Abstract
Abstract: :
Purpose: To show how much binocular summation has been overestimated by effects of pupil size. Methods: The nine healthy volunteers (mean age 21.2 years old) took part in this study. Continuous recording of natural pupil diameters under monocular and binocular conditions was performed during each examination; visual acuity at distance and near, contrast sensitivity (CS), refraction. The pupil diameters were measured with an infrared electronic pupillometer FP–10000 (TMS, Japan), which can measure in open–view and real times under examinations of visual performances. Aberrometry measurements were performed . Zernike coefficients were calculated for pupil diameters under the binocular and monocular conditions. Results: The monocular visual acuity (log MAR) at the distance and near were significantly worse than the binocular acuity (p < 0.01). Significant differences were found between the monocular log CS and the binocular log CS at the spatial frequencies greater than or equal to 6 c/deg (p < 0.05). Therefore, binocular summation ratio significantly heightened with the increase of the spatial frequencies (p < 0.05). Then mean pupil diameters under examinations of the monocular conditions significantly increased as compared to binocular conditions (p < 0.0001). In proportion to increases in the pupil diameters, the optical aberrations significantly increased (p < 0.05). Conclusions: This result suggests that the enlargement in pupil diameters from the binocular to the monocular viewing conditions cause for the increase of optical aberration to reduce retinal image quality and decrease of subjective visual performances consequently. We conclude that the effect of pupil size has overestimated in binocular summation.
Keywords: pupil • contrast sensitivity • binocular vision/stereopsis