[The influence of ocular dominance on monovision--the influence of strength of ocular dominance on visual functions].
OBJECTIVE
Monovision is a method of correction for presbyopia. We have reported the advantage of conventional monovision (the dominant eye is corrected for distance). In this study, we investigated the influence of interocular imbalance of dominancy on the visual function.


METHODS
Ten healthy subjects without any ophthalmologic disease participated. After cycloplegia, the eyes of the subjects were corrected by soft contact lenses with an artificial pupil (diameter: 3.0mm). The dominant eye was corrected for distance, and the difference in lens power between the lenses was 2.5 D. The subjects were classified into two groups by strength of the imbalance of sensory dominance, which was determined by using binocular rivalry. Binocular visual functions (visual acuity at various distances, contrast sensitivity, near stereoacuity) were compared between the two groups.


RESULTS
Subjects with strong imbalance of sensory dominance showed decreased near visual acuity as well as decreased binocular summation of contrast sensitivity at low spatial frequencies. On the other hand, near stereoacuity was not affected by the imbalance of sensory dominance.


CONCLUSIONS
These results suggest that strong imbalance of sensory dominance interferes with binocular visual functions in monovision. Thus, the evaluation of ocular dominance is crucial for clinical applications of monovision.
Nitta
Marie
M
Department of Rehabilitation, Orthoptics and Visual Science Course, School of Allied Health Sciences, Kitasato University, Sagamihara, Japan. nitta-m@kitasato-u.ac.jp
Shimizu
Kimiya
K
Niida
Takahiro
T
D000065:Accommodation, Ocular; D000328:Adult; D003263:Contact Lenses, Hydrophilic; D023882:Dominance, Ocular / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011305:Presbyopia / Q000628:therapy*; D014785:Vision, Ocular / Q000502:physiology*; D014792:Visual Acuity