Capsule Bag Research Articles

Methods of intraocular lens implantation for posterior capsule rupture during phacoemulsification

目的 探讨晶状体超声乳化吸出术中后囊破裂的处理及人工晶状体植入的方法.方法表面麻醉下晶状体超声乳化术中发生后囊破裂,术中及时发现破孔,充分利用黏弹剂,并联合前段玻璃体切除术.30例(30眼)全部植入后房人工晶状体.结果人工晶状体的两个襻植入囊袋内者10眼,一襻植入囊袋内另一襻在睫状沟内或两个襻都在睫状沟内共16眼,人工晶状体两个襻缝线固定于巩膜瓣下4眼.术后4周随访,视力＞0.5者20眼,占66.67%;0.3～0.5者6眼,占20.00%;0.05～0.2者共4眼,占13.33%.结论晶状体超声乳化术中如果发生后囊破裂,只要及时发现,妥善处理,仍可以安全地植入后房人工晶状体,术后视力恢复较好。

Laserinterferometric assessment of pilocarpine-induced movement of an accommodating intraocular lens: A randomized trial

Purpose To measure the axial movement of an accommodating intraocular lens (IOL) induced by ciliary muscle contraction after application of pilocarpine. Design Randomized, controlled, patient- and examiner-masked trial with intrapatient comparison. Participants and controls One hundred ten eyes of 55 patients with age-related bilateral cataract. Methods This study was divided into 3 parts. In the first, the accommodating IOL (1CU) was compared with a 3-piece open-loop acrylic IOL that served as the control. In the second, to assess the effect of capsule fibrosis on the potential accommodating performance of the accommodating IOL, extensive polishing of the anterior capsule with a slit cannula was compared with standard surgery. In the third, the effect of a posterior capsulorhexis was compared with that of standard surgery. Anterior chamber depth (ACD) was assessed with partial coherence interferometry, measured before and after topical application of pilocarpine 2%, and near visual acuity (VA) was evaluated 3 months after surgery. Main outcome measure Pilocarpine-induced change in ACD. Results The accommodating IOL showed a forward movement under pilocarpine with a median amplitude of movement of −314 μm (95% confidence interval [CI]: −148 to −592), compared with the backward movement of 63 μm (95% CI: 161 to −41) for the open-loop control IOL ( P = 0.001). Capsule polishing and a posterior capsulorhexis had no effect on IOL movement with the accommodating IOL. The median near VA with distance correction was 20/60. Conclusion Pilocarpine induced a small but significant forward movement of the accommodating IOL. However, the amount of movement was calculated to result in a refractive change of <0.5 diopters (D) in most patients, reaching 1 D or slightly more in only single cases, with a large variability of movement. Neither polishing of the capsule bag nor a posterior capsulorhexis could enhance the accommodative ability.

The causes and reposition of fixed intraocular lens pupillary capture in children

To analyze the cause of fixed intraocular lens (IOLs) pupillary capture in children and investigate the rational methods to reposit intraocular lens. Thirty-one eyes (30 cases) with fixed intraocular lens pupillary capture under 14 years old were analyzed based on clinical data; the causes and the complications were also evaluated. The IOL reposition procedure was performed in 8 cases (8 eyes) with severe complications. Different extent of secondary cataract, posterior iris synechia caused by severe postoperative uveal tract reaction were existed in all 30 cases, corecleisis was occurred in some severe cases. During reposition operation, different extent of lens cortex regeneration in the equator portion of capsule bag was found in all eight cases. Fixed pupillary capture of IOL is the common complication in children after cataract surgery. Severe postoperative uveal tract reaction and secondary cataract and lens cortex regeneration are the major causes of intraocular lens pupillary capture. The intraocular lens could be reposited through iris synechia separation, regenerated lens cortex cleaning and secondary cataract extraction.

Late anterior traumatic subluxation of a circular in-the-bag intraocular lens associated with lack of posterior capsule opacification

We report a case of traumatic subluxation of a circular poly(methyl methacrylate) intraocular lens (IOL) 5 years after surgery. Slitlamp examination revealed the lack of epithelial cells or fibrosis in the intact capsule bag. Trauma was minor, and no other complication was found in the eye and orbit. The subluxated IOL was easily relocated in the bag with a hook, revealing the poor capsule sealing. Among the factors ensuring the fixation of IOLs placed in the bag after continuous curvilinear capsulotomy are sealing of the anterior and posterior capsules and proliferation of epithelial cells from the equator of the bag.

Factors leading to lens implant decentration and exchange.

To examine the intra- and post-operative factors leading to posterior chamber intraocular lens (IOL) decentration in patients requiring IOL exchange, and to identify avoidable causes of IOL decentration. Case records of 17 patients who had undergone posterior chamber IOL exchange were examined for: (i) any complication or alteration to the original intended surgical procedure, (ii) IOL type and position at the completion of initial surgery, (iii) IOL position at the time of re-operation. The decentred lens implants were injected silicone plate-haptic IOLs in 10 patients, small (5.5 mm) optic diameter PMMA IOLs in 4 patients and large (7 mm) optic diameter PMMA IOLs in 3 patients. In all cases, decentration was due to IOL subluxation. Early decentration of the injected lenses was due to IOL implantation in eyes without a continuous capsulorrhexis. In contrast late decentration was due to subluxation associated with capsule fibrosis. Decentration of small optic PMMA IOLs was found to be associated with an anterior capsule tear and haptic malposition in the ciliary sulcus. Decentration of large optic PMMA IOLs was associated with posterior displacement of one haptic through a posterior capsule defect, zonule dehiscence or fixation of one haptic in the sulcus and one in the capsule bag. Clinically significant post-operative subluxation of injected silicone IOLs may be minimised by implanting only into a lens capsule bag with an intact capsulorrhexis. The risk of decentration of small optic PMMA IOLs may be minimised by positioning the haptics at 90 degrees to any capsulorrhexis tear. After cataract surgery complicated by posterior capsule rupture or zonule dehiscence, it is important to assess the remaining capsule support and, where sufficient, implant a large optic diameter posterior chamber IOL in the ciliary sulcus.

In situ tumbling of the AcrySof intraocular lens

The small incision through which foldable acrylic intraocular lenses (IOLs) are implanted does not allow easy explantation of the lens in the event of intraoperative complications. Reversal of the IOL optic during insertion, although rare, can predispose to postoperative complications such as pupillary capture of the IOL, capsule bag distension syndrome, and refractive problems. Explanting the IOL can damage it, the cataract wound, or both. We describe a technique of in situ tumbling of the AcrySof® IOL to correct reversed-optic implantation that preserves the integrity of the IOL and anterior segment structures.

Intralenticular implant study in pigmented rabbits: Opacity lensmeter assessment

Purpose: To quantitatively analyze the clarity of regenerated lens material afterendocapsular lens extraction and restoration of the lens capsular bag with and without implantation of an intralenticular disc lens. Setting: Shepherd Research Center, Allergan, Irvine, California, USA. Method: The clarity of regenerated lens material was evaluated by Interzeag OpacityLensmeter 701 (OLM) recordings after endocapsular lens extraction in New Zealand/Dutch Belt pigmented rabbits with (n = 21) and without (n = 16) placement of a disc-shaped intralenticular implant in the capsular bag. Postoperative objective measurements were performed at 1, 2, and 3 weeks and 1, 2, 3, and 6 months. Comparisons were made between young and adult rabbits. Results: Mean OLM results were similar in both groups at weeks 1, 2, 3, and 4. After 1 month,, progressive central compaction of early irregular regenerated lens fibers was associated with increased OLM readings that were higher in the intralenticular implant group than in the control group. Regenerated lens opacification was greater in tissue posterior to the intralenticular lens than in that anterior to the disc lens. Conclusion: Insertion of an intralenticular disc lens into the lens capsule bag was associated with poor optical clarity primarily of the posterior regenerated lens tissue. The OLM was useful in assessing the degree of opacification of the regenerated lenses.

Efficacy of equator rings in an experimental rabbit study.

To determine the efficacy of the equator ring in maintaining the circular contour of the capsule bag equator and transparency of the posterior capsule after crystalline lens extraction in 12 rabbit eyes. After phacoemulsification through a 5-mm window made by continuous circular capsulorrhexis in the central anterior capsule, a flexible silicone ring (outer diameter, 11.0 mm; width, 1.5 mm; and thickness, 1.5 mm) was implanted in the capsule in seven rabbit eyes. A 13.0-mm Sinskey-style posterior chamber intraocular lens was then implanted inside the ring. Three other eyes received only equator rings, and two others received only intraocular lenses. Eyes were followed up for 3.5 +/- 1.4 months (mean +/- SD) before enucleation and evaluation by stereomicroscopy; they then underwent light microscopic examination. The two eyes that received only the intraocular lens had equatorial distortion and severe posterior capsule opacification. In nine (90%) of the 10 eyes that were implanted with the rings, the circular contour of the equator was preserved, and seven (70%) of these 10 eyes had transparent posterior capsules. Implantation of the equator ring effectively maintained the circular contour of the capsule bag equator and inhibited cells at the bag equator from proliferating toward the center of the posterior capsule in the rabbit.

Importance of an intact posterior capsule for the vitreous body. Complication of posterior capsulotomy

The various extracapsular cataract surgery techniques keep the anatomy and physiology of the eye largely untouched, since both the intact posterior capsule and the crystalline lens form a diaphragm between the aqueous humour and the vitreous. If the posterior capsule opacifies--which occurs in up to 50% within five years postoperatively--a capsulotomy becomes necessary. This increases the rate of retinal detachment and cystoid macular edema. To date no pharmacologic or immunologic means exist to prevent posterior capsule opacification. Implanting the IOL into the capsule bag and the biconvex lens design by itself reduce the incidence of opacification. The biconvex optic of the IOL seals the gap in the capsule, if a capsulotomy has been performed; fluorophotometry shows us that the diaphragm function remains intact after in the bag implantation as compared to sulcus fixated IOL.

Histopathological Study of Anterior Segments of the Eye with the Intraocular Lens in the Posterior Chamber

We conducted a histopathological study of the anterior segments of the eye of a female who died 2 years after insertion of an intraocular lens (IOL), which had one end of the supporting loop inserted in the lens capsule bag and the other in the ciliary sulcus. No changes were noted in the iris and ciliary body located within the capsule. However, in the part in the ciliary sulcus, the iris root was bent towards the chamber angle and the trabecular meshwork was depressed. Moreover, the ciliary body exhibited hyaloid degeneration. A secondary cataract had formed in the periphery of the IOL. These findings suggest that the ideal site of IOL insertion might be within the capsule.

Restoring lens capsule integrity enhances lens regeneration in New Zealand albino rabbits and cats

In studies conducted by numerous investigators for 150 years, lenses regenerated following endocapsular lens extraction in New Zealand albino rabbits have been irregular in shape, appearing primarily doughnut-shaped as a result of lack of lens growth at the site of the anterior capsulotomy and its adhesion to the posterior capsule. In the present study, we restored the lens capsule integrity by inserting a collagen patch at the time of surgery to seal the anterior capsulotomy and to improve the shape and structure of the regenerated lenses. We then filled the capsule bag with air to prevent adhesions between the anterior and posterior capsule and maintain capsule tautness and shape. Lens regeneration was first noted as early as one to two weeks. Regenerated lens filled approximately 50% of the capsule bag at two weeks and 100% by five weeks. Subsequent growth was in the anterior-posterior direction and measured by A-scan biometry. Lens thickness increased by 0.3 mm per month. The regenerated lenses were spherical with normal cortical structure and a nuclear opacity. In conclusion, restoration of lens capsular integrity with a collagen patch following endocapsular lens extraction enhanced the shape, structure, and growth rate of the regenerated lenses. In addition, lens regeneration was shown to occur in two cats.

Size of the crushed cataractous capsule bag.

The size of the crushed cataractous bag was determined by measuring the diameters and widths of 50 cataracts removed by cryoextraction and then mathematically determining their individual areas and crushed bag size. These lenses had a collapsed bag size of 10.8 +/- 1.4 mm.

A Histopathologic Study of the Position of the Shearing Intraocular Lens in the Posterior Chamber

Three human eyes that had successfully undergone Shearing posterior-chamber intraocular lens implants were examined post mortem. Supporting loops of these lenses were located deep within the ciliary body adjacent to a major ciliary artery (the superior loop in two cases), within the ciliary sulcus (the superior loop in one case), within the lens capsule bag (the inferior loop in two cases), and embedded within the iris stroma (the inferior loop in one case).