. Refraction and motility of the eye, with chapters on color blindness and the field of vision . betweendiminution of vision by refractive conditions in which it isunimpaired and disease of the percipient elements in whichit is. (See chapter on Field of Vision). We have seen that few, if any, of the pigments, ofcolored papers, or glasses are pure colors and capable ofexciting uncomplicated retinal sensations. Consequentlyfor the scientific testing of the color sense the spectroscopential as the only means of giving us pure colors. Byits air] we can determine whether any portion of the spec-tru
. Refraction and motility of the eye, with chapters on color blindness and the field of vision . betweendiminution of vision by refractive conditions in which it isunimpaired and disease of the percipient elements in whichit is. (See chapter on Field of Vision). We have seen that few, if any, of the pigments, ofcolored papers, or glasses are pure colors and capable ofexciting uncomplicated retinal sensations. Consequentlyfor the scientific testing of the color sense the spectroscopential as the only means of giving us pure colors. Byits air] we can determine whether any portion of the spec-trum is wanting and by showing isolated portions of thespectrums we can determine the power to name them cor- 326 REFRACTION AND MOTILITY OF THE EYE. rectly and match them with other, similar colors. If thepatient is affected with red-blindness, the red end of thespectrum excites no sensation in the fibres for the perceptionof red and consequently the spectrum is shortened at thisend. The blue-green of the spectrum seems to him lessdeeply colored than the rest of the spectrum, giving rise to a. Fig. 104. sensation like that of a feeble white or gray. This is spokenof as a neutral band and it is characteristic of red-blind-ness that the band occurs between the blue and the the green-blind the spectrum is not shortened, but theneutral band falls in the green area, nearer the red end. For practical purposes, however, we can approach suffi-ciently close to spectral colors with pigments, dyes orcolored glass, to enable us to test the patients color capacityand to determine in what respect it is defective. In all COLOR-BLIXDXESS. 327 these tests it is important to bear in mind the compositionof these synthetic colors in order to understand the sensa-tion they give a patient who, being more or less color-blind,overlooks one or more of the constituent parts and so comesto a wrong conclusion regarding the color of the combina-tion (Fig. 104). There are several methods of ascertain
Size: 1583px × 1578px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1900, bookdecade1920, booksubjecteye, bookyear1920
