Aspiration curette for anterior capsule polishing: Laboratory and clinical evaluation

Immunohistochemical findings of lens capsules obtained from patients with dead bag syndrome

PURPOSE

To investigate the extracellular matrix and cellular components in lens capsules extracted from patients with dead bag syndrome (DBS) through immunohistochemistry.

SETTING

Department of Ophthalmology, Wakayama Medical University School of Medicine, Wakayama, Japan, and Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah.

DESIGN

Immunohistochemical experimental study.

METHODS

9 capsular bag specimens from DBS cases, as well as 2 control specimens from late-postoperative in-the-bag intraocular lens dislocation cases related to previous vitrectomy, pseudoexfoliation, and blunt trauma were included. They were processed for histopathology; unstained sections were obtained from each one and analyzed by immunohistochemistry targeting collagen type IV, laminin, vimentin, collagen type I, and fibronectin.

RESULTS

Immunohistochemistry in DBS showed lens capsule stained for basement membrane components. The outer part of the anterior capsule that was split from the inner part was more markedly stained for type IV collagen as compared with the posterior part. Faint staining for fibrous posterior capsular opacification (PCO) components, for example, collagen type I and fibronectin, was detected in limited areas, but the major portion of the capsule was free from these components. Small spotty vimentin-positive materials, suggesting the presence of cell debris, were also detected in limited samples.

CONCLUSIONS

Small amounts of fibrotic PCO components were detected in capsules extracted from patients with DBS, but their major parts were free from PCO components. Current findings suggest small amounts of lens epithelial cells were present after surgery and secreted fibrous components before undergoing cell death process.

The Effect of Anterior Capsule Polishing on Capsular Contraction and Lens Stability in Cataract Patients with High Myopia

Purpose

To evaluate the effect of anterior capsule polishing in patients with high myopia after cataract surgery.

Setting

The Eye Hospital of Wenzhou Medical University, Zhejiang, China.

Design

Prospective study.

Methods

High myopic patients with a bilateral cataract who underwent phacoemulsification with 360° anterior capsular polishing in one eye and without polishing in the contralateral eye were recruited. The following parameters were recorded at 1, 3, and 6 months postoperatively, including the area and diameter of the anterior capsule opening (area and D), IOL tilt and decentration, refraction, and postoperative aqueous depth (PAD).

Results

Paired samples of 38 eyes of 19 patients were enrolled. The area decreased significantly in both the polished group and unpolished group, whereas the diameter reduced more in the unpolished group. The IOL tilt and decentration at 3-month and 6-month follow-up showed significant differences between two groups. In the unpolished group, the IOL decentration firstly appeared between one-month to three-month visit, while the refraction error, PAD, and IOL tilt were significantly different between the three-month and six-month visits.

Conclusion

360° anterior capsule polishing can effectively reduce the extent of the anterior capsule contraction and increase the stability of IOL. The study was registered at http://www.clinicaltrials.gov, and the clinical trial accession number is NCT 03142269.

Cortex removal after laser cataract surgery and standard phacoemulsification: a critical analysis of 800 consecutive cases

PURPOSE

To evaluate the ease of anterior cortex removal and hydrodissection of the lens in femtosecond laser-assisted cataract surgery compared with standard phacoemulsification.

METHODS

In the femtosecond laser-assisted cataract surgery group (400 eyes), a femtosecond laser was used for capsulotomy and followed by lens fragmentation. In the standard group, the capsulorhexis was performed manually. In both groups, a normal hydrodissection was set, the nucleus was aspirated with or without ultrasound phacoemulsification energy, and residual cortex removal and posterior capsule polishing were performed using bimanual irrigation/aspiration. The primary end point was the time (in seconds) required for the removal of the cortex from instrument insertion in the eye until aspiration tip removal. Secondary end points were the effective phacoemulsification time, quality of the anterior capsule, and anterior or posterior capsule ruptures.

RESULTS

Cortex removal time measured 30 ± 13 seconds (range: 10 to 76 seconds) for the standard group and 27 ± 10 seconds (range: 9 to 72 seconds) for the femtosecond laser-assisted cataract surgery group (P < .005). After laser-assisted capsulotomy, one capsule was still adherent following removal by forceps. No anterior or posterior capsular tears were observed in either group.

CONCLUSIONS

In femtosecond laser-assisted cataract surgery, the biaxial cortex removal time was comparable with the time in standard phacoemulsification.

[Pseudoexfoliation syndrome and cataract surgery. Avoidance and treatment of complications]

Eyes with pseudoexfoliation syndrome often exhibit insufficient mydriasis, zonular weakness and pronounced fibrotic capsular shrinkage. This may make cataract surgery as such difficult but also leads to postoperative complications, such as rhexis ovalization or phimosis (capsule contraction syndrome) or progressive zonular weakening with final spontaneous dislocation of the capsule-implant complex (CIC). To avoid or correct for this special techniques and implants may be used: as prophylaxis, intracameral adrenalin and retroiridal capsulorhexis, iris retractors or dilators, various models of capsular tension and bending rings, bimanual capsule ring implantation, capsular bag stabilization with iris retractors or segments and secondary capsulorhexis may be used. Rhexis phimosis may be excised by a special diathermic probe, a subluxated CIC may be sutured to the sclera either in toto or the lens only after removal from the capsule bag, the latter also to the posterior iris surface. When luxated into the vitreous cavity, the CIC may be lifted to the iris plane and refixed as described or exchanged for a new lens sutured into the sulcus or an angle or iris-supported anterior chamber lens.

AFM study for morphological characteristics and biomechanical properties of human cataract anterior lens capsules

The aim of this study was to quantitatively investigate the morphologies (surface roughness) and biomechanical properties (Young's modulus) of human anterior lens capsules (ALCs) for noncataract and cataract groups using atomic force microscopy. Eight human ALCs obtained during phacoemulsification from patients with senile cataracts (72 ± 13 years) were investigated in both the hydrated and dehydrated conditions. The cataract group showed clearly the proliferated lens epithelial cells (LECs) with a monomorphic cell structure, a diameter of 12.54 ± 4.31 μm, and a height of 0.23 ± 0.04 μm, whereas the control group showed no LECs. A substantial amount of false-positive calcification was observed caused by the deposition of remnants of dried salt solution. Cataract group showed significantly higher surface roughness (382.06 nm, p ≤ 0.001) than control group in the anterior side of ALCs, whereas cataract group showed significantly lower surface roughness (353.79 nm, p ≤ 0.001) than control group in their posterior side. Cataract group showed significantly higher Young's modulus (69.52 kPa, p ≤ 0.001) compared to the control group, regardless of the ALC side. Therefore, it is significant that this study provides a new method to examine the nanostructural characteristic and biomechanical property of human ALCs through a nanometer-scale resolution microscopy technique.

Posterior capsulorhexis combined with optic buttonholing: an alternative to standard in-the-bag implantation of sharp-edged intraocular lenses? A critical analysis of 1000 consecutive cases

Background

Current after-cataract prevention relies on optimizing the natural barrier effect of the optic rim against lens epithelial cell (LEC) migration. However, deficiencies in circumferential capsular bag closure caused by the intraocular lens (IOL) haptic or delayed secondary re-division of the fused capsules by Soemmering´s ring formation lead to primary or secondary barrier failure. Consequently, surprisingly high posterior laser capsulotomy rates have been reported long-term, even with optimal capsular surgery and the most widespread hydrophobic acrylic IOLs, considered to be the most advanced. Intraoperative removal of the central posterior capsule has been shown to be effective in further reducing LEC immigration. However, efficacy has turned out to be limited because of the propensity of LECs to use the posterior optic surface as an alternative scaffold.

Material and methods

Technique: in pediatric cataract surgery, buttoning-in of the optic into an adequately-centered posterior capsulorhexis opening has been described previously. This technique was further elaborated and applied as the standard technique in a large series of adult eyes. In general, the diameter aimed at was 5–6 mm for the anterior, and 4–5 mm for the posterior capsulorhexis. Between September 2004 and June 2007, 1000 consecutive cases have thus been performed and systematically evaluated. One hundred and fifty eyes additionally underwent extensive anterior LEC abrasion. Another sub-series investigated the option of further reducing capsular fibrosis by creating an anterior capsulorhexis larger than the optic.

Evaluation: special scrutiny was applied to detect postoperative vitreous entrapment. Regeneratory and fibrotic after-cataract formation were both meticulously followed-up. Postoperative pressure course, anterior segment inflammation, macular thickness and morphology, as well as axial optic stability and optic centration, were evaluated in intraindividual comparison studies.

Results

A low rate of vitreous complications was found, which can be avoided by appropriate surgery. Vitreous entanglement occurred in six eyes, and vitreous herniation after PPCCC over-sizing in two. In three, anterior vitrectomy was performed. There was only one single case of retinal detachment—supposedly unrelated to the technique itself—and no case of cystoid macular edema. Retro-optical regenerate formation was completely abolished, while fibrosis was drastically reduced by the posterior capsule sandwiched in between the anterior LEC layer on the backside of the anterior capsule and the anterior optic surface, thereby blocking contact-mediated myofibroblastic LEC transdifferentiation. Additional capsular polishing further reduced residual fibrosis emerging from the anterior capsule contacting the optic adjacent to the haptic junction, as well as regeneratory LEC re-proliferation on the posterior capsule overlying the optic. Postoperative pressure course was almost identical to that found after standard in-the-bag implantation of the IOL, as was flare, and macular thickness and morphology. As opposed to bag-fixated IOLs, no axial movement of the optic was detected. IOL optics always perfectly centered even when the capsular opening was not optimally centered. Due to the exquisite stretchability and elasticity of the posterior capsule, the 6-mm IOL optic could safely be buttoned-in in a posterior capsulorhexis of 4 mm and smaller.

Conclusions

Posterior optic buttonholing (POBH) is a safe and effective technique which not only excludes retro-optical opacification, but also withholds capsular fibrosis by obviating direct contact between the anterior capsular leaf and the optic surface. Anterior LEC abrasion significantly reduced both the residual fibrosis and regeneratory LEC proliferation. Apart from pediatric cataract, POBH is currently recommended for eyes with pseudoexfoliation syndrome, high axial myopia, peripheral retinal disease, and multifocal IOL implantation. Toric IOLs and magnet-driven accommodative IOL systems are other potential applications. Generally, POBH holds promise for becoming a routine alternative to standard in-the-bag IOL implantation in the future.

Objective assessment of intraocular flare after cataract surgery with combined primary posterior capsulorhexis and posterior optic buttonholing in adults

AIM

Combining primary posterior capsulorhexis (PPC) and posterior optic buttonholing (POBH) in cataract surgery is an innovative approach to prevent after-cataract formation effectively and to increase postoperative stability of the intraocular lens (IOL). The present study was designed to compare the postoperative intraocular flare after cataract surgery with combined PPC and POBH to conventional in-the-bag implantation of the IOL.

METHODS

Fifty consecutive age-related cataract patients with cataract surgery under topical anaesthesia in both eyes were enrolled prospectively into a prospective, randomised clinical trial. In randomised order, cataract surgery with combined PPC and POBH was performed in one eye; in the other eye cataract surgery was performed conventionally with in-the-bag IOL implantation keeping the posterior lens capsule intact. Intraocular flare was measured 1, 2, 4, 6, 12 and 24 h postoperatively, as well as 1 week and 1 month postoperatively, using a KOWA FC-1000 laser flare cell meter.

RESULTS

The peak of intraocular flare was observed in POBH eyes and eyes with in-the-bag IOL implantation 1 h postoperatively. In both groups, the response was steadily decreasing thereafter. During measurements at day 1, small though statistically significant higher flare measurements were observed in eyes with in-the-bag IOL implantation (p<0.05). At 1 week and 1 month postoperatively, intraocular flare measurements were comparable again (p>0.05).

CONCLUSION

Cataract surgery with combined PPC/POBH showed slightly lower postoperative anterior chamber reaction compared to conventional in-the-bag implantation during 4-week follow-up, indicating that POBH might trigger somewhat less inflammatory response. This could be explained by the posterior capsule sandwiching between the optic and the anterior capsule, preventing direct contact-mediated myofibroblastic trans-differentiation of anterior lens epithelial cells with consecutive cytokine depletion.

Intraocular pressure rise after primary posterior continuous curvilinear capsulorhexis with a fixed dorzolamide–timolol combination

PURPOSE

To assess the safety, in terms of the intraocular pressure (IOP), of cataract surgery with primary posterior continuous curvilinear capsulorhexis (PPCCC) and a postoperative dose of a fixed dorzolamide-timolol combination and evaluate the effect of intraocular lens (IOL) haptic angulation.

SETTING

Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

METHODS

In this prospective randomized double-masked bilateral study, 88 eyes of 44 consecutive patients with age-related cataract were included in an intraindividual comparison study. All patients had standardized cataract surgery with PPCCC and IOL implantation in the capsular bag followed by a postoperative dose of a fixed dorzolamide-timolol combination. Patients were randomly assigned to receive an ACR6D SE IOL (Laboratoires Cornéal) in 1 eye and a Centerflex (C-flex) 570C IOL (Rayner Surgical GmbH) in the contralateral eye. The IOP was measured at baseline and postoperatively at 6 and 24 hours as well as 1 week.

RESULTS

Intraindividual comparison showed statistically significantly higher IOP measurements in the C-flex 570C nonangulated IOL group than in the ACR6D SE angulated IOL group at 24 hours (P = .003) and 1 week (P = .043). The highest IOP spikes (34 mm Hg) were at 6 hours in 2 eyes with a C-flex 570C IOL. The ACR6D SE group had statistically significant changes in IOP between preoperative and all postoperative time points. In the C-flex 570C group, the only statistically significant change in IOP was between preoperatively and 6 hours postoperatively.

CONCLUSIONS

Cataract surgery with PPCCC was safe in terms of the postoperative IOP course. Haptic angulation slightly decreased the overall IOP rise and the incidence of IOP rises above 30 mm Hg.

Postoperative course of intraocular pressure after cataract surgery with combined primary posterior capsulorhexis and posterior optic buttonholing

PURPOSE

To evaluate the natural course of intraocular pressure (IOP) after cataract surgery with combined primary posterior continuous curvilinear capsulorhexis (PPCCC) and posterior optic buttonholing (POBH) of the intraocular lens (IOL) in adult patients.

SETTING

Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

METHODS

Fifty consecutive patients with age-related cataract awaiting cataract surgery under topical anesthesia in both eyes were enrolled prospectively. In randomized order, cataract surgery with combined PPCCC and POBH was performed in 1 eye. In the fellow eye, cataract surgery was performed conventionally with in-the-bag IOL implantation and the posterior lens capsule kept intact. Standardized IOP measurements by Goldmann applanation tonometry were performed 1, 2, 4, 6, 8, and 24 hours postoperatively. Follow-up IOP measurements were taken at 1 week and 1 month. Twenty-five patients received 1-time IOP-lowering medication immediately after cataract surgery; the other 25 did not receive IOP-lowering drops.

RESULTS

During the first 24 hours postoperatively, no significant differences in IOP were observed between the PPCCC-POBH group and the conventional surgery group (P>.05). No IOP peaks greater than 27 mm Hg were observed in any eye. One week and 1 month postoperatively, no significant differences in IOP were found between groups (P>.05). The use of IOP-lowering drops significantly reduced postoperative IOP. However, no IOP spikes >27 mm Hg were found with and without the use of IOP-lowering drops.

CONCLUSION

The course of IOP after cataract surgery with combined PPCCC and POBH showed the technique to be as safe as conventional cataract surgery with in-the-bag IOL implantation.

[After-cataract following intraocular lens implantation. Part II: prevention with alternative implants and techniques]

The introduction of sharp-edged optics has drastically reduced, but not fully eradicated, retro-optical after-cataract formation. The effectiveness of capsular bending rings or primary posterior capsulorhexis is also limited, and these have not become widespread because of the demanding surgical technique and the costs associated with an additional implant. Anterior capsule polishing has been found to even increase the need for laser capsulotomy, and rinsing the sealed capsular bag with cell-toxic agents has not yet gained clinical application. Routine posterior optic buttonholing through a well-centered posterior capsulorhexis opening is a promising alternative because it precludes access of lens epithelial cells behind the optic while at the same time counteracting fibrosis of the anterior capsule. Because this effect is independent of optic rim design and lens material, future efforts in lens refinement may concentrate on reducing the reflectivity of the optic rim and optimizing the biocompatibility of the lens material.

[After-cataract following intraocular lens implantation. Part I. Genesis and prevention by optimizing conventional lens implants and surgical techniques]

After-cataract is the most common complication in cataract surgery. Implementing a sharp posterior optic edge has, together with improved cortical aspiration, drastically reduced its rate. The impact of optic design and material has been systematically studied in detail in Vienna in a series of prospectively randomized intra-individual comparison studies using objective evaluation methods. Circular rhexis-optic overlap is essential for the durability of the posterior sharp optic edge barrier effect. Using haptics with a capsular bag design and a slim junction to the optic enhanced it further. The use of fibrosis-inducing optic materials has been shown to prolong the barrier effect, which was decreased after anterior capsule polishing. Although the incidence of clinically significant after-cataract has been significantly reduced by these conventional measures, it still cannot be completely avoided.

Accommodating intraocular lenses: a critical review of present and future concepts

BACKGROUND

Significant efforts have been made to develop lens implants or refilling procedures that restore accommodation. Even with monofocal implants, apparent or pseudoaccommodation may provide the patient with substantial though varying spectacle independence. True pseudophakic accommodation with a change of overall refractive power of the eye may be induced either by an anterior shift or a change in curvature of the lens optic.

MATERIALS AND METHODS

Passive-shift lenses were designed to move forward under ciliary muscle contraction. This is the only accommodative lens type currently marketed (43E/S by Morcher; 1CU by HumanOptics; AT-45 by Eyeonics). The working principle relies on various hypothetical assumptions regarding the mechanism of natural accommodation. Dual-optic lenses were designed to increase the dioptric impact of optic shift. They consist of a mobile front optic and a stationary rear optic which are interconnected with spring-type haptics. With active-shift lens systems the driving force is provided by repulsing mini-magnets. Lens refilling procedures replace the lens content by an elastic material and provide accommodation by an increase of surface curvature.

RESULTS

Findings with passive-shift lenses have been contradictory. While uncorrected reading vision results were initially reported to be favorable with the 1CU, and excellent with the AT-45 lens, distant-corrected near vision did not exceed that with standard monofocal lenses in later studies. Mean axial shift from laser interferometric measurements under stimulation with pilocarpine showed a moderate anterior shift with the 1CU, while the AT-45 paradoxically exhibited a small posterior shift. With the 1CU, the shift-induced accommodative effect was calculated to be less than +0.5 D in most cases, while +1 D was achieved in a single case only. Ranges and standard deviations were very large in relation to the mean values. Under physiological near-point stimulation, however, no shift was seen at all. Prevention of capsule fibrosis by extensive capsule polishing did not enhance the functional performance. Dual optic lenses are under clinical investigation and are reported to provide a significant amount of accommodation. However, possible long-term formation of interlenticular opacifications remains to be excluded. Regarding magnet-driven active-shift lens systems, initial clinical experience has been promising. Prevention of fibrotic capsular contraction is crucial, and it has been effectively counteracted with a special capsular tension ring, or lens fixation technique, together with capsule polishing. Lens refilling has been extensively studied in the laboratory and in primates. Though it offers great potential for fully restoring accommodation, a variety of problems must be solved, such as achieving emmetropia in the relaxed state, adequate response to ciliary muscle contraction, satisfying image quality over the entire range of accommodation and sustained functioning. The key problem, however, is again after-cataract prevention.

CONCLUSIONS

As opposed to psychophysical evaluation techniques, laser interferometry measures what shift lenses are designed to provide: axial shift on accommodative effort. While under pilocarpine some movement was recorded, no movement at all was found under near-point stimulation with any of the lenses currently marketed. In contrast, magnetic-driven active-shift lens systems carry the potential of sufficiently topping up apparent accommodation to provide for clinically useful accommodation while using conventional lens designs with proven after-cataract performance. Dual optic implants significantly increase the impact of axial optic shift. The main potential problem, however, is delayed formation of interlenticular regenerates. Lens refilling procedures offer the potential of fully restoring accommodation due to the great impact of increase in surface curvature on refractive lens power. However, various problems remain to be solved before clinical use can be envisaged, above all, again, after-cataract prevention. The concept of passive single-optic shift lenses has failed. Concomitant poor capsular bag performance makes these lenses an unacceptable trade-off. Magnet-assisted systems potentially combine clinically useful accommodation with satisfactory after-cataract performance. Dual optic lenses theoretically offer substantial accommodative potential but may allow for interlenticular after-cataract formation. Lens refilling procedures have the greatest potential for fully restoring natural accommodation, but will again require years of extensive laboratory and animal investigations before they may function in the human eye.