On the mydriasis produced by the local application of cocaine to the eye / by Walter H. Jessop.

  • Walter Jessop
Date:
[1885]
Catalogue details

Licence: Public Domain Mark

Credit: On the mydriasis produced by the local application of cocaine to the eye / by Walter H. Jessop. 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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    The mydriasis is quickly attained and very large, and differs also from atropioe in the pupil acting always to light and accommoda- tion. When the mydriasis is extreme, viz., 10 mm., the movement to light is very slight, and the initial contraction can only be seen by magni- fying the pupil by the observer's putting on a pair of + 5D spectacles. The slight contraction is immediately followed by a recoil which almost induces the belief that a dilatation has taken place. The continuance of the myd]'iasis is comparatively short, the pupil attaining its normal size in from twelve to twenty-four hours. By drying the conjunctiva and cornea and placing the cocaine carefully on a limited part, the dilatation of the pupil will at first only take place at that spot, thus rendering the pupil irregularly dilated, and showing the limited action of the drug. The following cases show the main points in the mydriasis of cocaine, and that the stronger the solution the quicker the initial and ad maximum dilatation. I. H. C, 15. Pupils 6J mm. ; cocaine 4 per cent, on right eye at 2.5 P.M. ; at 2.25 p.m. pupil 10 mm., not further increased. The pupil had resumed its normal size twelve hours afterwards. II. W. H., 30. Pupils 5 mm., cocaine 20 per cent, in left eye; in seventeen minutes pupil 8 mm., and other instillations did not increase its size. Pupil regained its normal size ten hours afterwards. III. E. W., 31. Pupils 5 mm., at 11.20 cocaine 2 per cent., at 11.30 cocaine 2 per cent., and at 11.50 pupils 8*5 mm. Fourteen hours afterwards pupil normal size. In rabbits the mydriasis induced by cocaine is, as a rule, very large, and in two cases I could not make out any action to light, but in both the pupil was 11*5 mm.; and the reason probably was the great stretching of the sphincter muscle of the pupil incapacitating its action; mydriasis was induced by conjunctival instillation, and also by ijijection into the anterior chamber. Experivient II.—Cocaine and Atropine. In cases of full cocaine mydriasis the application of atropine had no effect on the size of the pupil, but stopped its action to light and accommodation. F. M., 25. Pupils 5*5 mm.; two instillations of cocaine 2 per cent, in right eye; pnpil 9'5, acting to light and accommodation; atrop. sulph. ^ grain, no increase in size of pupil, although atropine put in three times, but the pupil did not act to light and accommodation. Ua^perinient III.—Atropine and Cocaine. On adding cocaine to an eye fully under the influence of atropine.