A new lantern test using light-emitting diode lamps

Abstract

A lantern test using LED lamps has been devised. In this model, two lights each 4 mm in diameter placed 15 mm apart in tandem are presented for 2 seconds at a test distance of 5 m. The color of the light is either red (630 nm), green (555 nm), or yellow (580 nm). All possible combinations of three colors are included in one trial, which consists of nine pairs of lights. The color pairs are presented in random sequence and the number of errors in the second trial is scored. Test results are printed out.

Anomalous trichromats usually make from 3 to 7 errors out of a maximum of 9 errors in one trial, although some mild cases make fewer or no errors. Dichromats usually make 7 or more errors and they never recognize the colors correctly even if the viewing distance is shortened to 30 cm.

The lantern test is persuasive as well as important, especially for occupational purposes. This model is portable and easy to operate. In addition, the three colors are located on the confusion lines for both protanopia and deuteranopia, that provides a theoretical basis for its use as a color vision test.