The physical factor in conical cornea / by John Tweedy.

  • Tweedy, John, 1849-1924.
Date:
[1892?]
Catalogue details

Licence: Public Domain Mark

Credit: The physical factor in conical cornea / by John Tweedy. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    / Reprinted from Vol. XII of the ‘ Ophthalmologieal Society’s Transact^ The ^physical factor in conical cornea] By John Tweedy. At a recent meeting of the Society, in the course of a discussion on a case of conical cornea, I ventured incident- ally to offer an explanation of the physical cause of this disorder. Though I have during the past ten to twelve years often referred to this explanation at University College and at the Moorfields Hospital, and described it in an article on Conical Cornea^’ in ^ Heath’s Surgical Dictionary,^ published about six years ago, it seemed novel to most of those present. T have been asked to make it the subject of a special communication. In doing so I wish it to be understood that I do not intend to con- sider the various aetiological conditions of conical cornea, but only that which I regard as the constant physical basis upon which all other causes and conditions operate and depend. On referring to the text-books in common use I find the various causes given of conical cornea may be arranged into four classes, viz. (1) increased intra-ocular pressure (Graefe, de Wecker and Landolt, 1883) ; (2) malnutri- tion and atrophy of the centre of the cornea (Lawson, Nettleship, Swanzy, Berry, Noyes, Meyer, and others) ; (3) diminution of the resistance of the cornea (Soelberg Wells, de Wecker and Masselon, 1889) ; (4) inhe- rent weakness, and deficient firmness and thickness of the cornea (Macnamara and H. W. Williams, of Boston). All these explanations are necessarily only conjectural and hypothetical, as is also the explanation I propose. Now it has been laid down by the logicians that the true test of an hypothesis is its conformity and agreement with observed facts. Tried by this gauge, it seems to me that only the fourth of the above hypotheses is tenable. I take it that it will generally be allowed that though there may be in a few cases an increase of intra-ocular pressure.