Wu Haoran, Li Xiaoning, Tang Yao, Xu Qinglin, Zhang Xuhong, Zhou Lu, Lan Weizhong, Zhang Bin, Yang Zhikuan
Aier School of Ophthalmology, Central South University, Changsha, China.
Aier Institute of Optometry and Vision Science, Changsha, China.
Front Neurosci. 2020 Feb 18;14:133. doi: 10.3389/fnins.2020.00133. eCollection 2020.
Both optimal stereoacuity and integration time to achieve that are impaired in patients with intermittent exotropia. The deterioration of stereoacuity is more revealing since it correlates well with exotropia control score.
Despite the periodic misalignment of two eyes, some intermittent exotropia (IXT) patients exhibit normal stereoacuity, particularly when evaluated with static tests. It is not clear if the temporal integration process of stereopsis is altered in IXT patients, thus warranting further research.
IXT patients ( = 29) and age-matched normal controls ( = 36) were recruited. Static stereopsis was measured with the Titmus stereoacuity test. In computer-generated random dots tests, stereoacuity was measured with a stimuli presentation duration varying from 100 to 1,200 ms. And the relationship between stereoacuity and stimuli duration was fitted into a quadratic model. Optimal stereoacuity was achieved when fitted curve flattened and the critical integration time was the duration needed to achieve optimal stereoacuity.
IXT patients were not found to differ significantly from control subjects under the Titmus test, while the Random Dots stereotest showed significantly worse optimal stereoacuity and significantly longer critical integration time. Multiple regression analysis showed that age ( = -4.83; = 0.04) had statistically significant negative correlation on the critical integration time, age ( = -6.45; = 0.047) and exotropia control scores ( = 60.71; = 0.007) had statistically significant effects on optimal stereoacuity.
The temporal integration for stereopsis is impaired in IXT patients, requiring longer critical integration time to achieve elevated optimal stereoacuity.
间歇性外斜视患者的最佳立体视锐度以及实现该锐度所需的整合时间均受损。立体视锐度的恶化更具揭示性，因为它与外斜视控制评分密切相关。
尽管双眼存在周期性的不对准，但一些间歇性外斜视（IXT）患者仍表现出正常的立体视锐度，尤其是在进行静态测试时。目前尚不清楚IXT患者的立体视觉时间整合过程是否发生改变，因此需要进一步研究。
招募了29例IXT患者和36例年龄匹配的正常对照者。使用Titmus立体视锐度测试测量静态立体视。在计算机生成的随机点测试中，以100至1200毫秒的刺激呈现持续时间测量立体视锐度。将立体视锐度与刺激持续时间之间的关系拟合为二次模型。当拟合曲线变平坦且临界整合时间为实现最佳立体视锐度所需的持续时间时，即达到最佳立体视锐度。
在Titmus测试中，未发现IXT患者与对照者有显著差异，而随机点立体测试显示最佳立体视锐度明显更差，临界整合时间明显更长。多元回归分析表明，年龄（β = -4.83；P = 0.04）与临界整合时间呈统计学显著负相关，年龄（β = -6.45；P = 0.047）和外斜视控制评分（β = 60.71；P = 0.007）对最佳立体视锐度有统计学显著影响。
IXT患者的立体视觉时间整合受损，需要更长的临界整合时间才能实现提高的最佳立体视锐度。
