背景 平面画面中有多种视觉线索构成深度或距离感知信息,但目前尚不清楚究竟是哪些深度线索对人眼的调节起主要作用,以及注视距离的不同是否使这种影响存在差异. 目的 研究不同距离的单眼空间深度感知对人眼调节反应的影响,分析线性透视和大小知觉恒常性深度线索对调节反应水平及波动幅度所起的作用. 方法 运用FLASH软件设计4组视标,视标1为静止环形图案;视标2包含大小知觉恒常性深度线索,动态表现从远至近或从近至远的环形图案;视标3包含线性透视和大小知觉恒常性2种深度线索,动态表现从远至近及从近至远的连续变化的车行轨迹;视标4去除线性透视深度线索,仅表现视标3中车的大小的动态变化.纳入26名22～ 26岁的受试者,球镜度数平均为(-4.06±1.99)D,柱镜度数平均为(-0.38±0.41)D,在矫正视力下单眼分别注视50 cm和33.3 cm的视标,采用Grand Seiko WAM-5500近红外开放视野自动验光仪,以5次/s的调节反应记录方式,全程记录受试者在注视变化过程中的调节反应及调节微波动. 结果 在50 cm的注视距离下,由大小知觉恒常性和线性透视共同作用时(注视视标3),由近处的距离感知引起的调节反应值为(1.52±0.46)D,远处为(1.37±0.46)D,两者间差异有统计学意义(P=0.016);由大小知觉恒常性独立作用时(注视视标4),大车的调节反应值为(1.43±0.35)D,小车为(1.43 ±0.36)D,差异无统计学意义(P=0.467).在33.3 cm的注视距离下,由大小知觉恒常性和线性透视共同作用时(注视视表3),由近处的距离感知引起的调节反应均值为(2.40±0.53)D,远处为(2.35±0.51)D,差异无统计学意义(P=0.379);由大小知觉恒常性独立作用时(注视视标4),大车的调节反应均值为(2.38±0.48)D,小车为(2.39±0.52)D,差异无统计学意义(P=0.820).只有线性透视深度线索(注视视标3)参与的由远近距离的心理感知所引起的总调节微波动曲线呈现明显的周期性波动. 结论 单眼的空间深度知觉在一定距离可以影响调节反应.构成空间知觉的深度线索中,线性透视提供了高层次的深度知觉,对调节反应水平及波动幅度起主要作用,而大小知觉恒常性依赖于线性透视等其他深度线索的辅助,其本身对调节反应水平及波动幅度的作用微小,甚至起反向作用.%Background Different depthes or distances are prompted with many visual cues on the flat screen.Which kind of depth cues plays a major role in the accommodation of human eyes,in addition,whether this effect exists in the different distance are still below understood.Objective This study was to research the effect of the monocular space depth perception on accommodative response at different distances,and to analyze the effect of linear perspective and size-constancy perceptual depth cues on the level and amplitude of accommodative fluctation.Methods Four groups of visual targets were designed by FLASH software and placed at the front of eyes with the distance of 50 cm or 33.3 cm,representing static change from far to near and dynamic change from far to near,from near to far respectively.Twenty-six healthy volunteers aged 22-26 years were included in this study,with the spherical power of (-4.06± 1.99) D and cylindrical power of (-0.38±0.41) D under the informed consent.The accommodative response and accommodative fluctuations during monocularly watching the targets were recorded at 5 times/second by Grand Seiko WAM 5500 automatic infrared refractor.This study was approved by Ethic Committee of Wenzhou Medical University,and written informed consent was obtained from each subject before entering the study group.Results At the distance of 50 cm,the accommodative response caused by the depth perception of near was (1.52±0.46) D,the one of distance was (1.37±0.46) D,with a significant difference of 0.15 D under the combined effect of linear perspective and size-constancy (P =0.016).The accommodative response caused by the depth perception of big car was (1.43 ± 0.35) D,and the one of small car was (1.43 ± 0.36) D,without statistically significant difference under the effect of size-constancy alone (P =0.467).At the distance of 33.3 cm,the accommodative response caused by the depth perception of near was (2.40±0.53)D,and the one of distance was (2.35 ±0.51) D,without significant difference under the combined effect of linear perspective and size-constancy (P=0.379).The accommodative response caused by the depth perception of big car was (2.38±0.48)D,the one of small car was (2.39±0.52)D,without statistically significant difference under the effect of size-constancy alone (P =0.820).In addition,the total curve of accommodative microfluctuation showed apparent fluctuation periodically caused by the distance perception involving linear perspective only.Conclusions Monocular space depth perception has some impacts on the accommodative response at certain distance.Linear perspective,which is one of the depth cues of space perception,plays a major role in the accommodative response.Compared with the size-constancy,linear perspective can provide depth perception at higher level.The size-constancy has a little or contrast impact to the accommodation,because it depends on the assistance from other depth cues like linear perspective.
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