發鋅含量與中學生視力關系的研究

 

    摘  要  對西寧市82例不同程度近視眼疾的中學生及28例正常視力的對照學生的頭發鋅含量采用火焰原子吸收光譜法進行了測定，分析結果表明：近視眼患者發鋅Ⅰ、Ⅱ組含量低于正常對照組(P<0.01)。男、女性發鋅含量差異無顯著性。對所有近視患者的發鋅含量與近視程度作相關分析，結果表明：近視程度與發鋅含量呈負相關關系(r＝-0.4302，P＜0.01)。

    關鍵詞   中學生  發鋅  視力

 

    鋅是人體必需的生命元素，是維持機體正常新陳代謝的要素。近年來在免疫、遺傳營養、優生優育、兒童保健、抗衰老及各種疾病病因的研究與防治等方面取得了一系列的研究成果。研究表明，鋅與人體眼科疾病關系密切^[1]。人體各種器官中，眼組織中含有較高濃度的鋅，鋅存在于眼組織中的各種鋅激酶或鋅酶中，其中主要是睫狀體中的碳酸酐酶，角膜中的膠原酶、晶狀體中的亮氨酸基鈦酶和視網膜脫氫酶，因而，眼組織對缺鋅特別敏感^[2]。白內障病人晶體房水和血清中鋅的含量顯著低于正常值，而且隨著年齡增長而逐漸降低^[3,4]。體內鋅降低易引發夜盲癥^[5]。我國人口中近視眼己成為常見病，尤其中學生近視眼思考迅速增加，其病因過去一直認為是由于長期用眼不良、遺傳、疾病、體質等因素所致．新近研究表明：體內微量元素缺乏亦是重要因素^[6,7]。本文研究了中學生視力與頭發中鋅含量的關系，旨在探討近視眼發病的其他機理，為尋求眼科保健與預防近視的醫學新方法提供科學依據。

1  對象與方法

1．1  對象

    近視眼組和對照組均選自西寧市第七中學的初三學生，其中近視眼組82例，對照組28例，年齡14—17歲，平均年齡為15.5土l.5歲：學生家庭出身為干部的占63.6%，工人占36.4%。生活水平普遍較好。各組男、女比例基本均等，身體健康，無嚴重疾病史．近視組除眼睛視力較低外．無其它病變，發育狀況與對照組相同。為了排除影響發鋅含量的外在因素，選擇了在西寧居住5年以上，居住區無嚴重的鋅元素環境污染的學生。近視眼組分為近視組Ⅰ(鏡片度數為100º以上，27例)；近視組Ⅱ(250º以上，28例)；近視組Ⅲ(400º～700º，27例)。視力以標準對數視力表檢查、視力表有充足的光線照明，被檢查者距視力表5m，兩眼分別檢查，先右后左^[8]。

1. 2  方法    發祥均采自學生后枕部，用不銹鋼剪刀剪取約l克，用0.2%海鷗牌洗滌劑浸泡4h后，自來水沖洗干凈，再用二次蒸餾水沖洗3～4次，在50～60℃烘箱烘干，準確稱取0.3～0.5克樣品，在450～500℃灰化2h，灰分用1：1HN0₃溶解．50ml容量瓶中用去離子水定溶。在GGX－5型原子吸收儀上用火焰法直接測定鋅含量。國家人發標準物質GBW-08551和實際樣品標準回收率為96.8～102.4%。

    統計方法結果以x土s表示，顯著性檢驗用方差分析和Dunnett檢驗．并作直線相關分析。

2  結果

2．1  近視組與對照組一般生理指標

近視組與對照組一般生理指標見表1。

 

組別               視力                      鏡片度

             右眼        左眼            右眼        左眼

近視Ⅰ     4.33土0.33    4.38土0.33  205.4土37.7   189.4土37.8

近視Ⅱ     4.29土0.25    4.32土0.25  309.8土51.1   307.1土52.6

近視Ⅲ     4.16土0.22    4.22土0.24  492.6土103.5  489.8土112.7

對照組     5.03土0.21    5.04土0.17      －          －

 

2.2  發鋅含量與視力的關系

各組發鋅分析結果見表2。近視Ⅰ、Ⅱ和Ⅲ組發鋅均低于正常對照組，且近視程度越高，發鋅含量越低。近視Ⅰ組與對照組比較，發鋅含量差異無顯著性(P＞0.05)，而近視Ⅰ、Ⅱ、Ⅱ組發鋅含量與對照組比較差異有高度顯著性(P＜0.01)。對所有近視[－Ⅲ組的近視程度與發鋅含量之間作相關性分析。結果表明，它們之間是負相關關系(r＝－O.4302，tr＝4.262，P＜0.01)。

 

  組別    n       χ土S          P值

 對照組   28   196.1土29.35      －

 近視Ⅰ   27   187.9土22.52    >0.05

 近視Ⅱ   28   179.5土22.50    <0.01

 近視Ⅲ   27   171.9土19.72    <0.01

 

2．3  性別與發鋅含量

    近視組與對照組不同性別發鋅含量見表3。各組發鋅男性略高于女性，但經t檢驗男女性之間發鋅含量的差別均無顯著性差異(P＞0.05)。

 

  組別   性別     n        χ土S

 近視Ⅰ   男     13    192.0土24.03

          女     14    189.6土12.13

 近視Ⅱ   男     13    178.6土21.31

          女     15    176.1土20.62

 近視Ⅲ   男     13    171.5土14.36

          女     14    170.3土20.21

 對照組   男     13    199.3土30.65

      女     15    196.5土27.07

 

3         討論

微量元素鋅與人體健康的研究報道甚多^[2]。近年研究表明在我國缺鋅與缺維生素一樣常見。缺鋅可引起人體一系列病變、尤其對少年兒童的正常生長發育帶來嚴重的影響，使發育受阻，智能低下，免疫機能被抑制，導致異食癖及食欲減退。由于人體眼組織中富含鋅，因而眼組織對鋅元素的缺乏尤為敏感^[3]。

    賈鐳等^[4]研究表明，大學一年級學生急性視力下降與體內微量元素缺乏有關。30例題者平均發鋅179.69土25.14mg/kg，而30例正常對HB學生平均發鋅為280.11土69.34mg/kg，差異極其顯著。本研究結果與文獻報道一致，缺鋅是導致視力下降的主要因素之一。因為鋅在體內蛋白質生物合成過程中發揮重要作用，缺乏時一方面將影響視蛋白及神經介質的合成，從而影響眼睛的神經興奮性功能，當缺乏時導致眼部神經肌肉的收縮與舒張功能受阻，從而影響眼部肌肉的正常生理功能，導致視力下降。

    有關鋅與視力下降的關系目前還不很清楚，從本結果看出，視力與發鋅含量關系密切。發鋅隨近視程度的增加而下降。而近視學生鋅偏低的原因很多，最主要的是學習緊張，影響睡眠與食欲，以及偏食等，因而在預防中學生視力下降中．應特別注意膳食中鋅的攝入。關于中學生視力降低，發鋅下降與其他臨床表現之間的關系有待進一步研究。

同時本研究結果顯示，發鋅監測可作為視力下降或其他眼科疾病調查與診治的輔助手段。

 

參考文獻   

1.       汪芳潤．微量元素鋅與眼．國外醫學眼科分冊，1982；[6]：1

2.       王夔主編．生命科學中的微量元素(下卷)．北京：中國計量出版社、1992：137-138

3.       馬慶余．微量元素－老年性白內障的關系探討．微量元素與健康研究．1993；特刊：39

4.       李小梁，梁業成，李增禧等．補鋅對兔眼晶體、清水、血清中其他微量元素的影響．微量元素與健康研究．1993；10(1)：10

5.         周大驤，鋅與人體健康．新疆環境保護．1988；(4)：56

 

 

Invest Ophthalmol Vis Sci 2004;45: E-Abstract 5161.

© 2004 ARVO

5161—B485

 

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

 

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

 

H. Bahrami, M. Melia, L. Yang, J. Stone, D.等醫學博士為了證明在色素性視網膜炎患者中，葉黃素補充能夠保存他們的視力功能，做了一個以安慰劑控制的雙盲隨機臨床實驗。論文發表于《Invest Ophthalmol》（2004;45: E-Abstract 5161.）

目的：評估葉黃素補充對防止RP患者進行性失視的有效性。方法是：將45個患有色素性視網膜炎的成年人隨機分成兩組，做交叉實驗。一組接受葉黃素補充24周（前12周給予每天10mg量，后12周增加到30mg每天。），另一組使用安慰劑。在實驗過程中，兩組患者均服用額外的多種維生素補充。結果：分析顯示，葉黃素組對視力靈敏度提高作用有顯著性意義（p<0.001）。但葉黃素對保存視野沒有太大的作用。

結論：葉黃素是能有效改善視網膜色素變性患者視力功能的補充劑。

 

 

 

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

 

S.P. Richer, M. Tsipursky and J. Pulido共同研究了葉黃素在AREDS的視網膜疾病階段與黃斑色素光學密度或視力功能的關系。論文發表于《Invest Ophthalmol》（2003;44: E-Abstract 969.）。方法是：選取35mm視網膜彩色幻燈的男性萎縮型AMD(ICD9 362.51)患者（n＝60）為治療組（服用10mg非酯化葉黃素和麥芽糊精安慰劑）。在最后階段的研究中，依照Friedman的非參數統計，評估MPOD、GR、CSF在超過1年的AREDS研究（階段Ⅱ,Ⅱ&Ⅳ）的情況。結果：葉黃素補充能夠增強在AREDS中的階段Ⅳ (P=0.05)，階段Ⅲ (P<0.09)的MPOD，同時加快眩光的恢復。在AREDS的階段Ⅱ或Ⅲ，葉黃素對對比靈敏度沒有明顯功效，但在地理階段IV卻能增高對比靈敏度3/4的空間頻率。

結論：補充葉黃素相比于安慰劑，在AREDS每個階段中均能增高MPOD；葉黃素可能對萎縮性AMD有效；GR是增強黃斑色素的最佳指標。