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U. Polat, A. Sterkin; Enhancing Processing Speed Improves Visual Functions in Presbyopia. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3629. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
During the last decade it has been established that perceptual learning is practical for improving visual functions (Polat 2009, Vision Research 49, 2566-73). The applicability of the gains to other visual functions, such as reading, is an important advantage of perceptual learning. In presbyopia, the visual input to the brain is limited by the optics of the eye.
We have developed a structured perceptual learning method for improvement of the visual functions in presbyopia. Subjects were trained on contrast detection of Gabor targets under backward masking conditions, posing temporal constraints on the visual processing. The training covered a range of spatial frequencies and orientations that were modified in accordance with the improvement of the subjects. The subjects were trained in a dark room from a distance of 40 cm with both eyes open. The visual acuity, spatial and temporal contrast sensitivity, as well as reaction time were tested before and throughout the treatment. The subjects practice for at least two sessions of about 30 min per week. The results of the first 35 subjects (51 ± 1 years, mean ± se) of the on-going study that completed at least 20 sessions are presented.
The results show a substantial improvement in the spatial and temporal contrast sensitivity, leading to improved processing speed of target detection as well as in reaction time. Most importantly, the improvement in other visual functions was also observed, such as the improvement of 73% in the visual acuity (more than 2 ETDRS lines). Moreover, after training, there was a real benefit for the subjects; most of them were able to read with no reading glasses. The subjects reported a subjective feeling of improvement in their daily activities as well. The gains were retained when retested several months after the cessation of the treatment.
The training method that is based on improving the processing speed provided the neuronal basis for improving several visual functions, including near vision. A parallel study in younger subjects provided neurophysiological support for the brain changes in the brain induced by a similar training procedure (Sterkin, Yehezkel, Lev and Polat, ARVO 2009). Thus, our method is effective in improving visual functions in people with impaired or blurred vision by enhancing the image representation in the brain.
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