. Apparent squint. Paralytic and typical squint. Law of association. Squint angle and linear measure of the deviation. Permanent, periodic, latent, monolateral, and alternating squint 1 8

CONVERGENT SQUINT.

Donders' theory and the test of it by statistics. Limits of error in the subjective and objective determination of hypermetropia. Statistics of convergent squint. Hypermetropia and favouring circumstances. Participation of the accommodation. Preponderance of the interni and insufficiency of the externi. Nebulæ of the cornea. 9 26

PERIODIC CONVERGENT SQUINT.

In myopia, emmetropia, and hypermetropia. Intermittent squint. Accommodative squint 27 35

CONVERGENT SQUINT IN MYOPIA 36 38

SQUINT FROM PARALYSIS OF THE ABDUCENS 39 40

HYSTERICAL SQUINT 41 43

DIVERGENT SQUINT.

Absolute and relative divergence. Statistics of divergent squint. Causes 44 49