图形结构的知觉显著性与弱视眼的拥挤效应

目的研究图形整体结构是否影响弱视眼的拥挤效应.方法选择12名屈光参差性弱视患者,将复合图形呈现在计算机荧屏上的空白背景或由十字组成的背景上,分别记录患者的患眼和健眼分辨复合图形的整体和局部形状时的反应时和错误率.结果患眼和健眼分辨整体形状均比分辨局部形状的反应时短,这种整体图形的优势在患眼更强.患眼分辨局部形状的错误率受背景的影响,当复合图形呈现在空白背景上时较高,而呈现在由十字组成的背景上则较低.结论被分辨图形组成的整体结构的知觉显著性使患眼的拥挤效应增强

Perceptual salience of global structures and the crowding-effect in amblyopia

Objective The crowding effect refers to stronger deficits in linear acuity(e.g.,letter in a line) than in single letter acuity in amblyopia. The current work investigated whether the salience of a global structure in which the target for identification is embedded influences the crowding effect in amblyopia. Methods Compound shapes were presented to the amblyopic and fellow eyes respectively of twelve anisometropic amblyopes. The compound stimuli were presented on either a blank or a cross background so that the salience of global structures were manipulated. Reaction times (RTs) and response error rates were recorded when subjects identified global or local shapes, respectively. Results RTs were faster to global than local shapes for both the amblyopic and fellow eyes. Interestingly, when viewing the stimuli with the amblyopic eye, subjects made more errors to local targets when the compound stimuli were presented against the blank than the cross background. Conclusion The results suggest that the salience of global structures of visual stimuli contributes to the crowding effect in amblyopia.