Impaired speed perception but intact luminance contrast perception in people with one eye

It is generally accepted that early visual deprivation from monocular enucleation (ME; the surgical removal of one eye) results in intact spatial vision. Yet, motion perception studies in this population yield inconsistent findings. Here, we investigated speed and luminance contrast perception in a group of ME individuals.

Twelve ME participants (mean age = 24 years; mean age at enucleation = 24 months) and 17 controls (mean age = 25 years) viewing binocularly (BV) and monocularly (MV) completed a series of speed discrimination and luminance contrast detection and discrimination tasks. Stimuli consisted of 0.5 cpd vertical sine wave gratings varying in speed (3.8°/s-24°/s) or luminance contrast (0%-78%). A second set of luminance contrast tasks with 4 cpd gratings teased apart any spatial frequency effects.

The ME group exhibited elevated speed discrimination thresholds compared with BV (P = 0.001) and MV (P = 0.027) controls, but intact luminance contrast discrimination (P = 0.530). Notably, both ME and MV groups displayed elevated luminance contrast detection thresholds compared with the BV group (Ps ≤ 0.006). However, the ME group exhibited slightly lower thresholds compared with MV controls for all 4 cpd tasks.

Our data indicate a disruption in the development of speed perception, but not luminance contrast perception with monocular enucleation. These data highlight the importance of receiving healthy binocular vision during postnatal development for the maturation of cortical regions associated with motion processing.