Eyes and Spectacles (Classic Reprint) - Tapa blanda

Reseña del editor

Excerpt from Eyes and Spectacles

An attempt has been made in the accompanying book to bring together the most important points about spectacles. In the modern science of spectacles the chief importance must be laid upon vision with moving eyes (looking about); it was therefore necessary to consider in the first place the eye itself, and also perspective as a form of perception by means of which the arrangement in space of the outer world became manifest to the observer. This is dealt with by the introduction of the perspective bundle of rays with its apex at the centre of rotation of the eye, and is further more clearly explained and illustrated by means of an assumed - generally plane - projection surface.

The second and most important section of the book deals with spectacle lenses, and in this the two problems which are so important in the modern theory of spectacles are dealt with, namely, the increased clearness of vision of ametropic eyes and the alteration of direction of the object perceived. In the single glass the increased clearness of vision is the most important, and this is followed through the different forms of anastigmatic (axially symmetrical), prismatic, and astigmatic lenses, in so far as the exactly reproducing lenses and systems bear upon this problem. In dealing with spectacles for the two eyes the alteration in direction is shown to be of considerable importance.

About the Publisher

Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com

This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.