Psychophysical assessment of color vision with the Cambridge Color Vision Test in unilateral functional amblyopia

Amblyopia is a cortical neurological disorder caused by abnormal visual experiences during the critical period for visual development. Recent works have shown that, in addition to the well-known visual alterations, such as changes in visual acuity, several perceptual aspects of vision are affected. This study aims to analyze and compare the effects of different types of amblyopia on visual color processing and determine whether these effects are correlated with visual acuity.

Our study sample comprised 42 amblyopic individuals, aged 7-40 years, (strabismus, n=16; anisometropia, n=18; and mixed-cause, n=8) and 33 age-matched controls. Color vision was tested by measuring the chromaticity threshold of each patient on the protan, deutan, and tritan axes using version 02 of the Cambridge Color Test. Spatial stimulation cues were eliminated using spatial noise and luminance.

The color discrimination thresholds on the protan, deutan, and tritan axes were similar between control participants and amblyopic patients (p>0.05). There was no correlation between VA values and color thresholds (p>0.05).

Patients with amblyopia have normal color vision in contexts that include luminance and spatial noise. Our results may be indicative of independent neural pathways for spatial and chromatic visual processing.