Night Blindness Due to Vitamin A Deficiency: A Consideration of Its Importance in Traffic Problems

Abstract

operations should have died is evidence of bad obstetrics. Elective cesarean sections were done for specious reasons. Some were done on badly infected cases. It is interesting to note that no craniotomies were found in this whole series.A report such as this is depressing. Good obstetrics is practiced in Boston, but this report brings out the fact that there is also a good deal of bad obstetrics. The results of this study are a direct challenge to those men that have done poor work, and it is their duty to perform, in the future, only work that they are capable of doing. The report is a direct warning to all physicians that improperly selected operations or operations badly performed carry with them a high maternal mortality. It is also a direct challenge to the hospitals that have allowed bad obstetrics to be practiced by members of their staffs.NIGHT blindness, often called hemeralopia, dysaptatio visualis, or erroneously, nyctalopia, is the difficulty, and occasional inability, of adapting the faculty of vision to very faint illumination. While this condition may result from various intraocular diseases, such as glaucoma, detached retina, choroiditis, retinitis pigmentosa and optic neuritis, it may also occur without any ophthalmoscopically demonstrable lesion being present in the eye and is then termed essential or idiopathic hemeralopia.1'2 To establish satisfactorily the presence or absence, of this type of hemeralopiat requires the performance of a test not commonly used at present.In a recent paper on the subject, Frandsen1 summarizes the objective data concerning essential hemeralopia as follows: "These patients show an increased minimum light visible. In reduced illumination the acuity of vision is lowered, the field of vision is narrowed for white as well as for colored objects, so that the field of vision for blue in higher degrees of hemeralopia becomes smaller than' the field for red. Dark scotoma appears at higher clarity than in the ease of normal light sense, the adaptation time is prolonged, the power of distinction is lowered-all signs which signify that the range of adaptation is reduced." These objective manifestations can be quantitatively measured and constitute the means available at present of detecting mild to moderate degrees of night blindness. The practical aspects of these different methods are discussed clsewhere.3 There is, now abundant evidence available to show that in older children and adults essential

The effect of changes in vitamin A content in the diet upon recovery from glare blindness.

“…"writers, that with the close association known to exist between vitamin A and visual purple, it might be possible to show a relationship between vitamin A content in diet and recovery time from glare stimulation. The demonstration of this relationship would be an important step m the attack upon the problem of night accidents That the rate of dark adaptation can be altered by changes in the vitamin A intake has been demonstrated by other investigators (Jeghers, 1938, Hecht and Mandelbaum, 1939, "Wald and Stevens, 1939 The present study differs from these investigations m several respects In the first place, the method of measuring the eyes' recovery from light stimulation by means of the photometer or some adaptation of it is too complex and requires too much time for this instrument to be used on the wide scale testing demanded in the examining of hundreds of thousands of automobile drivers Consequently, a similar method, requiring only a few minutes of testing time, is needed Secondly, changes in the vitamin A intake through changes in the diet of the subjects, as contrasted with administering vitamin A concentrates, needed to be studied. It was thought that any wide use of vitamin A therapy in the treatment of automobile drivers suffering from glare weakness could be best accomplished through correct regulation of dietary requirements.…”

“…Tansley (1933) has shown that the concentration of visual purple m the retinas of rats and dogs, which have been subjected to a vitamin A deficient diet, is very low and ma} r be totally absent She (1931) previously had presented evidence which indicated that vitamin A is a precursor of visual purple, and that the amount of visual purple in the eye at any given 369 time is in part conditioned upon the amount of vitamin A present. Some investigators have used the relationship between the rate of recovery following stimulation with a bright light and vitamin A as a basis for detecting subclinical states of vitamin A deficiency (Jeans and Zentmire, 1934;Park, 1936;Jeans, Blanchard, and Zentmire, 1937;Jeghers, 1937;Hecht and Mandelbaum, 1939;Wald and Stevens, 1939) In the report of Jeans and Zentmire (1934), 21% of a group of 213 children were considered to be suffering from avitaminosis A On testing 275 adults, Park (1936) found two in a group considered to be vitamin A deficient who also experienced difficulties when driving at night due to the glare of the headlights of approaching cars Some of Jeghers' (1937) subjects also experienced similar difficulties On questioning those individuals who had long recovery times, several of them reported that they preferred not to do any night driving because of experiencing relatively long periods of blindness from the headlights of approaching cars In a later and more extensive study (1938) those subjects having difficulties in night driving were given large doses of vitamin A concentrates They all gained relief and could again drive at night with little ill effect from glaring headlights In these investigations the photometer or some adaptation of it was used, and the measure of the dark adaptation rate was the rate of change in the threshold for absolute intensity following stimulation with a very bright light. The present writers became interested in the relationship between glare weakness and vitamin A intake in connection with studies on the factors conditioning efficiency in automobile driving.…”

Army motor transport personnel.

“…Several writers have pointed out the important role that night blindness plays in automobile accidents after dark (29,36,37,42). Although a number of devices have been developed to measure adaptation to the dark, time of recovery from glaring lights, and ability to see in the face of glaring lights, little has been done to correlate these three different types of tests and to determine how important normal night vision and normal glare vision are in driving a car after dark.…”

Diet in Relation to Health: Dark Adaptation as Index of Vitamin A Intake

“…A high proportion of flying accidents occur at night, and of motoring accidents at twilight. Delayed dark adaptation is probably of importance also with reference to dazzling by strong head-lamps (Jeghers, 1937). The problem is therefore not of merely academic interest.…”