视力低常学龄前儿童散光特征及分析

目的了解学龄前儿童散光性质、散光度、散光轴向分布情况。方法 1%阿托品眼膏常规散瞳检影验光。结果学龄前儿童散光度大多分布在0.50D～2.00D之间,散光轴向：顺规散光占96.24%,逆规散光占2.14%,斜轴散光1.62%。结论学龄前儿童散光以顺规散光为主,逆规散光次之,斜轴散光最少见,散光情况则以远视散光为主。     

散光相关性屈光不正近视化状况

目的 探究散光相关性屈光不正近视化进程的状况.方法 病例系列研究.选取4～6岁散光儿童210例（412眼）,男114例,女96例.检测其最佳矫正视力、眼轴长度、扩瞳验光度数（1%硫酸阿托品滴眼液）等指标,随访24个月.应用SAS 9.2统计软件中的混合效应模型,分析不同度数和轴向的散光对球性屈光不正度数和眼轴长度的影响.结果 2年内,210例儿童中散光度数越高,眼轴长度和近视度数增加越显著（F分别为7.380、10.636,P均＜0.01）;超高度组明显重于轻、中、高度组（P均＜0.05）,而轻度与中度组差异不明显;眼轴长度和近视度数增加值在轻度组分别为（0.19±0.10）mm、（0.78±0.79）D,中度组为（0.20±0.14）mm、（0.94±0.79）D,高度组为（0.33±0.14）mm、（1.36±0.68）D,超高度组为（0.38±0.12）mm、（1.60±0.58）D.2年内,散光轴向对儿童眼轴长度和近视度数存在影响（F分别为12.351、12.384,P均＜0.01）;顺规性散光组近视度数增加最少,斜轴性散光组眼轴长度增加最多（P＜0.05）,而斜轴和逆规组眼轴、近视程度增加值组间差异无统计学意义：眼轴长度和近视度数增加值在顺规组分别为（0.20±0.17）mm、（0.74±0.49）D,逆规组为（0.28±0.17）mm、（1.26±0.98）D,斜轴组为（0.43±0.20）mm、（1.61±0.74）D.结论 在眼睛近视化过程中,散光度数越高,近视化进程越快：斜轴散光对近视进展的影响较顺规散光、逆规散光大.故在近视防治工作中要充分考虑到散光对近视化的影响. 关键词：散光;近视化;眼轴;儿童     

散光眼与Toric人工晶状体

散光眼的性质、度数及轴位是由角膜散光和晶状体散光共同决定的。散光的度数及轴位并非一成不变 ,它随年龄的增长而增加 ,且年长者以逆规性散光多见。目前认为 ,散光度为零并不是视功能的最佳状态 ,低度数的近视顺规性散光有利于视远 ,低度数的近视逆规性散光有利于视近。在散光眼的矫正中 ,如何避免视物变形是最大的问题。用框架眼镜矫正时 ,因镜眼距 (眼镜与眼球之间存在的距离 )的影响 ,不同轴向放大率不同而引起视物变形 ,尤其在矫正斜轴散光时 ,这种现象最显著。正是基于上述认识 ,目前Ｔｏｒｉｃ人工晶状体已应用于临床。通过植入Ｔｏ…     

角膜后表面散光对Toric人工晶状体矫正效果的影响

目的评价角膜后表面散光对临床Toric人工晶状体（IOL）矫正效果的影响。方法回顾性系列病例研究。选择天津医科大学眼科医院准备行白内障超声乳化摘除术患者36例（36眼）,角膜散光为1.0～3.0 D,其中顺规散光（顺规组）18眼,逆规散光（逆规组）18眼。根据角膜模拟散光值（SimK,未考虑角膜后表面散光）计算植入相应型号的Toric IOL。术前使用Lenstar进行眼部生物测量,手动角膜曲率计与Pentacam分别测量3.0 mm直径范围内SimK及全角膜散光（TCA,考虑了角膜后表面散光）,并使用SimK与TCA进行全眼目标散光（TRA）的计算。术后3个月使用i-Trace进行3.0 mm直径范围验光,并检查Toric IOL轴位。采用矢量分析方法将TRA与术后i-Trace验光得到的残余散光（RA）进行比较。根据两者差值即散光矫正误差（ERA）（其中SimK方法为ERA1,TCA方法为ERA2）,定量分析角膜后表面散光对Toric IOL矫正效果的影响。将2种计算方法获得的TRA按照矢量进行分解,与RA进行相应矢量方向上的配对t检验分析。结果36眼总体角膜后表面散光为（0.39±0.30）D,其中顺规组为（0.51±0.32）D,逆规组为（0.26±0.19）D。36眼中ERA1=0.38×（φ+96）°,ERA2=0.12×（φ+93）°,两者相差0.26 D。其中顺规组ERA1=0.65×（φ+87）°,ERA2=0.13×（φ+92）°,两者相差0.52 D;逆规组ERA1=0.28×（φ+3）°,ERA2=0.05×（φ+4）°,两者相差0.23 D。将总体、顺规组、逆规组SimK得到的TRA与RA进行比较,其K（φ）成分差异均有统计学意义（t=2.28、3.51、1.92,P＜0.05）,K（φ+45）成分差异均无统计学意义;TCA得到的TRA与RA进行比较,其K（φ）、K（φ+45）成分差异均无统计学意义。此外,顺规组角膜散光普遍过矫,逆规组角膜散光普遍欠矫。结论忽略角膜后表面散光会导致Toric IOL矫正误差增加,术后RA增大。顺规散光容易出现散光过矫,逆规散光容易出现散光欠矫。采用TCA计算选择Toric IOL可以减小ERA,提高Toric IOL矫正效果。     

儿童总散光与角膜散光及眼内散光的多重线性回归分析

目的：探讨儿童眼总散光与角膜散光、眼内散光的线性关系。方法：系列病例研究。选取2018年 6─12月在连云港市妇幼保健院行睫状肌麻痹验光且散光度≥1.00 D的3～6岁儿童,按入选标准选 取76例（126眼）,收集睫状肌麻痹后角膜散光度及轴位、眼总散光度及轴位4组数据。运用矢量的 平行四边形法则及三角函数公式分析并计算眼内散光度及轴向,对总散光度与角膜散光度、眼内 散光度做多重线性回归分析。结果：眼总散光度与角膜散光度、眼内散光度遵循Ctotal=0.004+0.988 ×Ccorneal+0.928×Cintraocular（R2 =0.998,P<0.001）。眼总散光轴向与角膜散光轴向、眼内散光轴向遵循 Atotal=48.391+0.708×Acorneal-0.185×Aintraocular（R2 =0.531,P<0.001）。126只散光眼的眼内散光中远视性 散光92眼（73.0%）,散光度最小值+0.25 D,最大值+2.00 D,平均（+0.58±0.29）D;近视性散光34眼 （27.0%）,散光度最小值-0.03 D,最大值-1.03 D,平均（-0.26±0.24）D。结论：眼总散光度与角膜 散光度、眼内散光度呈高度线性相关。可通过公式Ctotal=0.004+0.988×Ccorneal+0.928×Cintraocular反推计 算出眼内散光度,且准确性高。大部分眼内散光对角膜散光起补偿抵消作用,对角膜散光轴向影响小, 眼内散光以逆规散光为主。     

角膜地形图在预测学龄前儿童散光中的应用

目的探讨角膜地形图检查在预测学龄前儿童散光中的作用。方法分析356例(679只眼)角膜地形图检查散光与睫状肌麻痹后视网膜检影的散光度数和散光轴的相互关系,采用SPSS11统计软件包分析,作配对t检验。结果角膜地形图方法组,循规散光性散光占94.62%,逆规性散光占2.15%,斜轴性散光占3.23%。散瞳检影验光方法组,循规散光性散光占95.74%,逆规性散光占2.78%,斜轴性散光占1.48%。角膜地形图方法组散光度数的分布以1.00~3.00D为主,散瞳检影验光方法组的分布以0.50~2.00D为主。角膜地形图测得的散光度为1.92±0.88D,散瞳检影验光测得的散光度为1.39±0.83D,两者比较差异有统计学意义(t=8.974,P<0.01)。角膜地形图测得的柱镜轴向为101.46±32.57度,散瞳检影验光测得的柱镜轴向为99.73±48.12度,两者比较差别无统计学意义(t=1.08,P>0.05)。结论角膜地形图检查仅反映角膜屈光状况,对验光中散光轴的确定有一定的价值,但临床最终检查结果仍应以睫状肌麻痹后检影作为确定散光度及散光轴的标准。     

准分子激光原位角膜磨镶术矫正近视散光的临床探讨

目的 探讨准分子激光原位角膜磨镶术(LASIK)矫正近视散光的临床疗效.方法 对散光等于和高于-1.50D的复性近视散光和单纯近视散光69例(115眼)施行LASIK矫正,其中循规性散光76眼,逆规性散光24眼,斜轴散光15眼.散光度-1.50D～-4.00D的106眼,-4.00D以上的9眼.结果 术后6个月达预期矫正视力者105眼(91.30%),实际矫正散光度接近术前预期矫正散光度,柱镜差值(-0.75±0.50)D者101眼.角膜地形图由术前96眼(83.48%)领结形到术后90眼(78.26%)为平滑的圆形或椭圆形.术前散光高于-4.00D的9眼中3眼未达到术前最佳矫正视力,4眼眩光、虚影不适症状持续存在.结论 LASIK矫正近视散光同治疗单纯近视一样安全有效,预测性好,但-4.00D以上的高度散光疗效欠佳.视觉质量下降.     

2.2 mm透明角膜切口飞秒激光辅助白内障超声乳化手术术源性散光的临床研究

目的观察飞秒激光辅助白内障超声乳化手术中2.2 mm透明角膜切口引起的术源性散光（SIA）的影响因素。方法前瞻性研究。纳入2014年3月至2016年4月期间,在山西省眼科医院白内障一科行飞秒激光辅助白内障超声乳化手术的患者84例（105眼）,测量并记录患者术前,术后1、3、6个月的裸眼视力（UCVA）,球镜度和角膜地形图数据。视力记录为logMAR视力,使用Alpins矢量分析法计算SIA。并从术后随访时间（术后1、3、6个月3个时间点）、晶状体核硬度（分Ⅱ、Ⅲ、Ⅳ级核3组）、角膜散光类型（分顺规组、逆规组、斜轴组）、眼别（左眼组、右眼组）4个方面分析SIA。符合正态性分布的数据的比较使用重复测量的方差分析。结果84例（105眼）患者UCVA术前为0.65±0.24,术后1、3、6个月为0.07±0.02、0.06±0.01、0.06±0.01;手术前后比较差异有统计学意义（F=321.14,P<0.01）;术后各时间点比较差异无统计学意义。术后1、3、6个月SIA分别为（0.28±0.11）D、（0.25±0.13）D、（0.24±0.10）D;3个时间点比较差异无统计学意义。按晶状体核硬度分组从时间上及组别间比较差异均无统计学意义;顺规组、逆规组、斜轴组3组从时间上及组别间比较差异均无统计学意义;右眼组与左眼组从时间上及组别间比较差异均无统计学意义。结论2.2 mm透明角膜切口飞秒激光辅助白内障超声乳化术后SIA稳定,术后UCVA显著提高,且SIA与UCVA于术后1个月趋于稳定。     

白内障术中飞秒激光弧形角膜切开术矫正角膜散光的疗效

目的：研究白内障术中飞秒激光弧形角膜切开术（FSAK）矫正术前角膜散光的临床疗效。方法：回顾性病例对照研究。连续纳入北京爱尔英智眼科医院2017年3月至2021年12月术前规则角膜散光为0.75~2.00 D且接受飞秒激光辅助白内障手术的患者89例（89眼）。所有患者按照术前角膜散光轴位分为顺规散光组（90°±30°）、逆规散光组（180°±30°）及斜轴散光组（45°±15°、135°±15°）。飞秒激光辅助白内障手术及弧形角膜切开术使用Lensx平台。观察患者总体和顺规、逆规散光组术前及术后3个月角膜散光的变化及分布情况。使用配对样本t检验或Wilcoxon符号秩检验比较总体及各亚组术前、术后的散光差异；使用独立样本t检验或Mann-Whitney U检验比较顺规散光组及逆规散光组的差异；散光变化的分析采用Alpins矢量分析法。结果：纳入的89例（89眼）患者中，顺规散光组38例，逆规散光组44例，斜轴散光组7例。所有患者角膜水平径为（11.48±0.57）mm，垂直径为（10.66±0.60）mm。患者总体术后裸眼远视力、最佳矫正远视力相比术前有显著改善（Z=8.01、-7.49，P<0.001）。总体术前角膜散光为（1.28±0.33）D，术后3个月残余散光（0.67±0.37）D，散光矫正量为（0.61±0.33）D。顺规及逆规散光组角膜散光矫正量分别为（0.48±0.27）D、（0.74±0.34）D。总体及顺规、逆规散光组术后平坦轴角膜曲率均有明显升高，而陡峭轴角膜曲率则出现明显下降。矢量分析法显示总体散光矫正指数为0.63±0.30，平坦指数为0.58±0.30，成功指数为0.51±0.25，误差角为-1.83°±12.59°。逆规散光组矫正效果最佳，矫正指数为0.81±0.25，平坦指数为 0.75±0.26，成功指数为0.40±0.24；顺规散光组次之，矫正指数为0.42±0.21，平坦指数为0.39±0.21，成功指数为0.63±0.21。结论：白内障术中FSAK矫正术前角膜散光具有良好的有效性和安全性，相同的弧形切口设计方式在逆规散光中取得了更好的疗效，角膜直径可能是产生影响的重要因素。     

白内障患者角膜后表面散光的测量及相关因素分析

目的　研究白内障患者角膜后表面散光(posterior corneal astigmatism，PA)的分布情况及相关影响因素。方法　回顾性分析2017年1月至8月确诊为老年性白内障的患者174例（190眼），分为角膜前表面散光(anterior corneal astigmatism，AA)组:顺规散光组67例（75眼）、逆规散光组77例（80眼）、斜轴散光组32例（35眼）及总AA组174例（190眼）；PA组:顺规散光组23例（23眼）、逆规散光组138例（149眼）、斜轴散光组18例（18眼）及总PA组174例（190眼）。术前通过Pentacam测得患者的角膜曲率、中央角膜厚度（central corneal thickness,CCT）、角膜水平直径（white-to-white,WTW），通过IOL Master测量患者的眼轴（axial length，AL）、前房深度（anterior chamber depth，ACD）。Bland-Altman分析模拟角膜散光值（simulated keratometry,SimK）与总角膜散光的差异；线性回归分析AA与PA的相关性；使用Pearson及Spearman相关分析其他眼内生物参数与PA的相关性。结果　角膜SimK与总角膜散光的散光值及轴位差异均有统计学意义（均为P<0.05）。Bland-Altman显示95%一致性界限分别为-0.70~0.55 D、-63.4°~70.2°。顺规散光组AA与PA呈弱的正相关（r=0.316，P=0.005）；逆规散光组PA与WTW呈弱的负相关（r=-0.214，P=0.015）；而AL、CCT、ACD均与PA无明显相关性（均为P>0.05）。结论　逆规性PA与WTW有弱的负相关，而PA与AL、ACD、CCT等参数没有相关性，且数值大小稳定。     

不同年龄段马凡综合征晶状体不全脱位患者角膜特征及意义

目的 比较不同年龄段马凡综合征晶状体不全脱位患者的角膜特征并探讨其临床意义.方法 马凡综合征组45例84眼和对照组84例84眼列入研究,前者按年龄分为两组:儿童组(5 ～14岁)49眼和非儿童组(＞14岁)35眼.使用Pentacam测量角膜曲率、角膜散光和中央角膜厚度.结果 与对照组相比,马凡综合征组患者角膜变平、散光增大,两组间差异均具有统计学意义(均为P =0.000).马凡综合征患者角膜前表面曲率儿童组为(40.02±1.42)D,非儿童组为(41.03±1.57)D;角膜后表面曲率儿童组为(-5.71±0.23)D,非儿童组为(-5.89±0.31)D;总角膜散光儿童组为(-1.71±0.84)D,非儿童组为(-1.34 ±0.78)D,两组相比差异均具有统计学意义(均为P＜0.05).角膜前表面散光儿童组高于非儿童组(P=0.017),而后表面散光两组间差异无统计学意义(P =0.377).儿童组总角膜散光和角膜前表面散光以顺规散光(69.39％)为主,而非儿童组顺规散光和斜向散光的比例相当.两组角膜后表面都以逆规散光为主(儿童组占85.71％,非儿童组占77.14％).以角膜前表面散光估计总角膜散光时约有一半的患者会高估约0.32 D.结论 马凡综合征晶状体不全脱位患者角膜变平、散光增大.儿童组角膜更扁平,总角膜散光和角膜前表面散光值较高,以顺规散光为主.马凡综合征患者的角膜后表面散光值较稳定,以逆规散光为主.忽视角膜后表面散光,以角膜前表面散光值估计总角膜散光时易高估.     

The prevalence of astigmatism in Taiwan schoolchildren.

PURPOSE: To understand the prevalence and distribution of astigmatism in schoolchildren in Taiwan, we analyzed and compared the nationwide survey data in 1995 and 2000. METHODS: A total of 11,175 students were enrolled in 1995, and 10,878 students were enrolled in 2000. The refractive status of each student was measured with an autorefractor during cycloplegia and rechecked with retinoscopy. RESULTS: About half of schoolchildren (57.5% in 1995 and 49.0% in 2000) had no astigmatism (<0.5 D). About one third of schoolchildren's astigmatism was <1 D (27.9% vs. 32.6%). Eleven percent of schoolchildren in 1995 and 13% in 2000 had astigmatism between 1.0 and 2.0 D. Less than 2% of students had astigmatism >3.0 D (1.3% in 1995 and 1.8% in 2000). Most astigmatism was with-the-rule: 83.3% in 1995 and 89.9% in 2000. Only 16.6% of children in 1995 and 9.7% in 2000 had against-the-rule astigmatism. Very little astigmatism was oblique (0.1% in 1995 and 0.4% in 2000). The rate of myopic astigmatism increased with age. In contrast, the rate of hyperopic and mixed astigmatism decreased with age. In addition, the rate of with-the-rule astigmatism increased and the rate of against-the-rule decreased with respect to age, but oblique astigmatism was rather stable with age. CONCLUSIONS: Most schoolchildren had little or no astigmatism. In Taiwan, most astigmatism is <1 D and is myopic with-the-rule astigmatism. There was more myopic astigmatism and with-the-rule astigmatism in 2000 than in 1995.     

Natural history of corneal astigmatism after cataract surgery.

Little information on the natural course of corneal astigmatism following cataract surgery exists. We report a prospective, computerized analysis of postoperative astigmatism, based on keratometry measurements, of 137 cases of extracapsular cataract extraction with intraocular lens implantation performed by one surgeon. No sutures were cut postoperatively. Surgery induced 1.44 diopters (D) of with-the-rule astigmatism at one month, which declined at a rate of 0.77 D and 0.35 D per month for the next two months, respectively, with a more gradual decline thereafter. The mean surgically induced astigmatism at the last postoperative visit ranged from 0.29 D at six months (minimum follow-up) to 1.23 D at 48 months; both were against-the-rule. Mean follow-up was 28.92 months. These findings may be technique specific and suggest that (1) corneal curvature continues to change slowly even two to four years postoperatively; (2) most patients develop against-the-rule astigmatism, thus more with-the-rule astigmatism is desirable in the early postoperative period; (3) selective suture removal is necessary only when significantly more than 3.00 D of surgically induced with-the-rule astigmatism is present.     

Longitudinal study of postoperative astigmatism

A prospective longitudinal study of 503 eyes that had extracapsular cataract extraction with posterior chamber intraocular lens implantation was conducted. Each patient was followed for a minimum of one year. Data were collected, analyzed, and the following information ascertained: temporal behavior of induced keratometric and cylindrical changes, induced with-the-rule, against-the-rule, and oblique astigmatism, comparison of keratometric and refractive astigmatism, and the effect of cutting sutures upon induced astigmatism. Though a large amount of with-the-rule astigmatism was immediately induced after surgery, by the end of one year over 60% of patients shifted toward against-the-rule.     

The aging effect on corneal curvature and the validity of Javal's rule in Hong Kong Chinese

PURPOSE: The current study compared the central corneal curvature and the refractive error of Hong Kong Chinese to study the validity of Javal's rule. METHODS: Subjects without corneal pathology were recruited at different age ranges. Their refractive error and the corneal curvature were measured and compared for the right eye only. Two instruments were used for the measurement of corneal curvature including a conventional Bausch & Lomb (B&L) keratometer and a computer-assisted videokeratoscope (TMS-1). RESULTS: Subjects age ranged from 21 years to 77 years were recruited and were categorized into five groups according to age. The Bausch & Lomb keratometer was found to provide corneal information similar to that from the TMS-1. The corneal astigmatism was found to change from with-the-rule to against-the-rule with advancing age. The spectacle astigmatism followed a similar trend. There was a hyperopic shift in the spherical component of the refractive error with aging as well. A regression equation: Spectacle astigmatism = 0.93 (Corneal astigmatism) + (-0.58D x 90) was found, which is similar to the simplified Javal's rule. There was a shift of 1.03D in hyperopia (spherical equivalent) for each decade. CONCLUSIONS: Both the corneal and spectacle astigmatism demonstrated a shift from with-the-rule to against-the-rule with age. The simplified Javal's rule is more suitable for predicting the spectacle astigmatism from corneal astigmatism in Hong Kong Chinese.     

非球面和球面人工晶状体植入术后视功能观察

目的 分析白内障患者术前角膜散光情况评估经不同位置透明角膜切口行超声乳化术后的角膜散光变化情况.方法 218例(295只眼)白内障患者分为三组,第一组选择颞侧切口,第二组选择颞上方切口,第三组选择上方切口,三组患者通过透明角膜切口行白内障超声乳化及折叠式后房型人工晶体植入术.术前及术后一周、一月、三月分别检测患者角膜散光情况,并通过Holladay-Cravy-Koch方法 计算术源性散光.结果 术前角膜散光0.5至1.5D的占60.68%,大于等于1.5D的占11.86%,顺归散光占29.49%,逆归散光占51.19%,其余为斜轴散光.术后三次随访颞侧切口组的术源性散光最低,上方切口组的术源性散光最高,具有统计学差异(P<0.05).另外,在上方切口组中发现患者术后角膜散光有向逆归散光转变的趋势.结论 白内障患者术前大多存在小于1.5D的角膜散光.在白内障术后早期阶段,颞侧透明角膜切口引起的术源性散光较小,而上方透明角膜切口不仅可引起较显著的术源性散光,并且术后角膜散光有向逆归散光转变的趋势.

Abstract：

Objective To analyze the corneal astigmatism before cataract surgery and evaluate the astigmatism changes after cataract surgery performed using clear corneal incisions with different locations.Methods: This randomized prospective clinical study comprised 295 eyes of 218 patients having phacoemulsification and implantation of foldable intraocular lens through a corneal tunnel incision. Patients were randomly divided into three groups depending on the different locations of the incision: temporal, superotemporal and superior. Corneal topography was performed preoperatively and 1 week, 1 month, and 3 months postoperatively. Surgically induced changes were calculated by vector analyses using the Holladay-Cravy-Koch method. Results: Preoperatively, in 60.68% of eyes, corneal astigmatism was between 0.5 and 1.5 diopters (D) and in 11.86%, it was 1.5 D or higher. Meanwhile, about 29.49 percent of eyes had with-the-rule (WTR) astigmatism, while 51.19% had against-the-rule (ATR) astigmatism, and the others had oblique astigmatism. At three follow-up visits postoperatively, the mean magnitude of surgically-induced astigmatism (SIA) was lowest in the temporal incision group and highest in the superior incision group. In addition, an ATR shift was found in the superior incision group. Conclusions: Corneal astigmatism less than 1.5 D was present in most cataract surgery candidates. Cataract surgery using temporal clear corneal incision induced significantly less SIA in the early postoperative period. Superior incision may lead to an ATR astigmatism shift.     

Corneal and lenticular components of total astigmatism in a preschool sample.

PURPOSE: To examine the contribution of corneal and lenticular components to total astigmatism in preschool low and high astigmats to determine whether there was any compensation for high astigmatism by the lenticular component. METHODS: Cycloplegic refractive and keratometric measures using the Retinomax K-Plus (Nikon Inc., Melville, NY) were conducted on 129 children (mean age, 51.1 +/- 8.4 mo) in Oxford County, Canada. We divided the sample into high astigmats (total cylinder > or =1 D; mean, 1.38 +/- 0.43 D; n = 29) and normal astigmats (total cylinder < or =0.75 D; mean, 0.22 +/- 0.20 D; n = 100). Measures of total and corneal cylinder were transposed into J0 and J45 components, where positive and negative J0 values quantified with-the-rule (WTR) and against-the-rule astigmatisms, respectively, and J45 quantified oblique astigmatism. RESULTS: WTR astigmatism was dominant in both the high and normal astigmatic group. J0 and J45 components of corneal astigmatism were highly correlated with total astigmatism in high astigmats, whereas only J0 was significantly correlated with total astigmatism in normal astigmats. Although the magnitude of total and corneal cylinder was significantly greater in high astigmats, overall lenticular cylinder was similar in both groups. However, the Fourier transforms showed high astigmats to have significantly lower lenticular J0 and higher lenticular J45 than the normal astigmats. CONCLUSIONS: Astigmatism in 3- to 5-year-old children is primarily corneal. In preschool children, the lens does not vary in response to high amounts of corneal WTR astigmatism, and in fact, it increases the oblique astigmatism component when the corneal component is high. In high astigmats, lenticular astigmatism contributes to both J0 and J45 components, whereas the corneal contribution is primarily J0.     

The effect of the type of astigmatism on the incidence of myopia

PURPOSE: To determine whether and how with-the-rule, against-the-rule or oblique astigmatism influence the creation of myopia. MATERIAL AND METHODS: A total of 167 people with myopia (117 women and 50 men) of the age between 12 and 51, were examined. The overall average age was 24. Routine ophthalmological examinations as well as autorefractometry were carried out. The data was analysed using the coefficients of rang Spearman's correlation. RESULTS: It was found that with the rise of with-the-rule astigmatism myopia increases (P < 0.000001). Any correlation between the people with low, medium, and high myopia and the against-the-rule as well as oblique astigmatism was not observed. CONCLUSIONS: (1) With-the-rule astigmatism predisposes the creation of myopia. (2) Against-the-rule as well as oblique astigmatism has no influence on the creation of myopia.