On paralytic, neuralgic, and other nervous diseases of the eye / [Arthur Jacob].

  • Jacob, Arthur, 1790-1874
Date:
[1841]
Catalogue details

Licence: Public Domain Mark

Credit: On paralytic, neuralgic, and other nervous diseases of the eye / [Arthur Jacob]. Source: Wellcome Collection.

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    affects the third nerve, extending to the optic, because it cannot be supposed that the integrity of the third nerve is essential to the sensibility of the retina. When dilatation of the pupil accompanies this para¬ lysis, vision is as defective as it is when the pupil is dilated by belladonna. There is double vision and squint when the patient looks in one direction, none while be looks in the opposite : for this reason. Sup¬ pose the right eye affected: when he looks to the left side, the adductor muscle cannot act, being para¬ lyzed ; while the abductor of the left turns the eye in that direction. The axis of the right eye, therefore, no longer is parallel to that of the left, and conse¬ quently, the images of objects are not formed on cor¬ responding points of the retina, and, therefore, two objects are seen, or there is double vision. But when the patient looks as directly forward as he can, or in any degree to the right, the axes preserve their parallelism by means of the abductor of the right eye, which is still active, being supplied by the. sixth nerve, and vision is single. To ascertain all this, the upper lid must of course be sustained by the finger, while the experiment is made. That this is, in many cases, a paralytic stroke, can¬ not be denied, especially when it occurs suddenly, and not preceded or accompanied by other symptoms of disease of the brain, its membranes, or vessels. I have seen it, as in the case of the optic nerve, the first paralytic seizure, and followed by hemiplegia and other formidable forms of apoplexy. The practi¬ tioner is, therefore, bound to view it very seriously. It is true that patients recover from it more frequently than they do from paralytic strokes affecting the optic nerve, and producing blindness ; but that should not throw us off our guard. Mr. Mackenzie, in his valu¬ able work on diseases of the eye, speaks of this form of paralysis as sometimes arising from cold, and being of a rheumatic character. This is certainly true: but, then, what is the precise effect of this rheumatic inflammation from cold? Where is the exact seat of the mischief? Not, I presume, in the muscles them¬ selves ; for, in that case, the abductor could scarcely escape ; neither could we have such complete paralysis from rheumatic inflammation, without a correspond¬ ing degree of pain and tumefaction. If it be from rheumatic inflammation, caused by exposure to cold.