The main thrust of this project has been to monitor the visual efficiency of eye patients while conducting tests, research, and experiments directed toward improving, replacing, or standardizing the procedures involved. These psychophysical tests consist mainly of threshold measurements of color and visibility under different conditions. They are necessarily subjective measurements, but the degree of subjectivity has in some cases been effectively reduced to make them more useful in diagnosis, treatment, and prognosis of known or suspected ocular abnormalities.