Measurements of the Pulfrich effect over days of exposure.

Mean depth settings and subjective reports appear to confirm previous subjective reports from users of the X-Chrom prescription lens that Pulfrich Effect depth distortions decrease with continued exposure to light intensity disparity. Depth setting variability across Days of exposure indicates a rapid increase in depth judgment errors which persists without decrement across Days. This increased variability, the apparent depth decrements, and color discrimination improvements shed light on the visual processing underlying the Pulfrich Effect and reveal a potentially dangerous illusion.