PTM模型的参数分析以及在成人弱视疗效评价中的应用研究

发布时间：2018-02-09 06:16

本文关键词： 知觉模板模型成人弱视知觉学习对比敏感度　出处：《浙江工业大学》2011年硕士论文　论文类型：学位论文

【摘要】：弱视是一种常见的视觉发育性疾病,在临床上通常表现为视力、对比敏感度以及立体视觉等视功能的损害。由于许多儿童弱视患者延误了治疗的最佳时期,使得我国成人弱视患者数量大幅增加。为了找到治疗成人弱视的有效方法,近年来国内外专家在弱视视觉缺损机制的研究中,发现了利用知觉模板模型(Prepertural Template Model,PTM)可以解释成人弱视视功能损害的潜在机制,对该机制的研究有助于更全面的了解弱视的视功能缺陷,为应用知觉训练方法治疗成人弱视提供了重要的依据。国内外研究者利用PTM模型在研究成人弱视患者的视觉缺损机制中,发现成人弱视患者视觉敏锐度和对比敏感度的损害与内部加法噪声和模板匹配能力紧密相关,表现为内部加法噪声的增加和模板匹配能力的变差,但由于没有给出正常人PTM模型的参数,因此不能定量描述弱视患者经过知觉学习训练后内部加法噪声和视觉模板匹配能力的改变程度。本文分析了正常眼的PTM模型参数,并通过分析成人弱视患者知觉学习训练前后的PTM模型参数,确定患者视力和对比敏感度提高的潜在影响因素。本文的主要工作有以下几个方面: 1、采用Xu(2006) PTM模型的心理物理学实验方案,测量了平均年龄为24.3的正常被试21人(42只正常眼)在外加噪声情况下的对比度阈值,通过最优参数拟合,得到正常人PTM模型的内部加法噪声、内部乘法噪声、信号增益、非线性因素,以这4个参数作为基准参数对比分析成人弱视患者在知觉学习训练前、后表征内部加法噪声和模板匹配能力的参数。 2、在现有知觉学习治疗成人弱视的研究基础上,设计并实现了基于知觉学习的成人弱视训练系统。根据知觉学习的特异性和迁移性,设计了Gabor的识别训练,在训练中改变Gabor光栅的方向,对比度和空间频率。另外,采用侧翼加干扰的训练方式,来提高弱视患者的空间交互作用,促进弱视患者视功能的恢复。在训练过程中根据患者当前的训练情况实时调整训练参数,每次训练的参数由系统根据最新的训练结果自动获得,确保患者始终在阈值附近训练。 3、对实验组平均年龄为20.2的5名成人弱视患者训练前后PTM模型的参数,患者的视力、对比敏感度进行分析。通过知觉学习进行为期一个月的训练后,分析训练前后的数据表明:弱视视觉系统表征内部加法噪声的参数Aa和表征模板匹配能力的参数Af均有不同程度的下降,且趋向于正常眼的参数值1,其中内部加法噪声的降低更为显著,对训练前、后Aa进行Wilcoxon符号秩检验,p0.05,具有显著性差异。同时,经标准对数E字视力表测量训练后视力平均提高1.4行,使用OPTEC6500测量训练后对比敏感度在5个空间频率上均有不同程度的提高,经配对t检验,p0.05,差异显著。通过本文的知觉学习训练方法可以降低成人弱视患者的内部加法噪声和改善模板匹配能力,对提高视力和对比敏感度具有较好的作用。
[Abstract]:Amblyopia is a developmental disease common vision, usually in clinical performance for visual acuity, contrast sensitivity and stereoscopic vision and visual function damage. Because many children amblyopia patients delayed treatment period, the number of China's adult amblyopia patients increased significantly. In order to find the effective method to treat adult amblyopia in recent years. Domestic and foreign experts in the amblyopic visual defect mechanism, found using perceptual template model (Prepertural Template Model, PTM) can explain the potential mechanism of adult amblyopia visual function impairment, contribute to a more comprehensive understanding of visual function deficits in amblyopia research on the mechanism, which provides an important basis for the application of perceptual training method for the treatment of adult amblyopia.
Using the PTM model in the visual defect mechanism of patients with adult amblyopia in research at home and abroad, found that adult patients with amblyopia visual acuity and contrast sensitivity damage and internal additive noise and template matching ability is closely related to increased additive noise and template matching ability of the poor, but because the parameters did not give normal people PTM model, it can not describe the change degree of amblyopia by perceptual learning training after internal additive noise and visual template matching ability. This paper analyzes the PTM model parameters of normal eyes, and through the analysis of adult amblyopia patients perceived PTM parameters before and after training, to determine the potential impact of visual acuity and contrast sensitivity improvement factor. The main work of this paper has the following several aspects:
1, using Xu (2006) psychophysical experiment scheme of PTM model, measured the average age of 24.3 normal subjects and 21 people (42 normal eyes) with contrast threshold of noise, the optimal parameter fitting, normal PTM model of internal additive noise, internal multiplicative noise, signal gain. Nonlinear factors on these 4 parameters as the benchmark parameter comparative analysis of adult patients with amblyopia in perceptual learning training, parameter characterization of internal additive noise and template matching ability.
2, learning the basic research on treatment of adult amblyopia in the existing perception, the design and implementation of the adult amblyopia training system based on perceptual learning. According to the specificity of perceptual learning and migration, the design of Gabor recognition training, change the direction of Gabor grating in training, contrast and spatial frequency. In addition, the wing added interference of training methods, to improve the spatial interaction of amblyopia patients, promote the recovery of visual function in amblyopia. In the process of training according to the current situation of training patients adjust the training parameters, the parameters of each training session automatically by the system according to the new training results, to ensure that patients are always near the threshold training.
3, the average age of the experimental group for the parameters of the PTM model before and after the 5 of 20.2 adult patients with amblyopia training, visual acuity, contrast sensitivity analysis. For a month of training through perceptual learning, data analysis before and after the training showed that the parameters of Aa and characterization of template amblyopia visual system characterization of additive noise the matching ability parameters of Af were decreased in varying degrees, the parameters of normal eyes and tend to value 1, which reduce the additive noise is more significant, for before training, after Aa Wilcoxon signed rank test, P0.05, with a significant difference. At the same time, the standard logarithmic visual acuity chart visual acuity E measurement after training on average improve the 1.4 lines, using OPTEC6500 measurements after training contrast sensitivity at 5 spatial frequencies were increased to different extent, the paired t test, P0.05, significant difference. Through the perceptual learning training method can be reduced The internal addition noise and the improved template matching ability of the patients with low adult amblyopia have a good effect on improving vision and contrast sensitivity.

【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：R777.44

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