An inquiry into the action and uses of atropia / by Alex. Fleming.

  • Fleming, Alex
Date:
[1863]
Catalogue details

Licence: Public Domain Mark

Credit: An inquiry into the action and uses of atropia / by Alex. Fleming. Source: Wellcome Collection.

    2/6 page 2
    healthy fellow. This has been generally referred to diminished sen¬ sibility of the retina; but my observations (made in 1856)1 prove beyond doubt that it is altogether due to the width of the pupil, and the loss of power in the eye to adapt itself to near vision. That it is in part due to the large pupil admitting too many and too divergent rays is shown by the vision being improved in a dusky light, and in looking through a hole—smaller than the dilated pupil—in a black card held close to the eye. But it is especially due to the inability of the eye to adjust itself to near vision. The defective sight is more marked the closer the object, and diminishes with distance. As the influence of the atropia is wearing off, while yet the difference between the two eyes is decided with a near object, scarcely any difference is perceived with a distant one. The type of a book appears smaller to the atropised eye than to its fellow at the same distance. Hence vision with both eyes conjointly is confused, and, for reading, the dilated eye must be covered. The solution of strength indicated above (1 grain to 10 drachms) serves well for ordinary use to dilate the pupil. To obtain the deeper effects upon the eye a stronger solution of 3 grains to 10 drachms should be employed. This reduces the iris to a mere line, and completely impairs the sight. The blindness continues from one to four days, and subsides some time before the pupil regains its normal size. The eye thus atropised bears the sun’s rays better than its fellow, which seems to show that the iris itself is, in part at least, the seat of the incident impressions which contract the pupil and protect the retina. When this stronger solution is applied carefully to the outer side of the eye, the adjoining or outer part of the circle of the iris dilates some time before that of the inner side. This fact points to a strictly local action. Atropia does not redden the conjunctiva. It has no action on the iris of the dead eye. Among other observations which I have made on the atropised eye, I found that in adapting the telescope to it the instrument requires to be lengthened, as compared with the other eye; but the focus having been adjusted, vision is perfectly clear, although the eye, without the help of the telescope, be absolutely blind. Indeed, several of those who made trials with the telescope maintained that they saw better with the atropised eye—a fact deserving of the astronomer’s attention. In using the microscope with the atropised eye, the object has to be removed a little farther from the instru¬ ment; but the focus having been adjusted, vision is as good as with the healthy eye. I was able to make the smaller image of the atropised eye, as compared with the other, very manifest by means of the reflecting stereoscope. Mode of Action.—The atropised eye is altered as if for distant 1 Medical Times and Gazette, 1857, vol. i, pp. 270 and 345.
    digitised image 1
    digitised image 2
    digitised image 3