The optomotor response (OMR) assay is designed primarily to assess visual acuity and contrast sensitivity, and it cannot reliably measure color vision in preclinical animal models.
Color vision discrimination requires separating chromatic cues from luminance cues under strictly isoluminant conditions. Generating true isoluminant stimuli for laboratory animals is experimentally impractical because calibration depends heavily on species-specific photoreceptor spectral sensitivity, the optical filtering properties of ocular media (cornea, lens, and vitreous), and the relative abundance of cone subtypes across the retina.
For preclinical study design, relying on standard drifting grating OMR to infer chromatic processing creates a high risk of confounding data, as animals frequently respond to residual luminance differences rather than true wavelength discrimination. Misattributing luminance-driven tracking to color vision can lead to false-positive conclusions in retinal efficacy or gene therapy studies.
Researchers should reserve OMR testing strictly for tracking spatial frequency thresholds and global contrast sensitivity. When project objectives require evaluating specific cone pathways or spectral discrimination, functional endpoints should instead prioritize specialized electroretinography (ERG) paradigms or dedicated operant behavioral assays.