[The influence of ocular dominance on monovision--the interaction between binocular visual functions and the state of...

To examine the interaction between binocular visual functions and the correction of the dominant eye, i.e., for far vs. near vision in monovision.

Ten healthy subjects without any ophthalmological disease were examined. After cycloplegia, the eyes of the subjects were corrected by soft contact lenses (difference in lens power between the lenses: 2.5 D) with an artificial pupil(diameter: 3.0 mm). Visual acuity at various distances, contrast sensitivity, and near stereoacuity were measured while the dominant eye determined by the hole-in-card test (sighting dominance) was corrected for far and near vision.

Binocular visual acuity was better than 1.0(20/20) at all distances. When the dominant eye was corrected for distance, the binocular visual acuity at 0.7 m was better than the monocular visual acuity; contrast sensitivity was better within the spatial frequency range of 0.5-4.0 cycles per degree, and near stereoacuity by Titmus stereo tests improved.

These results suggest that dominant eyes should be corrected for far vision for better binocular summation at middle distances, and near stereoacuity.