Atlas of rare ophthalmoscopic conditions : and supplementary plates to the atlas of ophthalmoscopy / by J. Oeller ; the text translated into English by Thos. Snowball.

  • Oeller, Johann Nepomuk, 1850-1932.
Date:
1904
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Licence: In copyright

Credit: Atlas of rare ophthalmoscopic conditions : and supplementary plates to the atlas of ophthalmoscopy / by J. Oeller ; the text translated into English by Thos. Snowball. 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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    of the individual pigment-spots, and the rapidity of their formation also speak against their origin from the blood. When chemically active foreign-bo dies, e.g. chips of iron, are present in the interior of the eye, we know that as a result of their solubility and the consequent irritation the pigment epithelium may proliferate in places. But this factor is not applicable for our case either, for the lead, which in itself is chemically inactive, is not lying inside the globe at all, as examination with the ophthalmoscope and the x-rays shows. Nor can we seek an explanation for our case in the experimental researches of Marckwort, Wagenmann and Kriickmann, who found pigmentation of the fundus after ligaturing and dividing the ciliary vessels, or in the clinical observation of Siegrist on pigmentation of the fundus after a probable thrombosis of the ophthalmic artery, for the reason that from the path and position of the projectile the ciliary vessels that supply the macular area of the fundus could not possibly have been injured by it. There is, therefore, no other explanation possible than to consider the severe contusion of the globe produced by the impact of the shot as responsible for the pigmentary changes. At the same time it cannot have been a contusion in the ordinary sense of the word at the seat of injury, as the point of greatest proliferation of pig- ment, viz. the macular area, does not correspond at all to the place where the shot struck the globe. Evidently there has been a momentary displacement of the membranes spreading from the point of impact, and as a consequence of this a forced tearing of their elements. Obviously the macula possesses a peculiar vulnerability dependent on its anatomical relations, and reacts extremely sensi- tively to contusions even at a distance from it. From the very bad prognosis of these cases we may assume with certainty that the perceptive elements of the retina must be destroyed by tliis momentary tearing, since in our case at least immediately after the accident (with clear media and no Berlin's opacity at the macula) the vision was reduced to the perception of hand move- ments close to the eye. Since the rods and cones and pigment epithelium are all in immediate contact both physiologically and anatomically, it cannot be surprising that on tearing away the rods and cones from the layer beneath them the pigment epithelium cells are also so injured that they perish in great numbers, but that in order to cover the defects thus arising there sets in a proliferation of the surviving cells with irregular growth of pigment. Denig') states in his experimental study on commotio retinae that, when the blow on the eye was a very severe one, a wandering of pigment into the retina also took place. It is most probable that with the appearance of such a result to his experiment a very similar process had taken place. In cases similar to ours Siegfried has emphasised the presence of red spots among the patches of pigment, whicli probably must be referred to small rents in the retina. Haab, again, has made us acquainted with the real occurrence of a traumatic perforation of the macula, when the latter appears as a red spot (supposing the choroid intact). In the present case, too. we liave probably to deal with a central red spot, which does not correspond in its shape to the normal macula. Nevertheless 1 would not venture to assume a perforation of the macula here, because the edges of tlie spot were not sufficiently sharply defined and throughout a considerable period of observation never showed any grey infiltration. ') Denia: 1st die Weissfiirbiing der Netzbaut elc Arcbiv filr Augenbeil- kunde. Vol 34. Part. I, p. 56.