儿童散光检测的准确性和规律性探讨

目的进一步探讨儿童散光检测的准确性和规律性。方法对６２例（１０８只眼）儿童散光进行检测，采用睫状肌麻痹下检影验光和角膜曲率计测量，分别得出眼散光（ＥＡｓ）和角膜散光（ＫＡｓ）的数据。结果表明二种散光的散光度和散光轴有很好的一致性；两散光的相关系数ｒ＝０９１；关系式为ＥＡｓ＝０９４ＫＡｓ－０２２，与以往关系式非常一致。７５％的散光度在３００ＤＣ以内，７５％的散光轴向在１８０°±５°范围内。结论圆柱镜检影法是确定眼散光轴向的可靠技术；角膜曲率测量对于检影验光起到重要的辅助作用；儿童散光的散光度和散光轴的分布有明显的规律     

角膜地形图和角膜曲率计测量散光的研究

目的探讨角膜地形图和角膜曲率计对屈光手术前、后角膜散光的应用价值。方法采用计算机辅助的角膜地形图、角膜曲率计及散瞳验光三种测量散光的方法,对屈光不正患者３６０只眼进行检查,同时对准分子激光角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ,ＰＲＫ）后７２只眼和准分子激光原位角膜磨镶术（ｅｘｃｉｍｅｒｌａｓｅｒｉｎｓｉｔｕｋｅｒａｔｏｍｉｌｅｕｓｉｓ,ＬＡＳＩＫ）后９５只眼的角膜散光用角膜地形图和角膜曲率计进行测量并比较。结果术前三组测量方法在散光轴位方面差异无显著性（Ｐ＞０．０５）。在散光度数上,角膜地形图△ＳｉｍＫ和角膜曲率计△Ｋ间差异无显著性（Ｐ＞０．０５）;而散瞳验光组与另两组间差异有显著性（Ｐ＜０．０１）。ＰＲＫ和ＬＡＳＩＫ术后△ＳｉｍＫ与△Ｋ值间差异有显著性（Ｐ＜０．０１）。结论角膜曲率计与角膜地形图对术前角膜散光测量具有相似的临床价值,角膜地形图图形与参数△ＳｉｍＫ值有关。但术后角膜地形图△ＳｉｍＫ测量的角膜散光较为准确     

IOLMaster、角膜地形图及Pentacam测量年龄相关性白内障患者角膜散光的比较

目的　比较年龄相关性白内障患者术前ＩＯＬＭａｓｔｅｒ、角膜地形图及Ｐｅｎｔａｃａｍ测量角膜散光各参数的差异。方法　收集我院年龄相关性白内障患者５６例（６７眼）,术前分别通过ＩＯＬＭａｓｔｅｒ、角膜地形图及Ｐｅｎｔａｃａｍ测量平坦子午线角膜屈光力即最小角膜曲率（ｆｌａｔｋｅｒａｔｏｍｅｔｒｙ,Ｋｆ）、陡峭子午线角膜屈光力即最大角膜曲率（ｓｔｅｅｐｋｅｒａｔｏｍｅｔｒｙ,Ｋｓ）、平均角膜曲率（ｍｅａｎｋｅｒａ-ｔｏｍｅｔｒｙ,Ｋｍ）、散光度参数Ｊ０（ｃｙｌｉｎｄｅｒａｔ０-ｄｅｇｒｅｅｍｅｒｉｄｉａｎ）及轴向参数Ｊ４５（ｃｙｌｉｎｄｅｒａｔ４５-ｄｅｇｒｅｅｍｅｒｉｄｉａｎ）;采用配对ｔ检验对三组测量结果的差异进行比较,不同测量仪器所得的数据的相关性采用Ｐｅａｒｓｏｎ相关性分析,三种方法测量结果的一致性采用Ｂｌａｎｄ-Ａｌｔｍａｎ分析。结果　ＩＯＬＭａｓｔｅｒ测量Ｋｆ、Ｋｓ、Ｋｍ、Ｊ０、Ｊ４５分别为（４３．５２４±１．７５１）Ｄ、（４４．３５２±１．８３９）Ｄ、（４３．９３８±１．７５３）Ｄ、（０．０５９±０．４５５）Ｄ、（０．２６４±０．２２８）Ｄ;角膜地形图所测Ｋｆ、Ｋｓ、Ｋｍ、Ｊ０、Ｊ４５分别为（４３．４０４±１．７４０）Ｄ、（４４．２９０±１．８４３）Ｄ、（４３．８４７±１．７５３）Ｄ、（０．０４６±０．４５３）Ｄ、（０．２４２±０．２２２）Ｄ;Ｐｅｎｔａｃａｍ所测Ｋｆ、Ｋｓ、Ｋｍ、Ｊ０、Ｊ４５分别为（４３．４０１±１．７３９）Ｄ、（４４．２８５±１．８３８）Ｄ、（４３．８４３±１．７５１）Ｄ、（０．０４７±０．４５６）Ｄ、（０．２４１±０．２２１）Ｄ;ＩＯＬＭａｓｔｅｒ和角膜地形图及Ｐｅｎｔａｃａｍ的检测结果比较差异均有统计学意义（均为Ｐ＜０．０５）,角膜地形图及Ｐｅｎｔａｃａｍ检测结果比较差异无统计学意义（Ｐ＞０．０５）;Ｐｅａｒｓｏｎ相关分析显示,Ｋｆ、Ｋｓ、Ｋｍ、Ｊ０、Ｊ４５等５个指标在三种检查仪器检测结果之间均有高度的正相关性（均为Ｐ＜０．００１）。Ｂｌａｎｄ-Ａｌｔｍａｎ一致性分析说明三种仪器的检测结果具有较好的一致性。结论　ＩＯＬＭａｓｔｅｒ、角膜地形图及Ｐｅｎｔａｃａｍ均可以应用于年龄相关性白内障患者术前测量角膜散光的各项参数。     

LASIK术后角膜曲率、前房深度及眼轴长度的改变

目的　探讨准分子激光角膜原位磨镶术对患者的角膜曲率、前房深度及眼轴长度产生的影响。方法　准分子激光角膜原位磨镶术患者６１例１２２眼,用光学相干生物测量仪（ＩＯＬ-Ｍａｓｔｅｒ）分别测量术前及术后０．５ａ的角膜曲率、前房深度及眼轴长度,用电脑自动验光仪分别测量术前及术后０．５ａ的角膜曲率,对结果进行统计学分析比较手术前后各个参数的改变,用临床病史法计算出术后矫正角膜曲率（Ｋ矫正）,建立Ｋ矫正对术后测量的角膜曲率（Ｋ术后）的回归公式,并比较ＩＯＬ-Ｍａｓｔｅｒ和电脑自动验光仪测量术前和术后角膜曲率的一致性。结果　ＩＯＬ-Ｍａｓｔｅｒ测量术前和术后的角膜曲率分别为（４３．２５±１．１５）Ｄ和（３９．１３±１．９２）Ｄ,前房深度分别为（３．６５±０．２１）ｍｍ和（３．５５±０．２０）ｍｍ,眼轴长度分别为（２５．５８±０．８９）ｍｍ和（２５．４９±０．８７）ｍｍ,手术前后三组数据相比差异均有统计学意义（均为Ｐ＝０．０００）。电脑自动验光仪测量的手术前后角膜曲率分别为（４３．２０±１．１５）Ｄ和（３９．０６±１．８９）Ｄ,推导的回归公式为:Ｋ矫正＝１．０９３×Ｋ术后－４．０１３。Ｂｌａｎｄ-Ａｌｔｍａｎ分析显示ＩＯＬ-Ｍａｓｔｅｒ和电脑自动验光仪在测量术前和术后角膜曲率上一致性较好。结论　准分子激光角膜原位磨镶术后患者的角膜曲率、前房深度及眼轴长度均较术前降低,相比较角膜曲率改变更明显,可采用回归公式对术后角膜曲率进行矫正。ＩＯＬ-Ｍａｓｔｅｒ和电脑自动验光仪在测量术前和术后角膜曲率上一致性较好,临床上可以替代使用。     

准分子激光散光性角膜切削术治疗复合性近视散光

目的 探讨准分子激光散光性角膜切削术（ｐｈｏｔｏａｓｔｉｇｍａｔｉｃ ｒｅｆｒａｃｔｉｖｅ ｋｅｒａｔｅｃｔｏｍｙ,ＰＡＲＫ）矫治复性近视散光的有效性、准确性和预测性。方法 采用Ｃｏｍｍｐａｋ－２００型准分子激光机,对３４例４６眼复性近视散光行角膜椭圆形切削,根据散光度大小分为２组;Ａ组（－１．７５～－２．７５Ｄ）,Ｂ组（－３．００～－５．２５Ｄ）,并随访０．５ａ以上,观察手术前后的视力、屈光度、     

三种巩膜隧道外切口超声乳化白内障吸除术后手术源性散光的动态研究

目的 比较３种不同长度巩膜隧道外切口超声乳化白内障吸除术后产生手术源性散光（ｓｕｒｇｉｃａｌｌｙ ｉｎｄｕｃｅｄ ａｓｔｉｇｍａｔｉｓｍ,ＳＩＡ）度数及方向的变化规律,并评价手术效果。方法 将１０４例（１０４只眼）白内障患者分为Ａ、Ｂ、Ｃ３组,分别以３．２、５．５及７．０ｍｍ巩膜隧道外切口施地超声乳化白内障吸除术,测定术前、术后１周、１、３和６个月的角膜曲率,运用Ｃｒａｖｙ向量分析法计算ＳＩＡ度数     

角膜缘松解切开术矫正白内障术前散光对角膜曲率的影响

目的　观察角膜缘松解切开术在白内障超声乳化术中对角膜散光的矫正效果,以及其对角膜前后表面的中央曲率、周边曲率的影响。方法　选取在我院诊治的白内障患者３５例３５眼,患者术前角膜散光均≥１．０Ｄ,行角膜缘松解切开术联合白内障超声乳化吸出＋人工晶状体植入术,所有患者均在术前及术后１ｄ、１周、１个月、３个月进行眼科常规检查,包括术眼裸眼视力（ｕｎｃｏｒｒｅｃｔｅｄｖｉｓｕａｌａｃｕｉｔｙ,ＵＣＶＡ）、最佳矫正视力（ｂｅｓｔｃｏｒｒｅｃｔｅｄｖｉｓｕａｌａｃｕｉｔｙ,ＢＣＶＡ）,进行显然验光,用Ｐｅｎｔａｃａｍ眼前节分析系统测量角膜前后表面中央３ｍｍ范围内的最大曲率、最小曲率,同一子午线上角膜前后表面周边７ｍｍ范围最大及最小曲率。比较患者术前及术后各时间点ＵＣＶＡ、ＢＣＶＡ、中央及周边角膜前后表面曲率的变化。结果　患者术后不同时间点的ＵＣ-ＶＡ及ＢＣＶＡ与术前比较均显著提高,术前ＵＣＶＡ＞０．５占０％,ＢＣＶＡ＞０．５占８．６％,而术后３个月ＵＣＶＡ ＞０．５占４２．９％,ＢＣ-ＶＡ＞０．５占７７．１％,差异均有统计学意义（均为Ｐ＜０．００１）;术后各时间点与术前相比,最佳矫正柱镜度数和角膜散光均减少,差异均有统计学意义（均为Ｐ＜０．００１）;前表面角膜中央和周边曲率与术前相比,早期均是陡峭轴曲率呈减小趋势,扁平轴曲率呈增加趋势,之后稳定（Ｐ＜０．０５）,中央陡峭曲率ＦＫ２减少了（１．０６±０．６６）Ｄ,周边陡峭曲率ＦＰＫ２减少了（０．７６±０．５０）Ｄ,中央平坦曲率ＦＫ１增加了（０．３３±０．２８）Ｄ,周边平坦曲率ＦＰＫ１增加了（０．３５±０．２６）Ｄ。角膜后表面中央及周边曲率与术前比较有变化,但没有明显规律性。结论　角膜缘松解切开术矫正白内障术前角膜散光是安全有效的,松解切开术会引起角膜前后表面中央曲率和周边曲率的变化,且前表面中央曲率变化对角膜散光的影响较大,后表面曲率变化对角膜散光的影响很小。     

反射式角膜镜检测儿童角膜散光的临床研究

反射式角膜镜用于无角膜曲率计情况下临床角膜曲率定性检测，操作较Ｐｌａｃｉｄｏ盘方便。对１３０只儿童角膜散光眼作角膜镜与角膜曲率计检测，以角膜曲率计检测结果为准，反射式角膜镜检测结果与之比较，两法检测相关密切（Ｐ＜０．００５），符合率高（８９．２３％）。说明反射式角膜镜检出角膜散光的效用与角膜曲率计基本一致，对儿童角膜散光早期诊断颇具价值，可为进一步的检查和矫治提供依据。     

老年性白内障患者中角膜后表面散光对总角膜散光的影响

目的　研究老年性白内障患者模拟角膜曲率计散光和总角膜散光大小及轴位的差异,评价角膜后表面散光对总角膜散光的影响。方法　８０例老年性白内障患者（１０５眼,左４７眼,右５８眼）手术前行Ｐｅｎｔａｃａｍ检查,记录角膜前后表面散光,并对角膜前后表面散光行相关性分析。模拟角膜曲率计散光用屈光指数１．３３７５及角膜前表面曲率半径计算,总角膜散光由前后表面散光在角膜后表面的矢量合计,计算模拟角膜曲率计散光和总角膜散光的矢量差Ｅ→、大小差Ｅ和轴位差Ａ。结果　角膜前表面散光和后表面散光大小间无明显相关性（Ｐ＝０．９８）,后表面散光对前表面散光的平均补偿作用为５．７９％。总角膜散光及模拟角膜曲率计散光大小分别为（１．１２±０．６５）Ｄ和（１．０７±０．６４）Ｄ,差异具有统计学意义（ｔ＝－２．４０,Ｐ＝０．０２）;两者轴位分别为（６７．９３±５６．５０）°和（６８．９０±５９．６８）°,差异无统计学意义（ｔ＝－０．２７,Ｐ＝０．７９）。散光值大小及轴位差异的算术均值分别是（０．０５±０．２３）Ｄ和（－０．５７±１３．０２）°,绝对值是（０．１９±０．１５）Ｄ和（７．００±１０．９７）°。两者散光大小差别大于０．５０Ｄ或轴位差别大于１０°的有３０眼,占２８．５７％。结论　老年性白内障患者忽略角膜后表面测量可能会导致具有临床意义的角膜散光值估计的差异。     

应用角膜地形图评价PRK矫正近视散光的疗效

目的以ＰＲＫ矫正近视性散光术后１ａ临床结果和角膜地形图检测结果评价ＰＲＫ矫正近视散光的效果。方法对６１只眼近视散光在－２．００Ｄ以上者应用ＰＲＫ治疗，术后随访１ａ，并对手术前后散光的变化进行角膜地形图比较。结果患者ＰＲＫ术后１ａ检查，其中６０只眼散光在０～－１．００Ｄ之间，角膜切削区中心距瞳孔中心均≤０．５ｍｍ，角膜地形图检测术前△Ｋ值为１．８５±０．５９Ｄ，术后△Ｋ值为０．９０±０．４３Ｄ，显示术后散光下降明显。结论ＰＲＫ治疗散光效果明显，但应解决角膜切削区域偏中心情况。     

Pentacam系统评估白内障术后角膜后表面屈光力及散光的变化

目的:基于Pentacam眼前节分析系统测量白内障手术不同时期角膜后表面屈光力及角膜后表面散光的变化。方法:选取2019-01/2020-01在我院眼科收治的年龄相关性白内障患者96例116眼为研究对象,所有患者均行白内障超声乳化联合人工晶状体植入术,术后1wk,1、3mo进行随访行Pentacam检查,获取角膜前表面屈光力、后表面屈光力、总屈光力的平坦子午线屈光力、陡峭子午线屈光力、平均屈光力、角膜前表面散光、后表面散光、总散光等参数值。Spearman秩相关对各眼前节参数进行相关性分析。结果:术后1wk角膜前表面屈光力(平坦值、陡峭值、平均值)均较术前变小,在术后1、3mo逐渐趋于术前水平;术后1wk角膜后表面屈光力、总屈光力(平坦值、陡峭值、平均值)较术前增大,均在术后3mo趋于稳定。术后1wk角膜前表面散光、后表面散光、总散光较术前增大,后逐渐降低至术后3mo稳定。角膜前表面屈光力与角膜总屈光力呈显著正相关,角膜后表面屈光力与角膜总屈光力呈显著负相关,与其绝对值呈显著正相关(P<0.05)。角膜总散光术前,术后1wk,3mo与角膜前表面散光相对应时期呈明显正相关(P<0.01),与角膜后表面散光相关性较小。结论:白内障手术导致的角膜后表面屈光力及角膜后表面散光变化发生在术后3mo内,Pentacam眼前节分析系统可准确评估术前及术后角膜前后表面屈光力及散光的动态变化,具有很大的临床价值。     

自动角膜曲率计与角膜地形图仪测量儿童角膜屈光力的比较研究

目的 比较KR-8100自动角膜曲率计与TMs-4角膜地形图仪测量屈光不正儿童角膜屈光力及散光轴向的差异,并对两种测量方法进行一致性评价.方法 采用KR-8100自动角膜曲率计及TMS-4角膜地形图仪对53例(106只眼)屈光不正儿童进行测量,应用配对t检验对两种方法测量的陡峭 子午线角膜屈光力(Ks)、平坦子午线角膜屈光力(Kf)、角膜散光Ks-Kf大小及轴向进行比较,并应用Bland-Altmann分析对两种测量方法进行一致性评价.结果 角膜地形图仪测量的Ks、Kf、Ks-Kf值均高于角膜曲率计的测量值(P<0.01);角膜地形图仪与角膜曲率计的散光轴向测量值差异有统计学意义(P<0.01).两种仪器测量Ks的差值的均数为1.72D,测量Kf的差值的均数为1.37D,这种测量差别临床上不能接受,说明两种仪器测量角膜屈光力的一致性较差.结论 KR-8100自动角膜曲率计与TMS-4角膜地形图两种测量方法在临床上不能替代使用.     

Relaxing incision guided by videokeratography for astigmatism after keratoplasty for keratoconus.

PURPOSE: To evaluate the efficacy of topographic measurements for relaxing incisions in astigmatism following penetrating keratoplasty for keratoconus. METHODS: Twenty patients (20 eyes) had relaxing incisions between July 1989 and August 1994 for high astigmatism after penetrating keratoplasty for keratoconus. Ten eyes were evaluated using a HaagStreit keratometer (1989-1991) and 10 eyes were evaluated using EyeSys videokeratography (1991-1994). Relaxing incisions were performed at the steep meridians in the donor/host wound. RESULTS: Mean preoperative astigmatism was 7.75 +/- 2.05 D (range, 4.50 to 12.00 D) for the keratometry group, and 6.49 +/- 3.24 D (range, 1.11 to 10.13 D) for the videokeratography group. Mean astigmatism following relaxing incision was 3.90 +/- 2.02 D (range, 0.93 to 6.50 D) for the keratometry group and 3.06 +/- 1.62 D (range, 0.07 to 5.64 D) for the videokeratography group (no significant difference). Vector analysis revealed a vectorial change of 4.64 +/- 2.54 D for the keratometry group and 4.68 +/- 2.08 D for the videokeratography group (no significant difference). Mean spectacle-corrected visual acuity was significantly improved in the topography-guided group following the procedure (P = .021). Complications included perforations in 3 of 20 eyes. Four patients (4 eyes) in the keratometry group and one patient (1 eye) in the videokeratography group had residual astigmatism greater than 5.00 D. Four patients in the keratometry group needed a second procedure of relaxing incision because of irregular (2 eyes) or high (2 eyes) astigmatism. One patient (1 eye) in the videokeratography group needed a second relaxing incision. CONCLUSIONS: Videokeratography as a guide for relaxing incision has some benefits over standard keratometry. Preoperative evaluation with videokeratography did not significantly improve the postoperative astigmatism. Fewer reoperations were needed when videokeratography was used.     

Paired relaxing incisions for the control of astigmatism

The problem of astigmatism, occurring both congenitally and in conjunction with cataract and refractive surgery, is a common and significant one. A review of patients in this study shows 18% greater than 2 diopters and 6% greater than 3 diopters of astigmatism measured by keratometry. Many methods for correcting this astigmatism have developed, including long peripheral incisions, both straight and curved, the many varieties of the Ruiz procedure, and short paired relaxing incisions. I have reviewed my results for short paired incisions following cataract surgery, congenital astigmatism, and radial keratotomy at 6 months following surgery. The average change in astigmatism was 2.69 +/- 0.78 (manifest)/2.35 +/- 1.09 (keratometry) for the 5-mm optic zone following cataract surgery. Paired relaxing incisions following radial keratotomy showed a change in astigmatism of 0.92 +/- 0.19 (manifest)/1.29 +/- 1.29 (keratometry) diopters for the 6-mm optic zone and 2.12 +/- 0.34 (manifest)/2.25 +/- 0.49 (keratometry) diopters for the 5.5-mm optic zone. No significant complications and no large overcorrections were encountered.     

Induced corneal astigmatism after macular translocation surgery with scleral infolding.

OBJECTIVE: To document the corneal astigmatism that occurs with macular translocation after scleral infolding surgery. DESIGN: Retrospective case series of a nonrandomized clinical trial. PARTICIPANTS: Eight consecutive age-related macular degeneration patients (eight eyes) with choroidal neovascularization who underwent macular translocation with scleral infolding at the Duke University Eye Center from December 1998 through October 1999. METHODS: We retrospectively reviewed the charts of eight consecutive patients who underwent macular translocation surgery involving scleral infolding in the superotemporal quadrant. Two patients subsequently underwent release of scleral infolding. MAIN OUTCOME MEASURES: After surgery, these eyes were evaluated for corneal astigmatism with manifest refraction, keratometry, and computerized corneal topography. RESULTS: All eight eyes of eight patients revealed marked degrees of corneal astigmatism. Measurement of astigmatism via manifest refraction, keratometry, and corneal topography confirmed postoperative astigmatism corresponding to the axis of the scleral infolding. The amount of corneal astigmatism ranged from 1.75 to 7.37 diopters (D; mean, 4.60 D), with steepening along the axis of scleral infolding in the superotemporal quadrant of each eye (mean, 42.50 degrees from vertical; range, 24 degrees -66 degrees from vertical). Release of scleral infolding in two patients resulted in significant reduction of corneal astigmatism. CONCLUSIONS: Scleral shortening procedures used in macular translocation surgery may induce large amounts of corneal astigmatism. These patients should be assessed with keratometry and corneal topography to determine the accurate amount and axis. Thereafter, contact lens fitting or scleral infolding release may be considered as therapeutic options for large amounts of astigmatism persisting after surgery.     

眼前段光学相干断层扫描仪CASIA2测量白内障患者角膜曲率和散光的重复性和再现性

目的　探讨基于扫频OCT（SS-OCT）原理的眼前段光学相干断层扫描仪CASIA2测量白内障患者角膜曲率和散光的重复性和再现性。方法　选取2020年3月至7月在川北医学院附属医院眼科就诊的白内障患者91例114眼(右眼64眼,左眼50眼)进行检测。术前检查者A连续测量受检眼3次,检查者B也连续测量相同受检眼3次,记录模拟角膜陡峭曲率（K_s ）、模拟角膜平坦曲率（K_f）、模拟角膜平均曲率（K_m）、模拟角膜散光（J₀和J₄₅）、角膜后表面K_s、角膜后表面K_f、角膜后表面K_m、角膜后表面J₀和J₄₅、全角膜K_s、全角膜K_f、全角膜K_m和全角膜J₀和J₄₅。通过组内标准差（S_w）、重复性限（2.77S_w）、组内变异系数（CoV）、组内相关系数（ICC）来评价重复性和再现性。S_w、2.77S_w、CoV越小,ICC越接近1,说明重复性和再现性越好。结果　重复性评价方面,两名检查者测得的各角膜曲率（K_s、K_f、K_m）值和散光（J₀和J₄₅）值的S_w、2.77S_w、CoV均较小,并且ICC均值均≥0.903,其中各角膜曲率（K_s、K_f、K_m）值的ICC均值均≥0.993（接近于1）,说明CASIA2测量白内障患者角膜曲率和散光的重复性较好。再现性评价方面,各角膜曲率（K_s、K_f、K_m）值和散光（J₀和J₄₅）值的S_w、2.77S_w、CoV均较小,并且ICC均值均≥0.902,其中各角膜曲率（K_s、K_f、K_m）值的ICC均值均≥0.991（接近于1）,说明CASIA2测量白内障患者角膜曲率和散光的再现性较好。结论　基于SS-OCT原理的眼前段光学相干断层扫描仪CASIA2测量白内障患者角膜曲率和散光具有较好的重复性和再现性。     

Cost-efficient vision screening for astigmatism in native american preschool children

PURPOSE: To design and test a cost-efficient, community-based vision screening program for a population of Native American preschool children in which there is a high prevalence of astigmatism. METHODS: Based on analysis of vision screening and eye examination data from a preschool population with a 33% prevalence of astigmatism, comparative costs to conduct a 1000-child screening program with a target sensitivity of 90% were estimated for photoscreening, noncycloplegic autorefraction, autokeratometry, and Lea symbols distance visual acuity testing. Results of the cost analysis and examination of sensitivity and specificity data from the preschool population led to development of a hybrid screening program of autokeratometry and visual acuity screening with referral thresholds of 2.25 D of corneal astigmatism or inability to read a 20/63 Lea symbols line on two separate attempts. The screening program was prospectively implemented in a community-based screening of a similar cohort of 167 children, and its efficiency was evaluated by comparison to results of cycloplegic refraction. RESULTS: The community-based screening showed 96.8% sensitivity and 79.2% specificity for detecting the presence of refractive astigmatism of 1.50 D or more. CONCLUSIONS: Referring children who have at least 2.25 D of corneal astigmatism or acuity worse than 20/63 on two attempts, provides the high sensitivity and specificity associated with automated keratometry while maintaining an acuity component that can detect other causes of reduced acuity in the absence of astigmatism.     

超声乳化白内障吸除术前患者角膜散光状况的调查

目的 了解年龄相关性白内障患者术前角膜散光的特征.方法 连续收集2008年7至12月诊断为年龄相关性白内障,并拟行超声乳化白内障吸除术的患者1389例(1389只眼)的术前角膜曲率资料.双眼患者纳入第一手术眼,对患者角膜散光的大小、类型和分布情况进行描述性统计,并分析年龄、眼轴等因素与角膜散光的关系以及双眼角膜散光的对称性.构成比比较用x2检验,两个变量间的相互关系用Spearman相关分析,对称趋势采用一元线性回归分析.结果 患者平均年龄(67.8±12.3)岁(40.0～79.0岁).角膜散光的中位数0.84 D(0.12～4.36 D),角膜散光≥1.00 D的占32.9%(457只眼),其中逆规性散光(ATR)占53.2%(243只眼).随年龄增加,角膜散光有ATR方向漂移的趋势.眼轴与角膜散光量无相关关系(r=0.179,P=0.203).双眼角膜散光量呈对称趋势,并且散光轴呈镜面对称趋势.结论 在年龄相关性白内障患者中,术前角膜散光患病率较高,主要以轻度散光为主;而且角膜散光有双眼对称趋势;眼轴不是角膜散光大小的直接影响因素.     

人工晶状体植入术后角膜散光

目的探讨人工晶状体植入术后角膜散光的规律与程度。方法随机对５１例５３眼人工晶状体植入术者进行了术前、术后０．５ｍｏ及术后６ｍｏ的角膜曲率计检查。结果术后均出现不同程度的逆规性角膜散光。结论多缝线的这种人工晶状体植入术后角膜散光在较低水平,且这种散光在６ｍｏ内趋向稳定。     

Biometry characteristics in congenital cataract patients before surgery in a tertiary eye care centre in Nepal

PurposeTo evaluate the anterior segment biometry characteristics in congenital cataract patients before undergoing surgery in a tertiary eye care centre.MethodsWe retrospectively reviewed the charts of congenital cataract patients aged less than 15 years who had undergone the congenital cataract surgery from Jan-Dec, 2015. 451 eyes of 351 patients were reviewed. The eyes were examined using an autorefract-keratometer, applanation A-scan and parameters like keratometry, axial length, corneal astigmatism were noted.ResultsThe mean age at the surgery was 92.4 ± 4.13 months (range 6 months to 15 years). The ratio of boys to girls was 2.34:1. The mean axial length was 21.94 ± 1.94 mm. Girls had shorter axial length than boys (21.53 mm vs 22.11 mm, p = 0.01). The axial length in the cataractous eyes in bilateral cases was significantly smaller than that in the unilateral cases (21.46 mm vs 22.55 mm, p < 0.0001).The mean keratometry was 44.12 ± 2.6 D. Girls had larger mean keratometry value than boys (44.71 vs 43.88, p = 0.0032). Keratometry values were higher in cataractous eyes in bilateral cases than in the unilateral cases (44.61 D vs 43.51 D, p < 0.0001). The mean corneal astigmatism was 1.49 ± 1.13 D. The prevalence of the corneal astigmatism of 2.0 D or more was 25.5%. The with-the-rule astigmatism was the most frequent type (62.53%). Girls had higher mean astigmatism than boys (p = 0.0122). The mean corneal astigmatism was higher in the cataractous eyes in bilateral cases than in the unilateral cases (p = 0.0094).ConclusionsThe axial length, mean keratometry and corneal astigmatism in congenital cataract patients varied with age, gender, and laterality. The data on biometry characteristics of Nepalese pediatric patients provided in the present study are of clinical significance and hence greatly enhance the guidelines for treatment decisions, IOL power calculations and management of congenital cataract patients.