Extra-papillary colobomata / by G. Lindsay Johnson.

  • Johnson, G. Lindsay (George Lindsay), 1853-1943.
Date:
[1890]
Catalogue details

Licence: Public Domain Mark

Credit: Extra-papillary colobomata / by G. Lindsay Johnson. 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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    due to a rotation of the eyeball, and a consequent displace- ment of the foetal cleft; but I am convinced that when I have mentioned some of the cases which have come to my notice, it will be clear that this theory must be abandoned. Hoffman has floated the ingenious theory that colobomata confined to the choroid may be due to intraocular pressure, tearing asunder the barely closed foetal cleft; but here again, apart from a priori objections, many of my cases are incompatible with this hypothesis. Schweigger's theory,^ which might be termed the foetal inflammation theory, is very widely accepted at the present time, and overcomes many difficulties in the way of the other suppositions, and yet, although affording a probable clue to certain cases, will, I believe, fail in accounting for some of the cases I hope to show. The first point which I think I can demonstrate is that extra-papillary colobomata can occur in any part of the fundus, and I believe that the number of cases which have already come to my notice are sufficient to authorize my making such statements.' Besides the colored drawings of twelve cases, published with this paper, I have in my possession a number of other drawings similar in character to these. The two following diagrams represent the fundus of the right and left eye, and I have indicated thereon a number of the extra-papillary colobomata which I have seen, as well as some few which have been illustrated by previous writers. I may, however, add that those illustrated by previous writers are, with scarcely an exception, found in the region of the macula. All the above cases, with five exceptions, have come under my own observation. Two of these exceptions, Nos. 4 and 20, are inserted by kind permission of Prof. Tweedy, and the three remaining are copied from the drawings of ' Schweigger : Lehrb. d. Augenheilkunde. ' The same remarks apply equally well to iris-colobomata. The usual direction we know is downwards, and deviations from that direction were considered not to be colobomata (Manz: Graefe-Saemisch. Hand-book, II., 2, p. 65) ; but V. Mittelstadt has described cases occurring both outwards and inwards ; and Prof. Tweedy assures me he has met with an undoubted con- genital iris coloboma directed vertically upwards.