Li Roger W, Levi Dennis M
School of Optometry and Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA.
J Vis. 2004 Jun 1;4(6):476-87. doi: 10.1167/4.6.7.
Adult amblyopes can improve positional acuity through practice; however, the neural mechanisms underlying this improvement are still not clear. In this study, seven adult amblyopes repeatedly practiced a position discrimination task in the presence of positional noise. We found that six of the seven showed systematic and significant improvements in position acuity that were both eye and orientation specific. Using a position-averaging model, we were able to parse the improvement in performance with practice into two factors: improvement in sampling efficiency and reduction of equivalent input noise. Three of the seven showed improved efficiency with no change in equivalent noise, two showed a significant reduction in equivalent noise with no change in efficiency, and one showed both improved efficiency and reduced equivalent noise. Interestingly, all observers showed substantial improvement in visual acuity, and one observer showed substantial improvement in stereoacuity. Three observers were also tested on a counting task, and all three improved after practicing positional discrimination. Our results reveal the mechanisms underlying perceptual learning in amblyopic vision, and may provide a basis for developing more effective and efficient strategies for the treatment of amblyopia.
成年弱视患者可通过练习提高位置敏锐度；然而，这种改善背后的神经机制仍不清楚。在本研究中，七名成年弱视患者在存在位置噪声的情况下反复练习位置辨别任务。我们发现，七名患者中有六名在位置敏锐度上表现出系统性且显著的改善，这种改善具有眼特异性和方向特异性。使用位置平均模型，我们能够将练习带来的性能改善分解为两个因素：采样效率的提高和等效输入噪声的降低。七名患者中有三名显示效率提高而等效噪声无变化，两名显示等效噪声显著降低而效率无变化，一名显示效率提高且等效噪声降低。有趣的是，所有观察者的视力都有显著改善，一名观察者的立体视锐度有显著改善。三名观察者还接受了计数任务测试，在练习位置辨别后，三人都有进步。我们的结果揭示了弱视视觉中感知学习的机制，并可能为开发更有效和高效的弱视治疗策略提供基础。
