Ophthalmic Review Volume 6 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1887 Excerpt: ...fails to restore the original pressure to the tissue chamber. Our authors regard Scliulten's experiments upon the effects of the circulation upon the intraocular pressure as the most trustworthy of those performed on the living eye (Vide O. R., Vol. III., p. 370). It is shown by Schulten that increased blood supply, diminished vascular tonus, or lessened venous outflow all raise the intraocular pressure, while lessened blood supply and increased vascular tonus lower it. These experiments are in complete harmony with those of our authors, and the natural conclusion is that the intraocular pressure is regulated by the mechanism described in the present paper. The hypothesis that the blood pressure affects the intraocular pressure by the mere contraction or dilatation of the vessels (that is, by direct decrease or increase of the contained blood) and not through the process of filtration is untenable. The variations are too great to be accounted for by such an hypothesis, and are also of too permanent a character. It is noteworthy, too, that precisely analogous arrangements exist in the cranium in the rigid walled sinuses of the dura mater, into which the cerebro-spinal fluid can filter by means of the Pacchionian bodies, there being no important lymph vessels to conduct this fluid by any other route. Our authors have shown in the first part of their paper that the glaucomatous eyes examined by them exhibited conditions tending to raise the intraocular pressure in the narrowing of lumen in the emissaries of the vortex veins, the adhesive inflammation round the venous trunks, and the thickening of their walls. (The ligature of even one vein, as Schulten has shown, is enough to raise the pressure inside the globe by restricting the venous outflow.) Besides this ...