Determining Spatial Summation and Its Effect on Contrast Sensitivity across the Central 20 Degrees of Visual Field.
Determining Spatial Summation and Its Effect on Contrast Sensitivity across the Central 20 Degrees of Visual Field.
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DOI：
10.1371/journal.pone.0158263
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Kalloniatis M
中科院分区：
文献类型：
--
作者：
Choi AY;Nivison-Smith L;Khuu SK;Kalloniatis M
最近的研究表明，使用在或接近完整空间总和的目标刺激可以显示眼部疾病中较大的阈值升高。汉弗莱视野分析仪（Humphrey Visual Field Analyzer， HFA）用于评价黄斑中央区域的视觉功能，但其空间综合特征尚不明确。因此，我们希望利用10-2测试网格的高采样密度，在中央20°视野范围内建立对比敏感度与刺激大小（空间总和）之间的关系。使用HFA 10-2测试网格测量37名正常受试者的一只眼睛的阈值，所有五个Goldmann (G)目标（GI到GV）。使用已公布和计算的特定地点十年校正因子将受试者数据转换为50岁的等效数据。对所有地点的所有数据进行空间求和曲线拟合。建立了完全空间求和的Ricco临界区域（Ac）的大小（k = 1）和部分求和的斜率（k < 1：表征部分求和）。对10-2 HFA测试网格中所有Goldmann刺激大小的50岁年龄标准数据进行测定，结果显示小刺激（如GI）的对比敏感性有显著变化，大刺激（如GV）的对比敏感性变化不大。Ac和k值都不随年龄变化，允许年龄校正因子的应用。Ac和k值随偏心率增大，GI保持在完全空间和范围内，GI接近或处于完全空间和范围内。GIII或更大的试验规模总是在完全空间和之外，在不同水平的部分和内运行。开发的规范数据现在允许使用10-2网格对具有高采样密度的数据集进行比较，而不考虑受试者的年龄。当评估眼部疾病时，测试的大小是很重要的，但只有GI或GII刺激在黄斑的完全空间总和附近或范围内起作用。目前的视野测试方案采用的是GIII，它总是在完全空间求和之外，在不同的部分求和值下工作，GIII可能不是评估影响黄斑的眼部疾病的最合适的测试大小。
Recent studies propose that the use of target stimuli within or close to complete spatial summation reveal larger threshold elevation in ocular disease. The Humphrey Visual Field Analyzer (HFA) is used to assess visual function yet the spatial summation characteristics are unexplored for the central macular region. We therefore wanted to establish the relationship between contrast sensitivity and stimulus size (spatial summation) within the central 20° visual field using the high sampling density of the 10–2 test grid. Thresholds were measured for one eye from 37 normal subjects using the HFA 10–2 test grid with all five Goldmann (G) targets (GI to GV). Subject data were converted to 50-year-old equivalent using published and calculated location-specific decade correction factors. Spatial summation curves were fitted for all data at all locations. The size of Ricco’s critical area (Ac) within which complete spatial summation operates (k = 1), and the slope of partial summation (k < 1: to characterize partial summation), was established. The 50-year-old age normative data were determined for all Goldmann stimulus sizes for the 10–2 HFA test grid and showed a marked change in contrast sensitivity for small test stimuli (e.g. GI) and little change in larger test stimuli (e.g. GV). Both the Ac and k values did not vary with age allowing for the application of the age correction factors. Ac and k values increased with eccentricity with GI remaining within complete spatial summation and GII was close or within complete spatial summation. GIII or larger test sizes were always outside complete spatial summation operating within various levels of partial summation. The developed normative data now allows comparisons of data sets with high sampling density using the 10–2 grid irrespective of subject age. Test size is important when assessing ocular disease yet only GI or GII stimuli operate close to or within complete spatial summation in the macula. Current visual field testing protocols employ GIII which is always outside complete spatial summation and operates under various values of partial summation: GIII may not be the most suitable test size to assess ocular disease affecting the macula.