282 Thèse de Paris.
283 Transactions of the Ophthalmological Society of the United Kingdom, vol. i. pp. 139-154.
Unclassified Nerve Diseases.
DIABETES.284
284 This affection has been placed here for convenience of classification, and because there is a form of the disease which is of neurotic origin.
DIABETES MELLITUS.—This disease, which affects so profoundly all tissues of the body, necessarily manifests its influence on the tissues of the eyes. It frequently impairs the nutrition of the vitreous and causes the formation of cataract. The presence of grape-sugar is readily detected in such lenses by chemical examination. Mitchell and other experimenters have produced cataract in frogs by placing them in a solution of sugar. In such instances the lens tissue is said to become transparent when the animal is removed from its sugar bath and placed for a time in water; therefore, it is probable that the cataract has been developed by the simple abstraction of water. Diabetic cataracts are often extracted successfully, and the wound usually heals well; but we occasionally have intraocular hemorrhage during the course of healing. At times the nutrition of the patients is so impaired that a slight accident is dangerous, such as happened in a patient of the writer, where the striking of the hand against an iron bedstead caused gangrene and death. Nettleship285 has recorded an analogous case, where accidental injury during convalescence caused death from gangrene. At times marked retinitis and hemorrhages with clear media have been encountered; thus, Jaeger in 1855 gave us an admirable picture of such a case, in which there was retinal swelling so great as to hide the outlines of the nerve, it being accompanied by numerous hemorrhages and yellow splotches. In his description of the case he also states that there was a marked central scotoma (a denser inside of a lighter one) in the field, while the periphery of the retina was so little affected that the patient could still decipher large letters (No. 18 of Jaeger's test-types). We might perhaps think that the scotomata are accidental and due to the location of the retinal changes in the given case, but later researches seem to show that we may have them in diabetes without retinal changes, Nettleship and Edmunds describing two such cases. In one of these cases there seems to be some doubt whether it was not a tobacco amblyopia which had been developed in a diabetic subject; but in the other case there was no such complication. The retinal changes which have been recorded in some cases have much resembled those due to albuminuria, but these alterations in the eye-ground have been seen in a number of cases where no albumen in the urine could be obtained.
285 Transactions of the Ophthalmological Society of the United Kingdom.
Diabetes also may, by impairing the nutrition, diminish the power of accommodation in the young and cause a rapid increase of presbyopia in old persons (Graefe, Nagel, Foerster). Horner286 proved that a hypermetropia of 1/14 in a patient of fifty-five years of age rapidly diminished to H. = 1/48, and the amount of presbyopia remained unaltered, while the general health had improved and the quantity of sugar had diminished. He attributes this rapid increase and subsequent diminution of the hypermetropia to a change in the amount of the fluid contents of the eye. Were this reporter any less careful an observer, one might be inclined to suspect swelling of the lens; but he specially mentions that there was no trace of cataract formation.
286 Klin. Monatsbl. f. Augenheilkunde, 1873, p. 490.
EPILEPSY.