A manual and atlas of medical ophthalmoscopy / by W.R. Gowers.

  • Gowers, W. R. (William Richard), 1845-1915.
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: A manual and atlas of medical ophthalmoscopy / by W.R. Gowers. Source: Wellcome Collection.

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    advances. The latter constitutes by far the greatest danger, because the contraction which causes it continues, and increases for a long time, and the amblyopia due to it usually continues and increases until, and even after, the disc has reached its normal level. The progress of the amblyopia from this cause ma}^, however, be interrupted by the recovery of fibres damaged only during the active inflammatory stage, and when the amount of new tissue formed is small in proportion to the irritative changes in the disc (as in many cases of syphilitic disease duly treated), a considerable in- flammatory amblyopia may clear away and be followed by very slight consecutive defect. The latter is usually more or less permanent, but, after it has reached its height, consider- able subsequent improvement does, in some cases, slowly occur (see p. 130). Not unfrequently after a neuritis has subsided, with or without impairment of vision, a further loss of sight, complete or incomplete, may occur from intra-cranial causes without any fresh ophthalmoscopic appearances. It will thus be seen that a considerable disparity between the affection of sight and the course of the papillitis indicates the influence of retro- ocular mischief. A good illustration of this is afforded by the case figured in PI. YII. 1 and 2, in which the papillitis was unilateral, the other eye presenting normal characters throughout; but the sight of both eyes failed after the subsidence of the papillitis (see Fig. 35). Causes.—The most common causes of optic neuritis are encephalic diseases, and of these tumour is incomparably the most frequent. Neither the nature, size, nor the seaf^ of the tumour appears to exercise much influence on the occur- rence of neuritis. The next most frequent cause is certainly ^ From an analysis of cases made by Edmunds and Lawford it would appear tha.t, ceteris paribus, tumours near the convexity of the brain arc somewhat less liable to cause optic neuritis than those situated near the base. Cerebellar tumours seemed particularly prone to excite optic neuritis, often of a severe type. Of twelve cases of primary tumour of the cortical motor area, on the other hand, not one was associated with optic neuritis (Trans. Ophth Soc, vol. iv. 1884, p. 172).