Two important reasons might be given for studying the refractive condition of the peripheral field of the eye: (a) to study its relation to determinations of acuity in the peripheral field, and (b) to study its relation to determinations of chromatic and achromatic sensitivity in the peripheral field. In former studies we have made rather elaborate series of determinations on both of these points. There remains for this study an investigation of the refractive condition of the peripheral field. Another angle of approach has been to complete our study of the variable factors that influence the determination of the limits of the color and form fields. This is, of course, but an aspect of (b).
In listing the factors that cause a variation of result for a given person, we find the following: wave length and purity of stimulus, intensity of stimulus, size of stimulus or of angle subtended at