Question 13 of 14

(demo test)

The Farnsworth Panel D-15 is the most useful test in discriminating between congenital versus acquired color defects.  In this test, the patient is asked to arrange a series of 15 color blocks (see image below).  For patients with congenital color defects, a very ordered pattern will emerge that is easy to see.  

In contrast, for those with an acquired cause of color deficiency (e.g. optic neuropathy), a very irregular pattern will be the result.

The Ishihara and HRR pseudoisochromatic plates are useful screening tests for gross color deficiencies.  However, they cannot be used to specify whether the defect is from a congenital versus an acquired cause.

By the way, "Takayasu pseudoisocromatic plates" is completely made up.