On unusual mobility of the iris, his own case / by John Paxton ... with remarks by Dr. Allen Thomson, in a letter to the editor. Further remarks on Dr. Paxton's case, with observations on the structure and action of the parts concerned in the focal adjustment of the eye / by Allen Thomson.

  • Paxton, John, M.D.
Date:
[1856?]
Catalogue details

Licence: Public Domain Mark

Credit: On unusual mobility of the iris, his own case / by John Paxton ... with remarks by Dr. Allen Thomson, in a letter to the editor. Further remarks on Dr. Paxton's case, with observations on the structure and action of the parts concerned in the focal adjustment of the eye / by Allen Thomson. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    possess voluntary power over the motion of the iris, because 1 can produce either contraction or dilatation, with the accompanying state of vision, while looking at the same object, whether that be the point of a pen 1 may be writing with, or a tree a mile distant. 4th. Whether, in first waking from sleep, I require any effort for adjustment for ordinary vision?—In waking from sleep, ] am conscious of having the eves always adjusted for distinct vision. 5th. Whether the eye is disposed spontaneously to fall out of adjustment, and to what extent it is so ? Whether the state of the general health has any influence on the state of the eyes?—The state of health has no effect on the eyes. They are not disposed to fall out of adjustment when I am in an active state of body. They sometimes do so, however, while staring in vacancy, as in a state of reverie; but in that case, and with the eyes not fixed on any object, they can be adjusted instantly by the slight effort before mentioned. 6th. Whether I had tried the effect of belladonna on the eye ? —The inconvenience to me in my professional avocations which would attend this experiment, has always deterred me from trying the effects of any medicine having the power of inducing mydriasis. 7th. Whether the effect of convex and concave glasses is the same in myself as in other persons, and, more especially, what is the effect of using a convex lens wrhen the eye has fallen out of adjustment? If possible, to ascertain what strength of lens is equivalent to the ordinary power of restoring the adjustment.— The effect of convex and concave glasses is the same in my own as on eyes in the normal condition. \\ ithin the last three years I have been under the necessity of using very slightlv convex spectacles; prior to this my sight had been excellent. When the pupil is dilated, and the vision in its indistinct state, concave glasses increase the defect; convex glasses, on the other hand, remedy it in proportion as their focal distance is the shorter, fill, with a lens of the focal length of sixteen inches, the convexity compen- sates, as nearly as possible, for the maladjustment; more convex than this, they cause indistinct vision in proportion as their focal distance is decreased. ] have only further to add, that since these questions were put by Professor Thomson, 1 find that when I close one eye by pressing down the eyelid with the finger, 1 retain the power of producing these conditions of vision with the other; but when it is shut without the assistance of the finger, I find that 1 lose this abnormal control over the iris altogether.* * Since writing the above notes, my attention hnRbeen called to a very similar case occurring in the person of and related by Dr. Roget in a letter to Mr. Travers, and bv him published in his works on diseases of the eye, (London, 1820,) at page 72.