The Farnsworth Test* accurately interprets colour blindness and should be done with physical tiles.

The patient is instructed to locate the cap within the group of 15 that is closest in colour to the starter cap, which remains fixed in the storage box. The goal is to make the caps proceed logically from left to right in terms of their spectral hue progression.

Complete passing of either test occurs when the sequence of cap placement is exactly correct, and the circular plot for that test has no crossovers (Figure A).

A mild failure of either test occurs when crossovers are occurring around the circle, usually involving 1 or 2 cap positions. Major errors occur when the crossovers go across the circle graph, often defining an axis of the colour deficiency type (figure B). This should be noted in the results, e.g. strong protan, mild protan, strong deutan, moderate deutan, mild deutan, tritan colour blind or no deficiency identified.

*If your clinic does not have a Farnsworth test, please advise KINNECT and we will organise for an Optometrist to do the testing.