Improved color vision testing.
Pseudoisochromatic color vision testing plates have traditionally provided the clinician with screening-type information regarding the color with screening-type information regarding the color vision of patients. The introduction of a variable-color filter, through which the patient views these plates during testing, produces quantifiable results while exploiting the clinical advantages of the color plates. Thus, this approach allows the quick classification and quantification of color vision defects in a clinical setting. The results of this study on 153 subjects show that a variable-color filter combined with a series of traditional pseudoisochromatic plates can be successfully used on patients in a typical ophthalmology clinic to identify normal persons, protanopes, and deuteranopes. The results of the new test correlated well with those of standard tests.