Prevention of postoperative capsular bag opacification using intraocular lenses and endocapsular devices maintaining an open or expanded capsular bag

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.

Twelve-Month Clinical Outcomes After Implantation of a Novel, Modular, Anterior Shape-Changing Fluid Optic Intraocular Lens

PURPOSE

To report the initial safety and effectiveness profile for an anterior shape-changing, modular IOL, Juvene (JIOL), for the treatment of aphakia and presbyopia after removal of the natural crystalline lens due to cataract.

SETTING

Two private practices in Monterrey and Tijuana, Mexico.

DESIGN

Exploratory, prospective, multi-center, open-label, non-comparative clinical trial.

METHODS

A convenience sample of subjects aged 50-80 years with planned cataract surgery were recruited to undergo unilateral or bilateral implantation with the JIOL. Subjects were required to complete an informed consent and be able to dilate to at least 6.0 mm pharmacologically, be in good overall health, and have no significant eye health history to qualify. Visual acuities, defocus curves, and contrast sensitivity were measured for all subjects 12 months postoperatively.

RESULTS

Fifty-one of 58 eyes completed the 12-month visit. Intraoperative complication rates were extremely low (N=1; missed base lens tab). The most frequent adverse events (AE) were prolonged inflammation (N=6) and cystoid macular edema (N=4); all AEs were resolved without sequelae by the 12-month visit. Mean monocular logMAR corrected distance visual acuity (CDVA), distance-corrected intermediate (DCIVA) and near (DCNVA) were 0.01, 0.08, and 0.24, respectively. Defocus testing showed VA > 20/40 from approximately +1.00 D through -2.00 D. Binocular implantation (n=16) provided superior performance over monocular implantation.

CONCLUSIONS

The Juvene IOL offers a novel solution to treat presbyopia, providing clear functional vision performance across a range of distances with an acceptable initial safety profile.

Use of P1-P4 Purkinje reflections as a surrogate sign for intraoperative patient fixation

Circumferential, even anterior capsular overlap maximizes intraocular lens stability and posterior capsular opacification mitigation and provides best long-term outcomes for the cataract patient. P1 and P4 Purkinje reflections at patient fixation may provide a reliable marker for capsulotomy centration. However, patient fixation may be hindered during surgery because of anesthesia or light sensitivity. In this study, we demonstrate that the relationship between the P1 and P4 Purkinje reflections previewed prior to surgery when the patient is fixating may be recreated intraoperatively if fixation becomes difficult. The final position of P1 and P4 relative to one another at fixation is invariant in a given patient, but there are variations among patients. Knowledge of the P1 and P4 relationship can be used as a surrogate sign of patient fixation to assist in capsulotomy centration during cataract surgery.

Long-term uveal and capsular biocompatibility of a new fluid-filled, modular accommodating intraocular lens

PURPOSE

To evaluate long-term uveal and capsular biocompatibility of a new fluid-filled modular accommodating intraocular lens (IOL) consisting of base and fluid lenses.

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA.

DESIGN

Experimental study.

METHODS

Bilateral phacoemulsification was performed on 8 rabbits; 1 eye received the test IOL (Juvene) and the other a hydrophobic acrylic control IOL (SA60AT). Slitlamp examinations were performed at postoperative weeks 1 and 4, and at months 2, 3, and 6. The rabbits were killed humanely at 6 months. After gross examination from the Miyake-Apple view, IOLs were removed for implant cytology. All globes were then processed for histopathologic examination.

RESULTS

Uveal biocompatibility was similar between test and control IOLs up to 6 months postoperatively. Anterior capsule opacification appeared absent in the test group, and posterior capsule opacification (PCO) was significantly less in comparison with the control group throughout the study. At 6 months, central PCO was scored as 0.12 ± 0.23 with test IOLs and as 4.0 ± 0 with control IOLs (P < .0001, 2-tailed t test: paired 2-sample for means). Histopathologic examination confirmed the relative lack of capsular opacification in test eyes in comparison to controls and the absence of toxicity in any eye.

CONCLUSIONS

Six weeks in the rabbit model corresponds to approximately 2 years in the human eye for PCO. In this model, the Juvene IOL maintained an open and expanded capsular bag, preventing overall capsular bag opacification while retaining excellent uveal and capsular biocompatibility.

Explantation/exchange of the components of a new fluid-filled, modular, accommodating IOL

PURPOSE

To evaluate the ease of replacement and capsular stability of a new fluid-filled, modular, accommodating intraocular lens (IOL) system composed of a monofocal base lens with a fluid lens clipped inside of it.

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

DESIGN

Experimental study.

METHODS

Five New Zealand rabbits underwent bilateral phacoemulsification with implantation of the test lens (Juvene, LensGen, Inc.) in both eyes (4 rabbits), or a control IOL in 1 eye (AcrySof, Alcon Laboratories, Inc.) and the test IOL in the other (1 rabbit). At 2 weeks, the 4 rabbits with bilateral Juvene IOLs had the clipped-in fluid lens exchanged for a new fluid lens in 1 eye, and the base and fluid lenses exchanged for a control lens in the contralateral eye. Slitlamp examinations were performed weekly for 4 weeks. The globes were enucleated and evaluated with ultrasound biomicroscopy, grossly from the posterior Miyake-Apple view, and histopathologically.

RESULTS

Explantation/exchange of the fluid lens was considered straightforward by the surgeon. Explantation of the base lens (4) was also safely performed, albeit more demanding, without any signs of damage to the capsular bag under clinical, ultrasound biomicroscopy, and pathological examination in the exchanged eyes. Less capsular bag opacification was observed with the Juvene lens system.

CONCLUSIONS

Explantation/exchange of the fluid lens component, or both fluid and base lenses, of this new lens system can be safely accomplished if necessary, because of its modular design and the relative lack of postoperative capsular bag opacification associated with it.

Factors Affecting Posterior Capsule Opacification in the Development of Intraocular Lens Materials

Posterior capsule opacification (PCO) is the most common complication arising from the corrective surgery used to treat cataract patients. PCO arises when lens epithelial cells (LEC) residing in the capsular bag post-surgery undergo hyper-proliferation and transdifferentiation into myofibroblasts, migrating from the posterior capsule over the visual axis of the newly implanted intraocular lens (IOL). The developmental pathways underlying PCO are yet to be fully understood and the current literature is contradictory regarding the impact of the recognised risk factors of PCO. The aim of this review is firstly to collate the known biochemical pathways that lead to PCO development, providing an up-to-date chronological overview from surgery to established PCO formation. Secondly, the risk factors of PCO are evaluated, focussing on the impact of IOLs’ properties. Finally, the latest experimental model designs used in PCO research are discussed to demonstrate the ongoing development of clinical PCO models, the efficacy of newly developed IOL technology, and potential therapeutic interventions. This review will contribute to current PCO literature by presenting an updated overview of the known developmental pathways of PCO, an evaluation of the impact of the risk factors underlying its development, and the latest experimental models used to investigate PCO. Furthermore, the review should provide developmental routes for research into the investigation of potential therapeutic interventions and improvements in IOL design in the aid of preventing PCO for new and existing patients.

Long-term myofibroblast persistence in the capsular bag contributes to the late spontaneous in-the-bag intraocular lens dislocation

Late spontaneous in-the-bag intraocular lens (IOL) dislocation is a complication presenting 6 months or later after cataract surgery. We aimed to characterize the cells in the lens capsules (LCs) of 18 patients with spontaneous late in-the-bag IOL dislocation. Patients' average age was 82.6 ± 1.5 years (range 72-98), and most of them had pseudoexfoliation syndrome (PEX). Cells from the LCs were positive for myofibroblast (αSMA), proliferation (Ki-67, PCNA), early lens development/lens progenitor (SOX2, PAX6), chemokine receptor (CXCR4), and transmembrane (N-cadherin) markers, while negative for epithelial (E-cadherin) marker. Moreover, the cells produced abundant fibronectin, type I and type V collagen in the nearby extracellular matrix (ECM). During ex vivo cultivation of dislocated IOL-LCs in toto, the cells proliferated and likely migrated onto the IOL's anterior side. EdU proliferation assay confirmed the proliferation potential of the myofibroblasts (MFBs) in dislocated IOL-LCs. Primary cultured lens epithelial cells/MFBs isolated from the LC of dislocated IOLs could induce collagen matrix contraction and continuously proliferated, migrated, and induced ECM remodeling. Taken together, this indicates that long-lived MFBs of dislocated IOLs might contribute to the pathogenic mechanisms in late in-the-bag IOL dislocation.

Intraocular Lenses: Overview of Designs, Materials, and Pathophysiologic Features

This article provides an overview of intraocular lenses (IOLs) currently used in cataract surgery. Aspects presented include design features related to IOL construction and sites of fixation; optic, filter, and haptic materials; as well as pathophysiologic features of uveal biocompatibility, capsular biocompatibility, and postoperative IOL opacification. This overview also includes supplementary (add-on; piggyback) lenses implanted in eyes that are already pseudophakic and considerations on IOLs used in the pediatric population. Different IOLs are made available to surgeons each year, including lenses with increasingly complex design characteristics owing to advancements in manufacturing and surgical techniques.

Precision pulse capsulotomy: Initial clinical experience in simple and challenging cataract surgery cases

PURPOSE

To evaluate precision pulse capsulotomy (PPC) in simple and challenging cataract surgery cases.

SETTING

Clínica Quesada, San Salvador, El Salvador.

DESIGN

Prospective case series.

METHODS

This single-center prospective study assessed cataract surgeries with anterior capsulotomy performed using a PPC device through a 2.2 mm corneal incision in the presence of an ophthalmic viscosurgical device. This was followed by phacoemulsification and intraocular lens implantation. Outcomes included capsulotomy appearance and diameter, surgical complications, and postoperative visual acuity.

RESULTS

The study comprised 38 eyes. All cases resulted in 360-degree complete, round capsulotomies averaging 5.5 mm in diameter with intracapsular IOL fixation. No PPC-related complications were observed intraoperatively or on follow-up at 3 to 8 months. The PPC was useful in challenging cases with corneal opacities that obscured the capsulotomy path or with poorly dilated pupils. Precision pulse capsulotomy occurs instantaneously everywhere along the capsulotomy path, which allowed safe release of subcapsular pressure in intumescent cataracts with consistent creation of a round, appropriately sized capsulotomy. The PPC edge quality was shown in a case with 6 clock hours of zonular dialysis in which iris hooks held the capsulotomy edge for over 45 minutes for removal of a 4+ cataract.

CONCLUSIONS

Precision pulse capsulotomy had a short learning curve and was integrated seamlessly into the surgical routine. The combination of suction with ultrafast capsulotomy provided capsulotomy roundness, sizing, safety, and edge quality that significantly facilitated difficult cases. The ease of use, consistency, and efficiency of PPC capsulotomy might support its use under many practice scenarios.

A Review of Laser-Assisted Versus Traditional Phacoemulsification Cataract Surgery

The use of femtosecond laser surgery improves the precision and reproducibility of corneal incisions and the capsular opening; it also reduces the amount of ultrasound energy required for lens nucleus work-up. The rate of complications reported so far appears to be low. There are a number of contraindications such as a history of cornea and/or glaucoma surgery and certain anatomical features like deep-set eyes, kyphosis, tremor, and obesity. Visual recovery and refractive results of both techniques are excellent. Comparing laser cataract surgery (LCS) with manual cataract surgery (conventional phacoemulsification) based on meta-analysis currently reveals slight differences in refractive and visual outcome. Both methods are extremely successful and safe. LCS is a technique still on the rise, with its full potential not yet tapped.