Comparison of various capsulectomy techniques in cataract surgery. An experimental study]

Radial tears at the edge of an anterior capsulectomy are often associated with the occurrence of intraocular lens (IOL) loops coming out of the capsular bag with subsequent IOL decentration. We analyzed the incidence of radial tear formation in 40 human eyes obtained postmortem. These eyes were randomly assigned to four groups: "can opener," linear capsulotomy, capsulopuncture ("postage stamp"), and continuous curvilinear capsulorhexis (CCC). The CCC appeared to be much less likely to be associated with anterior capsular radial tears as opposed to the other three techniques. With the nucleus expression technique used in this study, radial tears occurred in all cases of "can opener," linear capsulotomy and capsulopuncture, whereas no tears occurred with the CCC technique. The results of this study show that CCC is currently the best available anterior capsulectomy procedure for minimizing the incidence of radial tears and sequelae such as decentration.     

不同截囊方法的比较研究

以兔眼为实验材料，以临床操作模式为方法，在标准条件下，比较４种截囊术前囊膜辐射状撕裂的发生率，４种截囊术是：开罐式截囊，邮票（点刺）式截囊，线状截囊和环形撕囊术。实验结果证实，环形囊术较其它３种截囊方法有更多优点，应用本文介绍的后压法娩出晶体核后，撕囊术组中未见发生前囊膜辐射状撕裂，其它３组则１００％发生。     

白内障术中后囊膜破裂行后囊膜连续曲线形撕囊术

目的：讨论白内障囊外摘除、超声乳化摘除及针吸摘除术中后囊膜破裂时行后囊膜连续曲线形撕囊术（ｐｏｓｔｅｒｉｏｒ ｃｏｎｔｉｎｕｏｕｓ ｃｕｒｖｉｌｉｎｅａｒ ｃａｐｓｕｌｏｒｈｅｘｉｓ,ＰＣＣＣ）的方法和作用。方法：利用撕囊镊对１０例（１０眼）白内障摘除术中后囊膜破裂眼行ＰＣＣＣ,５例联合行前段玻璃体切除术。结果：１０例后囊膜破裂后行ＰＣＣＣ眼９例成功完成ＰＣＣＣ,１ 均植入后房人工晶体。术后观察１月～３年（平均１６月）,９例行ＰＣＣＣ眼视轴均清晰,未发生视网脱离及后发性白内障,无明显的人工晶体光学部偏中心或人工晶体异位。结论：ＰＣＣＣ可有效避免后囊膜破孔进一步无限放射状撕裂,保持周边后囊膜的完整性。使人工晶体稳固于囊袋内。     

Posterior continuous curvilinear capsulorhexis. An experimental study with clinical applications.

The posterior continuous curvilinear capsulorhexis technique has been advocated in cases of posterior capsule rupture during extracapsular cataract extraction. The authors compared posterior continuous curvilinear capsulorhexis with posterior capsular sharp-edged tears. Two different types of forces were experimentally created on the posterior capsule of 30 human eyes obtained after death: (1) implantation and dialing of posterior chamber intraocular lenses (PC IOLs) and (2) increased intravitreal pressure by injection of balanced salt solution. All posterior capsular tears extended toward the equator, causing major capsular defects. In contrast, the posterior continuous curvilinear capsulorhexis remained intact in all cases. This experimental study proves that in cases where an inadvertent posterior capsular tear occurs, a posterior continuous curvilinear capsulorhexis is useful in preventing further capsular damage. Also, in cases where a posterior capsulotomy is indicated, a smooth edge created by a posterior continuous curvilinear capsulorhexis may be useful to maintain the integrity of the capsular bag for PC IOL capsular implantation.     

Prospective experimental study of factors related to posterior chamber intraocular lens decentration.

The effect of posterior chamber intraocular lens (IOL) dimensions, design, style, loop fixation, and anterior capsular tears on decentration were investigated in an experimental model. Nine posterior chamber IOLs of various designs and styles with loop diameters between 12.0 and 14.0 mm and optic diameters between 5.0 and 7.0 mm were implanted in human eyes obtained post mortem. Symmetrical and asymmetrical fixation were investigated in eyes with and without radial tears using the Miyake posterior view technique. Location of IOL loops proved to be the most significant factor in IOL decentration. Decentration was least with symmetrical bag/bag fixation and no radial tears (mean = 0.20 +/- 0.05 mm). Asymmetrical bag/sulcus fixation in the presence of anterior capsular tears was associated with the highest decentration rate (mean 0.68 +/- 0.28 mm). Optic size and total loop diameter had no apparent effect on IOL centration in the immediate postoperative period.     

Anterior chamber and sutured posterior chamber intraocular lenses in eyes with poor capsular support

PURPOSE: To compare the clinical outcomes and complications of patients who had surgical placement of anterior chamber (AC IOLs) and sutured posterior chamber intraocular lenses (PC IOLs) after cataract surgery resulting in poor capsular support. SETTING: Department of Ophthalmology, Bascom Palmer Eye Institute, Miami, Florida. METHODS: A retrospective interventional comparative case series of 181 eyes of 181 patients that had implantation of an intraocular lens with inadequate capsular support was conducted. A chart review of all patients that had implantation of AC IOLs or sutured PC IOLs at a tertiary care eye hospital between 1995 and 2001 was conducted. RESULTS: Outcome measures included final best-corrected visual acuity, spherical equivalent, and postoperative complications (pseudophakic bullous keratopathy, elevated intraocular pressure [IOP] inflammation, retinal detachment, suture erosion, cystoid macular edema). Of 702 charts reviewed, 181 were found to fit inclusion and exclusion criteria. The postoperative complication risk ratio was 0.80 (95% confidence interval [CI]: 0.52-1.23) for AC IOLs compared with PC IOLs. The most common complication experienced by patients having implantation of either lens type was elevated IOP (AC IOL: 38%; PC IOL: 42%). The incidence of other complications was similar between the groups. Best-corrected visual acuity was similar; however, final spherical equivalent trended toward more myopic values in the PC IOL group (-0.82 +/- 1.67 for AC IOL versus -1.32 +/- 2.12 for PC IOL). CONCLUSIONS: The findings suggest that no significant differences in outcome exist when comparing AC IOLs to sutured PC IOLs in complicated cataract extraction with poor capsular support. Recent advances in AC IOL design have yielded lenses that provide a safe, effective alternative to sutured PC IOLs.     

Intraoperative management of posterior capsule tears in phacoemulsification and intraocular lens implantation

OBJECTIVE: This paper presents the incidence, causes, and management of posterior capsule (PC) tears and their postoperative outcomes in a large series of eyes that underwent cataract removal and intraocular lens (IOL) implantation, operated on by one surgeon. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Eighteen thousand four hundred seventy consecutive eyes (1992-1999) were reviewed with the assistance of electronic medical records for incidence of PC tears in patients seeking treatment at an outpatient cataract surgery clinic. INTERVENTION: Eyes in this series underwent continuous curvilinear capsulorrhexis (CCC), nucleofractis phacoemulsification, and IOL implantation under topical anesthesia. Different intraoperative surgical strategies such as posterior continuous curvilinear capsulorrhexis (PCCC) were used in the management of PC tears. MAIN OUTCOME MEASURES: Routine preoperative and postoperative visual and refractive outcomes were recorded, including incidence of lens capsule tears, IOL position, and postoperative complications. RESULTS: Posterior capsule tears occurred in 83 of 18,470 eyes, resulting in an overall incidence of 0.45%. Of these 83 eyes with PC tears, 49% received vitrectomy. Fifty-one of 83 PC tears (61.4%) were amenable to be converted to PCCC. Of these 51 procedures, 50 eyes had PC IOL in-the-bag fixation. One eye had PCCC with optic capture. There were no eyes with dropped nuclei or nuclear fragments requiring pars plana vitrectomy. Seventeen eyes (20.5%) had Neuhann anterior capsule rhexis fixation with the haptics placed in the sulcus and IOL securely in the bag. Ten eyes (12.1%) had the IOL placed in the sulcus, and 5 eyes (6.0%) required anterior chamber IOL fixation. None of the 83 PC tears resulted in clinically evident cystoid macular edema, retinal detachment, or endophthalmitis. CONCLUSIONS: With an intact CCC and with conversion of PC tears to PCCC, in-the-bag fixation of IOLs can be achieved in most eyes.     

Spontaneous disinsertion of a multipiece foldable acrylic intraocular lens haptic 3 and 12 months after implantation

We report 2 cases of spontaneous postoperative haptic disinsertion with the Alcon AcrySof MA60BM posterior chamber intraocular lens (PC IOL). A 14-year-old girl with a history of acute retinal necrosis and pars plana vitrectomy with lensectomy for retinal detachment repair had secondary implantation of a PC IOL in the ciliary sulcus. Three months later, the superior haptic disinserted from the optic and dislocated into the anterior chamber. In the second case, a 22-year-old man had lens aspiration and PC IOL implantation in the capsular bag. One year after surgery, the PC IOL had a similar problem, with the disinserted superior haptic remaining in the capsular bag while the optic and inferior haptic dislocated into the anterior chamber. In both patients, the PC IOLs were exchanged for rigid single-piece PC IOLs. The patients have had no further problems.     

二次撕囊术在白内障超声乳化摘除及人工晶状体植入术中的应用

目的 :探讨在白内障超声乳化摘除及人工晶状体植入术中行二次撕囊术 (secondarycapsulorhexis)的方法和作用。方法 :对 6例因皮质膨胀或液化眼行计划性的二次撕囊 ;10例行非计划性的二次撕囊 ,其中 3例因撕囊口过小难于植入囊袋内位固定人工晶状体 ,3例因超声乳化白内障摘除时前囊膜切迹破裂 ,4例因撕囊口偏中心 ,为防止囊膜收缩综合征发生以致遮盖瞳孔区而行二次撕囊。结果 :二次撕囊术后完成前囊膜连续曲线形撕囊 13眼 ,16眼均植入囊袋内位固定人工晶状体。结论 :二次撕囊术可使晶状体皮质膨胀或液化的白内障眼易于完成前囊膜连续曲线形撕囊 ;可避免白内障术中前囊膜切迹破裂以至进一步放射状撕裂 ;可维持完整曲线形撕囊口边缘 ,防止发生人工晶状体植入后光学部偏中心 ,囊襻异位 ;使过小撕囊口易于植入囊袋内位固定人工晶状体 ;使撕囊口偏下而让难于被吸除的上方赤道部残收稿日期 :2 0 0 2 -0 3 -2 6;修回日期 :2 0 0 2 -0 6-0 4作者简介 :周坚强 ( 1973 -) ,男 ,嘉兴人 ,眼科医师。通信作者 :周坚强 (E -mail:zhjq @mail.jxptt.zj.cn)。余皮质易于被吸除 ;可减少或避免过小前囊膜撕囊口或明显偏中心撕囊口发生囊膜收缩综合征 (capsulecontractionsyn drome)等。     

Delayed posterior dislocation of silicone plate-haptic lenses following anterior and posterior Nd:YAG laser capsulotomy

To observe the stability of silicone plate-haptic intraocular lenses implanted following cataract surgery and analyze the reasons related to decentration and dislocation into the posterior segment. · METHODS: We report 3 cases of posterior dislocation of silicone plate-haptic lenses (Bausch and Lomb C11UB and Chiron C11UB) in patients who underwent uneventful phacoemulsification. · RESULTS: One occurred 4 years following sectoral anterior capsulotomy for advanced anterior capsular contraction, the other in the early post-operative period following posterior capsulotomy and the third is a delayed (3 months), dislocation following uneventful posterior capsulotomy. None of the cases were associated with a history of trauma or other precipitating event. · CONCLUSION: Silicone plate haptic IOLs seem to be prone to dislocation due to poor capsular adherence as they are only held in place by the fibrotic fusion of the haptics. If either the posterior or anterior capsules are disrupted, the forces created by capsular contraction may cause extension of radial tears, with subsequent posterior dislocation of the implant. Though the use of silicone plate-haptic lenses has been surpassed by other models, there are patients who had implantation of such lenses that may undergo YAG laser capsulotomy. It is important to inform them about the potential risk of posterior dislocation as an early or late complication following this procedure.