THE ILLUSTRATED

OPTICAL MANUAL

OR

HANDBOOK OF INSTRUCTIONS

FOR THE GUIDANCE OF SURGEONS IN
TESTING QUALITY AND RANGE OF VISION, AND

IN DISTINGUISHING AND DEALING WITH

OPTICAL DEFECTS IN GENERAL.

BY

SURGEON-GENERAL SIR T. LONGMORE, C.B., F.R.C.S.

HONORARY SURGEON TO THE QUEEN;

PROFESSOR OF MILITARY SURGERY AT THE ARMY MEDICAL SCHOOL;

OFFICER OF THE LEGION OF HONOUR;

ASSOCIATE OF THE SOCIETY OF SURGERY OF PARIS ;
CORRESPONDING MEMBER OF THE ACADEMY OF MEDICINE OF FRANCE;

ETC.

FOURTH EDITION,

ENLARGED, AND ILLUSTRATED BY 74 FIGURES FROM DRAWINGS AND DIAGRAMS

BY INSPECTOR-GENERAL DR. MACDONALD, R.N., F.R.S., &c.

BOSTON MEDICAL LIBRARY
IN THE

FRANCIS A. COUNTWAY
LIBRARY OF MEDICINE

LONDON: ✔

LONGMANS, GREEN, AND CO.

AND NEW YORK: 15 EAST 16th STREET.

1888.

All rights reserved.

PREFACE

ΤΟ

THE FOURTH EDITION.

I HAVE endeavoured to make the present edition of the Optical Manual as complete a guide as possible to the diagnosis and management of optical defects, in the hope that it may prove useful as a text-book on the subject for civil as well as for military surgeons. In the former editions the necessities of military practice were almost exclusively kept in view, but in the present revised and illustrated edition, while bringing the text up to date in respect to the visual requirements and regulations of the military, naval, and other public services of Great Britain and India, I have added very materially to the work in order to try, in addition, to meet the wants of general practice. The explanations given in the several chapters into which the book is divided are expressed in as concise and simple terms as appeared to me compatible with a sufficient elucidation of the matters treated on in them, having regard to the needs of those who have not previously given particular attention to the branch of ophthalmic practice with which the work deals, and not forgetting the little time which, as a rule, is at the disposal of practitioners for the study of any special subjects beyond those which the demands of ordinary practice render essential. I have found it convenient to reprint a portion of the Preface to the third edition of this Manual, in order to show the aim and scope of those parts of the work which especially bear on optical practice in the public services. The advantages that are afforded by the illustrations, which appear for the first time in this edition, and, with the single exception of fig. 65, are taken from original drawings furnished by my late colleague, Inspector-General Dr. Macdonald, R.N., F.R.S., will be sufficiently apparent on observation of the illustrations themselves.