Department of Optometry and Vision Sciences, The University of Melbourne, Victoria, Australia.
Optometry, School of Medicine, Deakin University, Waurn Ponds, Australia.
Invest Ophthalmol Vis Sci. 2021 Aug 2;62(10):35. doi: 10.1167/iovs.62.10.35.
Research on infantile nystagmus syndrome (INS) and velocity discrimination is limited, and no research has examined velocity discrimination in subjects with INS at their null position and away from it. This study aims to investigate how individuals with INS perform, compared with controls, when carrying out velocity discrimination tasks. Particularly, the study aims to assess how the null position affects their performance.
INS subjects (N = 21, mean age 24 years; age range, 15-34 years) and controls (N = 16, mean age 26 years; age range, 22-39 years) performed horizontal and vertical velocity discrimination tasks at two gaze positions. Eighteen INS subjects were classified as idiopathic INS and three had associated visual disorders (two had oculocutaneous albinism, and one had congenital cataract). For INS subjects, testing was done at the null position and 15° away from it. If there was no null, testing was done at primary gaze position and 15° away from primary. For controls, testing was done at primary gaze position and 20° away from primary. Horizontal and vertical velocity discrimination thresholds were determined and analyzed.
INS subjects showed significantly higher horizontal and vertical velocity discrimination thresholds compared with controls at both gaze positions (P < 0.001). Horizontal thresholds for INS subjects were elevated more than vertical thresholds (P < 0.0001) for INS subjects but not for controls. Within the INS group, 12 INS subjects who had an identified null position showed significantly lower horizontal and vertical thresholds at the null than at 15° away from it (P < 0.05).
Velocity discrimination was impaired in INS subjects, with better performance at the null. These findings could assist in understanding how INS affects the daily activities of patients in tasks involving moving objects, and aid in developing new clinical visual function assessments for INS.
婴儿眼球震颤综合征（INS）和速度辨别力的研究有限，尚无研究检查 INS 患者在零位和偏离零位时的速度辨别力。本研究旨在研究 INS 患者与对照组相比在进行速度辨别任务时的表现。特别是，该研究旨在评估零位如何影响他们的表现。
INS 患者（N=21，平均年龄 24 岁；年龄范围 15-34 岁）和对照组（N=16，平均年龄 26 岁；年龄范围 22-39 岁）在两个注视位置进行水平和垂直速度辨别任务。18 名 INS 患者被归类为特发性 INS，3 名患者伴有视觉障碍（2 名患有眼皮肤白化病，1 名患有先天性白内障）。对于 INS 患者，测试在零位和偏离零位 15°处进行。如果没有零位，则在主注视位置和偏离主注视位置 15°处进行测试。对于对照组，在主注视位置和偏离主注视位置 20°处进行测试。确定并分析水平和垂直速度辨别阈值。
INS 患者在两个注视位置的水平和垂直速度辨别阈值均明显高于对照组（P<0.001）。与对照组相比，INS 患者的水平阈值升高幅度大于垂直阈值（P<0.0001），但对照组则不然。在 INS 组中，12 名具有明确零位的 INS 患者在零位时的水平和垂直阈值明显低于偏离零位时的阈值（P<0.05）。
INS 患者的速度辨别力受损，在零位时表现更好。这些发现有助于了解 INS 如何影响患者在涉及移动物体的日常活动中的表现，并有助于为 INS 开发新的临床视觉功能评估。
