角膜地形图引导下白内障手术切口对角膜散光的矫正

目的:比较不同位置和形态的手术切口对白内障摘除术后角膜散光及裸眼视力的影响。方法:选取术前角膜散光值>1.00D的白内障患者43例52眼,将患者随机分成两组,A组患者采用超声乳化白内障吸除联合人工晶状体植入术,手术切口为位于上方10∶30～11∶30的透明角膜隧道切口。B组患者采用手法碎核白内障摘除联合人工晶状体植入术,其中角膜散光值为1.00～2.00D的患者,切口为位于角膜最大屈光度径线的直线形巩膜隧道切口,长度为6.0～7.0mm,角膜散光值>2.00D的患者,在上述直线形切口对侧角膜缘处,另作一弧形板层松解切口。分别于术后2wk,3mo随访患者,检查裸眼视力及行角膜地形图检查。结果:B组患者术后2wk,3mo裸眼视力好于A组。B组患者术后角膜散光度在术后2wk,3mo时均小于A组。结论:位于角膜最大屈光度径线的6.0～7.0mm直线形巩膜隧道切口,及此切口联合作对侧弧形板层松解切口均能有效矫正白内障术前存在的角膜散光,能够使患者获得更好的术后裸眼视力。     

Limbal relaxing incisions versus on-axis incisions to reduce corneal astigmatism at the time of cataract surgery

PURPOSE: To compare limbal relaxing incisions (LRIs) with placement of the corneal cataract incision on the steepest keratometric axis for the reduction of preexisting corneal astigmatism at the time of cataract surgery. SETTING: The Queen Elizabeth Hospital, Adelaide, South Australia, Australia. METHODS: In a prospective single center study, patients having 1.5 diopters (D) or more of keratometric astigmatism were randomly assigned to 2 surgical techniques: on-axis incisions (OAIs) consisting of a single clear corneal cataract incision centered on the steepest corneal meridian or LRIs consisting of 2 arcuate incisions straddling the steepest corneal meridian and a temporal clear corneal incision. Vector analysis of the target axis flattening effect was used to assess the efficacy of treatment. RESULTS: Seventy-one eyes of 71 patients were evaluated, 33 in the OAI group and 38 in the LRI group. Six weeks postoperatively, the flattening effect was 0.41 D (median and interquartile range 0.15 to 0.78 D) in the OAI group and 1.21 D (range 0.43 to 2.25 D) in the LRI group (P = .002). After 6 months, the flattening effect was 0.35 D (range 0.00 to 0.96 D) and 1.10 D (range 0.25 to 1.79 D), respectively (P = .004). CONCLUSION: The amount of astigmatism reduction achieved at the intended meridian was significantly more favorable with the LRI technique, which remained consistent throughout the follow-up period.     

Corneal astigmatism after cataract surgery with 4.1 mm BENT scleral and 4.1 mm plus meridian corneal incisions

PURPOSE: To determine whether the 4.1 mm BENT (between 9 and 12 o'clock) scleral incision or the 4.1 mm plus meridian corneal incision (PMCI) is better at minimizing postoperative astigmatism. SETTING: Department of Ophthalmology, Kobe City General Hospital, Kobe, Japan. METHODS: This prospective study comprised 58 eyes of 29 consecutive patients with bilateral cataract. One eye was randomly assigned to have cataract surgery with a 4.1 mm BENT scleral incision and the other eye, with a 4.1 mm PMCI. Corneal astigmatism was measured before surgery and 1, 3, 10, 30, and 100 days after surgery. RESULTS: Mean astigmatism preoperatively and on postoperative days 1, 3, 10, 30, and 100 in the BENT scleral incision group was 0.99 +/- 0.66, 1.53 +/- 1.11, 1.12 +/- 0.72, 1.26 +/- 0.81, 1.16 +/- 0.73, and 1.09 +/- 0.64 diopters (D), respectively. Means in the PMCI group were 1.14 +/- 0.79, 1.38 +/- 0.98, 1.17 +/- 0.88, 1.31 +/- 0.77, 1.01 +/- 0.70, and 1.00 +/- 0.60 D. respectively. Astigmatism on days 1 and 10 postoperatively was significantly greater than preoperatively in the BENT group (P < .03) but not in the PMCI group. The changes in astigmatism were less in the PMCI group at every examination and were significantly different 30 days postoperatively (P < .05). The negative correlation between preoperative astigmatism and the final postoperative change was significant in both groups (P < .032); the value of x-intercept of the regression line was 1.37 D in the BENT scleral incision group and 0.82 D in the PMCI group. CONCLUSION: In cataract surgery using a 4.1 mm incision, the PMCI surpassed the BENT scleral incision in minimizing postoperative corneal astigmatism.     

Controlling astigmatism in cataract surgery requiring relatively large self-sealing incisions

PURPOSE: To evaluate the results of a modified self-sealing incision for achieving astigmatic neutrality in cataract surgery requiring a 6.0 to 7.0 mm incision as well as the methods of correcting preexisting astigmatism using these incisions. SETTING: Department of Ophthalmology, Kushimoto Rehabilitation Center, Kushimoto, Japan. METHODS: To achieve astigmatic neutrality, a frown-shaped, oblique incision-the BENT (between 9 and 12 o'clock) frown-was used. To reduce preexisting against-the-rule or with-the-rule astigmatism, the incisions were placed on the temporal or superior steep astigmatic axis, respectively. A frown incision was used when aiming for mild astigmatic reduction and an arcuate incision when aiming for relatively large astigmatic reduction. RESULTS: In the 6.0 to 7.0 mm BENT frown incision group, mean flattening was minimal throughout 6 months of follow-up, with a maximum of 0.18 diopter (D) 1 week postoperatively. Surgically induced astigmatism was less than that with other incisions. Ninety-four percent of cases had a difference in absolute astigmatism of less than 0.50 D between preoperatively and 6 months postoperatively. Relatively large flattening was observed in eyes with 6.0 to 7.0 mm steep-axis incisions of superior arcuate, temporal arcuate, superior frown, and temporal frown, with means of 1.03, 0.79, 0.64, and 0.52 D, respectively, at 6 months. Ninety-eight percent of cases had a reduction in preexisting absolute astigmatism postoperatively. CONCLUSIONS: In cataract surgery using relatively large scleral self-sealing incisions, the BENT frown incision effectively achieved astigmatic neutrality. The incisions on the temporal or superior steep astigmatic axis (with selective shape) reduced astigmatism in almost all cases.     

角膜地形图引导下3.0mm角膜切口对白内障术后角膜散光的影响

目的:观察角膜地形图引导下3.0mm透明角膜切口白内障超声乳化手术前后患者角膜散光的变化。方法:在角膜最大曲率子午线上做3.0mm切口行白内障超声乳化手术,对术前散光度数≤1.0D的144例156眼术前、术后3mo的资料进行回顾性分析,统计手术前后角膜地形图散光的变化。采用t检验、单因素方差分析、Pearson相关分析对数据进行统计学处理。结果:3.0mm角膜透明手术切口的术源性散光为0.77±0.53D。患者手术前后的散光对比有统计学意义(P<0.05),散光变化具有相关性(r=-0.69,P<0.01)。术前角膜散光≤0.25D者术后散光增大,其余组术后散光变小。结论:利用角膜地形图定位手术切口位置,可以改变超声乳化术后的角膜散光。对于散光范围在0.37～1.0D的患者更适合3.0mm的透明角膜切口。     

Astigmatism outcomes of horizontal temporal versus nasal clear corneal incision cataract surgery

PURPOSE: To compare the short- and long-term astigmatism outcomes after cataract surgery using temporal clear horizontal corneal incisions and nasal horizontal clear corneal incisions. SETTING: Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland, USA. METHODS: This retrospective study included a consecutive series of eyes having phacoemulsification with implantation of a 6.0 mm foldable acrylic intraocular lens through a 3.5 mm horizontal clear corneal incision at 180 degrees (temporal incision in right eyes, nasal incision in left eyes). Astigmatism was measured by keratometry readings before surgery and 6 weeks and 12 months postoperatively. RESULTS: The mean preoperative astigmatism in the 178 eyes (94 right, 84 left) of 161 patients was 0.78 diopter (D); 54.5% of eyes had against-the-rule (ATR) astigmatism, 22.5% had with-the-rule (WTR) astigmatism, and 14.0% were astigmatically neutral. A significant shift toward WTR astigmatism occurred postoperatively. At 6 weeks, 48.3% of eyes had WTR astigmatism and 23.0% had ATR astigmatism. At 12 months, 43.8% had WTR astigmatism and 25.8% had ATR astigmatism. Vector analysis revealed a mean surgically induced astigmatism (SIA) of 1.17 D at 6 weeks and 1.04 D at 12 months. The side of the incision significantly affected SIA. At 6 weeks, temporal incisions yielded a mean SIA of 0.74 D and the nasal incisions, of 1.65 D. This trend in SIA persisted at 12 months: 0.71 D for temporal incisions and 1.41 D for nasal incisions. CONCLUSIONS: Cataract surgery using a horizontal clear corneal incision induced WTR astigmatism 6 weeks and 12 months postoperatively. Temporal incisions induced significantly less astigmatism than nasal incisions.     

多焦点IOL植入联合角膜松解切口矫正白内障合并角膜散光的分析

目的:比较多焦点IOL植入联合角膜切口矫正散光与单焦点IOL植入术治疗白内障合并低度散光患者的视觉质量差异。方法:选取老年性白内障合并低度散光患者80例100眼,按随机原则分为对照组及干预组,各40例50眼。干预组行最陡角膜散光轴向上做一对透明角膜松解切口,同时按常规行透明角膜切口白内障超声乳化+多焦点IOL植入术;而对照组仅行透明角膜切口白内障超声乳化+单焦点IOL植入术。分别于术后1d;1wk;1,3mo观察两组术眼的角膜散光情况及裸眼远视力(uncorrected distance visual acuity,UCDVA),裸眼近视力(uncorrected near visual acuity,UCNVA);3mo时最佳矫正远视力(best corrected distance visual acuity,BCDVA)、最佳矫正近视力(best corrected near visual acuity,BCNVA)及最佳矫正远视力下最佳矫正近视力(distant corrected near visual acuity,DCNVA)并进行统计分析。结果:术后UCDVA和UCNVA干预组均高于对照组,而各时期角膜散光干预组均低于对照组。两组患者术后3d均有明显改善。术后1wk;1,3mo,UCDVA和UCNVA及3mo时BCDVA,BCNVA无显著差异。结论:多焦点IOL植入联合透明角膜松解切口可有效矫正白内障术前散光,提高全程视力,从而扩大多焦点IOL适用人群。     

Effect on astigmatism of the location of clear corneal incision in phacoemulsification of cataract

PURPOSE: To investigate the refractive results of clear corneal incision performed at the steepest meridian of pre-existing corneal astigmatism. METHODS: One hundred eighty-two patients with astigmatism > 0.75 diopters (D) were evaluated. Superior, temporal, nasal, superotemporal, or superonasal clear corneal incisions were performed at the steep meridian. Refraction, visual acuity, and topography values were evaluated, and changes in surgically induced astigmatism were calculated by vector analysis using the Fourier formula. Paired t test was used to compare mean values. RESULTS: Postoperative cylinder values showed minor changes in all groups, except the nasal group. Nasal incision increased preoperative cylinder from 1.13 D to 1.83 D 6 months after surgery. Temporal and superotemporal incisions resulted only in small astigmatic changes. Conversely, superior, superonasal, and nasal incisions induced more pronounced astigmatism. CONCLUSIONS: Performing clear corneal incision for phacoemulsification of cataract at the steep meridian resulted in small changes with temporal incisions, whereas nasal incisions resulted in higher surgically induced astigmatism.     

Minimizing induction of astigmatism in preoperative spherical cornea a. by mini-incision surgery with foldable IOL and b. by corneal tunnel incision with limbal relaxing incision]

BACKGROUND: In case of a spheric cornea preoperatively the refractive effect of a clear corneal cataract incision is undesirable. We studied two actual techniques to minimize the surgically induced astigmatism. PATIENTS AND METHODS: Temporal clear corneal incision was performed in 77 patients with practically spherical cornea (0.2 +/- 0.1 D). 27 patients with 4.1-mm clear corneal stretch incision and 5 mm PMMA lens implantation served as control. 25 further patients were operated on with the same technique, but 2 additional limbal relaxing incisions (LRI) of 0.55-mm depth and 8 mm length at 6 and 12 o'clock were performed. In 25 patients a foldable acrylic lens (Acrysof) was implanted through a 3.2-mm temporal clear corneal incision. Corneal topography results were evaluated in all patients by the Jaffe and the Holladay analysis. RESULTS: The surgically induced astigmatism of 0.8 +/- 0.5 dpt in the control group was reduced to 0.4 +/- 0.3 dpt by LRI and by reduction of the incision size as well in the treatment groups. With-the-wound-change (WTW) in the Holladay analysis was 0.6 +/- 0.7 dpt in the control group and around 0 in the groups with astigmatism reducing techniques. CONCLUSION: To preserve a spherical cornea in clear corneal-tunnel incision, compensating limbal relaxing incisions (LRI) or ultra-small incisions with foldable lens implantation should be performed.     

两种不同切口人工晶状体植入术后角膜地形图对比分析

目的 研究两种不同切口人工晶状体植入后角膜形态和散光的变化。方法 通过３．２ｍｍ透明角膜切口植入折叠人工晶状体５０眼和６．０ｍｍ巩膜隧道切口植入ＰＭＭＡ人工晶状体４８眼,术后应用计算机辅助角膜地莆图仪对这些病人的角膜形态进行检查。结果 角膜组术后早期角膜地形图垂直于切口径线的角膜轻度变平,于术后１个月即可稳定。巩膜组有膜垂直轴上出殃蝴蝶结样改变,而后蝴蝶结逐渐变小,或向水平方向转变而减少,至３个月时基本稳定。两组在术后１天至１个月的角膜散光和手术性角膜散光巩膜组大于角膜组（Ｐ〈０．０５）。结论 ３．２ｍｍ透明角膜切口组术后角膜形态改变小,视力恢复快。     

白内障切口对角膜散光的影响

目的:研究不同方位3.2mm切口超声乳化白内障术对角膜散光25度以内患者的影响。方法:收集Orbscan检测出角膜散光在25度以内白内障患者共40例,随机分成A,B两组。在Orbscan引导下,A组20例20眼行3.2mm角膜散光轴向切口,B组20例20眼在90度轴上行3.2mm透明角膜切口,并由同一位手术医师行超声乳化白内障吸除人工晶状体植入术。观察患者术前及术后Orbscan检测的角膜Simk值及PolarK的变化。结果:各组内术前与术后各个时间点PolarK比较,差异有显著统计学意义;两组之间术后各个时间点PolarK比较,差异无统计学意义,两种切口术后3mo都会增加角膜PolarK0.3D左右。结论:对于角膜散光25度以内白内障患者,3.2mm透明角膜切口可能引起角膜PolarK0.3D左右散光。     

角膜地形图引导下白内障手术切口构建的变异对角膜散光影响

目的 观察根据角膜地形图选择白内障手术切口位置及其构建变异,以进一步降低术前角膜散光.方法 对白内障患者123例(126只服),术前常规作角膜地形图检查.病人随机分成5组,A组、B组、E组为小切口手法组,A组和B组分别于上方和根据角膜地形图在强子午线方向行反眉形巩膜隧道切口;E组根据角膜地形图在强子午线方向行水平巩膜隧道切口;C组和D组为超声乳化组,分别于上方和根据角膜地形图在强子午线方向行透明角膜隧道切口;观察术后1d及7d后视力、角膜地形图等情况.结果 ①视力:术后7d,发现B组与E组患者差异有统计学意义,余各组间差异无统计学意义,组间裸眼视力≥1.0者差异亦无统计学意义.②术后散光轴向变化:A～D组变化不明显,E有12例散光轴向发生改变.③角膜散光:A组、B组散光变化较小,B组和E组术后7d较术前减少,差异有统计学意义;C组、D组术后1d角膜散光较大,7d后渐回复,但C组仍高于术前水平;A组与B组、C组与D组及A组与C组比较术后差异均无统计学意义;B组与D组术后1d差异有统计学意义,术后7d差异无统计学意义;B组与E组比较,术后1d差异无统计学意义,术后7d差异有统计学意义.结论 通过观察角膜地形图来选择白内障手术切口位置及其构建,可降低手术源性角膜散光或术前存在的角膜散光,明显改善术后早期视力.对进一步提高白内障术后的视觉质量具有临床指导意义.     

Lamellar keratotomy to correct astigmatism in cataract surgery

Background For the correction of astigmatism in cataract surgery, several incisional procedures have been developed. In this study, a modification of lamellar keratotomy was evaluated to correct astigmatism in cataract surgery.Methods Prospectively 32 eyes of 25 patients with a preoperative astigmatism greater than 1.5 D were studied. All patients were treated with lamellar keratotomy with an incision width of 6 mm and a radial length of 1.5 mm placed at the limbus in the steep meridian. Phacoemulsification and IOL implantation were then performed through a 3.2-mm corneal tunnel incision. After 4 weeks, mean astigmatism, mean corneal power changes, and mean surgically-induced astigmatism derived from vector analysis in the central 3-mm optical zone were determined.Results The mean astigmatism decreased from 2.75±0.80 D preoperatively to 1.58±0.91 D after 4 weeks (P<0.001). There were no significant changes (P=0.614) of the mean corneal power. The mean surgically-induced astigmatism was 2.59±1.50 D. The induced changes were more accentuated in superior incisions. In corneal topography, 78% of the treated eyes revealed a characteristic threefold pattern of the mid-peripheral cornea postoperatively, which impaired the corneal optical performance in ray-tracing analysis.Conclusions Lamellar keratotomy effectively reduced high preoperative astigmatism in cataract surgery. This surgical approach was combined with a superior, temporal, or oblique corneal incision.Presented in part at the Annual Meeting of the Deutsche Ophthalmologische Gesellschaft in Berlin, September 2003.     

Limbal relaxing incisions to correct astigmatism in clear corneal cataract surgery.

PURPOSE: To prevent surgically induced astigmatism following clear corneal cataract surgery. METHODS: Limbal relaxing incisions of 6- or 8-mm length and 0.55-microm depth were performed in 52 patients (52 eyes) with a spherical cornea (20 eyes) or mean with-the-rule astigmatism (32 eyes) of 0.80 +/- 0.30 D after temporal corneal cataract incision. A control group (47 eyes; 19 spherical and 28 with-the-rule astigmatism) underwent the same surgical procedure without limbal relaxing incisions. RESULTS: Six months after surgery, mean with-the-wound change using the Holladay analysis was -0.08 +/- 0.50 D in spherical eyes with limbal relaxing incisions and +0.50 +/- 0.70 D in control eyes. Patients with preoperative with-the-rule astigmatism showed a mean with-the-wound change of -0.09 +/- 0.50 D after limbal relaxing incisions; in corresponding control eyes, mean change was +0.39 +/- 0.70 D. CONCLUSION: Limbal relaxing incisions are a reliable and safe procedure to reduce postoperative astigmatism.     

Clear corneal incision of 2.75 mm for cataract surgery induces little change of astigmatism in eyes with low preoperative corneal cylinder

PURPOSE: To assess the early astigmatic effect induced by 2.75 mm clear cornea incisions with different locations for cataract surgery. METHODS: A total of 146 eyes of different patients were studied prospectively. Cataract surgery was performed by three surgeons, two using a temporal approach and one using a superior approach. For both approaches, the site of the 2.75 mm incision was allowed to vary slightly according to the characteristics of the eye and orbit. Computerized videokeratography was used to measure corneal astigmatism before surgery and after 1, 4, and 12 weeks. Corneal astigmatism was recorded as cylinder and axis and it was then converted to 2 power vector. Model based prediction and comparisons were made for the most commonly used corneal incision sites: 12 (both eyes), 2 (left eye), and 8 (right eye) o'clock meridian. RESULTS: After 3 months the differences in corneal astigmatism (JCC 0 ) between the incisions performed at 12 and 2 o'clock were not statistically significant (-0.08, 95% CI: -0.19, -0.02); the differences in JCC 0 between incisions at 12 and 8 o'clock were -0.17 (95% CI: -0.30, -0.05; p<0.01). After 3 months the change in JCC 0 for the patients with 0.5 D with-the-rule preoperatively were -0.32 (95% CI: -0.44, 0.21; p<0.01) for incisions at 12; -0.24 (95% CI: -0.36, 0.13; p<0.01) for incisions at 2; and -0.15 (95% CI: -0.27, -0.03; p<0.05) for incisions at 8. After 3 months the changes of JCC 0 for the patients with -0.5 D against-the-rule pre-operatively were 0.10 (95% CI: 0.04, 0.23) for incision at 12; 0.18 (95% CI: 0.04, 0.32; p<0.05) for incisions at 2; and 0.27 (95% CI: 0.14, 0.40; p<0.01) for incisions at 8 o'clock. The oblique astigmatic vector (JCC 45 ) was very modest in this sample before surgery and underwent minimal and nonsignificant change after it. CONCLUSIONS: This study has shown that a 2.75 mm clear corneal incision causes a small change of corneal cylinder regardless of incision site.     

Corneal astigmatism correction with scleral flaps in trans-scleral suture-fixed posterior chamber lens implantation:a preliminary clinical observation

AIM:To study the impact of scleral flap position,under which the posterior chamber intraocular lenses(PC-IOL) were sulcus-fixed by trans-scleral suture,on cornea astigmatism.METHODS:Twenty-six aphakic or cataract eyes were comprised in this prospective noncomparative case series study.Eleven eyes had traumatic cataract removed without sufficient capsular support,3 had blunt trauma with subluxated traumatic cataract,8 had undergone vitreoretinal surgery and 4 had congenital cataract removed.The average age was 54 years(range 21-74 years),with 17 men and 7 women.The foldable PC-IOL was fixed in sulcus by trans-scleral suture.The incision for IOL implantation was made 1mm posterior to limbus along the steepest meridian of cornea,while scleral flaps to bury the knots of trans-scleral suture were made along the flattest meridian.All the surgeries were performed by a single doctor(Ma L),and the follow up was at least 13 months(range 13-28 months).The preoperative,3 months and 1 year postoperative corneal curvature along the steepest and flattest cornea meridian and overall cornea astigmatism were compared.RESULTS:The curvature along the steepest meridian changed from 44.25±2.22D preoperatively to 44.08±2.16D at 3 months postoperatively,and 43.65±5.23D at 1 year postoperatively(P >0.05);the curvature along the flattest meridian changed from 41.24±2.21D preoperatively to 43.15±3.94D at 3 months postoperatively,and 42.85±5.17D at 1 year postoperatively(P <0.05);and the surgery induced astigmatism(SIA) on cornea was calculated by vector analysis,which was 2.42±2.13D at 3 months postoperatively,and 2.18±3.42D at 1 year postoperatively,the difference was statistically significant(P <0.05).CONCLUSION:The scleral flap made along the flattest meridian,under which the posterior chamber intraocular lenses(PCIOL) were sulcus-fixed by trans-scleral suture,can steepen the cornea in varying degrees,thus reducing preexisting corneal astigmatism.     

3.2 mm透明角膜切口超声乳化术治疗放射状角膜切开术后白内障的效果及安全性

目的  评估3.2 mm透明角膜切口超声乳化术治疗放射状角膜切开术（radial keratotomy,RK）后白内障的效果与安全性。设计  回顾性病例系列。研究对象  既往有RK手术史的白内障患者8例13眼,其中RK角膜瘢痕为8刀者2例4眼,12刀者3例4眼,16刀者3例5眼。方法  由同一手术医师进行3.2 mm透明角膜切口超声乳化人工晶状体植入术。8刀RK组中,角膜主切口位于相邻两条放射状角膜瘢痕之间,未与瘢痕接触;12刀RK组中,主切口跨越1条角膜瘢痕;16刀RK组中,主切口跨越2条角膜瘢痕。于术后1天,1周,1、3、6个月,1、2、3年进行随访,观察角膜RK瘢痕情况、并发症处理及术后视力恢复情况。主要指标 有无RK瘢痕裂开、术后最佳矫正视力、角膜散光、角膜内皮细胞密度。结果  8刀RK组和12刀RK组术中均未发生角膜RK瘢痕裂开,术毕切口密闭良好;16刀RK组中,2眼发生术中角膜瘢痕裂开,1眼采用前房注气封闭切口,另1眼采用主切口下注入黏弹剂,侧切口前房注气封闭切口。随访过程中,所有13眼术后角膜切口密闭良好,均未出现新发角膜瘢痕裂开。最后1次复查时,最佳矫正视力为（0.67±0.18）较术前（0.29±0.20）提高（t=-6.077,P=0.000）,角膜散光（1.69±1.23 D）较术前（1.28±0.78 D）无明显变化（t=-0.758,P=0.470）,角膜内皮细胞密度（1716.95±906.79/mm2）较术前（2383.97±833.39/mm2）降低（t=2.995,P=0.012）。结论  8刀、12刀RK术后白内障患者行超声乳化手术时采用3.2 mm透明角膜切口是安全的,16刀者术中易发生角膜瘢痕裂开,对此应采用更小的角膜切口或采用传统的角巩膜隧道切口。     

角膜地形图指导白内障超声乳化摘除切口矫正原有散光的疗效分析

目的探讨在最高屈光度的子午线做白内障超声乳化切口联合对侧弧形角膜切开术对矫正白内障患者原有散光的疗效。方法23例（28只眼）术前散光（-1．50～-4．15D）的白内障患者在角膜地形图指导下，在最高屈光度的子午线做白内障超声乳化切口联合对侧弧形角膜切开术，分析术后的裸眼视力和矫正原有散光的效果。结果角膜地形图显示该术式可使术前（-2．36±1．25）D的散光降为术后3个月（-0．58±0．71）D的散光。结论最高屈光度子午线做白内障超声乳化切口联合弧形角膜切开术对原存有-1．50～-4．15D的散光矫正疗效好，该术式是屈光性白内障超声乳化术散光矫正较有效的术式。     

透明角膜小切口白内障手术后角膜散光变化

目的　评价透明角膜小切口超声乳化白内障吸除折叠式人工晶状体植入术后角膜散光的变化。方法　将62例(78只眼)白内障患者,按照切口位置位于颞上方及鼻上方或角膜曲率最大子午线轴位分为A、B两组,行透明角膜小切口超声乳化白内障吸除折叠式人工晶状体植入术,比较术后角膜散光的变化情况。结果　A、B两组术后3个月平均手术性角膜散光度分别为（0.83±0.65）D和（0.72±0.55）D,差异无显著性(P>0.05);平均角膜散光度分别较术前减少0.11D和0.39D,两者比较差异有显著性（P<0.05）。结论　以透明角膜小切口行超声乳化白内障吸除折叠式人工晶状体植入术,术后角膜散光度小;结合散光轴位选择切口位置,术后可明显减小角膜散光度。     

Corneal astigmatism correction with scleral flaps in trans-scleral suture-fixed posterior chamber lens implantation: a preliminary clinical observation

AIM: To study the impact of scleral flap position, under which the posterior chamber intraocular lenses (PC-IOL) were sulcus-fixed by trans-scleral suture, on cornea astigmatism. METHODS: Twenty-six aphakic or cataract eyes were comprised in this prospective noncomparative case series study. Eleven eyes had traumatic cataract removed without sufficient capsular support, 3 had blunt trauma with subluxated traumatic cataract, 8 had undergone vitreoretinal surgery and 4 had congenital cataract removed. The average age was 54 years (range 21-74 years), with 17 men and 7 women. The foldable PC-IOL was fixed in sulcus by trans-scleral suture. The incision for IOL implantation was made 1mm posterior to limbus along the steepest meridian of cornea, while scleral flaps to bury the knots of trans-scleral suture were made along the flattest meridian. All the surgeries were performed by a single doctor (Ma L), and the follow up was at least 13 months (range 13-28 months). The preoperative, 3 months and 1 year postoperative corneal curvature along the steepest and flattest cornea meridian and overall cornea astigmatism were compared. RESULTS: The curvature along the steepest meridian changed from 44.25±2.22D preoperatively to 44.08±2.16D at 3 months postoperatively, and 43.65±5.23D at 1 year postoperatively (P>0.05); the curvature along the flattest meridian changed from 41.24±2.21D preoperatively to 43.15±3.94D at 3 months postoperatively, and 42.85±5.17D at 1 year postoperatively (P<0.05); and the surgery induced astigmatism (SIA) on cornea was calculated by vector analysis, which was 2.42±2.13D at 3 months postoperatively, and 2.18±3.42D at 1 year postoperatively, the difference was statistically significant (P<0.05). CONCLUSION: The scleral flap made along the flattest meridian, under which the posterior chamber intraocular lenses (PCIOL) were sulcus-fixed by trans-scleral suture, can steepen the cornea in varying degrees, thus reducing preexisting corneal astigmatism.