PURPOSE: To evaluate the use of the Cone Contrast Test (CCT) as a color vision screening tool in an Asian population of aircrew applicants and compare it against the Ishihara Psuedo Isochromatic Plates (PIP) – Edridge Lantern Test (ELT) screening pathway, assessing its
impact on attrition with CCT cut-off scores of 55 and 75.METHODS: This is a retrospective review of 862 Republic of Singapore Airforce aircrew applicants tested with CCT and Ishihara PIP–ELT combination as screening. CCT repeatability was analyzed by comparing the subject’s
interocular (right vs. left eye) scores measured as the coefficient of repeatability (COR), with COR differing by ≥15 points considered to be outside normal limits.RESULTS: Of the applicants, 17 (1.97%) failed to achieve a CCT score of ≥55 (5 protan, 12 deutan), while 26 (3.02%)
applicants failed to achieve a score ≥75 (5 protan, 21 deutan). Of the 17 applicants who obtained a CCT score of <55, 16 failed the Ishihara PIP test. The only applicant who passed the Ishihara PIP test had a CCT score of 50. Of all applicants, 1.7% had a COR of ≥15, with 93.3% of
them identified as color vision deficient (CVD). Our results demonstrated excellent test repeatability, with 99.9% (835 out of 836) of color vision normal (CVN) applicants achieving a COR of <15 points.CONCLUSION: Our study demonstrated a high correlation between the CCT (passing
score of ≥55) and the Ishihara PIP. Employing the CCT with a passing score of ≥75, instead of the Ishihara PIP–ELT combination, led to an increase in attrition rate of 0.7–3.0%.Chay IW, Lim SWY, Tan BBC. Cone Contrast Test for color vision deficiency screening among a cohort of military aircrew applicants. Aerosp Med Hum Perform. 2019; 90(2):71–76.