认知与发展心理学研究室知识库

人是典型的双眼视觉生物，来自双眼的信号形成单一的视觉需要经过复杂的眼间相互作用。平衡的眼间相互作用可能是形成正常单双眼视觉功能的关键;眼间相互作用的异常则会引起弱视、斜视等视觉疾病的发生。目前，正常和异常的眼间相互作用分别存在怎样的特性，眼间相互作用与单、双眼功能之间的关系及眼间相互作用是否具有可塑性尚未完全清楚。本研究从眼间相互作用特性和可塑性两方面入手，针对不同群体的眼间相互作用特性，眼间相互作用的异常与单、双眼视觉功能之间的关系及亮度对眼间相互作用的调控等三个问题，设计了2个研究5个实验:

研究一考察眼间相互作用特性。实验一采用双眼相位和对比度共测量范式并结合多通道对比度增益控制模型，首次对正常人、弱视和临床己治愈弱视的眼间相互作用特性进行系统研究。结果表明，正常人的单眼信号和眼间相互作用信号与对侧眼基本平衡;弱视的弱视眼存在单眼信号的衰减，只有健眼的0.87，眼间相互作用也表现出损伤，健眼施于弱视眼的直接抑制为对侧的10倍，间接抑制为254.97倍;值得注意的是，临床己治愈弱视虽然原弱视眼单眼信号的衰减恢复，眼间相互作用依然存在异常，来自健眼的直接和间接抑制分别为对侧的3倍和3.25倍。在此基础上，实验二和实验三分别从双眼和单眼两个角度，考察了眼间相互作用的异常(弱视和己治愈弱视)与视觉功能的关系。实验二研究异常眼间相互作用与空间对比敏感度函数、双眼竞争和立体视功能的关系。我们发现，眼间相互作用与双眼竞争具有较强的相关性。其中，直接眼间抑制与(原)弱视眼与健眼的总占优势次数之比、总占优势时长之比及占优势平均时长之比相关显著(p=0. 017 ; p=0. 016 ; p=0. 016;间接眼间抑制与占优势次数比存在边缘显著的相关(p=0.057，与总占优势时长比、平均占优势时长比相关显著(p=0. 023 ;p=0.028。实验三测查了异常眼间相互作用与临床弱视诊断的金标准(即弱视眼视力、眼间视力差)的关系。结果表明，单眼信号衰减和眼间相互作用与(原)弱视眼视力、眼间视力差都存在显著相关。更有趣的是，眼间相互作用与二者的相关性更强。眼间直接抑制能解释(原)弱视眼视力53.1%的变异，眼间直接和间接抑制共同解释了57.3%的眼间视力差的变异。

研究二以亮度为切入点，围绕异常眼间相互作用的可塑性展开。实验四设置了2种亮度适应水平，被试在100%和1%透光率水平分别适应5分钟和20分钟后，完成两次双眼相位、对比度整合任务。模型分析表明，双眼亮度适应对眼间相互作用的调控不显著，但存在个体差异。5名被试(共10名)的眼间相互作用受到了亮度调制，主要表现为来自健眼的抑制减轻。在实验五中，我们采用了另一种思路调控眼间相互作用:单独降低健眼亮度至1%，形成眼间亮度差。结果显示，眼间亮度差对眼间相互作用具有显著的调控作用。所有被试的眼间相互作用信号与单眼信号均发生了变化，弱视眼与健眼更加平衡，甚至转化成了优势眼。

整体而言，不同群体呈现的眼间相互作用特性存在差异;异常眼间相互作用与单双眼视觉功能的损伤之间的相关性主要表现在双眼竞争、单眼视力和眼间视力差上;亮度差对眼间相互作用的调控效果比亮度适应更强。我们的结果将加深对眼间相互作用的认识，为弱视等眼间相互作用表现异常的疾病的治疗提供新的思路。

We have two eyes and complex interocular interaction works to combine two monocular visual signals to form a single vision. Balanced interocular interaction, is critical to develop normal monocular and binocular visual functions; abnormal interocular interaction will lead to visual diseases such as amblyopia and strabismus. It is presently unclear what the normal/abnormal binocular interaction is, whether it is relevant to other visual functions, and how plastic it is. This research focused on the characteristics and plasticity of interocular interaction, which covered 3 topics ranging from the characteristics of binocular interaction in three group(Exp 1)， the relationship between the abnormal interaction and deficits in binocular as well as monocular visual functions(Exp 2&3)，and the modulation of luminance on interocular interaction(Exp 4&5).

Study 1 is to investigate the characteristics of interocular interaction in normal, amblyopic and clinically "treated" amblyopia. Thirty subjects were recruited. A binocular phase and contrast combination paradigm and a multi-channel contrast gain model(MCM)were adopted. The results indicated that monocular signal and interocular interaction in normal subjects were essentially balanced; for amblyopia, however, there existed attenuated monocular signal in amblyopic eye(AE)and stronger interocular interaction (both direct and indirect) from fellow eye(FE)to AE. Notably, impaired interocular interaction remained in clinically "treated" amblyopia, despite visual acuity and monocular signal attenuation in AE had been rescued. To further identify the relationship between abnormal interaction and deficits in contrast sensitivity function(CSF)，binocular rivalry, stereopsis, visual acuity(VA) in AE and the VA difference between AE and FE, Exp 2 and 3 were conducted on amblyopia and treated amblyopia. We found that there was significant correlation between binocular interaction and the ratio of total dominant times(AE/FE)，the ratio of total dominant duration(AE/FE)，and the ratio of mean phase duration(AE/FE). Unexpectedly, the magnitude of abnormal interaction was highly correlated with visual acuity in AE and the VA difference between AE and FE, the gold standard to diagnose amblyopia and evaluate amblyopia treatment.

In study 2, we explored how luminance influence the plasticity of aberrant interocular interaction. Neutral density filter(ND filter)was applied to reduce luminous intensity in both eyes (Exp 4) and the fellow eye (Exp 5). In Exp 4, 10 amblyopes took binocular phase and contrast combination measurement at OND(100% transmittance)and 2ND(1% transmittance)levels after separately adapting for 5 or 20 minutes. Although interocular interaction was not influenced on average, interocular inhibition did have been relieved from FE to AE in half of the subjects. In Exp 5, we introduced a 2ND luminance difference by reducing the brightness to 1% transmittance only in FE and found that luminance-difference significantly changed both interocular interaction and monocular signal attenuation, leading to more balanced AE and FE and even reversed ocular balance .

To conclude, different population may have different characteristics of binocular interaction, the aberrant interaction has significant correlation to binocular rivalry, VA and VA difference in amblyopia. Luminance difference modulates this interaction more than luminance adaptation does. Our results will help understand binocular interaction and provide new ideas for developing treatments to patients with the aberrant interaction.