Objective Assessment of Eye Dominance Using the VEP: A Pilot Study

Objectives: To develop a clinical protocol for the determination of eye dominance using an objective method (i.e., the visual evoked potential [VEP]), and furthermore to determine the correlation of these objective findings with clinical subjective tests of eye dominance to provide guidance in clinical monovision refractive correction. Methods: The Diopsys NOVA-TR system was used to record the VEP amplitude and latency of 10 visually-normal, presbyopic, adult subjects aged 50 to 70 years ( [GRAPHICS] =60, SEM=0.17 years). First, eye dominance was assessed in two ways: a sensory-based "sensitivity to blur task" and a motor-based "sighting task." Next, while monocularly defocused, subjects binocularly viewed a black-and-white checkerboard (20-min arc size), pattern-reversal stimulus under 7 different test conditions: (1) baseline, (2) dominant (DE) eye blurred +1 diopter (D), (3) nondominant (NDE) eye blurred +1 D, (4) DE +2 D, (5) NDE +2 D, (6) DE +3 D, and (7) NDE +3 D. Results: Under nearly all conditions (22/24=92%), the amplitude and latency were significantly different from baseline with any amount of defocus (P<0.05). Monocular defocus decreased, and increased, the mean binocular VEP amplitude and latency, respectively. There were no significant differences in either the binocular VEP amplitude or latency values when comparing defocused dominant vs. nondominant eyes. Conclusions: Eye dominance type (i.e., sensory or motor) and status (i.e., DE or NDE) did not provide a differential effect with respect to the VEP findings. Thus, the VEP technique does not show promise as an objective adjunct in the fitting of monovision correction.