Copy 1

The economy of the eyes: : Precepts for the improvement and preservation of the sight. Plain rules which will enable all to judge exactly when, and what spectacles are best calculated for their eyes Observations on opera glasses and theatres, and an account of the pancratic magnifier, for double stars, and day telescopes. / By William Kitchiner, M.D.

  • Kitchiner, William, 1775?-1827.
Date:
1824
Catalogue details

Licence: Public Domain Mark

Credit: The economy of the eyes: : Precepts for the improvement and preservation of the sight. Plain rules which will enable all to judge exactly when, and what spectacles are best calculated for their eyes Observations on opera glasses and theatres, and an account of the pancratic magnifier, for double stars, and day telescopes. / By William Kitchiner, M.D. Source: Wellcome Collection.

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    surface, in so much that Dr. Petir found that the Crystalline of a man 81 years old, re- -sembled two pieces of beautiful Yellow Am- ber.” — Dr. PorTERFIELD on the Eye, 1759, 8vo. vol. 1. p. 229. The commencement and progress of the deterio- ration of the Sight, depends upon the health of the individual— upon the original formation of the Eye, —- and upon how it has been used. Some Eyes, at 30 years of Age, require the aid of art as much as others do at 50, — while the Sight of some persons continues almost as perfect at 50 as it was at 30. The average period of the Eyes requiring Spec-' tacles to read with, 1s about the 45th year. | Nature has decreed, that soon after our 40th year, the most perfect Eyes shall no longer retain the privilege she gives to Youth, of the power of adjusting them to See dis- tinctly at different distances: —this range of accommodation diminishes gradually, till it fails almost entirely— those to whom it is given to continue to discern distant things distinctly, — no longer see those which are near distinctly. Very few persons past the age of 40 can seé' quite so well by Candle-light, as they could