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。     

角膜地形图对近视散光眼的评价作用

目的探讨角膜地形图对近视散光眼的评价作用.方法对312例582只近视散光眼进行角膜地形图检查和检影验光,对所得散光度数、散光轴位及视力进行统计分析.结果两种方法所得散光度数差别≤0.25D和≤0.50D者分别占58.59%、84.19%;轴位差别≤5.和≤10.者分别为54.81%、75.43%;有367眼(63-06%)潜视力值(PVA)与最佳矫正视力(BcVA)相符.结论角膜地形图可对近视散光眼的散光度数、轴位及视力作出大致评价.验光前检查角膜地形图,将有助于提高验光的速度和准确度.     

OrbscanⅡ、电脑验光仪、综合验光测量散光的对比观察

目的分析准分子手术前近视散光患者术前应用OrbscanⅡ眼前节分析系统,自动电脑验光仪测得的柱镜和散光轴向与综合验光测得结果的差异及关系。方法采用OrbscanⅡ眼前节分析系统、小瞳下电脑验光、散瞳后电脑验光和综合验光4种测量方法,对130例（250只眼）近视散光进行检查并比较。结果综合验光、小瞳电脑验光和散瞳电脑验光3种方法测得的轴向基本一致,统计学分析无显著性差异（P〉0．05）,而OrbscanⅡ与综合验光测得的轴向统计学上有显著性差异（P〈0．01）;综合验光、小瞳电脑验光和散瞳电脑验光3种方法测得的散光度数统计学上有显著性差异（P〈0．01）。结论角膜地形图检查能反映角膜屈光状况,电脑验光仪对散光轴向的准确性较高,但临床检查仍应以睫状肌麻痹前后综合验光检查作为确定近视散光及散光轴的标准。     

近视眼全眼散光及角膜散光对LASIK术矫正近视散光的影响

目的:探讨全眼散光和角膜散光对LASIK手术矫正散光的影响。方法:回顾性分析84例162眼行LASIK手术矫正的近视散光患者,根据全眼散光与角膜散光轴向相差<15°,全眼散光度数<2倍角膜散光度数和全眼散光与角膜散光轴向相差≥15°,全眼散光度数≥2倍角膜散光度数分为A(112眼)、B(50眼)两组,分析术后视力、散光矫正效果。结果:患者中69%的全眼散光轴与角膜散光轴向相关,差异在15°以内,术后两组眼散光度数分别为-0.39±0.43,-0.73±0.21D,差异有统计学意义(P<0.05)。B组有4例患者主诉夜晚有眩光,近视力差、疲劳。结论:近视眼全眼散光与角膜散光有高度相关性。LASIK矫正散光术前应根据验光和角膜地形图结果分析,合理设计散光的切削量和轴位,选择个性化治疗方案。     

角膜地形图检查在低龄儿童散光检影验光中的应用

目的 通过比较在低龄儿童验光中角膜地形图所测得的角膜散光与检影验光测得的散光的相互关系,探讨角膜地形图检查在儿童散瞳检影验光中的应用价值.方法 采用计算机辅助的角膜地形图和散瞳检影验光两种测量方法,对285例(554只眼)复性远视散光眼进行检查并比较.结果 两种方法在检查散光轴方面差异无统计学意义(P>0.05),而在检查散光度数方面差异有统计学意义(P<0.05).结论 角膜地形图检查所得的散光度数及轴向可为散瞳检影验光的轴向确定提供重要的参考依据,患眼的总合散光仍以睫状肌麻痹后检影、插片接受的度数和散光作为标准,角膜地形图检查在提高低龄儿童散瞳检影验光速度和散光轴向准确度有一定作用.     

角膜地形图与散瞳验光散光差异分析

目的观察角膜地形图仪与散瞳验光测得的散光差异。方法以138眼（74例）近视眼为研究对象，角膜地形图仪记录角膜地形图形态、角膜屈光度、角膜散光度；散瞳后应用全自动电脑验光仪结合带状光检影及试镜．确定球镜度数、柱镜度数和轴位。所有数据用SigmaSTAT软件包进行统计学配对t检验。结果二组总的平均散光度，散瞳组为－1．21±0．9D，角膜地形图组为－1．37±0．63D，统计有显著性差异（P＜0．01）；总平均散光轴位：散瞳验光组为100．14°±76．4°，角膜地形图组为96．80°±78．0°，统计无显著性差异（P＞0．05）。结论　角膜地形图仪和散瞳验光记录的散光度有差异性，轴位无显著性差异，在设计屈光性手术时有指导意义。     

角膜地形图在儿童散光检影验光中的应用

通过比较儿童验光中角膜地形图所测得的角膜散光与检影验光测得的散光的相互关系,探讨角膜地形图检查在儿童散瞳检影验光中的应用价值。 方法：采用计算机辅助的角膜地形图和散瞳检影验光两种测量方法,对88例171眼非混合性散光眼进行检查并比较。 结果：两种方法在检查散光度数及散光轴方面差异无统计学意义(t=1.838,P＞0. 05;t=1.009,P＞0.05),实际最好矫正视力与角膜地形图PVA高值及低值比较差别有统计学意义（t=3.566,P＜0.01;t=3.445,P＜0.01)。 结论:角膜地形图检查所得的散光度数及轴向可为散瞳检影验光提供重要的参考依据,角膜地形图检查在提高低龄儿童散瞳检影验光速度和准确度有一定作用。     

新型眼前节相干光层析成像仪与Scheimpflug眼前节分析仪测量年龄相关性白内障患者角膜屈光力及散光的比较

目的比较新型扫频源眼前节相干光层析成像仪CASIA2与Scheimpflug眼前节分析仪Pentacam测量年龄相关性白内障患者角膜屈光力、角膜散光的差异性和一致性。方法横断面研究。收集2020年4至5月在天津医科大学眼科医院白内障科拟行超声乳化白内障吸除联合人工晶状体植入术的年龄相关性白内障患者共112例(112只眼),分别采用Pentacam和CASIA2测量角膜前后表面及全角膜的陡峭轴、平坦轴及平均角膜屈光力、散光度数及散光轴向,采用算术法和矢量法分析散光的差异。采用配对样本t检验或Wilcoxon符号秩检验进行两组测量结果间差异性分析,一致性评价采用Bland-Ahman分析。结果112例(112只眼)患者中,男性44例,女性68例,年龄(67±10)岁。Pentacam与CASIA2测量的角膜前表面陡峭轴及平均角膜屈光力差异均无统计学意义(均P>0.05);测量的平坦轴角膜屈光力分别为(44.24±1.73)、(44.14±1.64)D,差异有统计学意义(t=2.278;P<0.05)。Pentacam测量的角膜后表面陡峭轴、平坦轴及平均角膜屈光力分别为(-6.60±0.29)、(-6.34±0.27)、(-6.47±0.26)D,CASIA2测量的角膜后表面陡峭轴、平坦轴及平均角膜屈光力分别为(-6.45±0.28)、(-6.17±0.25)、(-6.31±0.25)D,二者差异均有统计学意义(t=-14.440,-13.522,-17.186,均P<0.01)。Pentacam测量的全角膜陡峭轴、平坦轴及平均角膜屈光力分别为(45.08±1.84)、(44.18±1.85)、(44.63±1.82)D,CASIA2测量的全角膜陡峭轴、平坦轴及平均角膜屈光力分别为(43.94±1.64)、(43.02±1.64)、(43.48±1.60)D,二者差异均有统计学意义(t=21.016,21.819,22.981;均P<0.01)。两设备散光度数及散光轴向的测量结果差异均无统计学意义(均P>0.05)。矢量运算结果显示,Pentacam与CASIA2测量角膜前表面散光差异矢量质心为0.06 D@57°±0.64 D,其中47只眼(41.96%)>0.50 D;角膜后表面散光差异矢量质心为0.07 D@174°±0.21 D,其中2只眼(1.79%)>0.50 D;全角膜散光差异矢量质心为0.13 D@3°±0.69 D,其中59只眼(52.68%)>0.50 D。相关性分析显示,两设备测量结果均呈正相关,角膜前表面陡峭轴、平坦轴、平均角膜屈光力及散光度数的r值分别为0.970,0.968,0.976,0.697;角膜后表面陡峭轴、平坦轴、平均角膜屈光力及散光度数的r值分别为0.918,0.875,0.925,0.517;全角膜陡峭轴、平坦轴、平均角膜屈光力及散光度数的r值分别为0.951,0.955,0.959,0.622(均P<0.01)。Bland-Altman分析显示,两设备测量角膜前、后表面陡峭轴、平坦轴、平均角膜屈光力及散光度数均有较好的一致性,2.68%~8.04%的测量差值在95%一致性界限(95%LoA)外;两设备测量全角膜陡峭轴、平坦轴及平均角膜屈光力的95%LoA范围分别为0.01~2.28、0.06~2.27、0.10~2.20 D,95%LoA范围较宽,一致性较差。结论CASIA2与Pentacam测量年龄相关性白内障患者角膜屈光力及散光,在角膜前表面差异性较小,一致性较好,但角膜后表面及全角膜屈光力测量结果差异性较大,临床上不建议互换。     

LASIK手术治疗-2.0D以上散光的角膜地形图分析

目的 利用角膜地形图评价LASIK治疗-2.0D以上散光疗效的准确性.方法 对25例(36只眼)散光度在-2.0D以上的近视散光患者于LASIK手术前后行角膜地形图和主觉验光检查,并将主觉验光测得的散光值换算成角膜平面的散光值,随访6月以上,比较手术前后角膜地形图测得的角膜散光的改变情况以及主觉验光所得的散光改变.结果 手术前后平均角膜地形图散光大小分别为(-2.29±0.61)D和(-1.91±0.68)D,主觉验光手术前后平均角膜平面的散光大小分别为(-2.22±0.61)D和(-0.46±0.43)D,两者手术前后差异均有统计学意义(P<0.05);手术前后平均角膜地形图散光轴位改变(3.19±3.04)度,手术前后显性散光轴位改变(29.61±29.49)度;术前角膜地形图散光和术前显然验光角膜平面的散光大小差异无统计学意义(P>0.05),散光轴位平均差异为(6.53±14.19)度,而术后角膜地形图散光和术后显然验光角膜平面的散光大小差异有统计学意义(P=0.00).结论 角膜地形图测量术前-2.0D以上散光与主觉验光结果基本一致,但LASIK术后,角膜地形图往往高估术后的散光值.     

儿童散光眼角膜地形图形态特征

目的　探讨儿童散光眼角膜地形图形态特点。方法　对 96例 1 92眼屈光不正眼儿童行角膜地形图检查 ,平均年龄 9 88岁 (5～ 1 4岁 )。根据曲率假色分布图对角膜前表面形态进行分类 ,并分析曲率数值分布图、SimK、CIM、SF值。结果　发现儿童屈光不正眼呈中央陡峭周边平坦的托力克面 ,角膜散光占 94 2 7% ,且以顺规为主。除了圆形、椭圆形和不规则形之外 ,角膜表面各图形之间角膜散光、眼散光不同具有统计学意义。表面形态以蝴蝶结形为主 ,随着散光度数增加 ,角膜前表面蝴蝶结形增多、表面变陡峭。 82 81 %地形图顶点、角膜顶点与瞳孔中心不重合 ,却不影响视觉质量。结论　利用计算机辅助角膜地形图仪有利于观察儿童角膜前表面形态特点、分析角膜曲率、△SimK值、粗略估计眼散光、区分病理性角膜 ,从而有利于临床工作顺利开展。     

Laser in situ keratomileusis for myopic astigmatism

PURPOSE: To evaluate the refractive results of laser in situ keratomileusis (LASIK) for myopic astigmatic eyes, and to assess the efficacy, accuracy, stability, and safety of the procedure. METHODS: LASIK was performed on 113 eyes of 73 patients for correction of myopic astigmatism ranging from 1.00 to 5.00 D, as measured by manifest refraction, with a mean baseline refractive astigmatism of 2.09 +/- 1.12 D. The Chiron Automated Corneal Shaper was used to create a corneal flap, and laser ablation was performed using the Chiron-Technolas Keracor 116 excimer laser. Follow-up time was 12 months for all eyes. RESULTS: Refractive astigmatism was stable by 3 months after surgery. At 1 year after LASIK, refractive astigmatism was reduced to a mean of 0.25 +/- 0.31 D (range 0 to 1.00 D). Sixty-one eyes (54%) had no residual astigmatism and 98 eyes (86.7%) had 0 to 0.50 D of refractive astigmatism. The mean percent reduction of preoperative astigmatism was 87.9 +/- 14.9%. The mean axis deviation of the surgically induced astigmatism was 2.1 +/- 3.1 degrees, with 96 eyes (84.9%) within 5 degrees of the desired axis. The percent correction of preoperative astigmatism in the proper axis was 97.1 +/- 15.5%. Spectacle-corrected visual acuity improved by 2 lines in 11 eyes (9.7%), and was reduced by 1 line only in 1 eye. There were no other significant complications. CONCLUSION: LASIK with the Chiron-Technolas Keracor 116 excimer laser was effective for correction of myopic astigmatism, with good stability after 3 months. The results were predictable with an acceptable degree of accuracy. LASIK is a safe procedure with very few complications.     

Vector summation of anterior and posterior corneal topographical astigmatism

PURPOSE: To determine whether vector addition of posterior corneal astigmatism improves the correlation between topographical and refractive astigmatism. SETTING: Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts, USA. METHODS: Orbscan topographical maps of 40 eyes (31 patients) showing 1.0 to 6.0 diopters (D) of astigmatism were analyzed. Topographical anterior and posterior corneal surface astigmatism was determined. Refractive astigmatism was compared to topographical astigmatism using 3 methods: anterior topographical astigmatism, overall topographical astigmatism obtained by vector summation of anterior and posterior topographical astigmatism, and simulated keratometry (SimK). RESULTS: Refractive astigmatism ranged from 0.25 to 5.00 D. The mean error in magnitude between topographical and refractive astigmatism was significantly smaller with the overall topographical method (1.06 D +/- 0.92 [SD]) than the anterior topographical method (1.37 +/- 1.04 D) (P <.0001). The mean error in axis between topographical and refractive astigmatism was smaller with the overall topographical method (10.4 +/- 13 degrees) than with the anterior topographical method (15.5 +/- 30.6 degrees) and with SimK (13.3 +/- 15.1 degrees), but these differences were not statistically significant. CONCLUSION: Consideration of the Orbscan measurement of posterior corneal surface toricity may improve the prediction of the magnitude of refractive astigmatism.     

准分子激光角膜切削术后散光的角膜地形图分析

了解准分子激光角膜切削术（ｐｈｏｔｏｇｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）前、后最大轴性散光的变化及对术后视力的影响。方法对ＰＲＫ后１年以上的６１例（１０９只眼）术前散瞳验光散光度一１．００～－２．００Ｄ的角膜地形图进行分析及视力检查。结果散瞳验光散光轴位与地形图记录散光轴位基本一致，而散光度数有一定差异。地形图检查显示，最大散光轴位以循规性极光最多，计６７只眼（６１％），斜轴性散光３６只眼（３３％），逆规性散光６只眼（６％）。手术前、后散光轴位变化极小。散光度多数在术后１０天及１个月开始增加，以后逐渐减少。６个月或１年趋于稳定。术后的残存散光对视力影响较小，实际矫正度在预期矫正度±１．００Ｄ以内者占９７％。结论采用球柱折算方法，进行ＰＲＫ，对矫正近视合并散光者（－２．００Ｄ以下），可以获得满意的屈光矫正。     

Topographical analysis of corneal astigmatism in patients with tilted-disc syndrome

PURPOSE: To evaluate the corneal topography in patients with tilted-disc syndrome to determine the relationship between optic disc dysversion and corneal astigmatism and the pattern of astigmatism in these patients. METHODS: The study included 23 eyes of the 13 tilted-disc syndrome patients with spheric refractive errors ranging between +1.00 D and -9.00 D (mean -4.00 +/- 3.4 D) and astigmatic errors ranging between -0.50 and -4.50 D (mean -1.95 +/- 0.93 D). Corneal topography was performed by computer-assisted videokeratoscope topographic modelling system 2 (TMS-2) and incidence of corneal astigmatism, corneal topographic patterns, and mean values of the topographic indices were determined. RESULTS: Corneal topographic analysis showed corneal astigmatism in 22 out of 23 patients with tilted discs. Corneal astigmatism was symmetric bow tie pattern in 10 eyes (45.45%), asymmetric bow tie pattern in 11 eyes (50%) and irregular in 1 eye (4.5%). Among the patients with bow tie pattern group (21 eyes), 14 eyes had with-the-rule astigmatism, 1 eye had against-the-rule astigmatism, and 6 eyes had oblique astigmatism. In 18 eyes, astigmatism was corneal, whereas combined corneal and lenticular in 4 eyes and lenticular in 1 eye. CONCLUSION: In the majority of tilted-disc cases, ocular astigmatism is mainly corneal. Morphogenetic factors in the development of the tilted disc might possibly influence the corneal development in such a way to result in corneal astigmatism.     

Is the relation between keratometric astigmatism and refractive astigmatism linear?

Javal's rule, which states that the total astigmatism of the eye--or refractive astigmatism--is equal to 1.25 (keratometric astigmatism) - 0.50 x 90, implies a linear relation between the two entities. Data published by Grosvenor, Quintero, and Perrigin (Am J Optom Physiol Opt 1988;65:292-7) show that for eyes having no more than 2.50 D of keratometric astigmatism, the slope of the regression line for refractive astigmatism plotted against keratometric astigmatism is less than 1.00, rather than the 1.25 required by Javal's rule. When data compiled for eyes having greater amounts of keratometric astigmatism are plotted in the same manner, the slope of the regression line is greater than 1.00, suggesting that the relation between keratometric and refractive astigmatism may be non-linear. However when data for these highly astigmatic eyes are plotted in combination with data published by Grosvenor, Quintero, and Perrigin, they are adequately characterized by a straight-line relation.     

Foldable toric intraocular lens for astigmatism correction in cataract patients

PURPOSE: To evaluate the results of AcrySof toric intraocular lens (IOL) (Alcon) implantation to correct preexisting astigmatism in patients having cataract surgery. SETTING: Ophthalmology Service, Donostia Hospital, San Sebastián, Spain. METHODS: This prospective observational study included 30 eyes of 15 consecutive patients with more than 1.00 diopter (D) of preexisting corneal astigmatism having cataract surgery. Bilateral implantation of the AcrySof toric IOL was performed after phacoemulsification. The uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), residual refractive sphere, residual keratometric and refractive cylinders, and toric IOL axis were measured. RESULTS: The UCVA was 20/40 or better in 93.3% of eyes and 20/25 or better in 66.6%. All eyes achieved 20/25 or better BCVA. The mean refractive cylinder decreased significantly after surgery from -2.34 D +/- 1.28 (SD) to -0.72 +/- 0.43 D (P<.01). Vector analysis of attempted versus achieved correction showed that 100% of eyes were within +/-1.00 D and 80% and 93.9% were within +/-0.50 D for J(0) and J(45), respectively. The mean toric IOL axis rotation was 3.63 +/- 3.11 degrees, with rotation less than 10 degrees in 96.7% of eyes. CONCLUSIONS: The results indicate that phacoemulsification and posterior chamber AcrySof toric IOL implantation is an effective option to correct preexisting astigmatism in cataract surgery. The AcrySof toric IOL showed good rotational stability.     

Photorefractive keratectomy for low-to-moderate myopia and astigmatism with a small-beam,tracker-directed excimer laser

ObjectiveTo assess the safety and effectiveness of the Autonomous Technologies Corporation LADARVision excimer laser system for photorefractive keratectomy correction of myopia and astigmatism.DesignA multicenter, prospective, noncomparative case series.ParticipantsThe cohort consisted of 467 eyes corrected for spherical myopia and 211 eyes corrected for myopia with astigmatism.InterventionTreatments were performed at six sites in the United States using a 6-mm ablation zone for spherical myopes and a 5.5-mm zone with a 1.0-mm blend for astigmats.Main outcome measuresVisual acuity, subjective refraction, corneal haze, intraocular pressure, complications, adverse reactions, patient satisfaction, and corneal endothelial changes.ResultsTwelve-month follow-up was available on 414 spherical eyes and 175 astigmatic eyes. The results for spherical eyes with correction between −1 and −5.99 diopters (D) were: uncorrected visual acuity (UCVA) of 20/40 or better achieved by 98.1%, 20/20 or better by 72%, 1.8% lost 2 lines and 0.3% lost greater than 2 lines of best spectacle-corrected visual acuity (BSCVA); 76.4% were within 0.50 D of the target correction and 94.4% were within 1.00 D. The results for myopia with astigmatism with spherical equivalent correction between −1 and −5.99 D were: UCVA of 20/40 or better in 97.4%, 20/20 or better in 61.7%, 2.5% lost 2 lines and no eyes lost greater than 2 lines BSCVA; 73.9% were within 0.50 D of the target correction and 95% were within 1.00 D. For spherical myopes combined with myopic astigmats corrected for 6 to 10 D, results were: UCVA of 20/40 or better in 93.4%, 20/20 or better in 61.2%, 2.3% lost 2 lines and no eyes lost greater than 2 lines of BSCVA; 67.2% were within 0.50 D of the desired correction and 87.8% were within 1.00 D. Refractive stability was achieved between 3 and 6 months for the spherical and astigmatic groups. No eyes had corneal haze graded as moderate or greater, and there was no significant decrease in endothelial cell density.ConclusionsPatients treated for 1 to 10 D of spherical equivalent myopia, with or without astigmatism, showed early refractive stability, excellent UCVA, no significant loss of BSCVA, no loss of endothelial cell density, and very low levels of corneal haze to 12 months after surgery.     

准分子激光屈光性角膜切削术矫正散光的准确性及预测性

目的 探讨准分子激光屈光性角膜切削术（ｅｘｃｉｍｅｒ ｌａｓｅｒ ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅ ｋｅｒｅｃｔｏｍｙ,ＰＲＫ）矫正散光的准确性及预测性。方法 根据角膜地形图提供的角膜屈光力数值,用Ｈｏｌｌａｄａｙ法计算复性近视散光３０例（５３只眼）和单纯近视２３例（３３只眼）患者术前与术后６个月角膜屈光力的差值,确定实际矫正散光度及轴位,及预期矫正散光度及轴位进行对比分析。结果 复性近视散光组５３     

Combined toric intraocular lens implantation and relaxing incisions to reduce high preexisting astigmatism

PURPOSE: To evaluate whether combining toric intraocular lens (IOL) implantation with astigmatic keratotomy (AK) can correct higher levels of astigmatism while minimizing undue effects on the optical qualities of the cornea. SETTING: St. Luke's Cataract and Laser Institute, Tarpon Springs, Florida, USA. METHODS: Thirteen eyes with corneal astigmatism greater than 2.50 diopters (D) (mean 5.54 D) had implantation of a Staar toric IOL combined with AK. RESULTS: All eyes had less than 1.00 D of refractive astigmatism postoperatively. Sixty-nine percent achieved an uncorrected visual acuity of 20/40 or better, and no patient lost best corrected visual acuity. CONCLUSIONS: Implanting a toric IOL in patients with high astigmatism reduced the amount of incisional surgery required. Combining techniques can correct all or most of even very high astigmatism (>5.00 D) while avoiding induced corneal irregularities.