Accommodation in the lensless eye : to what is it due? / by A. Edward Davis.

  • Davis, Achilles Edward, 1866-1941.
Date:
[1895]
Catalogue details

Licence: Public Domain Mark

Credit: Accommodation in the lensless eye : to what is it due? / by A. Edward Davis. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    ment had to be pulled slightly away from the eye in order to get them in perfect focus again. Or, if I had him focus on the black dot first and approximated the images, then let him look in the distance, the images separated slightly and the in- strument had to be pushed toward the eye to get it in perfect focus again. Letting the patient look still in the same direc- tion, but turning the .arc of the instrument in the vertical meridian, and repeating the above experiments, the results were just reversed ; that is, if I approximated the images while he was looking in the distance, then had him focus on the near point, the images separated slightly ; but, if the images were approximated while he focused on the near point, and then looked in the distance, they overlapped about one half diopter. The same changes took place when the lids were held open with a speculum, and even when the ciliary muscle was paralyzed with scopolamine. The changes produced in his cornea must, therefore, have been produced by the action of the external muscles of the eye. 2. It was impossible to detect any change in the depth of the fundus of the eye with the ophthalmoscope when the eye changed from a state of rest from looking in the distance with opposite eye to a state of accommodation. The fundus of the eye was normal, with the media perfectly clear. 3. The shape of the pupil is an irregular oval, from the iridectomy, and free from membrane, except a very narrow margin at the edge, though, when I reported him to the New York Ophthalmologi- cal Society, and before I had made a critical examination, I had thought there was more membrane present. The trans- verse diameter of his pupil is 3^ mm., the vertical about 7 mm. (see Fig. 1, A). B., Fig. t, shows pupil dilated and some remains of membrane at periphery. FIG. t Case 2. Master W. O. B.,* aged 13. School boy. Dr. Webster saw this patient first in Nov., 1891, when ten years of age, brought to him for double congenital cata- ract. The patient had already had eight discissions done on *This case, a private patient of Dr. Webster's, has been reported by him in a series of cases as: A Case of Congenital Cataract, both Lenses Removed by Operation. Arch. Pediatrics, New York, Nov., 1893, p. 932.