On the pathogeny of squint / by Professor Donders ; translated from the German, with a preface, by E. Perceval Wright.

  • Donders, F. C. (Franciscus Cornelis), 1818-1889.
Date:
1864
Catalogue details

Licence: Public Domain Mark

Credit: On the pathogeny of squint / by Professor Donders ; translated from the German, with a preface, by E. Perceval Wright. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    1U eye accommodates itself for its farthest point, brought to a focus before the retina, so that distinct images are formed on the retina only of those objects the rays of which impinge divergently upon the eye. In the myopic eye, when in a state* of rest, the focal point of the dioptric system lies before the retina. 3rd. Hypermetropic eyes are adjusted for convergent rays. In this case parallel rays are brought to a focus behind the retina when the eye is at rest; for in hypermetropic eyes the focal point of the dioptric system lies, when the eye is in a state of rest, behind the^/acillar layer of the retina. The accompanying illustrations, taken from Professor Donders's work On the Anomalies of Accommodation and Refraction of the Eye* will make this classification more easily understood. Figure 1 represents the emme- tropic eye, where the principal focus of the media of the eye at rest falls on the anterior surface of the most external layer of the retina, as at (. In Fig. 2 the principal focus, C, of the eye at rest falls in front of, and in Fig. 3 behind, the retina. In the former case divergent (dotted in the figure), in the latter convergent rays come to a focus on the retina. In the first case, therefore, in the condition of rest, objects are accurately 4 Translated by W. D. Moore, M.D. Now Sydenham Society for 1804. From this excellent translation of a most valuable work I have borrowed freely in writing these pages.