Robbiani Dermal Optic Test
From Star Trek : Freedom's Wiki
The Robbiani dermal-optic test is a medical diagnostic test that reveals a subject's basic emotional structure by analyzing skin and pupil response to visual stimulation at specific color wavelengths. Captain James T. Kirk was given a Robbiani derma-optic test upon taking command of the USS Enterprise.
In 2269, Doctor Leonard McCoy subjected Kirk to the test to compare with his previous results, when Kirk's emotional state seemed to be under duress. (TOS: "Turnabout Intruder")