Astigmatic keratotomy to correct preexisting astigmatism in cataract patients

We evaluated three general strategies for dealing with astigmatism control following phacoemulsification with posterior chamber intraocular lens surgery: (1) a neutral wound closure to minimize surgically induced cylinder; (2) wound revision techniques to minimize residual postoperative cylinder; (3) astigmatic keratotomy incisions to treat preexisting astigmatism. With the neutral wound closure, mean postoperative keratometric cylinder averaged less than 1 diopter (D). In the presence of moderate preoperative astigmatism (1.0 D to 1.9 D), the wound revision technique tended to undercorrect, while the astigmatic keratotomy tended to overcorrect. However, the keratotomy procedure resulted in less postoperative cylinder. For cases with substantial preoperative astigmatism (greater than or equal to 2 D), the astigmatic keratotomy groups corrected more of the preoperative cylinder, which resulted in a greater proportion of cases with less than 1 D of postoperative cylinder and a smaller proportion with more than 2 D. Results suggest that astigmatic keratotomy is a useful adjunct to correct preexisting astigmatism in cataract patients. However, this procedure as any incisional refractive surgery technique has a certain amount of inherent biological variability.     

有晶状体眼前房型人工晶状体植入术联合角膜松解切开术矫正散光的临床观察

目的 评估角膜松解切开术（AK）在有晶状体眼前房型人工晶状体植入术（ACPIOL）时矫正散光的临床疗效.方法 前瞻性病例对照研究.高度近视患者45例（75眼）,按主觉验光结果分组：联合组30例（52眼）,散光度≥1D,等效球镜度为（-16.89±4.45）D,最佳矫正视力为4.69±0.24,先行AK再行ACPIOL;单纯组15例（23眼）,散光度＜1 D,等效球镜度为（-15.33±3.36）D,最佳矫正视力为4.82±0.17,直接行ACPIOL.术后1周、9个月,观察最佳矫正视力、等效球镜度、眼总散光度和角膜散光度的变化.使用CRAVY矢量分析法将散光分解后进行相关分析.采用重复测量的方差分析和Wilcoxon秩和检验比较术前和术后观察样本的变化.结果 最佳矫正视力：术后1周、9个月,联合组为4.81±0.15 和4.85±0.16,较术前差异均有统计学意义（P=0.007,P＜0.01）;单纯组为4.88±0.16和4.93±0.14,较术前差异均无统计学意义（P=0.261,P=0.069）.等效球镜度：术后1周、9个月,联合组为（-0.61±1.14）D和（-0.68±1.06）D,单纯组为（-0.57±0.89）D和（-0.77±0.70）D,较术前差异均有统计学意义（P均＜0.05）.验光度数进行CRAVY矢量分解、换算后,术前和术后9个月,联合组为-2.10 D×0.82°和-0.44 D×92.60°,单纯组为-0.52 D×82.18°和-0.28 D×92.04°.术后与术前差异均有统计学意义（P均＜0.05）.角膜地形图进行CRAVY矢量分解和换算后,术前和术后9个月,联合组为-1.65 D×95.59°和-0.44 D×178.70°,单纯组为-0.52 D×7.82°和-0.28 D×92.04°,术后与术前差异均有统计学意义（P均＜0.05）.联合组的安全系数为1.03（4.85/4.69）,有效系数0.79（1.66/2.10）,预测性为-0.44 D.结论 AK在ACPIOL术中矫正规则性散光是安全、有效、稳定的,预测性还有待进一步提高.     

Opposite clear corneal incisions to correct pre-existing astigmatism in cataract surgery

In cataract surgery, the clear corneal incision (CCI) has a small flattening effect on corneal curvature, which can be used to reduce pre-existing astigmatism (PEA). Adding an identical, penetrating CCI opposite the first one can enhance the flattening effect. The paired opposite CCIs (OCCIs) are placed on the steepest meridian axis to flatten it. One CCI is used to perform cataract surgery, and the opposite CCI is made to enhance the flattening effect on the cornea to modulate PEA. During the past 12 months, we have used 2.8 to 3.5 mm OCCIs in 33 eyes with PEA greater than 2.00 diopters (D) having cataract surgery. The mean astigmatism correction achieved with this technique was 2.06 D. This technique is simple and effective and yields stable results that rival those of arcuate keratotomy. The OCCI technique has a potential application for the correction of astigmatism in general refractive surgery. Opposite clear corneal incision nomograms with variables such as width, length, and distance from the limbus will be needed for future applications.     

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.     

Arcuate keratotomy to correct residual astigmatism after stromal herpetic keratitis

CLINICAL CASE: A woman with a history of recurrent herpes simplex keratitis in the left eye developed endothelial and stromal keratitis after cataract extraction. Because of the resultant corneal distortion a high regular astigmatism appeared. An arcuate keratotomy was performed to improve her visual acuity. DISCUSSION: Corneal astigmatism can appear after herpetic keratitis. An arcuate keratotomy was effective in this case to decrease astigmatism and improve her vision. Keratitis reactivation is possible so antiviral prophylaxis is advisable. Our good results show that arcuate keratotomy can be a useful technique for these patients.     

Surgical approaches to correct corneal astigmatism at time of cataract surgery: a mini-review

Among refractive errors, astigmatism is the most common optical aberration, where refraction changes in different meridians of the eye. It causes blurred vision at any distance and includes corneal, lenticular, and retinal astigmatism. Cataract surgery used to cause a progressive increase in the pre-exisiting corneal astigmatism because of creating a surgically induced astigmatism, for example, a large size surgery incision. The development of surgical techniques during last decades has made cataract surgery interchange to treat preoperative corneal astigmatism at time of surgery. Nowadays, three surgical approaches can be used. By placing a sutureless clear corneal incision on the steep meridian of the cornea, a preoperative corneal astigmatism less than 1.0 D can be corrected. Single or paired peripheral corneal relaxing incisions (PCRIs) provide 1.0-3.0 D corneal astigmatism correction. PCRIs are typically used for treating 1.0-1.5 D of regular corneal astigmatism, if more than 2.0 D, the risk of overcorrection and irregular astigmatism is increased. When toric intraocular lenses (IOLs) are unavailable in markets, PCRIs are still a reasonable option for patients with up to 3.0 D of pre-existing corneal astigmatism. Toric IOLs implantation can correct 1.0-4.5 D of corneal astigmatism. Several IOLs are approved to correct a high degree of corneal astigmatism with cylinder power up to 12.0 D. These approaches can be used alone or in combination.     

Laser in situ keratomileusis to correct residual myopia and astigmatism after radial keratotomy

PURPOSE: To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) in selected post-radial-keratotomy (RK) eyes with residual myopia and astigmatism. SETTING: TLC-The Brea Laser Eye Center, Brea, California, USA. METHODS: Nine eyes of 6 patients who had had RK but had residual myopia and/or astigmatism had LASIK. All RK eyes had 8 radial incisions, were more than 1 year post-RK, had no epithelial inclusion cysts or corneal disease, and had had no subsequent ocular surgery. Follow-up was a minimum of 13 months, at which time uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction, cycloplegic refraction, keratometry, central and peripheral pachymetries, intraocular pressure, and a subjective assessment of visual function were obtained. RESULTS: At the last follow-up, the mean spherical equivalent (SE) was -0.156 diopter (D) +/- 0.174 (SD). All eyes treated for distance vision had a UCVA of 20/25 or better. No patient lost BCVA. No intraoperative or postoperative complications occurred. Seven eyes had morning and evening measurements. The mean change in manifest SE from morning to evening was -0.143 D. Six of the 7 eyes (86%) had 0 to 1 Snellen line change in UCVA from morning to evening. The subjective questionnaire revealed a high degree of satisfaction with overall vision, minimal glare, and less fluctuation in daily vision than before LASIK. CONCLUSION: Laser in situ keratomileusis is safe and efficacious for reducing residual myopia and astigmatism in properly selected RK patients.     

Acrysof toric人工晶状体植入矫正白内障患者角膜散光的疗效评估

目的 比较术前存在角膜散光的白内障患者植入Acrysof toric （Acrysof SN60TT）人工晶状体（IOL）和Acrysof SA60AT球面IOL后的视觉效果.方法 前瞻性病例对照研究.收集术前角膜散光大于1.0 D的白内障患者96例（104眼）,其中56眼植入Acrysof toric IOL（Toric组）,48眼植入Acysof SA60AT球面IOL（对照组）.术后3个月观察裸眼视力、最佳矫正视力、残余散光度、脱镜率、全眼总低阶和高阶像差、调制传递函数（5、10、15、20、25、30 cpd）以及Toric IOL轴位.采用配对设计t检验、独立样本t检验对数据进行分析.结果 术后Toric组裸眼视力（logMAR）0.22±0.12、最佳矫正视力0.05±0.07、残余散光度为0.36 D;对照组裸眼视力0.36±0.20、最佳矫正视力0.06±0.08、残余散光度为1.19 D;两组比较,裸眼视力和残余散光度差异均有统计学意义（t=4.526、4.275,P＜0.01）,最佳矫正视力差异无统计学意义.术后3个月,视远脱镜率Toric组为59％,对照组为32％.3 mm瞳孔直径下,Toric组术后低阶像差低于对照组,差异有统计学意义（t=11.146,P＜0.01）,但两组术后高阶像差差异无统计学意义,且术后Toric组MTF值于各空间频率均高于对照组,差异均有统计学意义（t=8.894、5.750、4.573、4.475、2.968、4.756,P＜0.01）.Toric组术后散光轴平均偏移5.84°±4.12°（0°～l8°）.结论 AcrySof toric IOL植入后可获得令人满意的术后裸眼视力、脱镜率、视觉质量,可预测性强,且具有良好的旋转稳定性.     

白内障手术中植入散光型人工晶状体矫正角膜散光的效果评价

目的:评价白内障手术植入散光型人工晶状体(MS6116TU)的术后效果和人工晶状体轴位的稳定性.方法:对154眼进行回顾性总结分析.采用颞侧透明切口的白内障超声乳化法,植入折叠式散光型人工晶状体.术后向量分析借助双角图表,统计学处理采用T2检验.结果:主观验光的平均散光向量术前为1.51D×178°,术后为0.07D×121°.术后1d有11眼(7.1%)Toric IOL的轴向比预定方向偏差15°以上,随访中有12眼(7.8%)轴向偏离在15°以上;晶状体在囊袋内稳定性能好,本组未有二次手术再定位者.无论是高度(≥5D)或低度(≤2D)的散光晶状体均取得了预期的效果.结论:在白内障手术中植入散光人工晶状体矫正术前角膜的散光,临床效果准确、可靠,并有着较好的预测性,具有一定的推广前景.     

Methods to control astigmatism in cataract surgery

The correction of astigmatism during cataract surgery has evolved due to recent basic and clinical studies. To control surgically induced astigmatism, the surgeon has many options, including varying incision parameters, astigmatic keratotomy, scleral flap recession and resection, toric intraocular lens implantation, and modifying postoperative medical treatment. The recent literature is reviewed, and our current approach for cataract surgery is discussed.     

两种术式矫正老年性白内障患者散光的疗效比较

目的:比较超声乳化白内障摘除联合Toric人工晶状体植入术与球面人工晶状体植入术联合周边角膜切开术矫正老年性白内障患者术前散光的疗效。方法:连续纳入老年性白内障住院手术患者54例54眼,男27例,女27例,平均年龄70.04±9.08(50～87)岁。A组(0.75D≤散光≤1.50D)30例,B组(1.75D≤散光≤2.50D)24例。每组患者随机分配进行周边角膜切开术(PCRIs)和Toric人工晶状体植入术矫正术前散光,比较两种手术方式术后6mo患者的裸眼视力(UCVA)、最佳矫正视力(BCVA)、残余散光(|EV|)、散光矫正量(|SIRC|)、散光矫正率(CR)。比较两种手术方式术后6mo与术后1mo的UCVA和|EV|的变化。结果:术后6mo,所有患者的BCVA均达0.6以上。PCRIs与Toric-IOL术后BCVA达到0.8以上者在A组中分别为86.7%vs93.3%(P>0.05),B组分别为75%vs91.7%(P=0.59),两种术式在两散光组中间差异均无统计学意义。术后6mo,PCRIs与Toric-IOL两种术式患者的UCVA、|EV|、|SIRC|、CR在A组患者中分别为0.70±0.21vs0.76±0.17(P=0.81)、0.48±0.22vs0.37±0.19(P=0.13)、0.87±0.30vs0.92±0.38(P=0.71)、0.75±0.16vs0.78±0.19(P=0.56),两种术式间各参数差异均无统计学意义;B组患者中分别为0.50±0.15vs0.78±0.11(P<0.01)、1.17±0.36vs0.54±0.33(P<0.01)、1.08±0.27vs1.68±0.32(P<0.01)、0.51±0.13vs0.81±0.14(P<0.01),两种术式间各参数差异均有统计学意义。A组中PCRIs术后1mo与术后6mo的UCVA、|EV|在分别为0.77±0.23vs0.70±0.21(P=0.09)、0.50±0.23vs0.48±0.22(P=0.58),Toric-IOL术后分别为0.77±0.223vs0.76±0.17(P=0.81)、0.40±0.18vs0.37±0.19(P=0.55),各参数间差异无统计学意义;B组患者中PCRIs术后1mo与术后6mo的UCVA、|EV|分别为0.63±0.17vs0.50±0.15(P<0.01)、0.81±0.34vs1.17±0.36(P<0.01),Toric-IOL术分别为0.81±0.12vs0.78±0.11(P=0.08)、0.48±0.31vs0.54±0.33(P<0.01),各参数间差异有统计学意义。结论:PCRIs与Toric-IOL两种手术方式矫正老年性白内障患者术前散光安全、有效。两种手术方式矫正低度数散光(0.75～1.50D)的疗效无差异,术后6mo内疗效稳定;Toric-IOL术矫正较高度数散光(1.75～2.50D)的疗效优于PCRIs;两种术式的疗效在术后6mo均有所回退,PCRIs回退较严重。     

PRK治疗RK后残余近视散光二年疗效分析

目的： 评价准分子激光屈光性角膜切削术治疗放射状角膜切开术后残余近视散光的预测性、稳定性和安全性。方法： 对５２ 眼 Ｒ Ｋ 术后残余近视散光患者行再次 Ｐ Ｒ Ｋ 治疗, 并连续随访两年以上。术前残余球镜屈光度－ ３７５±１３２ Ｄ,残余柱镜屈光度－ ２３６±１２５ Ｄ, 最佳矫正视力均≥０８。结果： 术后 ６ 个月球镜屈光度－ ０３２±０２４ Ｄ, 柱镜屈光度－ ０７８±０５２ Ｄ, 裸眼视力≥１０ 者４６ 眼 （８８４６％ ）, 术后 ２４ 个月球镜屈光度－ ０３７±０４２ Ｄ, 柱镜屈光度－ ０５６±０３７ Ｄ, 裸眼视力≥１０ 者 ４２ 眼 （８０７６％ ）。最佳矫正视力下降 １ 行以上者 ３ 眼 （５７６％ ）, 实际球镜矫正度与预期矫正度相差１０ Ｄ 以内 ５０ 眼 （９０１５％ ）, 柱镜相差 １０ Ｄ以内５１ 眼 （９８０７％ ）。结论： Ｐ Ｒ Ｋ 治疗 Ｒ Ｋ 术后残余近视散光的两年随访结果表明, 该方法预测性强、稳定性好和安全性高, 特别在矫正残余散光方面, 其结果令人满意。