A case of toxic amblyopia : with autopsy and microscopical examination of the specimens / by G. E. de Schweinitz.

  • De Schweinitz, G. E. (George Edmund), 1858-1938.
Date:
[1897]
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Licence: Public Domain Mark

Credit: A case of toxic amblyopia : with autopsy and microscopical examination of the specimens / by G. E. de Schweinitz. 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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    are secondary to the destruction of the nerve-cells of the macula. To be sure, there is no manner of doubt that macular-fibre degeneration will follow experimentally produced retinal lesions, as has been shown in the excellent research of Usher and Dean/ and clinically we know that atrophy of the tissue of the macula lutea, for example, in atrophic central retino-choroiditis, or in so-called macular coloboma, will cause quadrant-atrophy of the optic disk, precisely as this is seen in cases of intoxication-amblyopia If a specimen of this character were submitted to microscopic examination, I have no doubt atrophy of the papillo- macular bundle would be found precisely as it appears in the present instance. Ophthalmoscopic changes in the macula have been described in cases of toxic amblyopia by Nettleship, Hill-Griffith, and myself ; although we did not attribute them to the influence of a toxic agent, but re- garded them as coincidences. Macular changes have also been described by Nuel and W. G. Laws, but they are quite as indefinite as those previously recorded. Nuel has experimentally produced optic-nerve degeneration by admin- istering extract of male fern, and thinks that this disease attacks first the nerve-cells of the retina, and that their destruction brings about the degeneration of the fibres of the optic nerve. Moreover, this degenera- tion occurs without the intervention of a neuritis. Recently the same author,'^ in a discussion on sympathetic amblyopia, refers to this subject (I quote W. G. Sym's abstract of his paper) as follows: In a certain number of cases of filix mas amblyopia in dogs there is a distinct degree of neuritis, or at least of blurring of the papilla; but, microscopically, there is no trace of an interstitial neuritis, only an oedema of the nerve- head. This interstitial oedema is consecutive to the destruction of the nerve-fibres, and real neuritis, if it occurs, comes on later, but is neither interstitial nor retrobulbar. Many cases of toxic amblyopia are of this nature; they are instances of parenchymatous neuritis. In my own experiments in quinine-amblyopiathe extensive degeneration of the whole visual tract which followed the administration of this drug oc- curred without preceding neuritis.* It was essentially a degenerative pro- cess, but, as an examination of my specimens will show, there were no changes in the ganglion-cells of the retina. Therefore, while there may be a retinal origin of degeneration of the papillo-macular bundle, or, indeed, of more extensive disease of the entire nerve, it evidently is not 1 Trans, of the Ophth. Soc. of the U. K., 1896, vol. xvi. p. 248. Archives d'Ophtalmologie, March, 1897. 3 The Toxic Amblyopias; their Classification, Symptoms, and Pathology. Philadelphia, Lea Bros. & Co., 1896, pp. 193-198. * In luy earlier experiments in quinine-amaurosis (Trans. Coll. of Phys. of Phila., 1890) I found \ '\ many sections, in the earlier stages of the blindness, that the trabeculte were less marked and the individual fibrils spread apart, as if the tissue was oedematous and swollen This observation is similar to the one made by Nuel in dogs suflfering from the amblyopia of male fern.