Pulfrich stereo-illusion phenomenon: Poor man's VEP?

Abstract

he Pulfrich effect reflects the interocular latency difference subjectively. The VEP testing provides quantitative measures of the absolute transmission time in each eye and also detects subtle interocular latency difference better than Pulfrich. However, when the Pulfrich effect is present, VEP is always expected to be abnormal. Moreover, the Pulfrich effect reliably identifies the involved eye. When the Pulfrich effect fails to be abnormal, VEP may still be abnormal.

This test can be used as a screening procedure to detect optic nerve disease since it is simple, quick, and less expensive than VEP.

Key Words:

• Pulfrich phenomenon
• visual evoked potentials