69 Bericht über die zehrite Vorsammlung der Ophth. Gessellschaft Heidelberg, 1871, pp. 53-60.
70 Jahrbuch f. Ophthalmologie Literatur, 1879, p. 253.
71 Klin. Monatsblätter f. Augenheilkunde, 1877 (supplement), pp. 53-60.
72 Ibid., 1875, pp. 98, 99.
PROGNOSIS.—The prognosis is very unfavorable, and but few cases are recorded where there has been any improvement of sight.
PATHOLOGY.—The pathology of the affection is not well made out. Samelsohn,73 who has reported a number of interesting cases, supposes that where there is a great loss of blood the brain becomes anæmic and occupies less room in the skull, and serum exudes from the blood-vessels to fill the vacuum. As the patient regains strength and blood is re-formed, the increased intracranial pressure drives the fluid into the subvaginal space of the optic nerves and causes neuritis. In other cases a hemorrhage into the sheath of the nerve is assumed as the cause. For those very exceptional cases where, after slight loss of blood, there is sudden and complete blindness without marked changes in the optic nerves and retinæ (and prompt reaction of the pupils to light), we are obliged to assume some lesion of the optic centres. Samelsohn74 attempts to explain it by comparison with the observations of Lussana, Brown-Séquard, Ebstein, and Schiff, who found that wounds of the brain involving the anterior prominences of the corpora quadrigemina and the thalamus opticus may cause hemorrhage into the mucous membrane of the stomach; consequently, he assumes a central lesion which produces simultaneously the blindness and the hemorrhage. All this is, however, but ingenious speculation, and the true pathology is still to be made out by careful autopsies.
73 A. f. O., xviii., 2, pp. 225-235.
74 A. f. O., xxi., 1, pp. 150-178.
The study of the eye-ground after death is difficult; for, apart from any hindrances due to the position of the body or to social customs, Nature soon interposes an efficient barrier to such examination by the rapidity with which cloudiness of the corneal epithelium and of the lens substance sets in. These optical hindrances advance sufficiently soon to make it impossible to focus accurately any object in the eye-ground. Poncet75 asserts that this may be remedied to a certain extent by dropping water into the conjunctival sac, which will render the cloudy epithelium sufficiently transparent to permit examination from two to five hours after death. Most observers agree that in the human eye there is an immediate blanching of the disc and choroid, causing the latter to assume a pale-yellowish hue with a faint tint of rose, and that the arteries (by promptly emptying themselves) escape observation, while the veins retain for a time a considerable amount of their contents, the blood-columns often being discontinuous and broken. Later, these changes are followed by a gradually increasing haze of the retina, which gives the appearance of a bluish-white veil spread over the fundus. Schreiber76 gives an instructive picture of the eye of a patient dying of phthisis, and another of the same eye five minutes after death. Gayat, who had the opportunity of studying this subject in the eyes of five individuals recently decapitated by the guillotine, describes the formation of a small red spot at the fovea centralis similar to that seen in embolism of the central artery.77 On the other hand, Becker78 thinks that the emptying of the vessels after death is rather the exception than the rule, basing his observations not on ophthalmoscopic examinations, but on the fact that in opening freshly enucleated glaucomatous eyes, and in the eyes of those who had been hung, he had observed all the vessels, arteries as well as veins, full of blood. Weber79 also, while admitting that the vessels both in men and animals usually empty themselves soon after death, describes as an exception a case in which there was no visible change in the blood-columns of the retinæ of the eyes of a patient with brain tumor, and a consequent optic neuritis, who was gradually dying of paralysis of the organs of respiration. This circumstance, in the opinion of the narrator, was very probably due to the obstruction to the escape of blood from the eye which would naturally be caused by the swollen and prominent optic nerve. Landolt and Nuel80 assert that there is an increase in the refraction in rabbits' eyes after death, causing any existing hypermetropia to approach emmetropia. They call attention to the difficulty of such determinations, owing to rapidly-forming haze on the corneal epithelium and to more or less complete emptiness of the retinal vessels.
75 Archives générales de Médecine, Série 6, t. xv., 1870, pp. 408-424.