[Problems in the determination of color coordinates after the visual comparison method on the fundus of the eye...

A short description of color measurements on the fundus according to the method of visual comparison. The Zeiss Fundus camera equipped with an attachment served as the basic instrument. The method will not have clinical value until exact statistical values for the range of error of the different methods of measurement are available. A large number of color measurements in a short period of time on one patient's eye for gauging purposes is not possible. Therefore series of measurements are carried out on a phantom eye in order to determine the range of error in the color measurements under different conditions. Description of the results. The accuracy of the measurements which can be reached under ideal conditions with the phantom eye cannot always be reached with the patient's eye. Description of a model case for further series of measurements. The same errors of measurement appeared for reddish, yellow-orangeish, and almost white color areas. The fact that the adjustable lamp had to be replaced had practically no consequences. A series of measurements conducted according to the highest and lowest luminary densities allowed by the German Industrial Norms justifies the decision to limit the luminary density for the color measurements on the ocular fundus to 40 to 70 asb. Under the described conditions the error of measurement is smaller than is necessary clinically.