Effect of AcrySof versus Silicone or Polymethyl Methacrylate Intraocular Lens on Posterior Capsule Opacification

Application of Silicone in Ophthalmology: A Review

This paper reviews the latest trends and applications of silicone in ophthalmology, especially related to intraocular lenses (IOLs). Silicone, or siloxane elastomer, as a synthetic polymer, has excellent biocompatibility, high chemical inertness, and hydrophobicity, enabling wide biomedical applications. The physicochemical properties of silicone are reviewed. A review of methods for mechanical and in vivo characterization of IOLs is presented as a prospective research area, since there are only a few available technologies, even though these properties are vital to ensure medical safety and suitability for clinical use, especially if long-term function is considered. IOLs represent permanent implants to replace the natural lens or for correcting vision, with the first commercial foldable lens made of silicone. Biological aspects of posterior capsular opacification have been reviewed, including the effects of the implanted silicone IOL. However, certain issues with silicone IOLs are still challenging and some conditions can prevent its application in all patients. The latest trends in nanotechnology solutions have been reviewed. Surface modifications of silicone IOLs are an efficient approach to further improve biocompatibility or to enable drug-eluting function. Different surface modifications, including coatings, can provide long-term treatments for various medical conditions or medical diagnoses through the incorporation of sensory functions. It is essential that IOL optical characteristics remain unchanged in case of drug incorporation and the application of nanoparticles can enable it. However, clinical trials related to these advanced technologies are still missing, thus preventing their clinical applications at this moment.

Current State of the Art and Next Generation of Materials for a Customized IntraOcular Lens according to a Patient-Specific Eye Power

Intraocular lenses (IOLs) are commonly implanted after surgical removal of a cataractous lens. A variety of IOL materials are currently available, including collamer, hydrophobic acrylic, hydrophilic acrylic, PHEMA copolymer, polymethylmethacrylate (PMMA), and silicone. High-quality polymers with distinct physical and optical properties for IOL manufacturing and in line with the highest quality standards on the market have evolved to encompass medical needs. Each of them and their packaging show unique advantages and disadvantages. Here, we highlight the evolution of polymeric materials and mainly the current state of the art of the unique properties of some polymeric systems used for IOL design, identifying current limitations for future improvements. We investigate the characteristics of the next generation of IOL materials, which must satisfy biocompatibility requirements and have tuneable refractive index to create patient-specific eye power, preventing formation of posterior capsular opacification.

Posterior Capsule Opacification after Cataract Surgery via Implantation with Hydrophobic Acrylic Lens Compared with Silicone Intraocular Lens: A Systematic Review and Meta-Analysis

Hydrophobic acrylic intraocular lens (IOL) is the most popular material in cataract surgery. Posterior capsule opacification (PCO) is a long-term complication of cataract surgery. It can impair vision and adversely affect the prognosis of IOL delamination. The objective of this study was to perform a systematic review and meta-analysis to provide an updated evaluation of long-term complications and visual function after implantation with hydrophobic acrylic and silicone intraocular lenses. PubMed, Embase, and Cochrane Library were searched from January 2000 until March 2021. Randomized controlled trials (RCTs) and retrospective studies were finally included. The main outcomes were PCO value and neodymium-doped yttrium aluminum garnet (Nd : YAG) capsulotomy rate. Subgroup analysis was performed to compare hydrophobic acrylic and silicone IOLs during the follow-up period. Sensitivity analysis was also performed. The meta-analysis included a total of 17 studies. When the follow-up period was considered, the results of the analysis revealed higher PCO value (Group 3: standardized mean difference (SMD), −0.59; 95% confidence interval (CI), −0.90 to −0.28) and Nd : YAG capsulotomy rate (Group 3: risk ratio (RR), 0.60; 95% CI, 0.40–0.89) for hydrophobic acrylic IOLs than silicone IOLs during a long-term (≥6 years) follow-up. In conclusion, both the PCO value and the Nd : YAG capsulotomy rates were higher in hydrophobic acrylic IOLs group than the silicone IOLs group at long-term use (more than 6 years) after implantation.

Intraocular lens optic edge design for the prevention of posterior capsule opacification after cataract surgery

BACKGROUND

Posterior capsule opacification (PCO) is a clouding of the posterior part of the lens capsule, a skin-like transparent structure, which surrounds the crystalline lens in the human eye. PCO is the most common postoperative complication following modern cataract surgery with implantation of a posterior chamber intraocular lens (IOL). The main symptoms of PCO are a decrease in visual acuity, 'cloudy', blurred vision and reduced contrast sensitivity. PCO is treated with a neodymium:YAG (Nd:YAG) laser to create a small opening in the opaque capsule and regain a clear central visual axis. This capsulotomy might cause further ocular complications, such as raised intraocular pressure or swelling of the central retina (macular oedema). This procedure is also a significant financial burden for health care systems worldwide. In recent decades, there have been advances in the selection of IOL materials and optimisation of IOL designs to help prevent PCO formation after cataract surgery. These include changes to the side structures holding the lens in the centre of the lens capsule bag, called IOL haptics, and IOL optic edge designs.

OBJECTIVES

To compare the effects of different IOL optic edge designs on PCO after cataract surgery.

SEARCH METHODS

We searched CENTRAL, Ovid MEDLINE, Ovid Embase, Latin American and Caribbean Health Sciences Literature Database (LILACS), the ISRCTN registry, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) up to 17 November 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared different types of IOL optic edge design. Our prespecified primary outcome was the proportion of eyes with Nd:YAG capsulotomy one year after surgery. Secondary outcomes included PCO score, best-corrected distance visual acuity (BCDVA) and quality of life score at one year. Due to availability of important long-term data, we also presented data at longer-term follow-up which is a post hoc change to our protocol.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by Cochrane and the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

We included 10 studies (1065 people, 1834 eyes) that compared sharp- and round-edged IOLs. Eight of these studies were within-person studies whereby one eye received a sharp-edged IOL and the fellow eye a round-edged IOL. The IOL materials were acrylic (2 studies), silicone (4 studies), polymethyl methacrylate (PMMA, 3 studies) and different materials (1 study). The studies were conducted in Austria, Germany, India, Japan, Sweden and the UK. Five studies were at high risk of bias in at least one domain. We judged two studies to be at low risk of bias in all domains. There were few cases of Nd:YAG capsulotomy at one year (primary outcome): 1/371 in sharp-edged and 4/371 in round-edged groups. The effect estimate was in favour of sharp-edged IOLs but the confidence intervals were very wide and compatible with higher or lower chance of Nd:YAG capsulotomy in sharp-edged compared with round-edged lenses (Peto odds ratio (OR) 0.30, 95% CI 0.05 to 1.74; I² = 0%; 6 studies, 742 eyes). This corresponds to seven fewer cases of Nd:YAG capsulotomy per 1000 sharp-edged IOLs inserted compared with round-edged IOLs (95% CI 9 fewer to 7 more). We judged this as low-certainty evidence, downgrading for imprecision and risk of bias. A similar reduced risk of Nd:YAG capsulotomy in sharp-edge compared with round-edge IOLs was seen at two, three and five years but as the number of Nd:YAG capsulotomy events increased with longer follow-up this effect was more precisely measured at longer follow-up: two years, risk ratio (RR) 0.35 (0.16 to 0.80); 703 eyes (6 studies); 89 fewer cases per 1000; three years, RR 0.21 (0.11 to 0.41); 538 eyes (6 studies); 170 fewer cases per 1000; five years, RR 0.21 (0.10 to 0.45); 306 eyes (4 studies); 331 fewer cases per 1000. Data at 9 years and 12 years were only available from one study. All studies reported a PCO score. Four studies reported the AQUA (Automated Quantification of After-Cataract) score, four studies reported the EPCO (Evaluation of PCO) score and two studies reported another method of quantifying PCO. It was not possible to pool these data due to the way they were reported, but all studies consistently reported a statistically significant lower average PCO score (of the order of 0.5 to 3 units) with sharp-edged IOLs compared with round-edged IOLs. We judged this to be moderate-certainty evidence downgrading for risk of bias. The logMAR visual acuity score was lower (better) in eyes that received a sharp-edged IOL but the difference was small and likely to be clinically unimportant at one year (mean difference (MD) -0.06 logMAR, 95% CI -0.12 to 0; 2 studies, 153 eyes; low-certainty evidence). Similar effects were seen at longer follow-up periods but non-statistically significant data were less fully reported: two years MD -0.01 logMAR (-0.05 to 0.02); 2 studies, 311 eyes; three years MD -0.09 logMAR (-0.22 to 0.03); 2 studies, 117 eyes; data at five years only available from one study. None of the studies reported quality of life. Very low-certainty evidence on adverse events did not suggest any important differences between the groups.

AUTHORS' CONCLUSIONS

This review provides evidence that sharp-edged IOLs are likely to be associated with less PCO formation than round-edged IOLs, with less Nd:YAG capsulotomy. The effects on visual acuity were less certain. The impact of these lenses on quality of life has not been assessed and there are only very low-certainty comparative data on adverse events.

Effectiveness and Safety of the Clareon Monofocal Intraocular Lens: Outcomes from a 12-Month Single-Arm Clinical Study in a Large Sample

Purpose

This study assessed effectiveness and safety of the novel Clareon intraocular lens (IOL; model SY60CL; Alcon Vision LLC).

Patients and Methods

This was a prospective, single-arm, unmasked clinical trial at 16 investigative clinical sites in the United States. Included were adults ≥22 years who required cataract extraction by phacoemulsification. Following phacoemulsification, 350 subjects received SY60CL IOL unilaterally; 342 completed the study. Monocular best corrected distance visual acuity (CDVA) and uncorrected distance visual acuity (UDVA) were evaluated. The primary effectiveness endpoint was the percentage of subjects with CDVA ≤0.3 logMAR at month 12. Safety was assessed by monitoring adverse events (AEs). Visual acuity and safety outcomes were compared with historical safety and performance endpoint (SPE) rates.

Results

At 12 months post-implantation, 99.7% of subjects receiving the SY60CL IOL achieved monocular CDVA ≤0.3 logMAR (primary effectiveness endpoint; 1-sided 95% upper confidence limit >SPE rate); 99.7% and 86.8% of subjects achieved monocular CDVA of ≤0.34 (20/40 Snellen or better) and ≤0.04 logMAR (20/20 Snellen or better), respectively. At 12 months, >95% of subjects achieved mean monocular UDVA ≤0.3 logMAR; 97.1% and 57.6% of subjects achieved monocular CDVA of ≤0.34 and ≤0.04 logMAR, respectively. Mean monocular CDVA and UDVA were -0.05 and 0.04 logMAR, respectively. AEs were within SPE limits. The most common nonserious ocular AE was posterior capsule opacification (5.4%). Serious AEs were <1%, and no serious ocular AEs were assessed as related to the device. There were no observations for IOL glistenings at 12 months.

Conclusion

Results of this study supported effectiveness and safety of the SY60CL IOL. Visual acuity outcomes with the SY60CL IOL exceeded the SPE rates for monocular CDVA and AEs were within the limit of historic SPE rates. (Model number SY60WF is the Clareon lens approved by the FDA.).

ROCK inhibitor modified intraocular lens as an approach for inhibiting the proliferation and migration of lens epithelial cells and posterior capsule opacification

Lens epithelial cells (LECs) in the capsule play a critical role in posterior capsule opacification (PCO) formation following cataract surgery. Cytoskeleton remodeling and the related ROCK pathway are quite important during cell migration and proliferation, but their role in LECs is still unclear. This study aimed to explore the mechanism of the ROCK pathway in the behavior of LECs and established a drug modified IOL for PCO prevention. We observed that the ROCK pathway inhibitor (Y27632) or cofilin knockdown reduced HLEC-B3 migration and proliferation. Furthermore, we revealed that cofilin could regulate the migration and proliferation of LECs through its phosphorylation. Interestingly, the capping protein CAPZA1 and ERM family also had an effect on the behavior of LECs. In addition, we established Y27632-PLGA modified IOLs, implanted them into rabbit eyes and found them to exhibit good safety and biocompatibility in vivo. Moreover, satisfying PCO prevention results were observed at 28 days post-operation. In summary, the ROCK pathway and the cytoskeleton remodeling protein regulate cell migration and proliferation, and the Y27632-PLGA modified IOL can prevent PCO formation.

Identification and Description of Reliable Evidence for 2016 American Academy of Ophthalmology Preferred Practice Pattern Guidelines for Cataract in the Adult Eye

Importance

Trustworthy clinical practice guidelines require reliable systematic reviews of the evidence to support recommendations. Since 2016, the American Academy of Ophthalmology (AAO) has partnered with Cochrane Eyes and Vision US Satellite to update their guidelines, the Preferred Practice Patterns (PPP).

Objective

To describe experiences and findings related to identifying reliable systematic reviews that support topics likely to be addressed in the 2016 update of the 2011 AAO PPP guidelines on cataract in the adult eye.

Design, Setting, and Participants

Cross-sectional study. Systematic reviews on the management of cataract were searched for in an established database. Each relevant systematic review was mapped to 1 or more of the 24 management categories listed under the Management section of the table of contents of the 2011 AAO PPP guidelines. Data were extracted to determine the reliability of each systematic review using prespecified criteria, and the reliable systematic reviews were examined to find whether they were referenced in the 2016 AAO PPP guidelines. For comparison, we assessed whether the reliable systematic reviews published before February 2010 the last search date of the 2011 AAO PPP guidelines were referenced in the 2011 AAO PPP guidelines. Cochrane Eyes and Vision US Satellite did not provide systematic reviews to the AAO during the development of the 2011 AAO PPP guidelines.

Main Outcomes and Measures

Systematic review reliability was defined by reporting eligibility criteria, performing a comprehensive literature search, assessing methodologic quality of included studies, using appropriate methods for meta-analysis, and basing conclusions on review findings.

Results

From 99 systematic reviews on management of cataract, 46 (46%) were classified as reliable. No evidence that a comprehensive search had been conducted was the most common reason a review was classified as unreliable. All 46 reliable systematic reviews were cited in the 2016 AAO PPP guidelines, and 8 of 15 available reliable reviews (53%) were cited in the 2011 PPP guidelines.

Conclusions and Relevance

The partnership between Cochrane Eyes and Vision US Satellite and the AAO provides the AAO access to an evidence base of relevant and reliable systematic reviews, thereby supporting robust and efficient clinical practice guidelines development to improve the quality of eye care.

Effect of AcrySof versus other intraocular lens properties on the risk of Nd:YAG capsulotomy after cataract surgery: A systematic literature review and network meta-analysis

OBJECTIVE

The purpose of this study was to evaluate the impact of different intraocular lens materials (IOL) and optic edge designs on the incidence of Nd:YAG laser capsulotomy.

METHODS

Randomized controlled trials (RCTs) reporting incidence of Nd:YAG capsulotomy in patients with monofocal IOLs were identified for systematic literature review (SLR) using Cochrane methodology. A network meta-analysis was conducted under a Bayesian framework. Mean hazard ratios (HRs), 95% credible intervals, and one-sided p-values were estimated for Nd:YAG capsulotomy incidence by comparing AcrySof IOLs with a group of non-AcrySof hydrophobic acrylic, hydrophilic acrylic, silicone, and PMMA IOLs. Sensitivity analysis was conducted comparing the risk of Nd:YAG capsulotomy between sharp- and round-edged designs of the above IOLs.

RESULTS

AcrySof IOLs had a lower risk of Nd:YAG capsulotomy compared to hydrophobic acrylic (HR: 2.68; 95% CrI: 1.41, 4.77; p < 0.01), hydrophilic acrylic (HR: 7.54; 95% CrI: 4.24, 14.06; p < 0.001), PMMA (HR: 3.64, 95% CrI: 1.87, 6.33; p < 0.001), and silicone (HR: 1.13; 95% CrI: 0.59, 1.91; p <0.1) IOLs. The risk for Nd:YAG was highest among sharp-edged IOLs for hydrophilic acrylic IOLs (HR: 9.32; 95% CrI: 4.32, 19.29; p < 0.01), followed by other hydrophobic acrylic (HR: 2.91; 95% CrI: 1.27, 5.88; p < 0.01), silicone (HR: 0.838; 95% CrI: 0.328, 1.74; p = 0.69), and PMMA (HR: 0.39; 95% CrI: 0.042, 1.49; p = 0.93) IOLs, compared to AcrySof. Acrysof IOLs had a lower risk of Nd:YAG compared to PMMA (HR: 3.25; 95% CrI: 1.21, 7.37; p < 0.01) and silicone, round edge IOLs (HR: 3.84; 95% CrI: 1.08, 10.64; p = 0.015).

CONCLUSION

The risk of Nd:YAG capsulotomy is lower in eyes implanted with AcrySof IOLs compared to non-AcrySof hydrophobic or hydrophilic acrylic IOLs. Sharp-edged AcrySof, PMMA, and silicone IOLs are comparable in terms of reducing the risk of Nd:YAG laser capsulotomy.

Biomaterial Influence on Intraocular Lens Performance: An Overview

There is strong evidence that the IOL material is the factor having the greatest impact on posterior capsule opacification (PCO), anterior capsule opacification (ACO) development, and glistening formation after cataract surgery, even though there are other IOL features—such as haptic material and design and edge and optic design—that also have some influence. We reviewed the published literature describing the adverse events that are mainly related to the intraocular lens (IOL) material, such as PCO, ACO, and the subsequent capsule contraction, as well as glistening formation. The adverse events presented in this overview are the most common ones in clinical practice, and therefore, they are generally included in the clinical protocols for IOL evaluation.

Surface Modification of Intraocular Lenses

Objective:

This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs).

Data Sources:

All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect.

Study Selection:

The articles on the surface modification of IOLs were included, but those on design modification and surface coating were excluded.

Results:

Technology of surface modification included plasma, ion beam, layer-by-layer self-assembly, ultraviolet radiation, and ozone. The main molecules introduced into IOLs surface were poly (ethylene glycol), polyhedral oligomeric silsesquioxane, 2-methacryloyloxyethyl phosphorylcholine, TiO₂, heparin, F-heparin, titanium, titanium nitride, vinyl pyrrolidone, and inhibitors of cytokines. The surface modification either resulted in a more hydrophobic lens, a more hydrophilic lens, or a lens with a hydrophilic anterior and hydrophobic posterior surface. Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments.

Conclusion:

The surface modification is an efficient, convenient, economic and promising method to improve the biocompatibility of IOLs.

Orthopedic application of spikenard herbal rhizome decorated microstructured polymer biocomposites and their in vitro cytotoxicity

The present study explores the synthesis of highly potential polymer biocomposite from Nardostachys jatamansi rhizome extract. The polymer biocomposites were synthesized from methyl methacrylate by free radical polymerization. ATR-IR enunciate the functional groups attributed at 956 cm-1 (aromatic), a peak appeared at 1685 cm-1 (-C[bond, double bond]O), 1186 cm-1 (-O-CH3), 1149 cm-1 (-C-O-C) framework and 1279 cm-1 (-C-O), which are good agreement for the formation composites. The quantitative evaluations of antimicrobial studies were analyzed by serial dilution method and also improved activity in orthopedic infection pathogens. Cytocompatibility was analyzed by keratinocyte cell lines and it may be used for various biomedical applications.

Surface modification of intraocular lenses with hyaluronic acid and lysozyme for the prevention of endophthalmitis and posterior capsule opacification

Posterior capsule opacification is one of the complications of cataract surgery caused by the adhesion and reproduction of residual human lens epithelial cells (HLECs) on the posterior capsule.

Effect of hydrophobic acrylic versus hydrophilic acrylic intraocular lens on posterior capsule opacification: meta-analysis

PURPOSE

This meta-analysis aims to evaluate the differences in performance of posterior capsular opacification (PCO) between hydrophobic acrylic intraocular lens (IOLs) and hydrophilic acrylic IOLs.

SETTING

Tianjin Medical University, Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin, China.

DESIGN

Systematic review of randomized controlled trials (RCTs) or meta-analysis.

METHODS

An electronic literature search was performed using the PubMed, EMBASE and Cochrane Library database before May in 2013 to identify prospective RCTs comparing hydrophobic acrylic IOLs and hydrophilic acrylic IOLs in patients after phacoemulsification with IOL implantation with a follow-up time of at least 1 year. Pertinent studies were selected by meeting predefined criteria and reviewed systematically by meta-analysis. The PCO scores and YAG capsulotomy rate, as indicator of PCO, were measured and discussed in a meta-analysis. Standardized mean differences (SMD), relative risk ratio (RR), and the pooled estimates were computed according to a random effect model or fixed effect model.

RESULTS

Nine prospective RCTs involving 861 eyes were included in the current meta-analysis. The hydrophobic acrylic IOLs were favored and the pooled SMD of PCO severity was 1.72 (95% confidence interval (CI), 0.20 to 1.23, P = 0.0002) and 1.79 (95% CI, 0.95 to 2.64, P<0.0001) with 1-year follow-up and 2-year follow-up respectively. The pooled RR of Nd:YAG laser capsulotomy rates at postoperative 2-year follow-up was 6.96 (95% CI, 3.69 to 13.11, P<0.00001) comparing hydrophilic acrylic IOLs with hydrophobic acrylic IOLs.

CONCLUSIONS

Compared with hydrophilic acrylic IOLs, the hydrophobic acrylic IOLs showed superior reduction in rates of PCO and laser capsulotomy in 2-year follow-up. More RCTs with standard methods for longer follow-up are needed to validate the association.

Long-term effect of surface light scattering and glistenings of intraocular lenses on visual function

PURPOSE

To investigate the long-term effect of surface light scattering and glistenings of various intraocular lenses (IOLs) on visual function and optical aberrations after cataract surgery.

DESIGN

Case-control study.

METHODS

Thirty-five eyes that underwent implantation of a hydrophobic acrylic, silicone, or polymethyl methacrylate (PMMA) IOL more than 10 years ago were recruited. The scattering light intensity of the surface and internal matrix of the optic was measured using Scheimpflug photography. Visual acuity (VA) was measured using VA charts, and contrast VA and that with glare (glare VA) were examined using a contrast sensitivity tester. Ocular higher-order aberrations (HOAs) were measured using a Hartmann-Shack aberrometer.

RESULTS

Mean scattering light intensity of the surface and internal matrix of the optic was significantly higher in the acrylic group than in the silicone and PMMA groups (P < .0001). Mean uncorrected VA, photopic and mesopic contrast VA and glare VA, and HOAs did not differ significantly among groups, although mean corrected VA in the acrylic group was significantly better than that in the other groups (P = .0023). Scattering light intensity of the surface and internal matrix did not correlate with VA, contrast VA, or glare VA, and did not correlate with ocular and internal optic HOAs in the acrylic group.

CONCLUSIONS

At more than 10 years postoperatively, visual function, including contrast sensitivity, and ocular HOAs were comparable among eyes that received acrylic, silicone, and PMMA IOLs. Surface scattering and glistenings with the acrylic IOLs were not significantly correlated with visual function and optical aberrations.

Clinical outcomes of cataract surgery after bag-in-the-lens intraocular lens implantation following ISO standard 11979-7:2006

PURPOSE

To assess the clinical outcomes of bag-in-the-lens intraocular lens (BIL IOL) implantation following the International Organization for Standardization (ISO) 11979-7:2006 in pediatric eyes and eyes with ocular comorbidities.

SETTING

Antwerp University Hospital, Department of Ophthalmology, Antwerp, Belgium.

DESIGN

Cohort study.

METHODS

This cohort included the first series of patients having IOL implantation using the bag-in-the-lens technique. Surgeries were performed between December 1999 and September 2006. In addition to IOL implantation, the technique comprised creation of a primary posterior continuous curvilinear capsulorhexis (PCCC) equal in size to the anterior capsulorhexis.

RESULTS

The study enrolled 807 eyes of 547 patients; 326 of the eyes (40.40%) had ocular comorbidity. In the 481 eyes without ocular comorbidity, the mean decimal corrected distance visual acuity was 0.52 ± 0.24 (SD) (0.276 ± 0.206 logMAR) preoperatively and 0.94 ± 0.18 (-0.012 ± 0.053 logMAR) postoperatively. The mean postoperative achieved spherical equivalent was 0.48 ± 0.83 diopter (D) and the mean targeted refraction, -0.24 ± 0.71 D. The A-constant was modified from 118.4 to 118.04. Posterior capsule opacification (PCO) did not occur in any adult eye during the follow-up. Retinal detachment after IOL implantation occurred in 10 eyes (1.24%). In 19 eyes, the iris was captured by the IOL haptics postoperatively. Hypopyon occurred in 3 patients and toxic anterior segment syndrome in 1 patient.

CONCLUSION

The BIL IOL met the ISO criteria; that is, primary PCCC was safe in healthy eyes and in eyes with ocular comorbidities and no eye developed PCO over a mean follow-up of 26.1 ± 21.3 months.

Surface roughness of intraocular lenses with different dioptric powers assessed by atomic force microscopy

PURPOSE

To analyze the optic surface roughness and morphology of 2 types of hydrophobic acrylic intraocular lenses (IOLs) with various dioptric powers using atomic force microscopy (AFM).

SETTING

Technical University of Cluj-Napoca, Faculty of Mechanics, Cluj-Napoca, Romania.

METHODS

Atomic force microscopy was used to characterize the topography of 2 types of hydrophobic acrylic IOLs from a single manufacturer (SN60AT and SA30AL) with dioptric powers ranging from 10.0 diopters (D) to 30.0 D. The AFM analysis was performed in contact mode using a V-shaped silicon nitride cantilever with a pyramidal tip curvature of 15 nm and a nominal spring constant of 0.2 N/m. Detailed surface characterization of the IOL optic was obtained using 6 quantitative parameters provided by the AFM software.

RESULTS

Five of 6 roughness parameters indicated statistically significant differences (P<.05) between IOLs with different dioptric powers, with the 10.0 D IOL in both models providing the smoothest optic surface. Between models with the same dioptric power, the SN60AT model had lower values of each surface roughness parameter than the SA30AL model.

CONCLUSIONS

Atomic force microscopy was an accurate tool for assessing the surface properties of IOL optics. Manufacturing processes were responsible for introducing detectable differences in the topography of IOL biomaterials with identical copolymer constituents but different dioptric powers. Nanometric analysis may assist IOL manufacturers in developing IOLs with optimal surface characteristics.

CD44 expression is developmentally regulated in the mouse lens and increases in the lens epithelium after injury

Hyaluronan is an oligosaccharide found in the pericellular matrix of numerous cell types and hyaluronan-induced signaling is known to facilitate fibrosis and cancer progression in some tissues. Hyaluronan is also commonly instilled into the eye during cataract surgery to protect the corneal endothelium from damage. Despite this, little is known about the distribution of hyaluronan or its receptors in the normal ocular lens. In this study, hyaluronan was found throughout the mouse lens, with apparently higher concentrations in the lens epithelium. CD44, a major cellular receptor for hyaluronan, is expressed predominately in mouse secondary lens fiber cells born from late embryogenesis into adulthood. Surgical removal of lens fiber cells from adult mice resulted in a robust upregulation of CD44 protein, which preceded the upregulation of alpha-smooth muscle actin expression typically used as a marker of epithelial-mesenchyma transition in this model of lens epithelial cell fibrosis. Mice lacking the CD44 gene had morphologically normal lenses with a response to lens fiber cell removal similar to wildtype, although they exhibited an increase in cell-associated hyaluronan. Overall, these data suggest that lens cells have a hyaluronan-containing pericellular matrix whose structure is partially regulated by CD44. Further, these data indicate that CD44 upregulation in the lens epithelium may be an earlier marker of lens injury responses in the mouse lens than the upregulation of alpha-smooth muscle actin.

Comparison of posterior capsule opacification development with 3 intraocular lens types: five-year prospective study

PURPOSE

To compare the effects of hydrophobic acrylic, silicone, and heparin-surface-modified poly(methyl methacrylate) (HSM PMMA) intraocular lenses (IOLs) on posterior capsule opacification (PCO).

METHODS

In this 5-year prospective study, the same surgeon performed standard phacoemulsification in patients who were randomized to implantation of a round-edged HSM PMMA IOL (809C), a round-edged silicone IOL (SI-40NB), or a sharp-edged hydrophobic acrylic IOL (AcrySof MA60BM). The neodymium:YAG capsulotomy rate was recorded. To evaluate PCO and the position of the anterior capsulorhexis, retroillumination digital photographs were taken 5 years postoperatively and analyzed using the POCOman computer-analysis system.

RESULTS

After 5 years, there was no significant difference in the fraction or severity of PCO between the silicone IOLs and acrylic IOLs (both P =1.0). The silicone IOL group had a significantly higher capsulotomy rate (29%) than the acrylic IOL group (8%) (P=.0068). The HSM PMMA IOL group had a significantly higher PCO fraction, severity, and capsulotomy rate (54%) than the silicone and acrylic groups. In all eyes, the fraction (P=.0076) and severity (P=.0081) of PCO were statistically significantly higher when the anterior capsulorhexis was partly decentered than when it was completely on the optic; within each IOL group, there was no significant difference.

CONCLUSION

After 5 years, there was no significant difference in the semiquantitative evaluation of PCO between the sharp-edged acrylic IOL and round-edged silicone IOL. Eyes with the HSM PMMA IOL had more PCO than eyes with the other IOLs.

Three-year follow-up of posterior capsule opacification after AquaLase and NeoSoniX phacoemulsification

PURPOSE

To prospectively compare the degree of posterior capsule opacification (PCO) after AquaLase and NeoSoniX phacoemulsification methods during the 3-year follow-up period.

DESIGN

Prospective, randomized clinical trial.

METHODS

Setting at the Department of Ophthalmology, University Hospital in Hradec Králové. Patients with bilateral cataract were included. AquaLase was used in the right eye and NeoSoniX in the left eye of each patient. The AcrySof SA60AT intraocular lens (Alcon Laboratories, Fort Worth, Texas, USA) was implanted in all eyes. The Evaluation of Posterior Capsule Opacification (EPCO) 2000 software (Developed by Tetz MR and associates, Berlin, Germany) and the Open-Access Systematic Capsule Assessment (OSCA) system (Devised by Aslam TM, Edinburgh, United Kingdom) were used for PCO assessment 1, 2, and 3 years after cataract surgery.

RESULTS

Fifty patients were analyzed 1 year, 47 patients 2 years, and 46 patients 3 years after cataract surgery. Mean EPCO 2000 values were for the AquaLase group 0.324 +/- 0.305 and for the NeoSoniX group 0.298 +/- 0.341 (P = .53) 1 year after surgery, for the AquaLase group 0.429 +/- 0.322 and for the NeoSoniX group 0.478 +/- 0.337 (P = .30) 2 years after surgery, and for the AquaLase group 0.582 +/- 0.506 and for the NeoSoniX group 0.594 +/- 0.515 (P = .87) 3 years after surgery. The OSCA results were for the AquaLase group 0.7097 +/- 0.3778 and for the NeoSoniX group 0.8584 +/- 0.4323 (P = .046) 1 year after surgery, for the AquaLase group 0.7515 +/- 0.4555 and for the NeoSoniX group 0.8103 +/- 0.4498 (P = .44) 2 years after surgery, and for the AquaLase group 0.9667 +/- 0.736 and for the NeoSoniX group 0.9540 +/- 0.5250 (P = .91) 3 years after surgery. Neodymium-yttrium-aluminun-garnet capsulotomy rate for AquaLase vs NeoSoniX was 0:1 eyes 1 year, 1:3 eyes 2 years, and 1:4 eyes 3 years after surgery. No significant difference between those 2 groups was established, except the OSCA outcomes 1 year postoperatively.

CONCLUSION

There was only minimal PCO difference between these 2 approaches, AquaLase and NeoSoniX. Neither AquaLase nor NeoSoniX technique was able to prevent a natural progression of PCO.