老年黄斑病变（age - related macular degeneration，AMD）是目前全球主要致盲性眼病之一，发病率不断增加。在9月的《眼科学文献》（Archives of Ophthalmology）上，一项研究显示摄入较多的黄色植物色素——叶黄素和玉米黄素的人，患老年黄斑病变的风险较低。
老年黄斑病变（AMD）产生原因是黄斑随着时间发生退化，黄斑是视网膜后端产生视觉的区域。文章表示，AMD是造成欧洲老年人群失明的主要原因。
这项称为“年龄相关眼病研究”的项目，在1992到1998年间分析了4519位年龄在60－80岁之间的人。研究中，研究人员对参与者视网膜进行拍照以确定其是否患有AMD，如果有，则需进一步确定发展到疾病发展4个阶段中的哪一个阶段。参与者同时还需要完成一份针对食物的调查问卷，以评估其摄入富含某些维生素、矿物质和营养素的食物情况。这些被调查物质包括叶黄素、玉米黄素、胡萝卜素、番茄红素、维生素C和E。
参与者根据摄入每种营养素的情况被分成5组。结果食用叶黄素和玉米黄素最多的小组患AMD的比例明显较低。同时这些参与者患玻璃体疣、视网膜黄白沉积和其它AMD标志性疾病的几率也更低。除此之外未观测到其它营养素和这些症状间存在联系。
叶黄素和玉米黄素也被称为类胡萝卜素，它们存在于黄色和暗色叶片蔬菜中。类胡萝卜素能阻止光和氧气破坏眼睛的过程。叶黄素和玉米黄素能滤掉短波长光线，短波长光不但会造成光化学损伤，而且会产生攻击细胞脂类、蛋白和核物质的活性氧分子。此外，类胡萝卜素还能减少新产生的活性氧。
老年黄斑病变（age - related macular degeneration，AMD）是目前全球主要致盲性眼病之一，发病率不断增加。其病因和发病机制尚未完全明确，尚无非常有效的治疗方法。近年来在发病机制、遗传因素、危险因素等方面又有了新的研究，治疗手段也有增加，但也存在很多问题。中医中药在治疗AMD方面积累了很多经验，取得了一定的疗效，有其独特的优势，值得进一步研究。
老年黄斑病变，随年龄增长发病率和患病率不断增高，是目前国内外50岁以上人群低视力和致盲的重要原因。其病因不清，可能与慢性光损害、种族、遗传、吸烟、心血管疾病、饮食等危险因素有关。
由于黄斑点退化，引致患者的中央视觉受损。黄斑点位于视网膜的中央部位，具备精细视物功能。黄斑点有大量的感光细胞，把影像转换成电流脉冲，然后通过视神经传送到大脑。老年黄斑病变患者之所以视力受损，就是因为黄斑点的感光细胞退化。
老年黄斑病变的病人首先会感到视觉中央有些模糊，在阅读、做针线时尤为明显，看直线时会出现变形弯曲。随着病情发展，在视觉中央逐渐形成盲点。大部份案例显示，如果其中一只眼患上这种眼疾时，另一只眼也很可能得病。
原始出处:
Archives of Ophthalmology
Vol. 125 No. 9, September 2007
Age-Related Macular Degeneration and Cancer Mortality in the Atherosclerosis Risk in Communities Study
Ning Cheung, MBBS; Anoop Shankar, MD, MPH; Ronald Klein, MD, MPH; Aaron R. Folsom, MD, MPH; David J. Couper, PhD; Tien Yin Wong, MD, PhD; for the Atherosclerosis Risk in Communities (ARIC) Study Investigators
Arch Ophthalmol. 2007;125:1241-1247.
Objective To examine the prospective association of early age-related macular degeneration (AMD) with cancer mortality.
Methods A population-based cohort study of 10 029 persons aged 49 to 73 years free of cancer. The AMD signs were evaluated from retinal photographs taken in 1993 through 1995. Cancer mortality was determined from death records.
Results There were 464 cases of early AMD. Over 10 years, there were 234 cancer deaths (71 lung cancer deaths). After controlling for age, sex, race, field center, education, smoking status, pack-years of smoking, body mass index (calculated as weight in kilograms divided by height in meters squared), and diabetes mellitus, early AMD was associated with cancer mortality (rate ratio [RR], 1.68; 95% confidence interval [CI], 1.03-2.73). This association was overall stronger in African American individuals (RR, 3.93; 95% CI, 1.67-9.22) than white individuals (RR, 1.28; 95% CI, 0.71-2.32) and for lung cancer deaths (RR, 2.14; 95% CI, 0.97-4.72) than nonlung cancer deaths (RR, 1.50; 95% CI, 0.81-2.78). In African American individuals, early AMD was associated with a 5-fold higher risk of lung cancer deaths (RR, 5.28; 95% CI, 1.52-18.40).
Conclusions Middle-aged African American individuals with early AMD may be at increased risk of dying of cancer, particularly lung cancer. This association was not present in white individuals and needs confirmation in other studies.
Author Affiliations: Centre for Eye Research Australia, University of Melbourne (Drs Cheung and Wong), and Royal Melbourne Hospital (Dr Cheung), Victoria; Department of Community, Occupational, and Family Medicine, Yong Loo Lin School of Medicine (Dr Shankar), and Singapore Eye Research Institute (Dr Wong), National University of Singapore; Department of Ophthalmology, University of Wisconsin, Madison (Dr Klein); Division of Epidemiology and Community Health, University of Minnesota, Minneapolis (Dr Folsom); and Department of Biostatistics, University of North Carolina, Chapel Hill (Dr Couper).
Group Information: A list of the ARIC Study investigators was published in Am J Epidemiol. 1989;129:687-701.
