When comparing patients with congenital color vision deficiency (CCVD) and healthy controls, researchers recently discovered that patients performed better on stereoscopic acuity testing when they had better color discrimination ability.

The study assessed 53 binocular males, of which 27 were in the CCVD group and 26 in the healthy group. Most of the CCVD group, 20, had deuteranomaly and the remaining seven had protanomaly. The researchers used the Ishihara pseudo-isochromatic plate test for detecting CCVD, the Farnsworth Munsell 100 (FM100) hue test for color discrimination ability and the TNO and Titmus stereo tests for stereoscopic acuity.

Not surprisingly, the healthy controls had fewer recorded errors on the FM100 hue test for both blue/yellow and red/green discrimination compared with the CCVD patients. What was surprising was the difference in acuity testing—the healthy group displayed significantly higher stereoscopic acuity test scores.

The researchers did notice that the TNO test score was significantly and positively correlated with the total error score and blue/yellow LES in the healthy group. They conclude that the relationship between stereoscopic acuity and increasing discrimination ability could originate from the blue/yellow color region.

Koctkein B, Coban Dt, Ozen M, et al. Investigation of relationship between colour discrimination ability and stereoscopic acuity using Farnsworth Munsell 100 hue test and stereo tests. Can J Ophthalmol. September 14, 2019. [Epub ahead of print].