Reflectance Method for Measuring Macular Pigment

测量黄斑色素的反射法

• 批准号: 6766503
• 负责人: RICHARD A. BONE
• 金额: $ 2.63万
• 依托单位: FLORIDA INTERNATIONAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6766503
• 关键词: age difference; blood chemistry; carotenoids; clinical research; dietary supplements; eye disorder diagnosis; eye fundus photography; flicker fusion test; gender difference; high performance liquid chromatography; human subject; image processing; longitudinal human study; macular degeneration; method development; nutrition related tag; pharmacokinetics; retinal pigment epithelium; retinography; visual pigments; xanthine analog

There is evidence for an inverse association between the amount of macular pigment (MP) in the retina and risk of age-related macular degeneration (AMD). Dietary supplementation with lutein (L) or zeaxanthin (Z) can significantly increase MP density. These findings are relevant to an intervention study, the long-term goal of this research, to determine the efficacy of L and Z in preventing or delaying AMD. Heterochromatic flicker photometry (HFP) is a commonly used method for measuring MP density, but HFP is not suitable for many subjects, particularly those whose vision is impaired by AMD. Specific aim 1 is to develop a simple, inexpensive, objective, reflectance method of measuring MP density, suitable for an L or Z intervention study. The method will utilize a retinal camera equipped with a triple-band interference filter. The system will be designed so that 3 fundus images at different wavelengths may be extracted from a single image. Image analysis software will be used to generate an MP density map from these images. The wavelengths will be chosen to minimize the potential influence of photopigments and melanin on the measured densities. The validity of the technique will be investigated by comparing MP densities obtained by HFP and by the new reflectance method. Specific aim 2 is to compare the effects of L and Z supplementation, at 20 mg per day for 6 months, on L and Z concentration in the blood serum and on the density of MP determined by the reflectance method. Fifty subjects will participate. On a random basis, 20 will be assigned to each of the supplements and 10 will be assigned to a placebo. For a subset, HFP will also be used to monitor changes in MP density for comparison with reflectance data. The concentration of L and Z in the serum will be measured by HPLC. The study will quantify differences in response to supplementation in subjects, and will seek causes. Preliminary data indicate that the rate of increase in MP is driven by the serum concentration of L+Z. Specific aim 3 is to compare the reflectance and HFP methods for subjects with early-stage AMD. On average, such subjects may be expected to have below normal MP densities. Fourteen subjects will participate in a similar L trial to that in specific aim 2. The trial will permit evaluation of the reflectance method in subjects for whom HFP is likely to prove unsuitable. It will also determine their responsiveness to L supplementation.

有证据表明，视网膜中黄斑色素(MP)的数量与患老年性黄斑变性(AMD)的风险呈负相关。日粮中添加叶黄素(L)或玉米黄质(Z)可显著提高MP密度。这些发现与一项干预研究有关，该研究的长期目标是确定L和Z在预防或延缓AMD方面的有效性。异色闪烁光度法(HFP)是一种常用的MP浓度测量方法，但HFP法不适用于许多受试者，尤其是AMD视力受损者。具体目标1是建立一种简便、廉价、客观的MP密度测定方法，适用于L或Z干预研究。该方法将使用配备有三频干涉滤光片的视网膜摄像头。系统将 设计成可以从一张图像中提取3个不同波长的眼底图像。图像分析软件将用于从这些图像生成MP密度图。波长的选择将使感光色素和黑色素对测量密度的潜在影响降至最低。该技术的有效性将通过比较HFP和新的反射比法得到的MP密度来考察。目的2：比较补L和补Z对血清L和Z浓度及反射法测定MP浓度的影响。将有50名受试者参加。在随机的基础上，每个补充剂将被分配20个，而安慰剂将被分配10个。对于一个子集，HFP还将用于监测MP密度的变化，以便与反射率数据进行比较。L和Z在血清中的浓度将是 用高效液相色谱仪测定。这项研究将量化受试者对补充剂的反应差异，并寻找原因。初步数据表明，MP升高的速度是由血清L+Z浓度驱动的。具体目的3是比较反射法和HFP法在早期AMD患者中的应用。平均而言，这类受试者的MP密度可能低于正常水平。14名受试者将参加类似于特定目的2的L试验。该试验将允许在可能被证明不适合HFP的受试者中评估反射法。它还将确定他们对L补充的反应。