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

Date:
1879
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.

    47/428 (page 31)
    of atrophy, which resembles closely simple atrophy, except in the extremely small size of the vessels. The plug has in several cases been found after death, commonly just behind the bifurcation of the artery, in other cases in its course. In Case 46 (PI. XII. 2), the artery in the nerve contained an oval granular embolus (Fig. 3). Other smaller fragments were seen in the narrowed arteries, upon the disc. Yery rarely the circulation gets re-established by the normal com-se. Columns of blood appear in the arteries, in part broken, and for a long time easily broken by pressure. The arteries continue below normal size. Yision may be recovered, especially at the periphery, rarely at the centre. Commonl}', however, obstruction remains complete. The retinal artery is regarded as a terminal artery, i.e., one that has no anastomoses. In most cases very little collateral cu'culation is set up : the arteries remained narrowed to lines as far as they can be traced. But they are visible in almost all cases as red, not as white, lines. Hence they must contain blood, persistent and therefore circulating, which has come from some sHght collateral anastomoses, or from the obstruction being incomplete. Sometimes a much more considerable circulation is estab- lished. In PI. XII. 2, for instance, the arteries are filiform only upon the disc, and as far as they remain unbranched ; beyond this, they have nearly their normal size. A similar case has been recorded by Knapp. This points strongly to the establishment of a collateral circulation, probably by con- nection with the long ciliary arteries, although, in the researches of Leber, such connections could not, in the normal condition, be demonstrated. It is commonly supposed that the chief connection between the retinal and ciHary vessels is by means of the vessels of the optic disc, but it is ceriainly not by such means that a collateral circulation takes place, for the pallor of the disc is due to ansemia, and is almost universal in cases of embolism. Moreover, the arteries are never filled in the neighbourhood of the disc, but at a distance from it. A collateral circulation in tlie disc