Kvansakul Jessica, Rodriguez-Carmona Marisa, Edgar David F, Barker Felix M, Köpcke Wolfgang, Schalch Wolfgang, Barbur John L
Applied Vision Research Centre, Department of Optometry and Visual Science, City University, London, UK.
Ophthalmic Physiol Opt. 2006 Jul;26(4):362-71. doi: 10.1111/j.1475-1313.2006.00387.x.
Macular pigment (MP) is found in diurnal primate species when vision spans a range of ambient illumination and is mediated by cone and rod photoreceptors. The exact role of MP remains to be determined. In this study we investigate two new hypotheses for possible MP functions.
As MP absorption coincides partly with that of rhodopsin, MP may reduce rod signal effectiveness in the mesopic range, thus extend the usefulness of cone-mediated vision into the mesopic range. Forward light scatter in the eye can reduce retinal image contrast. If blue light contributes significantly to intraocular scatter, selective blue light absorption by MP could reduce the effects of scatter.
We investigated 34 subjects from a carotenoid supplementation trial. The measurements included high mesopic contrast acuity thresholds (CATs), macular pigment optical density (MPOD), wavefront aberrations, and scattered light. The measurements were made after 6 months of daily supplementation with zeaxanthin (Z, OPTISHARP), lutein (L), a combination of the two (C), or placebo (P), and again after a further 6 months of doubled supplementation.
The data reveal a trend toward lower CATs in all groups supplemented, with a statistically significant improvement in the lutein group (p = 0.001), although there was no correlation with MPOD. Light scattering in the eye and the root-mean-square wavefront aberrations show decreasing trends as a result of supplementation, but no correlation with MPOD.
The results suggest that supplementation with L or Z increases MPOD at the fovea and at 2.5 degrees , and that supplementation can improve CATs at high mesopic levels and hence visual performance at low illumination.
在日间灵长类动物中发现了黄斑色素（MP），其视觉跨越一系列环境光照范围，由视锥细胞和视杆细胞光感受器介导。MP的确切作用尚待确定。在本研究中，我们探讨了MP可能功能的两个新假说。
由于MP的吸收部分与视紫红质的吸收重合，MP可能会降低中间视觉范围内视杆细胞信号的有效性，从而将视锥细胞介导的视觉的有用性扩展到中间视觉范围。眼睛中的前向光散射会降低视网膜图像对比度。如果蓝光对眼内散射有显著贡献，MP对蓝光的选择性吸收可能会降低散射的影响。
我们调查了来自一项类胡萝卜素补充试验的34名受试者。测量包括高中间视觉对比度视力阈值（CATs）、黄斑色素光密度（MPOD）、波前像差和散射光。在每天补充玉米黄质（Z，OPTISHARP）、叶黄素（L）、两者组合（C）或安慰剂（P）6个月后进行测量，在进一步双倍补充6个月后再次测量。
数据显示，所有补充组的CATs均有降低趋势，叶黄素组有统计学显著改善（p = 0.001），尽管与MPOD无相关性。补充后，眼睛中的光散射和均方根波前像差呈下降趋势，但与MPOD无相关性。
结果表明，补充L或Z可增加中央凹和2.5度处的MPOD，并且补充可改善高中间视觉水平下的CATs，从而改善低光照下的视觉性能。
