Peter C. Kronfeld

Ein Beitrag zur Kenntnis der Refraktionskurve

Ein klinisches Material von 2229 unter Atropin skiaskopierten Augen, die nicht mehr als 0,5 Dioptrien Astigmatismus aufwiesen und deren Träger nicht unter 25 und nicht über 50 Jahre alt waren, wurde zur Konstruktion einer neuen Refraktionskurve verwendet. Die resultierende Kurve wich von der vonScheerer-Betsch veröffentlichten insofern ab, als sie relativ mehr Augen mit einer Refraktion von — 2 bis — 4 enthielt. Wurde der myope Schenkel der Kurve entsprechend den ZahlenScheerers korrigiert (ohne die mit Conus behafteten Augen auszuschließen), so resultierte eine fast symmetrische Kurve. Die Schiefheit betrug + 0,31, war demnach sehr gering und konnte sowohl Anlagefaktoren wie auch Umweltfaktoren ihre Entstehung verdanken. Der Hauptunterschied zwischen der menschlichen Refraktionskurve und der Binomialgleichung ist der hohe Exzeß der ersteren, welcher durch das Vorhandensein von zu vielen extremabweichenden Augen an beiden Enden der Kurve und durch Anhäufung von relativ zu vielen Augen um den Mittelwert der Refraktion bedingt ist. Die erstere Erscheinung wird durch das Vorhandensein mehrerer Genotypen, die letztere durch das Bestehen einer merklichen Korrelation zwischen Brechkraft und Achsenlänge, für welcheStraub, Zeeman undTron Beweise erbracht haben, erklärt. DieSteigersche Lehre von der freien und voneinander unabhängigen Kombination von Achsenlänge und Brechkraft muß daher dementsprechend modifiziert werden.

Metabolism of the Normal and Cataractous Lens

Since there is in the body no structure analogous to the lens its metabolism cannot be expressed in terms of any organ, but comparisons are self-limited. Metabolic activities are greatest near the surface of the lens and decrease gradually toward its center. The glycolysis of approximately 2.4 mg. and the consumption of 0.3 mg. of oxygen is performed by the normal lens per day, representing 1 percent and 0.25 percent of the total energy exchange of the eye. The metabolism of the cataractous lens is very incompletely known, for the specific toxicity of the experimental agent is not definitively known. Read before the Association for Research in Ophthalmology in Milwaukee, June 13, 1933. From the Eye Clinic of the University of Chicago, E. V. L. Brown, Director.

Modern viewpoints as to the mechanism of glaucoma

Recent views as to the mechanism of glaucoma are discussed. It is suggested that the “dark-light” test, or a study of the extent to which tension varies as between prolonged confinement in darkness and exposure to light, may be very valuable in the observation of certain glaucoma patients, a glaucomatous diathesis being manifested by rise of tension after a prolonged stay in darkness. The theory of Leber is still the most logical working hypothesis. From the department of surgery, University of Chicago. Read before the Chicago Ophthalmological Society, November 19, 1928.

Which Children Should Attend Sight-Saving Classes?

For those whose defects are stationary, the range of vision should ordinarily lie between 2/SO and 1/4, with a few exceptions up to 1/3 and down to 1/50. Most cases of refractive error are to be considered purely according to their range of vision. Those who have myopia of more than eight diopters at the time of commencing school life should be included, but need to attend the special classes only for departments of study that particularly tax their visual acuity. Children who suffer from asthenopia but have good visual acuity should be under medical care, but should not be placed in sight-saving classes. The address was delivered before the fifty-first meeting of the Rhenish and Westphalian Ophthalmologists, Diisseldorf, Germany, November-27, 1927; and the translation is now published by request of the National Society for the Prevention of Blindness.

GUNSHOT WOUND OF THE OPTIC NERVE: REPORT OF A CASE

Many cases of orbital injuries from gunshot have been reported. The effects of such wounds on the globe and its surroundings are well known. In most of the cases a bullet entered through the temple and lodged in the homolateral or contralateral orbit. Cases in which the entrance of the bullet was approximately the same, but the course of which was intracranial, are apparently infrequent, as we were unable to find an analogy to the following case. REPORT OF CASE A boy, aged 7, was brought to the hospital two days after receiving a gunshot wound of the head, inflicted by his father, who had suddenly become insane. The entrance of the bullet was 3 cm. in front of, and 5 cm. above, the right external auditory meatus. The boy was inclined to drop off to sleep, but could be aroused easily. He answered questions and cooperated well. There was