On conical cornea / by James H. Pickford.

Date:
1844
Catalogue details

Licence: Public Domain Mark

Credit: On conical cornea / by James H. Pickford. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    rately dilated pupil, about the substance of writing paper, with a marginal thickening, which gradually increased towards the sclerotic. Mr. Middlemore says, I have had one opportunity of ex- amining, after death, the state of the cornea in a person who was affected with conical cornea in an extreme degree, and in that instance its laminae were less moveable upon each other, its cir- cumference was of a natural and ordinary degree of thickness, but its apex was much thinner than usual, and rendered opaque on its exterior only, for its neural surface, even at the apex, was perfectly transparent; in other respects it did not appear to have undergone any change, unless I mention that alteration in the evenness and equality of its surface discovered by Dr. Brewster, but which was not visible to the naked eye.* In corroboration of these statements I may adduce the case of a gentleman, the subject of this disease, mentioned by Mr. Wardrop,t in whom the cornea burst from a blow received upon the eye. Some believe that the aqueous humour, being secreted in greater quantity than usual, distending the chambers, has the power of thrusting forward, as it were, the centre of the cornea, by a slow degree of stretching.^ I would ask, were this last hypothesis correct, why should the cornea assume a conical form ? It is easy to understand how increase of the aqueous humour may distend, attenuate, and in- flame the cornea, and enlarge its diameter, dilate the pupil, and impair the mobility of the iris ; occasion a sense of fullness and tension in the eye, and give rise to headach or circumorbital pain, none of which symptoms, however, attend conical cornea; but it is not so easy to comprehend why it should tend to the • Treatise on the Diseases of the Eye and its Appendages, by Richard Middle- ■e, M. R. C. S., vol. i. p. 532, note. London, 1835. I Op. cit. t Mr. Lyall, Op, cit. pp. 10, 11.