儿童白内障一期后囊截开及后房型人工晶体植入术的探讨

目的：探讨不同方法一期后囊截开对儿童白内障后房型人工晶体植入术后晶体后囊膜混浊的预防作用。方法：对28例（31只眼）儿童先天性白内障和外伤性白内障分别采用一期后囊膜切开、部分切除或联合前部玻璃体切除及后房型人工晶体植入术。术后随访3个月以上。结果：出院时矫正视力≥0．5者达71％，随访显示80％术眼视轴区透明，眼底清晰可见。结论：一期切开或部分切除后囊在一定程度上预防儿童白内障术后晶体后囊膜混浊的发生。对于穿通伤所致晶体囊膜破孔较大者宜联合前部玻璃体切除术。     

Intra-ocular lens implantation in children

Intra-ocular lens (IOL) implantation in a growing eye of a young child brings several problems unique to this age group. Better understanding of the rate of refractive growth in children's pseudophakic eyes may help predicting future refractions in these eyes more accurately. Opacification of the posterior capsule, if remained intact, interferes with visual rehabilitation in children. Primary posterior capsulectomy and anterior vitrectomy provides the clarity of visual axis. Optical rehabilitation of children with unilateral aphakia is usually problematic. Posterior chamber IOLs are preferred to anterior-chamber IOLs for secondary implantation. In the absence of adequate capsular support and contact lens intolerance, a scleral-fixated IOL can be implanted. Scleral fixation of a posterior chamber IOL has encouraging short-term results but the long-term risks are not known yet. Intra-ocular lens implantation in infants is associated with major complications and is not recommended at present. The occurrence of open angle glaucoma is a sight-threatening late complication of pediatric cataract surgery. Intra-ocular lens implantation plays a protective role against aphakic glaucoma in children.     

Capsular bag intraocular lens fixation with retention of the anterior capsule

In-the-bag fixation of a posterior chamber intraocular lens (IOL) may be performed with greater protection of the uveal tract if the anterior capsule is retained so the IOL is almost completely enveloped in the capsular bag. A surgical technique for capsular bag fixation without anterior capsulectomy and a bulbous-tipped scratcher devised for use with this technique are described.     

Pigment dispersion with elevated intraocular pressure after AcrySof intraocular lens implantation in the ciliary sulcus

A 45-year-old white woman had phacoemulsification with intraocular lens (IOL) implantation. The surgery was routine except for a linear tear in the posterior capsule; there was no disruption of the anterior vitreous face. After residual soft lens matter was removed, an AcrySof IOL was placed in the ciliary sulcus. One month postoperatively, the patient presented with an intraocular pressure (IOP) of 30 mm Hg and signs of pigment dispersion with 360 degrees of heavy pigmentation of the trabecular meshwork and iris transillumination defects. Intraocular pressure was controlled with a topical beta-blocker. The optic disc appearance and visual field remained normal, but the uniocular hyperpigmentation of the trabecular meshwork was still present. We hypothesize that the sharp square edge of the AcrySof IOL increases the risk of a chafing effect on the posterior iris pigment and advocate that this IOL be placed in the capsular bag and ideally have 360 degrees of protective overlapping of the anterior capsule over the edge of the optic.     

Lens anatomical principles and their technical implications in cataract surgery. Part I: The lens capsule

Optimal fixation and position of an intraocular lens (IOL) is achieved when it is located in the capsular bag. A peripheral tear from the central opening to the lens periphery is associated with a high incidence of dislocation of at least one loop from within the capsular bag and lens decentration. A central round continuous capsulectomy (capsulorhexis), within the zonule-free area, provides long-term and balanced IOL fixation. To perform a well-controlled capsulectomy, a deep and stable anterior chamber should be maintained throughout the surgery. This is achieved by using a continuous anterior chamber maintainer that regulates the pressure in the anterior chamber. This paper reviews the clinical anatomical guidelines of the lens capsule and the anterior chamber and presents the authors' preferred technique for optimal anterior capsulectomy.     

Risk factors for secondary membrane formation after removal of pediatric cataract

PURPOSE: To evaluate the incidence of secondary membrane formation, factors that lead to its development, and the frequency of procedures to treat these membranes in children after cataract surgery. SETTING: Department of Pediatric Ophthalmology, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA. METHODS: Clinical records of 152 patients (190 eyes) who had cataract extraction between January 1986 and 1996 were reviewed retrospectively. The mean follow-up was 6 years (range 2 to 13 years). Cataract surgery was performed through a limbal incision in all cases. Twenty-eight eyes had a primary posterior capsulectomy, and 120 eyes had posterior capsulectomy combined with an anterior vitrectomy. In 42 eyes, the posterior capsule was left intact. Nineteen eyes received a primary intraocular lens (IOL), 15 eyes received a secondary IOL, and 156 eyes were rehabilitated with spectacles or contact lenses. RESULTS: Seventy-two eyes (37.9%) developed secondary membrane a mean of 8.9 months postoperatively (range 3 weeks to 53 months). Membranes occurred in 78.6% of eyes with an intact posterior capsule, 42.9% with posterior capsulectomy, and 22.5% with combined posterior capsulectomy and anterior vitrectomy. Secondary membrane formation was associated with not performing a posterior capsulectomy with anterior vitrectomy (P < .001) and the presence of a primary IOL (P < .001). Younger age at surgery increased the chance of secondary membrane formation in patients who had posterior capsulectomy and anterior vitrectomy (P < .01). CONCLUSIONS: The younger the child at cataract surgery, the greater the risk of secondary membrane. Primary posterior capsulectomy combined with an anterior vitrectomy decreased but did not eliminate the incidence of secondary membrane.     

Capsular bag distension after endophacoemulsification and posterior chamber intraocular lens implantation

Six cases of capsular bag distension after capsulorhexis, endophacoemulsification, and posterior chamber intraocular lens (IOL) implantation are presented. Five cases had prominent posterior subcapsular cataracts preoperatively. In three cases, the anterior chamber depths were shallower and the apparent refractive errors were more myopic than normal after surgery. All six cases exhibited an apparent early complete sealing of the anterior capsular remnant against the anterior IOL optic. In each case, the capsular bag contained moderate particulate debris and flare while the adjacent vitreous and anterior chambers were clear. I suspect the particles are epithelial cell and cortical debris suspended in a fluid comprising lens epithelial protein, cellular breakdown products, balanced salt solution, and water. Five cases have received no specific treatment. In one case, a neodymium:YAG laser anterior capsulotomy allowed a forward egress of fluid from the distended capsular bag and a return to normal pseudophakic anatomy.     

前部玻璃体切除联合巩膜缝线固定后房型折叠式人工晶状体的临床观察

目的评价无后囊无晶状体眼行前部玻璃体切除联合巩膜缝线固定后房型折叠式人工晶状体的临床疗效。方法选用AMOZ900折叠人工晶状体,对无后囊或后囊破损严重不足以支撑人工晶状体者36例（36眼）行前部玻璃体切除联合人工晶状体缝线固定术,观察其术中、术后并发症及术后视力、角膜曲率、眼压的情况。结果术中无明显并发症,术后眼压升高2眼,玻璃体少量积血1眼,黄斑水肿2眼,无其他严重并发症。术后第1天的裸眼视力0．3以上者占41．67％,术后1周、1个月、3个月裸眼视力0．3以上者分为47．22％,80．56％和86．11％。结论前部玻璃体切除联合巩膜缝线固定后房型折叠式人工晶状体植入术是治疗无后囊支撑眼的较好选择。     

Silicone intraocular lens implantation in children: preliminary results

PURPOSE: To evaluate the safety and outcome of foldable silicone intraocular lens (IOL) implantation in children. SETTING: Department of Ophthalmology, University of Giessen, Giessen, Germany. METHODS: The results of cataract extraction and silicone IOL implantation in children having surgery between 1992 and 1997 were retrospectively analyzed in 8 eyes (7 patients). All IOLs were implanted in the capsular bag through a 3.5 mm clear corneal incision. In 4 eyes, primary posterior capsulectomy and anterior vitrectomy were performed. RESULTS: Mean patient age at the time of surgery was 5.1 years (range 8 months to 15 years). The surgeries were uneventful. All IOLs remained anatomically stable and well centered during the mean follow-up of 29.6 months (range 18 to 46 months). Postoperative inflammatory reaction was minimal. Neither fibrinoid exudation nor posterior synechias occurred postoperatively. Postoperative best spectacle-corrected visual acuity ranged from 20/800 to 20/20. All eyes with an intact posterior capsule developed posterior capsule opacification. In the 4 eyes that had primary posterior capsulectomy and anterior vitrectomy, the visual axis remained clear. CONCLUSIONS: These preliminary results suggest that silicone IOL implantation in children is a safe procedure with good and stable short-term anatomic results. Longer follow-up is necessary to answer questions about the long-term safety of silicone lens implantation in a child's eye.     

Complications of endocapsular tension ring implantation in a child with Marfan's syndrome

A 4-year-old boy with Marfan's syndrome had severe visual impairment after subluxation of the crystalline lens with bisection of the pupil. In the first eye, a capsular tension ring and an intraocular lens (IOL) were uneventfully placed in the capsular bag after phacoemulsification. During implantation of the endocapsular tension ring in the second eye, an inadvertent tear of the anterior capsule occurred, and the posterior chamber IOL was placed in the sulcus. In both eyes, severe lens epithelial proliferation with secondary IOL decentration developed postoperatively. Several surgical revisions were necessary to keep the IOL within the optical axis. In the eye with the sulcus-implanted IOL, the endocapsular tension ring was markedly decentered.     

Extracapsular cataract extraction and implantation in the capsular sac during vitrectomy in diabetics]

Removal of the lens is often performed during pars plana vitrectomy for complications of proliferative diabetic retinopathy, but correction of aphakia often remains unsatisfactory. Some authors have reported posterior chamber intraocular lens implantation during pars plana vitrectomy in diabetic patients who presented with coexisting cataract and vitreoretinal complications from proliferative diabetic retinopathy. Some patients were operated by pars plana lensectomy and vitrectomy followed by posterior chamber intraocular lens implantation in the ciliary sulcus, others by extracapsular extraction, posterior chamber intraocular lens implantation in the ciliary sulcus, and pars plana vitrectomy. Other authors have described phacoemulsification through the limbus, pars plana vitrectomy and implantation in the capsular bag in one operation in various indications, including complications of proliferative diabetic retinopathy. We inserted a posterior chamber intraocular lens into the capsular bag in 18 eyes of 16 patients with complications of proliferative diabetic retinopathy after extracapsular cataract extraction and pars plana vitrectomy in a single session. A standard extracapsular cataract extraction was performed before pars plana vitrectomy. Sufficient anterior capsule was left in place in order to facilitate implantation in the capsular bag after pars plana vitrectomy. The anterior chamber was filled with sodium hyaluronate in order to maintain anterior chamber depth, corneal clarity, and good mydriasis during the continuation of the procedure. A standard three port pars plana vitrectomy was performed in all cases. After closure of superior sclerotomies, superior corneal incision was partially reopened, an intraocular lens specifically designed for the capsular bag with an optic size of 7 mm was inserted, and the corneal incision was closed with interrupted 10/0 sutures.(ABSTRACT TRUNCATED AT 250 WORDS)     

Preventing recurrent opacification of the visual pathway after pediatric cataract surgery

PURPOSE: To determine the rate of secondary opacification of the visual pathway following pediatric cataract surgery in children between the ages of 10 months and 7 years. METHODS: The medical records of children less than 7 years old who underwent lens aspiration, posterior chamber intraocular lens (IOL) implantation, primary pars plana posterior capsulectomy, and anterior vitrectomy were reviewed retrospectively. Twenty-six eyes in 19 children were included in the study. All procedures were performed by an anterior segment surgeon and a vitreoretinal surgeon. Main outcome measures were the prevalence of re-opacification of the visual pathway and of early postoperative complications. RESULTS: The visual pathway remained clear in 25 of 26 eyes (96%) after pediatric cataract surgery combined with primary pars plana posterior capsulectomy and anterior vitrectomy. The mean age at surgery was 46 +/- 23 months (+/-SD). Secondary opacification of the visual pathway occurred in one eye (4%), requiring another surgical procedure. At last follow-up (mean, 26 months; range, 6 to 79 months), the visual pathway was clear in all 26 eyes (100%). No cases of clinically significant IOL displacement or of retinal detachment were noted. CONCLUSIONS: For children undergoing pediatric cataract surgery between the ages of 10 months and 7 years, IOL implantation combined with primary pars plana posterior capsulectomy and anterior vitrectomy is effective in preventing re-opacification of the visual pathway.     

Cataract extraction and intraocular lens implantation in children with uveitis

AIM: To evaluate the long term results of cataract surgery with intraocular lens implantation (IOL) in children with uveitis. METHODS: The study included 10 eyes in seven children (age 3.5-10 years, mean 6.5 years). The cataract surgery included capsulorhexis of the anterior and the posterior capsule, anterior vitrectomy in some eyes, and implantation of a heparin surface modified (HSM) poly(methyl methacrylate) (PMMA) IOL into the capsular bag. RESULTS: Follow up periods ranged from 1 to 5 years. Best corrected visual acuity after surgery reached 20/50-20/20 in all but two eyes. Opacities or membranes requiring reoperation developed in seven eyes. Glaucoma developed in three eyes after the cataract operation. CONCLUSION: These results suggest that implantation of a HSM PMMA IOL is an alternative to correct aphakia also in children with uveitis.     

Results of cataract extraction with IOL implantation in children aged 17 months to 8 years old

PURPOSE: To evaluate anatomical and functional results of cataract extraction and IOL implantation, together with posterior capsulectomy and anterior vitrectomy in children. MATERIALS AND METHODS: Cataract extraction and IOL implantation with posterior capsulectomy and anterior vitrectomy was performed in 32 eyes of children between 17 months and 8 years old. Patients were followed up for a mean period 36 months (from 6 months to 5.5 years). RESULTS: Good anatomical results were achieved in all, except 2 cases. One eye required removal of opacifications located posterior to the IOL In the second eye membrane from the anterior surface of the lens were excised. Final postoperative visual acuity in eyes with bilateral cataract was 0.59, whereas in unilateral cataract 0.25. Half of the children with bilateral cataract has significantly worse BCVA in one eye. CONCLUSIONS: Cataract extraction and IOL implantation with posterior capsulectomy and anterior vitrectomy in young children gives good anatomical results. Functional results are better in bilateral congenital cataract, comparing to unilateral cases. To achieve good functional results, visual rehabilitation is necessary.     

Pathogenesis of posterior capsular opacification. Part I. Epidemiological and clinico-statistical data

We examined 895 eyes having extracapsular cataract surgery; 403 had an intraocular lens (IOL) implanted and 492 did not. The incidence of posterior capsular opacification was 7.69% in the eyes with an IOL and 14.23% in the eyes without an IOL. If we exclude complicated cataracts from the cases that did not have an IOL, the incidence of posterior capsular opacification decreases to 9.06%. Various models of implanted IOLs showed different incidences of posterior capsular opacification: For J-looped lenses the incidence was 11.02%; for Frezzotti-Caporossi lenses, 7.35%. The follow-up was too short for soft lenses. The Frezzotti-Caporossi lens can be inserted with the convex side either anterior or posterior. A statistical evaluation shows that the reverse optic or posterior convex orientation in the bag caused a lower incidence of posterior capsular opacification (3.01%).     

Anterior chamber fixation of a posterior chamber intraocular lens: A novel technique

We aimed to evaluate the implantation of a posterior chamber intraocular lens (IOL) in the anterior chamber (AC) with the haptics passing through two iridectomies to the posterior chamber. A total of 33 eyes of 33 patients with inadequate posterior capsular support due to either previous aphakia or posterior capsular rupture during cataract extraction were included in the study. A double iridectomy was performed on all patients using a vitrectomy probe on the midperiphery of the iris. IOLs were implanted in the AC, and the haptics were passed through the iridectomies to the posterior chamber. The mean follow-up time was 25.3 months. AC hemorrhage occurred in five patients during the iridectomy procedure. Corneal edema was detected in eight of 14 patients with primary IOL insertions. Haptic dislocation was detected in only one patient. This technique may be a good alternative to scleral-fixated IOL implantation in eyes with aphakia.     

Spontaneous luxation of encapsulated intraocular lens onto the retina after a triple procedure of vitrectomy, phacoemulsification, and intraocular lens implantation

PURPOSE: To report the clinical and histological findings of a luxated intraocular lens (IOL) in the capsular bag. METHODS: Review of a case. RESULTS: Twenty-three months after a triple procedure of vitrectomy, phacoemulsification, and IOL implantation for diabetic vitreous hemorrhage and cataract, the encapsulated IOL spontaneously luxated. Scanning electron microscopy showed sparsely distributed anterior and equatorial zonules, with only a few posterior zonules on the surface of the removed capusular bag. CONCLUSION: The absence of the anterior hyaloid membrane and posterior zonules and contraction of the lens capsule may cause dialysis of the zonules. Therefore, the anterior hyaloid membrane should be left in place in patients at low risk for the development of postoperative proliferation to maintain the long-term stability of the IOL.     

Stenotrophomonas maltophilia Endophthalmitis after cataract extraction

PURPOSE: To report the clinical course, treatment response, and prognosis of Stenotrophomonas maltophilia endophthalmitis following cataract extraction. METHODS: The clinical records of six cases of S. maltophilia endophthalmitis after cataract extraction were retrospectively reviewed. Data were collected for surgical characteristics, disease course, culture growth, antibiotic sensitivity of the pathogen, response to treatment, and final visual acuity. RESULTS: Four patients underwent uncomplicated cataract extraction with phacoemulsification (PHACO) and intracapsular intraocular lens (IOL) implantation. One case was complicated by inadvertent posterior capsular tear during PHACO and IOL implantation. One patient underwent a combined extracapsular cataract extraction (ECCE) with IOL implantation and trabeculectomy, but vitrectomy was also performed because of cortical material loss into the vitreous cavity after a capsular tear. Symptoms began between postoperative days 1 and 19. All patients underwent a vitreous tap and intravitreal injections of antibiotics. Medical therapy alone was sufficient in five patients to treat the infection. One patient had four episodes of recurrence. Pars plana vitrectomy with subsequent capsulectomy and IOL extraction were performed in this patient to complete remission. CONCLUSION: S. maltophilia should be considered a pathogenic organism possibly causing endophthalmitis after PHACO+IOL implantation. The clinical picture resembles acute bacterial endophthalmitis. When the pathogen has settled in the capsular bag, the infection may persist and become refractory to medical treatment.     

Effect of intraocular lens and anterior capsule opening type on posterior capsule opacification.

PURPOSE: To determine the effect of intraocular lens (IOL) type and anterior capsulectomy technique on the incidence of posterior capsule opacification. SETTING: Department of Ophthalmology, Medical Faculty, University of Ondokuz Mayis, Samsun, Turkey. METHODS: Three hundred two eyes of 294 patients were examined retrospectively after IOL implantation in the capsular bag performed between February 1991 and November 1996. Patients were divided into 3 groups according to IOL type: poly(methyl methacrylate) (PMMA); heparin-surface-modified PMMA (HSM PMMA); plate-haptic silicone. Envelope capsulectomy or continuous curvilinear capsulorhexis (CCC) was used. Mean follow-up was 27 months (range 12 to 33 months). RESULTS: Posterior capsule opacification developed in 47 cases (15.6%): 21.7% in the PMMA lens group after planned extracapsular cataract extraction (ECCE), 17.4% in the HSM PMMA lens group after planned ECCE, and 7.7% in the plate-haptic silicone lens group after phacoemulsification. Posterior capsule opacification occurred less in patients who had anterior capsulectomy using the CCC technique (11.5%) than in those having an envelope capsulectomy (24.5%) (P < .05). Posterior capsule opacification was significantly less in eyes with a capsular-bag-fixated plate-haptic silicone lens than in those with a PMMA or HSM PMMA IOL (P < .05). CONCLUSION: This study demonstrated that the anterior capsulectomy technique and the IOL type influence the incidence of PCO.     

Bag-in-the-lens implantation of intraocular lenses

PURPOSE: To report a new intraocular lens (IOL) and an IOL implantation concept, the bag-in-the-lens implantation technique, designed to prevent posterior capsule opacification (PCO). SETTING: The University of Antwerp, Department of Ophthalmology, Edegem, Belgium, and the Netherlands Ophthalmic Research Institute, Department of Morphology, Amsterdam, The Netherlands. METHODS: After identical curvilinear capsulorhexes are created in both the anterior and posterior capsules, the capsules are inserted in a flange of the IOL, thus the term bag-in-the-lensas opposed to the currently used lens-in-the-bagtechnique. The IOL was implanted in an in vitro human capsular bag model and in 10 eyes of 9 patients with cataract. Lens epithelial cell (LEC) outgrowth and PCO formation were observed. RESULTS: When both capsular blades were well stretched around the IOL optic, the in vitro capsular bag model showed LEC proliferation only within the space of the remaining lens bag. The LEC proliferation was limited, and there was no tendency toward proliferation approaching the visual axis. In all 10 eyes, the optical axis remained clear during a follow-up between 4 and 15 months. CONCLUSIONS: This new IOL prevented LEC proliferation in vitro and seems promising in vivo. Target patients are those at risk of PCO including those with congenital cataract, uveitis, diabetes, or cataract extraction combined with vitrectomy.