Page:Plates illustrating the natural and morbid changes of the human eye.djvu/34

28 The choroid as regards colour appears somewhat anæmic.

(The retina appeared less transparent in some than in other parts.)

The veins of the retina appear full and tortuous, except in the optic disc. The retinal arteries are few in number and thin.

The changes in the arteries and veins of the retina observed at the margin of the optic disc, and in the area of the disc, are characteristic of long-continued increase of tension of the eyeball. On more careful examination, e. g. of the veins which from the lower margin of the figure pass through the retina towards the optic disc, we observe that the veins in the retina are tortuous and filled with blood, while in the optic disc, and where they pass over the white narrow rim which surrounds the disc, they appear thin and nearly empty.

The anomalous course of the vessels, where they bend round the margin of the optic disc, is not quite correctly represented in Fig. 29. In glaucoma of long standing the veins of the retina bend round the margin of the optic disc, and if the margin be unusually prominent they are lost sight of for some distance. This causes the portions of the veins in the optic disc to appear as if they were not the continuations of those in the retina. This change in course and apparent calibre, is visible more particularly in the veins which pass over the lower margin of the disc.

Fig. 30. ''Left eye. Hemorrhage into the retina.''

The optic disc and the tunics immediately adjoining it.

From a myopic person, whose optic disc, &c., of the fellow eye is represented in Plate VIII. Fig. 21.

The optic disc is masked by blood spots, and by swelling and impairment of transparency of the retina. The position of the optic disc can be inferred from the course of the retinal vessels, which converge towards and meet in the disc.

The blood spots are unusually large and numerous; into many we can trace the blood-vessels (? arteries) of the retina.