Benefits of retinal image motion at the limits of spatial vision
The visual benefit of correcting high-order aberrations may not be fully realized due to neural mechanisms that compensate for the aberrations of the eye. We examined the extent to which these neural mechanisms might be susceptible to perceptual learning in an adaptive optics (AO)-corrected test of visual resolution. Visual resolution was measured in an adaptive optics scanning laser ophthalmoscope (AOSLO) in 3 conditions: (1) low-order correction (defocus and astigmatism) without AO, (2) 3-mm pupil with AO correction, and (3) 5.81-mm pupil with AO correction. Measurements were made on both eyes in all three conditions before training. Subjects underwent 5 days of monocular training in both AO-corrected conditions and were retested in all three conditions in both eyes after training. The range of minimum angle of resolution (MAR) for each condition was: (1) without AO: 0.53-0.95 arcmin, (2) AO 3-mm pupil: 0.33-0.6 arcmin, and (3) AO 5.81-mm pupil: 0.36-0.56 arcmin. AO correction provided an immediate and significant improvement in visual resolution. There was no significant difference in resolution when correcting aberrations over a 5.81-mm pupil versus a 3-mm pupil. Training on this task provided a minimal improvement in performance. Adaptation to aberrations did not hinder AO correction from providing an immediate visual benefit.