Search

In the recent communication of my paper on a “Fourth Sensation in Colour Vision,” in April last, attention was called to the case of night-blind eyes as throwing light on the question of the functions of the rods and cones in the retina in regard to colour and colourless vision. I cited two cases of congenital stationary night-blindness, which, through the kindness of Mr. Nettleship, were brought to my laboratory for examination in view of certain researches in which Prof. (now Colonel) Watson and myself were together interested. As Colonel Watson has been long at the Front in France, and as he conducted a principal part of the only partially completed examination, I hesitated to give the details without his collaboration. I have now obtained his acquiescence in my request that I should communicate the results obtained to the Royal Society. I now do so. As a matter of fact, I had worked out the observations before my colleague left me for the Front some 2½ years ago, and these results I have put in the following com­munication: I may say that any other form of night-blindness than those to which the late Mr. E. Nettleship introduced us would have been useless for the investigation on which we were engaged, as, if it were not so, night-blindness due to disease might call in question some of the deductions to be made. Mr. Nettleship’s investigations of the family to which they belonged, and its history, left no doubt that we were dealing in our two cases with genuine cases of congenital stationary types.

In clinical electroretinography the extreme expression of rod- or cone dysfunction is found in the complete form of congenital total color blindness and in Schubert-Bornschein’s form of congenital night blindness. The ERG traces of both anomalies represent models for the analysis of rod- and cone function or dysfunction. Comparative studies of these conditions, first performed by Goodman & Bornschein, can enable investigators to gain a deeper insight into electrophysiology and patho-physiology of the eye.

In the analysis of the human electroretinogram, the study of subjects with congenital night blindness and total color blindness is of great value. The absence of specific electroretinographic components in these anomalies simplifies the complex pattern of response, allows a more detailed investigation of the remaining components, and aids in the analysis of the photopicscotopic nature of the different waves. However, the few investigations which deal with the electroretinogram in congenital night blindness and total color blindness have studied each condition separately; therefore, no direct comparison has been made between their electroretinographic responses. The purpose of this study is to investigate quantitatively the influence of dark-adaptation and stimulus intensity on the electroretinogram of normal, congenitally night-blind, and totally color-blind subjects,* examined under identical experimental conditions. Subjects The night-blind subject is a 28-year-old married white woman. She has been aware of poor night vision in both eyes since childhood, nonprogressive in

Since 1952, when Schubert & Bornschein published the electroretinographic results of a subject with congenital night blindness, the specific anomalies of the ERG in these cases are well known: a-wave and x-wave are recordable, but the scotopic b-wave is completely absent. Up to now slow potentials of ERG were not studied in this form of night blindness.

The photopic flicker ERG in response to intense intermittent light of fixed brief duration has been investigated in normal subjects and those with some specific congenital deficiencies of the retina.

THE PRESENCE of distinct defects in the electroretinogram (ERG) in the varying forms of night blindness has been well documented in recent reports. The most conspicuous changes have been recorded from frank cases of primary pigmentary degeneration of the retina. In these cases the tracings are usually extinguished or greatly reduced in amplitude.* A recent article in the Japanese literature 4 describes similar but less marked changes in Oguchi's disease. Bornschein and Vukovich 5 have observed subnormal recordings with avitaminosis A, and definite changes have also been seen in cases of congenital night blindness without fundus change.† This latter form of nyctalopia appears to us to be of more interest than other forms. The existence of clear-cut alterations is of pertinent significance when clinically evaluating alleged night blindness—especially in the military service. In the past such patients have been frequently looked upon as psychiatric problems, if not actually designated as