Corneal endothelial damage after Nd:YAG laser anterior capsulotomy

The Nd:YAG laser is used primarily in the management of posterior capsular opacification in patients who have had extracapsular cataract extraction. Despite wide clinical use little is known about its damaging effects on the ocular tissues particularly on the corneal endothelium. To evaluate the pathologic changes caused by high powered Nd:YAG laser pulses on the anterior segment of the eye we focused the beam of this laser on the anterior lens capsule in rabbit eyes. Six eyes underwent anterior capsulotomy and three power settings were used (3.4 mJ, 5.8 mJ, 8.6 mJ). The fellow eyes served as controls. We studied acute corneal endothelial changes 6 hours after the capsulotomy using transmission electron microscopy. Results indicate that especially in the high setting the laser energy can cause injury and destruction of endothelial cells and alterations in the Descement membrane. These effects may be crucial of patients with corneas in critical cell number after a cataract surgery.     

Effects of laser fragmentation of the lens mass on ocular tissues in experimental animals]

Side effects of laser on the posterior corneal epithelium and the retina during intracapsular YAG laser fragmentation of transparent lens fibers in various modes of laser operation were experimentally studied. The pulse power varied from 3 to 7.7 mJ, number of pulses from 55 to 160, length of exposure 10(-8) sec, diameter of the spot in the focus 30 microns. Animal eyes were enucleated on days 3-6 after the procedure. Posterior corneal epithelium was examined in the Hitachi scanning electron microscope, the retina in a light microscope. The findings evidence that injury to the posterior corneal epithelium in intracapsular YAG laser fragmentation of the lens depends mostly on the number of pulses and not on the exposure energy. A safe number of coagulates should not surpass 100, this being quite sufficient for fragmentation of the lens fibers at exposure power of 5-6 mJ. Such operation mode is safe for the retina as well, this recommending it for clinical use.     

钇铝石榴石激光治疗白内障摘除术后并发症的临床研究

目的探讨白内障摘除术后钇铝石榴石(yttriumaluminumgarnet,YAG)激光的应用范围,激光后囊膜切除术的方法、疗效和并发症.方法超声乳化白内障吸除人工晶状体(intraocularlens,IOL)植入手术4600只眼,术后YAG激光治疗451只眼,其中行后囊膜切除380只眼,切除方法采用连续环状切开及后推膜瓣二步法;连续环状切开时平均单脉冲能量为(1.21±0.31)mJ,平均总能量为(52.44±14.62)mJ;后推膜瓣时平均单脉冲能量为(2.12±0.43)mJ,平均总能量为(50.88±10.32)mJ.IOL前膜切除42只眼,脉冲能量为1.0～1.4mJ,平均总能量为(56.28±32.74)mJ.治疗其他术后并发症29只眼.结果白内障摘除术后行YAG激光治疗451只眼(9.8%).后囊膜切除手术率为8.3%;1次激光手术成功率为96.3%;平均裸眼视力提高0.26,矫正视力为0.85;未出现明显的IOL损伤和移位;362只眼(95.3%)眼压正常;2只眼视网膜脱离.结论YAG激光无需切口可在眼内完成精确的分割手术,且操作方便、安全,疗效好、并发症少、应用范围广.     

Q开关Nd:YAG激光治疗后囊膜混浊

目的:探讨Q开关Nd:YAG激光后囊膜切开术治疗后囊膜混浊的疗效及安全性。方法:回顾性分析行Q开关Nd:YAG激光后囊膜切开术后囊膜混浊患者165例(193眼),记录手术前后视力、眼压及并发症,并进行统计学分析。结果:①后囊膜一次性切开成功率为100%,所用激光脉冲数平均24±21.7次,激光总能量4~451mJ;②91.2%(176眼)视力较术前提高;③59.6%(115眼)出现一过性眼压升高;手术前后眼压变化与是否植入人工晶状体、所用激光脉冲数以及白内障手术与后囊膜切开术间隔时间有关;④19.3%(32眼)出现人工晶状体损伤。结论:Q开关Nd:YAG激光后囊膜切开术治疗后囊膜混浊安全、有效,但应严格掌握适应证,并合理选择激光参数。     

Results of Nd-YAG laser effects in manifest exudative reaction after implantation of intraocular lens

Thirteen patients (16 eyes) with artiphakia developed exudative reaction with formation of fibrinous conglomeration occupying up to 2/3 of the anterior chamber volume. Noninvasive YAG laser exposure was carried out to destroy the conglomeration. Complete cleansing of the anterior chamber and IOL was attained in 2-7 sessions (energy 0.8-8.0 mJ, up to 100 pulses). The difference in the periods between relapses and the number of relapses decreased after each exacerbation. YAG laser exposure destroyed the exudative conglomeration and stimulated its lysis with the minimum complications. Hence, Nd:YAG laser exposure is a promising method of choice.     

永存瞳孔膜激光切开术

目的 评价严重的永存瞳孔膜Nd∶YAG激光切开术的效果.方法 永存瞳孔膜26例（31眼）,表麻下置角膜接触镜,在裂隙灯显微镜引导下.Nd∶YAG激光准确聚焦于瞳孔缘处的瞳孔膜进行发射.单脉冲切开能量为0.4～0.8 mJ,每次治疗总量为5～10 mJ,平均（2±0.18）mJ.结果 永存瞳孔膜激光切开术1次切开者5眼,占16.13％;2～3次切开者12眼,占38.71％;4～5次切开者14眼,占45.16％.矫正视力;0.1 ～0.25者5眼,占16.13％;0.3～0.5者7眼,占22.58％;0.6～0.8者8眼,占25.81％;≥1.0者,11眼占35.48％.术后未发生晶状体浑浊、视网膜损伤或眼压持续增高等并发症.结论 Nd∶YAG激光切开术治疗严重的永存瞳孔膜可增进视力,不需要专门的手术设备,表面麻醉下就可在门诊施行手术,是一种简便、安全、有效的治疗方法.     

Nd：YAG激光治疗人工晶状体后发障的临床探讨

目的 探讨Ｎｄ：ＹＡＧ激光治疗人工晶状体植入术后后囊浑浊的疗效和方法。方法 应用Ｎｄ：ＹＡＧ激光仪,对３７例（３９眼）后房人工晶状体植入术后后浑浊行后囊切开术。结果 激光截囊前后视力有显著差异,而激光截囊后与后发障发生前视力针差异,儿童组复发率达５８．３％。人工晶状体损伤９例（１０眼）占２５．６％,但不影响视力,结论选择最佳激光能量与后退距离,可产生最低人工晶状本损伤和最高后囊爆破,从而大幅度减少     

Effect of anterior capsule contraction on visual function after cataract surgery

PURPOSE: To examine the effect of contraction of the anterior capsule opening after cataract surgery on visual acuity and contrast sensitivity. SETTING: Hayashi Eye Hospital, Fukuoka, Japan. METHODS: Thirty-two eyes of 32 consecutive patients who showed marked contraction of the anterior capsule opening after implantation of an intraocular lens were recruited. The area of the anterior capsule opening was measured by Scheimpflug videophotography before and after neodymium:YAG (Nd:YAG) laser anterior capsulotomy and was correlated with visual acuity and contrast sensitivity. RESULTS: After Nd:YAG laser anterior capsulotomy, the mean area of the anterior capsule opening increased significantly from 8.2 mm(2) to 18.0 mm(2) (P<.0001). Contrast sensitivity at most visual angles also improved significantly after Nd:YAG anterior capsulotomy, although visual acuity did not. The area of the anterior capsule opening before anterior capsulotomy was correlated significantly with contrast sensitivity but not with visual acuity, whereas there was no correlation between the opening area after anterior capsulotomy and visual acuity or contrast sensitivity. CONCLUSIONS: Contraction of the anterior capsule opening after cataract surgery significantly diminished contrast sensitivity in proportion to the opening area but did not markedly worsen visual acuity. Neodymium:YAG laser anterior capsulotomy improved contrast sensitivity.     

Large iridotomies by the linear incision technique using the neodymium:YAG laser at low energy levels. A study using cynomolgus monkeys

Multiple Q-switched neodymium:YAG (Nd:YAG) laser impacts at energy levels of 1.0 to 1.7 mJ, focused on the iris through the 103-diopter (D) iridotomy-sphincterotomy lens, were applied back and forth in a line across the radial fibers of the mid-peripheral iris in eyes of the cynomolgus monkey (Macaca fasicularis) to produce large iridotomies of controllable size. Oozing of blood was minimal and no lens capsule damage occurred. These iridotomies showed less iris concussion damage than did conventional Nd:YAG laser iridotomies made by directing high-energy laser shots through the Abraham lens upon a single iris spot.     

In situ ablation of lens epithelial cells in porcine eyes with the laser photolysis system

PURPOSE: To evaluate the efficacy of the laser photolysis system (LPS) (A.R.C. Laser GmbH) in removing lens epithelial cells (LECs) to prevent posterior capsule opacification (PCO) in an in situ model. SETTING: Department of Ophthalmology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany. METHODS: Twelve enucleated porcine eyes fixed in a specially developed eye holder were randomly assigned to the control or treatment group. The cornea and iris were removed from all eyes, and a small paracentral capsulorhexis was performed. The lens nucleus and cortex were extracted by hydroexpression. The tip of the LPS was inserted into the capsular bag of eyes in the treatment group, and 50 pulses (10 mJ) were applied to the anterior capsule. All capsules were evaluated for remaining LECs by confocal laser scanning microscopy (HRT II with the Rostock Cornea Module, Heidelberg Engineering) and standard histology (hematoxylin-eosin and periodic acid-Schiff stains). RESULTS: In the control group, a homogenous layer of LECs attached to the anterior capsule was seen with both evaluation methods. In the treatment group, no LECs adherent to the anterior capsule were detected, suggesting complete ablation of LECs from the capsule. Small islands of equatorial LECs were found in places in which the remaining cortical fibers protected cells from the laser shockwave. The results of the confocal laser scanning microscopy were confirmed by standard histology. CONCLUSIONS: The LPS completely ablated LECs in an in situ model of cataract extraction. This system might prevent formation of PCO in vivo.     

后极性白内障超声乳化术的临床观察

目的探讨后极性白内障超声乳化术的手术技巧及效果。方法回顾性分析鄂尔多斯市中心医院2015年12月至2018年12月后极性白内障行超声乳化术15例(21眼)的临床资料。探讨对后囊下浑浊的处理方式和维持前房稳定的技巧,观察术中、术后并发症及术后视力。术后随访6个月。结果所有患者均植入折叠人工晶状体,15眼后囊完整,6眼后囊破裂;15眼中环形撕囊者5眼、剪除浑浊者6眼、二期行YAG激光后囊切开者4眼。术后随访6个月,最佳矫正视力>0.5者12眼,0.1~0.5者9眼。结论后极性白内障患者行超声乳化术中选择合理处理后囊、维持前房稳定,可有效提高手术成功率,获得较好的术后视力。     

晶状体后囊膜前纤维机化膜摘除术

目的用手法撕除晶状体后囊膜的纤维机化膜,以恢复晶状体后囊膜的透明度,提高白内障手术的视力。方法对4581例(5028只眼)白内障施行囊外摘除或超声乳化手术,其中54例(61只眼)因术中晶状体后囊膜前存在较为致密的纤维机化膜,其中先天性白内障14例(19只眼),老年性白内障27例(27只眼),并发性白内障9例(11只眼),外伤性白内障4例(4只眼),估计手术后将会严重影响视力,故采用手术摘除。具体操作如下:前房内注入粘弹性物质,使晶状体后囊膜略低于平面,先用截囊针由切口插入,钩住纤维膜的边缘,向中央牵拉,使纤维膜的边缘与晶状体后囊膜粘连处游离,再改用撕囊镊,夹持游离的纤维机化膜,完整地从后囊膜撕去。结果采用粘弹性物质屏蔽和截囊针加囊膜镊撕去晶状体后囊膜前纤维机化膜,并保持后囊膜完整40例(42只眼);出现后囊膜裂隙、无缺损10例(13只眼);出现后囊膜裂口追加后囊膜连续环形撕囊4例(6只眼);其中2例(2只眼)施行前段玻切术。所有54例(61只眼)最终将人工晶体置入晶体囊袋内。结论在粘弹性物质屏蔽下,用截囊针将纤维膜游离,再用撕囊镊揭痂法撕除晶状体后囊膜前纤维机化膜是一种安全和有效的手术方法,它可以恢复后囊膜的透明度,提高视力;恢复后囊膜平整,使人工晶体置入后不会倾斜;不会因为术后YAG激光不能击破纤维机化膜,而影响白内障手术后效果。     

Effect of primary posterior continuous curvilinear capsulorhexis on clinical performance of ACR6D SE single-piece hydrophilic acrylic intraocular lenses

PURPOSE: To evaluate the effects of a primary posterior continuous curvilinear capsulorhexis (PCCC) on the clinical performance of a single-piece hydrophilic acrylic intraocular lens (IOL) with haptic angulation. SETTING: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. METHODS: A prospective study of 52 patients with bilateral age-related cataract was conducted. Patients had standard cataract surgery with implantation of the same IOL in both eyes. Randomly, a PCCC was created in 1 eye and the posterior capsule was left intact in the fellow eye. Assessed parameters were visual axis opacification (VAO) in eyes with a PCCC or regeneratory posterior capsule opacification (PCO) in eyes without PCCC (scale 0 to 10) in the central (3.0 mm eccentricity), intermediate (3.0 to 4.5 mm eccentricity), and peripheral (>4.5 mm eccentricity [capsulorhexis edge]) areas; neodymium:YAG (Nd:YAG) laser capsulotomy or laser polishing of ongrowing lens epithelium; anterior capsule opacification (ACO); best corrected visual acuity (BCVA); and contrast sensitivity. RESULTS: Thirty patients completed the 2(1/2)-year follow-up. Visual axis opacification was significantly lower in the central region in the PCCC group (mean 0.5 +/- 0.7 [SD]) than PCO in the central region of the non-PCCC group (mean 1.1 +/- 1.1) (P = .02). Forty percent in the non-PCCC group had an Nd:YAG laser capsulotomy during the follow-up period; none in the PCCC group had laser polishing. There were no significant differences in ACO, SE, BCVA, or contrast sensitivity. There was no additional gain in BCVA or contrast sensitivity in eyes with a PCCC compared with eyes without a PCCC when VAO and PCO were low. CONCLUSION: A PCCC significantly reduced PCO formation within the central 3.0 mm eccentricity as well as the need for Nd:YAG laser capsulotomy in eyes with a single-piece hydrophilic acrylic IOL with angulated haptics.     

Method of lensectomy in high myopia

The authors suggest a method of removing a transparent lens in high myopia patients aged over 40 with a dense lens nucleus. The method consists of 3 stages. Stage I consists in preliminary intracapsular YAG laser fragmentation of lenticular fibrils, performed 2-4 days before surgery. Stage II consists in YAG laser anterior capsulotomy directly before lens extraction. Stage III consists in lenticular mass aspiration irrigation via 2 small incisions on the cornea. The described lensectomy method was used in 23 patients (44 eyes) aged 40 to 55 with refraction of 16.0 to 23.0 diopters. The time of lenticular mass aspiration was cut down by half as against that after lensectomy without preliminary intracapsular YAG laser fragmentation of lenticular fibrils. No complications during or after surgery were recorded. After surgery vision acuity improved by 13 times without correction and two times with correction.     

Neodymium:YAG laser damage threshold of foldable intraocular lenses

PURPOSE: To determine the energy level of the neodymium:YAG (Nd:YAG) laser that induced a 50% incidence of intraocular lens (IOL) damage in 5 foldable IOL materials. SETTING: Department of Ophthalmology, Siriraj Hospital Mahidol University, Bangkok, Thailand. METHODS: To simulate the condition within the capsular bag, an IOL was sandwiched between 2 rubber membranes. The front membrane had a central opening mimicking the anterior capsulotomy; the back membrane acted as the posterior capsule. The model was submerged in a water-filled chamber. The Nd:YAG laser with an automatic focus 150 microm beyond the focus of the aiming beam was used to perform a posterior capsulotomy. Three IOLs of each of 5 foldable IOL materials were tested. One type of poly(methyl methacrylate) (PMMA) was studied as a reference. The incidence of IOL damage at various energy levels was recorded. Linear regression analysis was used to determine the 50% incidence damage threshold. RESULTS: The 6 materials tested included 1 silicone lens (SI-40NB, AMO), 1 hydrophobic acrylic lens (MA60BM, Alcon), 3 hydrophilic acrylic lenses (Haptibag Ang, IOLtech; ACR6D, Corneal; H60M, Bausch & Lomb), and 1 PMMA lens (LX10BD, Alcon). The 50% incidence damage threshold values were 0.37 mJ, 0.54 mJ, 0.58 mJ, 0.52 mJ, 0.66 mJ, and 0.68 mJ, respectively. CONCLUSIONS: The 50% incidence damage threshold in all the IOLs was below the energy level normally used to perform a posterior capsulotomy in clinical practice. However, setting the laser at the lowest possible energy, focusing the laser beam beyond the posterior capsule, and performing the capsulotomy early should minimize the risk of IOL damage.     

Nd:YAG激光治疗IOL植入术后后发性白内障的临床探讨

目的:探讨Nd:YAG激光治疗人工晶状体植入术后后发性白内障的方法和效果。方法:应用Nd:YAG激光对48例51眼后房型人工晶状体植入术后后囊混浊行后囊膜切开术。结果:后囊膜一次性切开成功率100%,增视率94%。结论:激光是治疗后发性白内障安全、有效的方法。根据最佳治疗时机,正确操作和预防并发症是治疗的关键。     

Wound healing by the rat lens after neodymium-YAG laser injury

Wound healing of the ocular lens after exposure to neodymium-YAG laser energy (3.9-4.2 mJ) was studied. Male Sprague-Dawley rats were killed 5 min and 5, 9 and 15 days after the anterior lens epithelium was injured by a laser pulse. Gross and biomicroscopic examination revealed that a white, opaque mass formed on the lens surface after about 30 min. Five days later, the opacified mass present on the lens surface was found to be composed of ectopic epithelial cells, protruding lens fibers and a variety of other cell types. Epithelial cells were also present in abundance on the capsule surface in the immediate vicinity of the wound. Deep to the capsule, the lens fibers were greatly swollen. Half of the epithelial mounts obtained 5 days after surgery showed disorganization of the epithelium at points distant from the eosinophilic scar. The opacified external mass had disappeared from all of the lenses obtained at the 15-day period. However, the scar was readily identifiable in epithelial whole mounts, methacrylate sections and SEM specimens obtained from lenses at this time period. At every time period, many cortical fibers were swollen although the amount of swelling was less at 15 days than at earlier periods. The changes observed are similar to the lenticular alterations that occur after experimentally induced, transcorneal mechanical injury of the lens.     

钕-钇铝石榴石激光玻璃体松解术治疗人工晶状体植入术后前部玻璃体混浊

目的 观察钕钇铝石榴石(neodymium-yttrium alurainum garnet，Nd：YAG)激光玻璃体松解术对人工晶状体植入手术后前部玻璃体混浊的治疗效果。方法对裂隙灯显微镜联合光相干断层扫描(optical cohelrence tomography，OCT)和B型超声检查确诊的人工晶状体植入手术后前部玻璃体混浊患者47例49只眼，采用Nd：YAG激光行晶状体后囊切开的同时进行前部玻璃体切开及松解，观察激光治疗前后的视力变化、前部玻璃体混浊的改善情况以及治疗后的并发症。结果49只眼中，前部玻璃体混浊伴有晶状体后囊混浊46只眼，晶状体后囊无明显混浊3只眼。Nd：YAG激光玻璃体松解术后视力均有改善，与术前比较差异有显著性的意义(t=32．50，P=O．007)。激光松解术后15mm前部混浊的玻璃体形成透明区者21只眼，占42．86％；24h内形成透明区者47只眼，占95．92％；2只眼在术后7d透明区小于瞳孔接受了第2次激光治疗。全部患眼术中和术后无并发症发生。结论人工晶状体植入手术后视力缓慢下降的患者，除考虑有后发障外，还应注意是否有前部玻璃体混浊的存在。Nd：YAG激光晶状体后囊切开联合前部玻璃体松解是治疗人工晶状体植入手术后前部玻璃体混浊的有效方法。     

Anterior capsulotomy using a neodymium YAG laser

The Neodymium YAG laser can be used to open the anterior capsule of the lens several hours to one day before extracapsular extraction surgery. Opening the capsule prior to cataract surgery allows hydration and spontaneous separation of the cortex from the capsule, simplifying the cataract operation. After the laser procedure, however, many patients develop inflammation and rise in intraocular pressure. The experience of the investigator with 42 consecutive cases in which an anterior capsulotomy was performed with the YAG laser prior to extracapsular cataract surgery is presented. This experience has resulted in an evolving regimen of prelaser medication which has drastically reduced the inflammation and pressure rise.     

两种先天性白内障手术方式预防后发性白内障的比较

目的比较2种先天性白内障手术方式预防后发性白内障的临床效果。方法回顾性分析先天性白内障患者89例（98眼）,按手术方式分为2组,A组42例（47眼）为超声乳化白内障摘出＋人工晶状体植入＋后囊膜撕囊术组;B组47例（51眼）为超声乳化白内障摘出＋人工晶状体植入＋后囊膜撕囊＋前段玻璃体切割术组,分别观察2组术后视力和后发性白内障的发生情况。结果A组发生后发性白内障者24眼,占51.06%;其中21眼行YAG激光后囊膜切开,3眼不合作者行手术后囊膜切开术。B组发生后发性白内障者10眼,占19.61%;其中8眼行YAG激光后囊膜切开术,2眼不合作行手术后囊膜切开术。2组术后后发性白内障发生率的比较,差异有统计学意义（P=0.001）。结论与超声乳化白内障摘出＋人工晶状体植入＋后囊膜撕囊术相比,超声乳化白内障摘出＋人工晶状体植入＋后囊膜撕囊＋前段玻璃体切割术能更好地减少先天性白内障术后后发性白内障的发生率。