Contour interaction for high and low contrast optotypes in normal and amblyopic observers
Contour interaction for high and low contrast optotypes in normal and amblyopic observers
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DOI：
10.1016/s0275-5408(98)00056-8
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发表时间：
1999-05-01
影响因子：
2.9
通讯作者：
Winn, B
中科院分区：
文献类型：
--
作者：
Simmers, AJ;Gray, LS;Winn, B
我们研究了刺激对比度对正常人和弱视受试者轮廓交互作用的影响。使用计算机生成的视力任务，对19名正常和11名弱视受试者进行了高对比度(80%)和低对比度(6%)下的侧视和非侧视视力的心理测量。高对比度字母的拥挤率显著高于低对比度字母，通过改变视标和侧翼条的间距来测量高对比度和低对比度下的拥挤区的程度。对于高对比度视力类型，使用屈光模糊重复测量拥挤区。在高对比度下，侧边轮廓的位置对字母分辨率有显著影响，但在低对比度时没有显著影响，在高对比度下，随着屈光模糊的增加，轮廓相互作用的影响变得可以忽略不计。这些发现支持这样的假设：(1)在阈值测试时，正常和弱视眼睛的拥挤效应相似；(2)只有高对比度的视力类型才会出现对比度相关的效应。(C)1999年视光师学院。爱思唯尔科学有限公司出版。版权所有。
We investigate the influence of stimulus contrast upon contour interaction in normal and amblyopic subjects. Using a computer generated acuity task, flanked and unflanked acuities were measured psychometrically at both high contrast (80%) and low contrast (6%), in a group of 19 normal and 11 amblyopic subjects. The crowding ratio for high contrast letters was found to be significantly higher than that for low contrast letters, The extent of the crowding zone was measured at high and low contrast by varying the separation of the optotype and flanking bars. The crowding zone measurement was repeated for the high contrast optotypes using dioptric blur. The position of the flanking contours was found to have a significant effect on letter resolution at high contrast but no significant effect was demonstrable at low contrast, With the addition of dioptric blur the effect of contour interaction became negligible at high contrast. These findings support the hypothesis that the crowding effect is: (1) similar in normal and amblyopic eyes when tested at threshold; (2) is contrast dependent appearing only for high contrast optotypes. (C) 1999 The College of Optometrists. Published by Elsevier Science Ltd. All rights reserved.