Glimne Susanne A M, Öqvist Seimyr Gustaf, Brautaset Rune L
a Unit of Optometry, Department of Clinical Neuroscience , Karolinska Institutet , Stockholm , Sweden and.
b Division of Ophthalmology and Vision, Department of Clinical Neuroscience , Karolinska Institutet, St. Erik Eye Hospital , Stockholm , Sweden.
Strabismus. 2015;23(3):121-5. doi: 10.3109/09273972.2015.1058400.
Since an interaction between binocular disparity and the vergence system takes place in order to reduce retinal disparity, it is likely that vergence control, as measured with the near point of convergence (NPC), will be better if the target used for measurement has 3-dimensional (3-D) features in its most central parts. The aim of the present study was therefore to investigate if the NPC would give a better result using a fixation target with centrally placed 3-D features when compared with a two-dimensional (2-D) target.
Twenty-three asymptomatic subjects (2 men, 21 women; average age 30.0 years ± 7.36 SD) who experienced diplopia when a fixation target was brought close to the eyes had their break point NPC measured using a modified RAF-ruler. A metal cube and a printed image of the cube were used as a 3-D and 2-D stimuli. The measurements were repeated 3 times in each subject for each test condition, for a total of 6 randomized NPC measurements.
On average a significant difference in NPC (p = 0.0172) was found for break point NPC with a 3-D stimuli (mean: 7.27 cm ± 2.37 SD), giving the better result as compared with a 2-D stimuli (mean: 8.02 cm ± 2.82 SD). Comparing the most remote recorded NPC values of the 3 repeated measurements under each stimulus condition, a significant difference was found (p = 0.0159, t = 2.612) with 3-D stimuli giving the better result.
The results of this study demonstrate the influence of binocular disparity stimuli on the vergence control as NPC was better if the target used for measurement had 3-D features in its most central parts.
由于双眼视差与聚散系统之间会发生相互作用以减少视网膜视差，因此，如果用于测量的目标在其最中心部分具有三维（3-D）特征，那么用集合近点（NPC）测量的聚散控制可能会更好。因此，本研究的目的是调查与二维（2-D）目标相比，使用具有位于中心的3-D特征的注视目标时，NPC是否会得出更好的结果。
23名无症状受试者（2名男性，21名女性；平均年龄30.0岁±7.36标准差），当注视目标靠近眼睛时会出现复视，使用改良的RAF尺测量其断点NPC。一个金属立方体和该立方体的打印图像用作3-D和2-D刺激物。在每个测试条件下，对每个受试者的测量重复3次，总共进行6次随机NPC测量。
平均而言，发现3-D刺激物的断点NPC的NPC有显著差异（p = 0.0172）（平均值：7.27厘米±2.37标准差），与2-D刺激物（平均值：8.02厘米±2.82标准差）相比，结果更好。比较每种刺激条件下3次重复测量中记录的最远距离的NPC值，发现有显著差异（p = 0.0159，t = 2.612），3-D刺激物的结果更好。
本研究结果证明了双眼视差刺激对聚散控制的影响，因为如果用于测量的目标在其最中心部分具有3-D特征，NPC会更好。
