Dissertation > Biological Sciences > Physiology > Neurophysiology

Improvement of Visual Functions in Normal Adults Through the Combination of Adaptive Optics Correction and Perceptual Learning

Author ZhouJiaZuo
Tutor ZhouYiFeng
School University of Science and Technology of China
Course Biophysics
Keywords Perceptual learning Plasticity Higher-order aberrations Adaptive optics Super vision
Type PhD thesis
Year 2011
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A basic theory of visual neuroscience is the development of the visual cortex critical period \At present, the evidence shows that many perceptual learning, even adult visual cortex plasticity. However, normal adult, the perceptual learning process reflects the plasticity exists, its extent is very small. This greatly limits of perceptual learning in improving the adult visual function. Most of the previous studies that this may be due to low adult visual nervous system plasticity result. But whether there may be other factors that limit normal adult plasticity in perceptual learning process play? Currently unclear. On the other hand, the use of astronomical adaptive optics correction technology, the field of optometry researchers ocular higher-order aberrations part through correction of human adult visual function. But normal adults, this visual function improvement is very weak, far less than the theoretical expectations; exist and can not be divorced from the adaptive optics correction instrument, and therefore can not be applied to the actual. On this basis, the paper combines advanced progress on perceptual learning and the human eye adaptive optics, in-depth study of the pros and cons of the human eye image quality of perceptual learning effect, a meaningful discussion on these issues. Specifically, we compare the ideal human eye in the case of correction of ocular higher-order aberrations (system) contrast detection task perceptual learning and correction of higher-order aberrations of the human eye (the ordinary human eye system ) Similarly, the task of perceptual learning, contrast sensitivity and visual acuity improved degree of difference. Experiment, 21 normal adults were randomly divided into two groups for training. The first group of 13 people, in the the perceptual learning correct higher-order aberrations case; second group of eight people for training, in the case of higher-order aberrations are not corrected. Two groups are using the high spatial frequency end of sinusoidal gratings training for 10 days, about one hour daily training. After training, the first group of subjects in the training frequency contrast sensitivity increased very significantly (P lt; 0.00001), increased by an average of 5.39dB (corresponding increased 86.1%), the learning curve slope 0.41log units per session reached a plateau in 7.35 sessions after training; group training frequency contrast sensitivity improve also reached a significant (P = 0.03) increased by an average of 3.42dB (corresponding to the increase rate of 48.2%), the learning curve the slope 0.35log units per session, and reached a plateau after training 4.12 sessions. Before and after training, we also tested two groups of contrast sensitivity function (Contrast Sensitivity Function CSF), under different spatial frequency contrast sensitivity and spatial frequency relations. Overall, the two groups were CSF training has significantly improved (comparing before and after training, the first set of the second group, F (1,7) = F (1,12) = 75.43, P lt; 0.00001; 5.46, P = 0.05), but the first group of the CSF raise more (two groups of CSF increased significantly different F (1,19) = 8.12, P = 0.01). Different subjects under different spatial frequency contrast sensitivity to improve the average value of the amplitude, the first group of 3.11dB, second group 1.3ldB. Training after CSF significantly increased in terms of (the first group of 13 subjects, and the second group of four subjects), the two groups were not significantly raise the value of the differences in the training frequency (P gt ; 0.5), but in the bandwidth characteristics of the transmission characteristic (the training frequency increases to the frequency of non-training) are very different, there are two: the first group of the learning effect, a nearby (bandwidth of 1.11octaves a specific training frequency ), another prevalent in all the test frequency (increase the range of the maximum increased half); second group of the learning effect is specific for only one the training frequency near improve (bandwidth of 1.42octaves). Another interesting finding is that the vision of the first group training significantly improved (P lt; 0.000001), and the second group (P = 0.199). The first group all have a vision to improve the average increased 2.32dB (corresponding to the margin of increase of 31%) was significantly higher than the second group (P = 0.0008). After 5 months, we retrieve the four subjects in the first group, found that the improvement of their vision also remains. By analyzing the groups before and after training were optical modulation transfer function and neural modulation transfer function changes, we confirmed that the contrast sensitivity training led to the increase from the visual nervous system rather than changes in the system of the human eye. The first group was this better learning effect, it is also likely to come from higher-order aberrations environment longer experiences. In order to exclude this, we have designed a third group was trained (Group3 6 people). The third group and the first group is the same for training in higher order aberration correction, the difference is that we have selected the low spatial frequency end of the \the spatial frequency, as the frequency of training. The results showed that the improvement of the third group of small, than the first group to be small. This shows that, although higher order aberrations can improve perceptual learning effect, but the use of low-spatial-frequency end of the training is not sufficient to meet the training effect, we must also use the high spatial frequency end training. In order to reveal the internal mechanism of the first group in training scores improve, we check the first group of four different noise levels under contrast threshold changes to correct higher-order aberrations were before and after the training. Analysis, we found that the improvement of learning from the visual nervous system information extraction efficiency, rather than internal noise reduction, which is similar to the results of the previous study of normal perceptual learning. Our results showed that the developmental critical period after the normal adult visual nervous system still has a considerable degree of plasticity, but the quality of these plasticity play limited by the training of the human eye when the optical system imaging. Only when the higher-order aberrations are corrected out to play the actual plasticity level. Our findings can be used to explore new methods of treatment to those caused by the development of early abnormal visual experience in the visual cortex of abnormal cause poor eyesight adult patients improve vision. The same time, the discovery of this article, also combining study the progress of the human eye and optic nerve system to achieve \

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