Engles Michael, Wooten Billy, Hammond Billy
Vision Science Laboratory, University of Georgia, Athens, Georgia 30606, USA.
Invest Ophthalmol Vis Sci. 2007 Jun;48(6):2922-31. doi: 10.1167/iovs.06-0883.
Schültze, in 1866, originally proposed that macular pigment (MP) could improve acuity by reducing the deleterious effects associated with the aberration of short-wave (SW) light. Although proposed well more than a century ago, the hypothesis has never been empirically tested. The authors chose to begin evaluating the acuity hypothesis by measuring MP levels, gap, and hyperacuity in the same observers.
Eighty healthy young subjects were assessed. Forty subjects were assigned to the gap acuity experiment and 40 to the hyperacuity experiment. Peak MP optical density (MPOD) was measured using heterochromatic flicker photometry (HFP). Resolution and hyperacuity were measured as the minimum perceivable gap between two solid black lines (1'' width) vertically separated and as a vernier offset, respectively. These targets were presented on a 0.5 degrees circular diffusing background that appeared either white (17 cd/m2) or yellow (16 cd/m2). The yellow background was produced by using light-emitting diodes (LEDs) with a peak lambda = 570 nm. The white background was produced by combining the yellow with a blue LED (peak lambda = 460 nm). The subject's head (5.33 m from the stimulus) was stabilized with a head-rest assembly, and the adaptive state was controlled with the use of a constant white surround (11 cd/m2). Thresholds were determined based on probit analysis of psychometric functions generated using a two-alternative forced-choice procedure.
MPOD ranged from 0.14 to 1.00 measured at 30' eccentricity. Gap and hyperacuity measures each varied by a factor of approximately 5 to 6. Average gap acuity (N = 38) for the white condition (filtered by MP) was 31.2'' (SD = 9.4) and did not differ from the average (N = 38) for the yellow condition (not filtered by MP), which was 32.1'' (SD = 10.9). Similarly, average hyperacuity for the white condition (7.0''; SD = 2.9) did not differ from that of the yellow condition (6.8''; SD = 3.5).
MPOD did not correlate significantly with gap or hyperacuity measured in the yellow or white conditions. These data, therefore, do not support the predictions of the acuity hypothesis.
舒尔策于1866年最初提出，黄斑色素（MP）可通过减少与短波（SW）光像差相关的有害影响来提高视力。尽管这一假说在一个多世纪前就已提出，但从未得到实证检验。作者选择通过测量同一观察者的MP水平、视差和超视力来开始评估视力假说。
对80名健康的年轻受试者进行评估。40名受试者被分配到视差视力实验，40名受试者被分配到超视力实验。使用异色闪烁光度法（HFP）测量MP的峰值光密度（MPOD）。分辨率和超视力分别通过垂直分开的两条实心黑线（1英寸宽）之间的最小可感知视差和游标偏移来测量。这些目标呈现于0.5度的圆形漫射背景上，该背景呈现为白色（17坎德拉/平方米）或黄色（16坎德拉/平方米）。黄色背景由峰值波长λ = 570纳米的发光二极管（LED）产生。白色背景通过将黄色LED与蓝色LED（峰值波长λ = 460纳米）组合产生。受试者的头部（距离刺激物5.33米）用头靠组件固定，适应状态通过使用恒定的白色背景（11坎德拉/平方米）来控制。阈值基于对使用二选一强制选择程序生成的心理测量函数的概率分析来确定。
在30°偏心率下测量的MPOD范围为0.14至1.00。视差和超视力测量值各自变化约5至6倍。白色条件（按MP过滤）下的平均视差视力（N = 38）为31.2英寸（标准差 = 9.4），与黄色条件（未按MP过滤）下的平均值（N = 38）32.1英寸（标准差 = 10.9）无差异。同样，白色条件下的平均超视力（7.0英寸；标准差 = 2.9）与黄色条件下的平均超视力（6.8英寸；标准差 = 3.5）无差异。
MPOD与在黄色或白色条件下测量的视差或超视力无显著相关性。因此，这些数据不支持视力假说的预测。
