摘 要 对西宁市82例不同程度
近视眼疾的中学生及28例正常视力的对照学生的头发锌含量采用火焰原子吸收光谱法进行了测定,分析结果表明:近视眼患者发锌Ⅰ、Ⅱ组含量低于正常对照组(P<0.01)。男、女性发锌含量差异无显著性。对所有近视患者的发锌含量与近视程度作相关分析,结果表明:近视程度与发锌含量呈负相关关系(r=-0.4302,P<0.01)。
关键词 中学生 发锌 视力
锌是人体必需的生命元素,是维持机体正常新陈代谢的要素。近年来在免疫、遗传营养、优生优育、儿童保健、抗衰老及各种疾病病因的研究与防治等方面取得了一系列的研究成果。研究表明,锌与人体眼科疾病关系密切
[1]。人体各种器官中,眼组织中含有较高浓度的锌,锌存在于眼组织中的各种锌激酶或锌酶中,其中主要是睫状体中的碳酸酐酶,角膜中的胶原酶、晶状体中的亮氨酸基钛酶和视网膜脱氢酶,因而,眼组织对缺锌特别敏感
[2]。
白内障病人晶体房水和血清中锌的含量显著低于正常值,而且随着年龄增长而逐渐降低
[3,4]。体内锌降低易引发夜盲症
[5]。我国人口中近视眼己成为常见病,尤其中学生近视眼思考迅速增加,其病因过去一直认为是由于长期用眼不良、遗传、疾病、体质等因素所致.新近研究表明:体内微量元素缺乏亦是重要因素
[6,7]。本文研究了中学生视力与头发中锌含量的关系,旨在探讨近视眼发病的其他机理,为寻求眼科保健与预防近视的医学新方法提供科学依据。
1 对象与方法
1.1 对象
近视眼组和对照组均选自西宁市第七中学的初三学生,其中近视眼组82例,对照组28例,年龄14—17岁,平均年龄为15.5土l.5岁:学生家庭出身为干部的占63.6%,工人占36.4%。生活水平普遍较好。各组男、女比例基本均等,身体健康,无严重疾病史.近视组除眼睛视力较低外.无其它病变,发育状况与对照组相同。为了排除影响发锌含量的外在因素,选择了在西宁居住5年以上,居住区无严重的锌元素环境污染的学生。近视眼组分为近视组Ⅰ(镜片度数为100º以上,27例);近视组Ⅱ(250º以上,28例);近视组Ⅲ(400º~700º,27例)。视力以标准对数视力表检查、视力表有充足的光线照明,被检查者距视力表5m,两眼分别检查,先右后左[8]。
1. 2 方法 发祥均采自学生后枕部,用不锈钢剪刀剪取约l克,用0.2%海鸥牌洗涤剂浸泡4h后,自来水冲洗干净,再用二次蒸馏水冲洗3~4次,在50~60℃烘箱烘干,准确称取0.3~0.5克样品,在450~500℃灰化2h,灰分用1:1HN03溶解.50ml容量瓶中用去离子水定溶。在GGX-5型原子吸收仪上用火焰法直接测定锌含量。国家人发标准物质GBW-08551和实际样品标准回收率为96.8~102.4%。
统计方法结果以x土s表示,显著性检验用方差分析和Dunnett检验.并作直线相关分析。
2 结果
2.1 近视组与对照组一般生理指标
近视组与对照组一般生理指标见表1。
表1 近视组与对照组一般生理指标(χ土S)
组别 视力 镜片度
右眼 左眼 右眼 左眼
近视Ⅰ 4.33土0.33 4.38土0.33 205.4土37.7 189.4土37.8
近视Ⅱ 4.29土0.25 4.32土0.25 309.8土51.1 307.1土52.6
近视Ⅲ 4.16土0.22 4.22土0.24 492.6土103.5 489.8土112.7
对照组 5.03土0.21 5.04土0.17 - -
2.2 发锌含量与视力的关系
各组发锌分析结果见表2。近视Ⅰ、Ⅱ和Ⅲ组发锌均低于正常对照组,且近视程度越高,发锌含量越低。近视Ⅰ组与对照组比较,发锌含量差异无显著性(P>0.05),而近视Ⅰ、Ⅱ、Ⅱ组发锌含量与对照组比较差异有高度显著性(P<0.01)。对所有近视[-Ⅲ组的近视程度与发锌含量之间作相关性分析。结果表明,它们之间是负相关关系(r=-O.4302,tr=4.262,P<0.01)。
表2 近视组与对照组发锌含量(mg/kg)
组别 n χ土S P值
对照组 28 196.1土29.35 -
近视Ⅰ 27 187.9土22.52 >0.05
近视Ⅱ 28 179.5土22.50 <0.01
近视Ⅲ 27 171.9土19.72 <0.01
2.3 性别与发锌含量
近视组与对照组不同性别发锌含量见表3。各组发锌男性略高于女性,但经t检验男女性之间发锌含量的差别均无显著性差异(P>0.05)。
表3 发锌与性别的关系
组别 性别 n χ土S
近视Ⅰ 男 13 192.0土24.03
女 14 189.6土12.13
近视Ⅱ 男 13 178.6土21.31
女 15 176.1土20.62
近视Ⅲ 男 13 171.5土14.36
女 14 170.3土20.21
对照组 男 13 199.3土30.65
女 15 196.5土27.07
3 讨论
微量元素锌与人体健康的研究报道甚多[2]。近年研究表明在我国缺锌与缺维生素一样常见。缺锌可引起人体一系列病变、尤其对少年儿童的正常生长发育带来严重的影响,使发育受阻,智能低下,免疫机能被抑制,导致异食癖及食欲减退。由于人体眼组织中富含锌,因而眼组织对锌元素的缺乏尤为敏感[3]。
贾镭等[4]研究表明,大学一年级学生急性视力下降与体内微量元素缺乏有关。30例题者平均发锌179.69土25.14mg/kg,而30例正常对HB学生平均发锌为280.11土69.34mg/kg,差异极其显著。本研究结果与文献报道一致,缺锌是导致视力下降的主要因素之一。因为锌在体内蛋白质生物合成过程中发挥重要作用,缺乏时一方面将影响视蛋白及神经介质的合成,从而影响眼睛的神经兴奋性功能,当缺乏时导致眼部神经肌肉的收缩与舒张功能受阻,从而影响眼部肌肉的正常生理功能,导致视力下降。
有关锌与视力下降的关系目前还不很清楚,从本结果看出,视力与发锌含量关系密切。发锌随近视程度的增加而下降。而近视学生锌偏低的原因很多,最主要的是学习紧张,影响睡眠与食欲,以及偏食等,因而在预防中学生视力下降中.应特别注意膳食中锌的摄入。关于中学生视力降低,发锌下降与其他临床表现之间的关系有待进一步研究。
同时本研究结果显示,发锌监测可作为视力下降或其他眼科疾病调查与诊治的辅助手段。
参考文献
1. 汪芳润.微量元素锌与眼.国外医学眼科分册,1982;[6]:1
2. 王夔主编.生命科学中的微量元素(下卷).北京:中国计量出版社、1992:137-138
3. 马庆余.微量元素-老年性白内障的关系探讨.微量元素与健康研究.1993;特刊:39
4. 李小梁,梁业成,李增禧等.补锌对兔眼晶体、清水、血清中其他微量元素的影响.微量元素与健康研究.1993;10(1):10
5. 周大骧,锌与人体健康.新疆环境保护.1988;(4):56
Invest Ophthalmol Vis Sci 2004;45: E-Abstract 5161.
© 2004 ARVO
5161—B485
The Effect of Lutein Supplementation in Preservation of Visual Function in Retinitis Pigmentosa; A Randomized Double–Blind Placebo–Controlled Clinical Trial
H. Bahrami, M. Melia, L. Yang, J. Stone, D. Bourdeau, F. Eshraghi, D. Maldenovich and G. Dagnelie
Wilmer Eye Institute, Department of Ophthalmology, Johsn Hopkins University, Baltimore, MD
Commercial Relationships: H. Bahrami, None; M. Melia, None; L. Yang, None; J. Stone, None; D. Bourdeau, None; F. Eshraghi, None; D. Maldenovich, None; G. Dagnelie, None.
Grant Identification: NEI Grant R03 EY 14416 and NCCAM Grant R21 AT00292
Abstract
Purpose: To evaluate the effectiveness of lutein supplementation in preventing progressive vision loss in patients with retinitis pigmentosa (RP)
Methods: Started in May 2001, as a combined phase I/II trial, 45 adult patients with retinitis pigmentosa were enrolled in this cross–over trial and randomized to two groups. One group received lutein supplementation and for 24 weeks (0 mg/d/PO for 12wks followed by 30 mg/d/PO) and then placebo for 24 weeks, Washout Group. In the other group, Buildup Group, placebo (24 weeks) was administered prior to lutein.. Subjects received multivitamin supplementation in addition to their lutein or placebo throughout the trial. Subjects visual function was measured by multiple tests, including visual acuity, contrast sensitivity, and visual field at up to three levels of illumination at baseline and every 6 weeks in the lab. Also, these tests were performed every week using a previously validated PC–based test in the home.
Results: Data from 35 subjects are reported here, and has been analyzed using the Generalized Estimating Equations (GEE) based on intention–to–treat analysis; 16 in the Washout Group, the other 19 in the Buildup Group. Analysis showed a significant beneficial effect of lutein on visual acuity (p<0.001), while contrast sensitivity was worsened significantly (p<0.001) during lutein usage; over the full trial period, though, contrast sensitivity among all subjects improved significantly. Lutein did not have a significant effect in preserving the visual field, but subjects in the Washout Group had significantly slower loss of visual field than those in the Buildup Group (p value: 0.02). No adverse effects were observed for lutein, while one patient could not tolerate multivitamin.
Conclusions: Lutein appears to be an effective supplement for preservation of visual function in patients with retinitis pigmentosa, which is important in view of the lack of effective intervention for these patients. Lutein appears to have differential effects on different components of vision loss in the same patients. The anomalous improvement of contrast sensitivity during washout may be attributed to a delayed incorporation and effect of lutein in the retina. Since all subjects were receiving multivitamin throughout the trial, preservation of visual function may in part be attributed to multivitamin, or its combination with lutein. Long–term lutein and multivitamin effects on vision in RP patients need to be further investigated.
Key Words: retinitis clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • low vision
中文摘要:
H. Bahrami, M. Melia, L. Yang, J. Stone, D.等医学博士为了证明在色素性视网膜炎患者中,
叶黄素补充能够保存他们的视力功能,做了一个以安慰剂控制的双盲随机临床实验。论文发表于《Invest Ophthalmol》(2004;45: E-Abstract 5161.)
目的:评估叶黄素补充对防止RP患者进行性失视的有效性。方法是:将45个患有色素性视网膜炎的成年人随机分成两组,做交叉实验。一组接受叶黄素补充24周(前12周给予每天10mg量,后12周增加到30mg每天。),另一组使用安慰剂。在实验过程中,两组患者均服用额外的多种维生素补充。结果:分析显示,叶黄素组对视力灵敏度提高作用有显著性意义(p<0.001)。但叶黄素对保存视野没有太大的作用。
Invest Ophthalmol Vis Sci 2003;44: E-Abstract 969.
© 2003 ARVO
969
Macula Pigment Optical Density is Enhanced with Lutein Supplementation Independent of AREDS AMD Disease Stage
S.P. Richer1, M. Tsipursky1 and J. Pulido2
1 Eye Clinic 112E, Department of VA Medical Ctr, North Chicago, IL, United States
2 Retina Service, Ophthalmology, University of Illinois, Chicago, IL, United States
Commercial Relationships: S.P. Richer, Kemin Foods, Inc Des Moine, IA F, R; Nutraceutical Sciences Institute, (Boynton Beach, FL). F; M. Tsipursky, None; J. Pulido, None.
Abstract
Purpose: Emerging evidence suggests lutein has therapeutic effects on macula pigment optical density (MPOD) and vision in atrophic AMD. Little is known about lutein intervention effect(s) vs. AMD stage. We evaluated AREDS retinal disease stage vs. MPOD/visual function in a subset of patients in the Veterans LAST Study (ARVO 2001, # 2542).
Methods: 35 mm retinal color slides of (n=60) primarily male veterans with atrophic AMD (ICD9 362.51) were ranked as to AREDS stage by a retinal specialist masked as to treatment group (10 mg non-esterified lutein vs. maltodextrin placebo). Using methodology defined in the LAST Study, MPOD, glare recovery (GR) and contrast sensitivity (CSF) were evaluated over 1 year by AREDS subgroup (stage II, II & IV), and subjected to Friedman’s non-parametric statistics.
Results: Lutein supplementation enhanced MPOD in AREDS geographic stage IV (P=0.05), stage III (P<0.09) and stage II (P=0.05). Lutein quickened glare recovery independent of AREDS retinal stage (mean(sec) +/-SD at baseline and after 12 months of lutein: stage IV, n=7, 102 +/-72 vs 80 +/- 63, (P=0.05), stage III, n=11, 82 +/-58 vs. 38 +/- 28 (NS), stage II, n=10, 111 +/- 76 vs 52 +/- 44 (P=0.02). Lutein supplementation had no significant effect on CSF for AREDS stage II or III, however significantly improved CSF at 3 of 4 spatial frequencies in geographic stage IV advanced disease (stage IV @ 6cc/deg (P=0.02); 12cc/deg (P=0.03); 18cc/deg (P=0.006).
Conclusions: This small population, brief time frame study demonstrates 1) Lutein supplementation increases MPOD at each AREDS stage compared with placebo; 2) Lutein may be beneficial at all stages of atrophic AMD; 3) GR appears the best indicator of enhanced macula pigment.
Support: Kemin Foods Inc, (Des Moines, IA), Nutraceutical Sciences Institute, (Boynton Beach, FL).
Key Words: age-related macular degeneration • macular pigment
中文摘要:
S.P. Richer, M. Tsipursky and J. Pulido共同研究了叶黄素在AREDS的视网膜疾病阶段与黄斑色素光学密度或视力功能的关系。论文发表于《Invest Ophthalmol》(2003;44: E-Abstract 969.)。方法是:选取35mm视网膜彩色幻灯的男性萎缩型AMD(ICD9 362.51)患者(n=60)为治疗组(服用10mg非酯化叶黄素和麦芽糊精安慰剂)。在最后阶段的研究中,依照Friedman的非参数统计,评估MPOD、GR、CSF在超过1年的AREDS研究(阶段Ⅱ,Ⅱ&Ⅳ)的情况。结果:叶黄素补充能够增强在AREDS中的阶段Ⅳ (P=0.05),阶段Ⅲ (P<0.09)的MPOD,同时加快眩光的恢复。在AREDS的阶段Ⅱ或Ⅲ,叶黄素对对比灵敏度没有明显功效,但在地理阶段IV却能增高对比灵敏度3/4的空间频率。
结论:补充叶黄素相比于安慰剂,在AREDS每个阶段中均能增高MPOD;叶黄素可能对萎缩性AMD有效;GR是增强黄斑色素的最佳指标。