Abstract
The present study conducted three psychophysical experiments to examine whether the visual system can compensate the retinal image blur induced by refractive error. In experiment 1, we measured the percentage of correct answers for Snellen letter (letter size = 0.15 deg) blurred by a myopia-simulated (2D-Gaussian) filter after 10 minutes of adaptation to blurred or non-filtered natural images. The result shows a significant improvement of percent correct by the blur adaptation. In experiment 2, an astigmatism-simulated (1D-Gaussian) filter was applied instead of the myopia-simulated filter in experiment 1. The percent correct systematically improved when the filtering orientation was identical in both letters and natural images. In experiment 3, in order to simulate the coma-like aberration, non-linear phase characteristics were added to the astigmatism-simulated filter in experiment 2. The percent correct, in a similar fashion with the other experiments, improved by the adaptation to natural images blurred by the identical filter used for the letters. However, only for the coma-like aberration, large adaptation area (at least up to 2 deg) was necessary for the improvement of percent correct. These results suggest the existence of neural compensational mechanisms that modulate not only amplitude but also phase spectra of perceived image.