Discrepant results obtained with two versions of the Farnsworth Panel D-15 test in patients with acquired blue-yellow...

Two commercially available Panel D-15 tests were administered to two patients with acquired blue-yellow defects. The results obtained with each test were different and apparently influenced by the cap construction which is the only difference between the two tests. In one test the surface of the cap is concave and polished while in the other test the cap surface is flat and has a matte or dull finish. The mechanism accounting for the different results is not obvious.