Text-book of ophthalmology . rhage) (Fig. 248). The retinal tissue then is not injured by thehemorrhage, so that after resorption of the blood vision becomes normal again. [Some-times, however, preretinal haemorrhages are not absorbed but form large membranes(retinitis proliferans), see page 582.] 572 TEXT-BOOK OF OPHTHALMOLOGY The extravasations are most frequently located in the neighborhood of the largervascular trunks. The causes of retinal haemorrhages are— 1. General fragility of the vessel walls. This is found very often in old peoplewith atheromatous vessels, particularly if they have
Text-book of ophthalmology . rhage) (Fig. 248). The retinal tissue then is not injured by thehemorrhage, so that after resorption of the blood vision becomes normal again. [Some-times, however, preretinal haemorrhages are not absorbed but form large membranes(retinitis proliferans), see page 582.] 572 TEXT-BOOK OF OPHTHALMOLOGY The extravasations are most frequently located in the neighborhood of the largervascular trunks. The causes of retinal haemorrhages are— 1. General fragility of the vessel walls. This is found very often in old peoplewith atheromatous vessels, particularly if they have a heart lesion, too. In such casesretinal haemorrhages are often the precursors of cerebral apoplexy. [See page 571.] 2. Local disease of the retinal vessels or of the adjacent vessels of the this head must be reckoned those haemorrhages which occur so frequently inexcessively myopic eyes in the region of the yellow spot. With the occurrence of sucha haemorrhage central vision is often permanently Fig. 248.—Preretinal represents the right eye of an elderly woman. The eye, in consonance with its myopia,shows a broad white crescent at the temporal border of its papilla; and the latter also has a prettylarge physiological excavation. The retinal arteries are very tortuous, the veins normal. The middleof the fundus is occupied by a large haemorrhage, covering the region of the macula lutea, and extend-ing upward as far as the superior temporal vessels, which are partially concealed by it. The lower partof the haemorrhage is dark red, and is separated by a sharp horizontal line from the upper, pale-redportion. This division into two parts is caused by the settling of the blood corpuscles to the bottomof the still fluid blood. In the vicinity of the large haemorrhage, especially at its upper and inner bor-ders, lie numerous small spots of blood. These extend up to and upon the white crescent adjoiningthe optic nerve and up to the superio
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