| Amblyopia is a disease of visual developmental disorder, which usually manifested as visual function damagements on visual acuity, contrast sensitivity and etc. In China, there is a huge number of adult patients with amblyopia. Through the research on amblyopic visual defect mechanism in recent years, it is found that using PTM model (Prepertural Template Model) can explain the potential mechanisms of amblyopic patients' visual function damagement, The study in perceptual mechanisms of amblyopia contribution a lot to completely understanding the visual deficiencies in amblyopia,and it's provide an important basis that treat adult amblyopia by perceptual learning.By applying PTM model into the visual defect mechanism resaerch for adult amblyopia, the experts from both domestic and overseas found that the damage of visual acuity and contrast sensitivity is somehow closely related with internal additive noise and perceptual template machting ability, and even showed as increased additive noise and deficient perceptual templates,but without giving the normal's PTM parameters,so it can't quantitative evaluation the range of internal additive noise and perceptual template after training.In this paper we analysis of the normal PTM parameters,and by analyzing the adult amblyopia PTM parameters before and after training so as to find the primary factors of the visual acuity and contrast sensitivity improved. The main research contents include the following:1. Based on the psychophysical experimental program for parameter estimation in PTM model made by Xu (2006), this paper measured the TvC curve (external noise versus contrast threshold) for 42 normal eyes(average age, 24.3 years old) and fitted the mesured TvC value with the best parameter, and then gained the parameter for normal people,it's the internal additive noise,internal multiplicative noise,signal gain,nonlinearity.To these four parameters as benchmarks for comparative analysis of adult amblyopia's parameters which characterizating internal additive noise and template machting ability before and after training.2. Based on the present research of the treatment to adult amblyopic patients through perception learning, this paper designed and even accomplished the perception learning-based adult amblyopia training system. According to the specificity and transfer of perceptual learning,designed the gabor identify training and change the direction,contrast and spatial frequency during the training. In addition, using interference with flanking training methods to improve amblyopia spatial interaction, thereby promoting the recovery of visual function in amblyopia.,and according to the patient in real time adjustment of the current training parameters, getting the parameters of each training session by the system according to the latest results automatically, to ensure that patients always near the threshold training.3. Analyzed the vision, Contrast sensitivity, PTM data measured from 5 amblyopic patients(average age, 20.2 years old) both before and after training. Through a one-month training, analysis of data shows that: the value of parameter Aa characterizing the internal noise and the parameter Af characterizing template machting ability are decreased in varying degrees,and their trend towards normal eyes in value 1,befor and after training, Wilcoxon signed rank test for Aa,p<0.05, it's significant difference. Meanwhile, the visual acuity has raised by an average of 1.4 lines (using the standard logarithmic visual acuity chart E word), and the contrast sensitivity also has gained improvement to varying degrees in 5 spacial frequencies(using OPTEC6500), by paired t test,p<0.05. The perceptual learning by this method can reduce the adult amblyopia internal additive noise and improve the temmplate matching capabilities,besides there are good effect to improve visual acuity and contrast sensitivity. |
PDF Full Text Request