The test starts with a red/green combination so that the patient can see these two colors before seeing a white light. During the test, there are nine different color combinations. The subject of the test is asked to identify the two colors (some of which are identical). How to perform the Farnsworth Lantern Test It detects red-green color deficiencies but not the far less common blue color deficiency. The Farnsworth Lantern Test (abbreviated FALANT) is a color vision test that was originally created to screen sailors for duties requiring color vision, such as recognizing signal lights at night.
