Neurophysiologic Basis of Color Perimetry-Reply

We are pleased that Dr Paulus accepts our data and our statement that a dim, white stimulus can produce the same visual field as a red stimulus of the same size. Dr Paulus argues that colored- and white-test stimuli excite X cells in different ways. But how clinically significant is this difference if, as he states, “we too believe that an isopter produced with a 3-mm red target may be reproduced with a dimmer, 3-mm black-white target?” We continue to use colored stimuli when performing confrontation testing of visual fields because the patient can more easily verbalize differences in degrees of color saturation than in degrees of whiteness. Kestenbaum, in reference 8 cited by Dr Paulus, stated this very well: “The patient may find that a red color becomes less saturated at a certain place, eg, in the center. Here the color appears ‘pinkish’ or ‘less red.’ Such.