Reflex Visual Sensations and Anomalous Trichromatism

Abstract

SYNOPSISSec. I. Introduction.—This contains a brief summary of the principle of reflex visual sensations as discovered by Allen. The author, whose vision is somewhat abnormal, sets out to determine the character of these reflexes for his abnormal vision.Sec. II. Apparatus and Methods of Measurement.—All experiments were performed in a daylight room, using the critical frequency of flicker method. The results, which are quantitative, were obtained by making measurements on pure spectral colors.Sec. III. Normal Curves.—Abnormal vision is shown by the character of the persistency curve, taken under normal conditions of daylight adaptation. The type of curve, which was found to be the same for both eyes, is compared with one for normal vision and one for partial red color blindness.Sec. IV. Reflex Curves.—This contains the descriptions and results of experiments carried out by fatiguing the left eye and making measurements of the changes in the visual response of the right to light from the different parts of the spectrum.The nature of any change in the response was always found to be an enhancement of brightness of the affected colors. Red and green were found to be more susceptible to this reflex enhancement than the violet. Certain colors, .660μ, .505μ, .425μ, and the entire region .520μ to .480μ, showed no reflex transferred to the other eye. The magnitude of the reflex was greatest for fatiguing colors near the ends of the spectrum. The effect of dark adaptation was also transferred to the other eye similarly to fatigue.Sec. V. Fatigue Curves.—This contains descriptions and results of experiments in which the measurements were made on the fatigued eye, the other being always in daylight adaptation.It was found that the red sensation was very difficult to fatigue, but very susceptible to enhancement. The violet showed the reverse character, and the green an intermediate position. No effect was obtained for fatigue colors, .665μ, .589μ, .570μ, and only a small effect for .520μ. The effects of darkness and strong white light are very similar, both showing fatigue characteristics.Sec. VI. The Theoretical Considerations.—The experimental results show that every ray of light produces both a direct and a reflex effect upon all three fundamental sensations, which are shown to be red, green, and violet. The author’s type of color vision is shown to be that of an anomalous trichromat, and experimental evidence is applied to give a fuller meaning to the phenomenon as well as to explain it. The principle of visual reflexes is applied to the Young-Helmholtz and Hering theories to show that the two can no longer be regarded as rival theories, but can be harmonized by this principle.