角膜瓣蒂位置对LASIK术后干眼症发生率影响随机对照研究的Meta分析

背景干眼症是准分子激光角膜原位磨镶术（LASIK）术后早期最常见的并发症。有研究提出术后干眼症的发生率与术中角膜瓣蒂的位置有关，然而也有研究认为两者关系不大。目的系统评价LASIK术中鼻／颞侧蒂和上方蒂角膜瓣对术后干眼症发生率的影响。方法采用严密设计的检索策略并选择关联检索词对1990--2011年已发表的有关比较LASIK术中不同位置角膜瓣蒂术后干眼症发生情况的随机对照研究进行检索，检索的数据库包括Medline、Embase、Cochrane图书馆和中国期刊全文数据库（CNKI），由2名研究者独立提取资料，对符合纳入标准的文献进行Meta分析。Meta分析中纳入的关联结局指标包括术后1周及3、6、12个月时泪膜破裂时间（BUT）、SchirmerⅠ试验及角膜敏感性。采用RevMan5．0统计学软件进行统计分析，并按照Jadad量表对检索文献的证据等级进行评价。若纳入的各项研究无异质性（即P≥0．1，异质性检验，2〈50％），采用固定效应模型进行分析，反之则采用随机效应模型。结果共检索到符合纳入标准的相关随机对照临床试验10篇，其中3篇未分别给出术后各组结局指标的详细资料，故予以排除，有7篇随机对照研究符合条件纳入，共331例652眼。纳入的文献经Jadad评分均为3分以上，其中5篇文献530眼对BUT进行评价，7篇文献652眼进行SchirmerI试验，4篇文献320眼对术后角膜知觉进行了评价，文献之间均无明显异质性（，〈50％）。Meta分析显示术后第1周上方蒂组的BUT明显短于鼻／颞侧蒂组，差异有统计学意义（WMD=-0．42，95％CI：-0．79～-0．06，P=0．020），而在术后3个月和6～12个月2个组差异均无统计学意义（P〉0．05）。术后3个月鼻／颞侧蒂组角膜敏感性明显高于上方蒂组，差异有统计学意义（WMD=-0．62，95％CI：-1．09～-0．19，P=0．005），而在术后1周和6～12个月2个组比较差异无统计学意义（P〉0．05）。2个组SchirmerⅠ试验结果在术后各时间点差异均无统计学意义（P〉0．05）。结论LASIK术中保留鼻侧或颞侧角膜瓣蒂能一定程度地缓解术后干眼症的发生和严重程度，今后还需要更多高质量、大样本的随机对照研究来证明二者之间的联系。

Meta analysis of randomized controlled clinical trial in the effect of hinge location on dry eye syndrome after LASIK

Background Dry eye syndrome is a frequent postoperative complication of laser in situ keratomileusis （LASIK）. Some studies reported that the hinge location of corneal flap has influence on dry eye syndrome following LASIK,but others showed inverse views. Objective This systematic review was to evaluate and compare the effects of a superior- and nasal/temporal-hinge location on dry eye syndrome after LASIK. Methods A systematic literature retrieval was conducted in the Medline, Embase, Cochrane Library and CNKI from 1990 to 2011 according to designed searching strategy and relevant words. Published randomized-controlled clinical trial （RCT） data of the effect of superior- and nasal/temporal-hinge location on dry eye syndrome were extracted by two researchers separately. The outcome parameters,such as tear film breakup time （BUT） ,Schirmer Ⅰ test and corneal sensation were analyzed 1 week,3 months and 6-12 months postoperatively. The statistical analysis was performed using a RevMan 5.0 software and the quality of included literatures were graded according to the Jadad scale. Fixed- effect model was used for the inhomogeneity multiple studies（ P ≥ 0. 1,homogeneity test I^2 〈50% ） , and random-effect model was used for the homogeneity studies. Results Ten pieces RCT papers were searched and 3 of them were rejected because of the lack of outcome data. In 7 included studies,652 eyes of 331 patients were involved in the Meta analysis,with the Jadad scores ≥ 3. BUT assessment was performed in 5 trials（530 eyes） , Sehirmer I test evaluation was in 7 trials（ 652 eyes） and corneal sensation observation was in 4 trials （320 eyes） , without significant homogeneity among the relevant literature（I^2 〈50% ）. Meta analysis revealed that BUT in the eyes with superior-hinge group was obvious shorter than that in the eyes nasal/temporal-hinge group at 1 week （WMD =-0.42,95% CI：-0. 79 to -0. 06, P=0. 020） ,but there was no significant difference in 3 months and 6-12 months duration postoperatively. Better corneal sensation was found at postoperative 3 months （ WMD = -0.62,95 % CI ： - 1.09 to -0. 19, P = 0. 005 ） in the nasal/ temporal-hinge group,but there was no difference in 1 week and 6-12 months duration postoperatively. No significant difference was seen between the two groups in Schirmer I test during the follow-up period（P〉0.05）. Conclusions LASIK with nasal/temporal-hinge corneal flap can improve the corneal sensation and relief the dry eye syndrome after LASIK to some extent. More high-quality evidence-based studies are still needed for the further clinical evaluation.