Abstract
Purpose: :
to determine the influence of binocular versus monocular vision on blur detection thresholds, using natural images.
Methods: :
blur detection thresholds (BDT) were measured monocularly for each eye and binocularly in 26 adults with normal or corrected to normal visual acuity, using simulated blur. Order was randomized. BDTs were measured for 3 images (E letters, face, scenery), using a six staircase method, one ascending and one descending for each image. Blur was changed in steps corresponding to 0.05D. Images were presented on a monitor at 1 meter from the subject in order to minimize lag of accommodation.
Results: :
BDTs were significantly influenced by the type of image presented (p<0.001), the 2 natural images having the highest thresholds, E letters the lowest, with an average difference of 28%. Monocular BDTs showed a significant average difference of 11% (p<0.01). High order RMS or differences in refraction between the two eyes did not explain this difference. Binocular BDT was comparable to the lowest monocular BDT (p=0.11). Standard deviations of BDT were comparable for each eye, but lower for binocular measurements (p=0.02).
Conclusions: :
binocular summation did not influence the threshold of blur detection, but improved its reliability.
Keywords: perception • binocular vision/stereopsis