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

Date:
1890
Catalogue details

Licence: Public Domain Mark

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

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    papillitis, and soon passing on to atrophy with narrowed vessels. Little is known of the exact anatomical changes in this form, except in the variety which has heen termed axial neuritis (Forster), in which chronic inflammation occupies the axis of the nerve, and causes a central scotoma. It will be- described further in the section on Atrophy. Retro-ocular Perineuritis is a condition of chronic inflam- mation of the sheath of tbe nerve leading to thickening of its tissues, and purulent infiltration among the trabeculse. The nerve may suffer from compression, or from a state of inter- stitial neuritis which may spread to it from the sheath. It has been found in periostitis of the orbit (Horner), and in thickening of the cranial bones constricting the optic nerve- (Michel). It causes papillitis in some, perhaps in all cases,, but this does not necessarilj^ assume the appearance described on p. 51 as perineuritis. Diagnosis.—The diagnosis of optic neuritis is often easy,, but sometimes presents great difiiculty. Of all its signs that which first attracts attention as the most conspicuous feature-— the increased redness—is of least value, except in conjunction with other characters. As already more than once stated, the redness of a disc free fi'om neuritis may nearly equal that of the adjacent choroid. The signs which are of greatest diagnostic value are (1) obscuration of the edge of the disc and (2) swelling. These, in conjunction with increased redness, or change of colour to a tint not normally seen (such as the peculiar lilac-grey so often presented), constitute the characteristic sjonptoms. The obscuration of the edge is especially significant. It indicates undue opacity of the tissue (layer of optic nerve fibres) in front of the edge. Most of the nerve fibres pass along the com-se of the great vessels, above and below the disc, and they often normallj^ obscui'e the edge of the disc slightlj^ in these situations. Sometimes they are densely packed, also, on the nasal side, especially when the central cup is very large, and a slight obscui-ation is produced there also ; but in these cases, as a rule, the lai'ge size of the physiological cup indicates the close arrangement