To explore changing disparity (CD)-based motion-in-depth (MID) perception in optic neuritis (ON) patients and to evaluate its relationship to inter-ocular delays.

Demyelination, resulting in delayed conduction velocities, may specifically affect temporal aspects of visual perception following an ON episode.  Monocularly, motion perception tests have demonstrated close association with VEP latency in the affected eye. Binocularly, reduced performance on a time-constrained stereo task was observed and found to be correlated with inter-eye difference in projection latencies along the visual pathways, suggesting that synchronization of the projection rate from both eyes is needed. Herein, we combine motion and binocularity using the CD-based MID stereoscopic cue in which the brain requires accurate spatial matching of the two eyes’ view to perceive the stimulus.

Fourteen ON (12 females, 36±14 years old; 21±11 months since ON episode) and 8 controls (5 females, 31±8 years old) underwent visual acuity, contrast sensitivity, VEP and MID tests. P100 measurements were extracted from VEP data. Student's t-test and Pearson correlation were used for statistical analysis.

The ON group showed lower performance level in the CD-based MID test relative to the controls. Negative correlation was found between performance level and difference in VEP latencies between the affected and fellow eyes. In addition, adding an artificial delay in presenting the stimulus to one eye only resulted in lower CD-based MID perception in the control group.

The ability to perceive motion-in-depth is impaired in ON patients due to lack of synchronization of the two eyes’ view. We hypothesize that adding a VEP-based delay in presenting the stimulus to the fellow eye will improve the ability of ON patients to perceive depth movement. If so, we may be able to use this system as a therapeutic tool for impaired binocular vision.