Posterior capsule opacification in silicone and hydrophobic acrylic intraocular lenses with sharp-edge optics six years after surgery

Posterior capsular opacification and Nd:YAG capsulotomy rates in patients implanted with square-edged and non-square-edged intraocular lenses in manual small-incision cataract surgery: A randomized controlled study

Purpose

To study posterior capsular opacification (PCO) and neodymium-doped yttrium aluminum garnet (Nd:YAG) capsulotomy rates in patients implanted with square-edged and non-square-edged intraocular lenses (IOLs) in manual small-incision cataract surgery (MSICS).

Setting

Tertiary eye care center.

Design

Prospective, comparative, and randomized controlled study.

Methods

This study included patients with senile cataracts scheduled for MSICS and IOL implantation. One eye of each patient was randomized to the implantation of square-edged (S group) or non-square-edged IOL (NSQ group). An independent observer analyzed PCO at 6, 12, 18, and 24 months under slit-lamp illumination.

Results

A total of 104 eyes were included in this study. The mean age of the participants in the two groups was 63.2 (±8.2) years, and there were 65 (62.5%) men and 39 women (37.5%). The mean best-corrected visual acuity (BCVA) values at 6, 12, and 18 months were 0.157 (±0.10), 0.11 (±0.12), and 0.12 (±0.11), respectively, in the S group and 0.17 (±0.10), 0.17 (±0.12), and 0.20 (±0.17), respectively, in the NSQ group. At 12 (P = 0.03) and 18 months (P = 0.01) follow-up, the BCVA of the S group was significantly better than that of the NSQ group. Four eyes in the NSQ group and one eye in the S group required Nd:YAG.

Conclusion

Evaluation of PCO and Nd:YAG capsulotomy rates showed that the 360° square of the posterior IOL edge plays a role in the prevention of PCO. Owing to the low cost of the material and the easy availability of IOLs manufactured from it, square-edged IOL has a definite role in the prevention of PCO in MSICS.

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.

Application of Collagen I and IV in Bioengineering Transparent Ocular Tissues

Collagens represent a major group of structural proteins expressed in different tissues and display distinct and variable properties. Whilst collagens are non-transparent in the skin, they confer transparency in the cornea and crystalline lens of the eye. There are 28 types of collagen that all share a common triple helix structure yet differ in the composition of their α-chains leading to their different properties. The different organization of collagen fibers also contributes to the variable tissue morphology. The important ability of collagen to form different tissues has led to the exploration and application of collagen as a biomaterial. Collagen type I (Col-I) and collagen type IV (Col-IV) are the two primary collagens found in corneal and lens tissues. Both collagens provide structure and transparency, essential for a clear vision. This review explores the application of these two collagen types as novel biomaterials in bioengineering unique tissue that could be used to treat a variety of ocular diseases leading to blindness.

Surface modification of intraocular lenses via photodynamic coating for safe and effective PCO prevention

Posterior capsular opacification (PCO) is an emerging complication in cataract phacoemulsification and intraocular lens (IOL) implantation surgery, mainly stemming from the adhesion, proliferation, and trans-differentiation of the post-surgery residual lens epithelial cells (LECs). Previous investigations have shown that an anti-proliferative drug eluting coating on the IOL surface provides an effective way to inhibit PCO. However, due to the undesirable elution of the anti-proliferative drug, the safety of such modification is one of the important issues to be solved. In this investigation, photodynamic coating was introduced into IOL surface modification. The photosensitizer chlorin e6 grafted α-cyclodextrin (α-CD-Ce6) was synthesized and self-assembled onto the poly(poly(ethylene glycol) methacrylate) (PPEGMA) brush established IOL surface via the supramolecular interaction between α-CD and poly(ethylene glycol) chains. The results of investigation into its optical properties, including transmittance, refractive index, and surface morphology, showed no obvious alterations after photodynamic coating modification on the IOL surface. The in vitro LEC behaviour investigation optimized the photodynamic therapy parameters when light illumination was used for the cell elimination on the photodynamic coating modified IOL. The results have also shown that this functional coating modification effectively eliminates the cells on the surface of the IOL material when treated with light illumination, whereas it keeps excellent cytocompatibility in the absence of light illumination. The investigation of the cell elimination mechanism shows that this kind of functional coating eliminates the adherent cells by ROS induced apoptosis. The in vivo implantation result confirms the excellent PCO inhibition effect, as well as their safety and biocompatibility to the surrounding tissues. As a result, the proposed photodynamic coating provides a safer and effective alternative of IOL modification for preventing PCO.

Capsular fibrosis: a review of prevention methods and management

Opacification of the posterior capsule caused by residual lens epithelial cells (LEC) is still the most frequent long-term complication of cataract surgery. Beside the opacification of the visual axis with posterior capsule opacification (PCO), resulting in a decrease in visual function, fibrotic changes may also have a mechanical effect on intraocular lens (IOL) position such as axial shift, decentration, tilt and capsule striae. In this article, two types of capsular fibrosis are explored, on the one hand the anterior capsule fibrosis and on the other hand PCO. Results from clinical trials concerning their causes, natural course, incidence, influencing factors and possible methods of prophylaxis are presented.

Open-capsule intraocular lens to prevent posterior capsule opacification

PURPOSE

To develop a single-piece open-capsule intraocular lens (IOL) that can be inserted through a small incision and that prevents posterior capsule opacification (PCO) by expanding the capsule and circulating aqueous humor into the capsular bag.

SETTING

Department of Ophthalmology, Dokkyo Medical University, Tochigi, Japan.

DESIGN

Experimental study.

METHOD

Using the same hydrophobic acrylic material as the NY-60 IOL, a prototype open-capsule IOL was constructed. The IOL has a single optic and 2 haptics, with a 2.8 mm high spacer and holes through which aqueous humor circulates into the capsular bag by separating the anterior capsule from the posterior capsule and expanding the capsule. The open-capsule IOL or NY-60 (as a control group) was inserted in rabbit eyes. Posterior capsule opacification development was evaluated by measuring the thickness of the cell layer at the center of the posterior capsule on histopathologic specimens and statistically comparing the thickness between the open-capsule IOL group and control group.

RESULTS

The open-capsule IOL could be inserted through a 3.2 mm corneal incision using a D cartridge. The mean thickness of the cell layer at the center of the posterior capsule was 4.78 μm ± 2.61 (SD) in the open-capsule IOL group and 101.14 ± 25.19 μm in the control group and was significantly smaller in the open-capsule IOL group.

CONCLUSION

The prototype single-piece IOL could be implanted through a small incision and prevented PCO by expanding the lens capsule and circulating aqueous humor into the capsular bag.

A meta-analysis of Nd:YAG capsulotomy rates for two hydrophobic intraocular lens materials

Purpose

The purpose of this study is to estimate and compare neodymium-doped yttrium aluminum garnet (Nd:YAG) capsulotomy rates for AcrySof ^® and Clareon^® intraocular lens (IOL) materials using historical data from the medical literature and Alcon-sponsored clinical studies.

Methods

Clinical trials that involved the implantation of AcrySof or Clareon monofocal IOLs in subjects with cataract or presbyopia were extracted from the literature and a company repository of clinical studies. The study duration, number of eyes, and cumulative percent of Nd:YAGs for posterior capsule opacification were extracted. Bayesian random effects meta-analyses were conducted to estimate and compare outcomes for the 2 different IOL materials.

Results

A Bayesian random effects, meta-analysis was performed that combined a literature review of published AcrySof Nd:YAG posterior capsulotomy rates and Nd:YAG rates observed in Alcon-sponsored clinical studies of AcrySof and Clareon. Sixteen Alcon studies contained Nd:YAG data suitable for meta-analysis. Three of these Alcon studies contained results for the Clareon material (2 one-year studies, and 1 three-year study). The literature review included 50 papers from 1998 to 2015. In combination, 30,891 eyes were available for analysis and 2040 Nd:YAG procedures were reported in studies with a follow-up duration ranging in length from 4 months to 10 years. The overall probability of performing a Nd:YAG capsulotomy within a year of implant for AcrySof was 1.44% (1.11% to 1.83%) and 0.62% (0.21% to 1.38%) for Clareon. There was small improvement in the probability of Nd:YAG within a year of implant for Clareon lenses of about 0.82% with a 95% credible interval of (0.07% to 1.36%) at 1 year. Results were similar for incidence rates per 100 surgeries in a year: 0.62 (0.21 to 1.40) for Clareon, 1.46 (1.12 to 1.87) for AcrySof, and the difference was 0.84 (0.07 to 1.39) favoring Clareon. At 3 years, the overall probability of performing a Nd:YAG capsulotomy for AcrySof was 4.19% (3.24% to 5.30%) compared with only 1.82% (0.63% to 4.02%) for Clareon.

Conclusion

A meta-analysis of Clareon multi-piece and single-piece clinical data predicts that the cumulative Clareon Nd:YAG probability will be ≤ AcrySof by 2.37% (0.18% to 3.91%) at 3 years. The results indicate that Clareon is likely to perform as well as, and possibly better than, AcrySof in terms of Nd:YAG capsulotomy rates.

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.

Epidemiological evaluation of YAG capsulotomy incidence for posterior capsule opacification in various intraocular lenses in Japanese eyes

Background and objective

We investigated the yttrium aluminum garnet (YAG) capsulotomy rates in various intraocular lenses (IOLs).

Study design/patients and methods

We retrospectively analyzed 23,440 eyes implanted with either MA60BM, MA60AC, VA-60BB, CeeOnEdge, Clariflex, Technis Z9002, SI-40NB, or UV26T IOLs. We calculated the YAG capsulotomy rates at 1, 3, 5, and 10 years post lens implantation.

Results

YAG capsulotomy rates at 3 years postimplantation for the eight groups of IOLs were, respectively, 3.7%, 3.9%, 23.7%, 3.4%, 4.5%, 4.7%, 10.4%, and 21.0%. YAG capsulotomy rates at 10 years postimplantation for the MA60BM and SI-40NB IOLs were, respectively, 9.1% and 15% (P<0.05). The average YAG rates for all sharp-edged and round-edged IOLs at 5 years postimplantation were, respectively, 5.2%±0.7% and 25.6%±9.0% (P<0.05).

Conclusion

In all studied IOLs, posterior capsule opacification prevention seemed to be associated with the posterior optic sharp-edge design. Round-edged silicone IOLs may also retard posterior capsule opacification formation, though not as much as sharp-edged IOLs. As the follow-up period progressed, round-edged silicone IOLs showed significantly higher YAG rates than sharp-edged IOLs.

The effect of single-piece hydrophobic acrylic intraocular lenses on the development of posterior capsule opacification

PURPOSE

To evaluate the long-term effect of a single-piece hydrophobic acrylic intraocular lens (IOL), AcrySof SN60AT (Alcon Laboratories, Fort Worth, Texas, USA), on the development of posterior capsule opacification (PCO) 5 years postoperatively.

DESIGN

Prospective, observational, consecutive, case series.

METHODS

setting: Iladevi Cataract and IOL Research Center, Ahmedabad, India.

STUDY POPULATION

Three hundred and ninety eyes with uncomplicated age-related cataract were included. Patients with diabetes mellitus, glaucoma, high myopia, pseudoexfoliation, traumatic cataract, subluxated cataract, previous ocular surgeries, and allergy to dilating drops were excluded. intervention procedures: Digital retroillumination photographic documentation was performed and analyzed for PCO using Evaluation of Posterior Capsule Opacification software. The scores and areas were calculated.

MAIN OUTCOME MEASURES

PCO development and the influence of the anterior capsule cover (total on and part on) on the IOL optic was studied within the capsulorrhexis margin and the central 3.0 mm optic area.

RESULTS

There was a significant increase in PCO up to 3 years. No significant change in PCO was observed between 3 and 5 years within the capsulorrhexis margin and central 3.0 mm optic area. In the total on group, within the capsulorrhexis margin, significantly lower scores and areas were observed when compared with part-on scores and areas.

CONCLUSION

The increase in PCO up to 3 years was significant. Stabilization in PCO was observed between 3 and 5 years with no difference at 5 years. There was a low incidence of PCO in eyes with total anterior capsule cover over the IOL optic.

Comparison of posterior capsule opacification at 360-degree square edge hydrophilic and sharp edge hydrophobic acrylic intraocular lens in diabetic patients

AIM

To compare posterior capsule opacification (PCO) degree and visual functions after phacoemulsification in eyes implanted with 360-degree square edge hydrophilic acrylic intraocular lens (IOL) (570C C-flex, Rayner) and sharp edge hydrophobic acrylic IOL (Sensar AR40e, AMO) in diabetic patients.

METHODS

Sixty diabetic patients underwent uneventful phacoemulsification and randomly implanted one of the two IOLs. The PCO value was measured by retroillumination photographs and Evaluation of Posterior Capsule Opacification (EPCO) 2000 image-analysis software at 1, 6, 12, and 24mo after surgery. Visual acuity, and contrast sensitivity in photopic and mesopic conditions were also examined at each follow up time point. The incidence of eye that required Nd:YAG laser posterior capsulotomy were also compared.

RESULTS

There was not any statistically significant difference in PCO scores between Rayner C-flex 570C group and Sensar AR40e group at each follow up time point. Visual acuity, Nd:YAG capsulotomy incidence and contrast sensitivity also had no significant difference during the 24mo follow-up.

CONCLUSION

For diabetic patients, Rayner 570C C-flex and Sensar AR40e IOLs are same effective for prevent PCO. The 360-degree square edge design maybe is a good alternative technique to improve PCO prevention.

Posterior capsule opacification with 3 intraocular lenses: 12-year prospective study

PURPOSE

To compare posterior capsule opacification (PCO) with 3 intraocular lenses (IOLs) 12 years postoperatively.

SETTING

St. Erik Eye Hospital, Stockholm, Sweden.

DESIGN

Randomized clinical trial.

METHODS

Patients having unilateral standard phacoemulsification were randomized to implantation of a round-edged heparin-surface-modified (HSM) poly(methyl methacrylate) (PMMA) IOL, a round-edged silicone IOL, or a sharp-edged hydrophobic acrylic IOL. The neodymium:YAG (Nd:YAG) capsulotomy rates and timing from surgery were recorded. Survival analysis was used to compare Nd:YAG rates. Retroillumination images were taken to evaluate PCO.

RESULTS

After 12 years, there was no significant difference in the fraction or severity of PCO between the silicone IOL and acrylic IOL. The HSM PMMA IOL had a significantly higher PCO fraction than the silicone IOL (P<.05), but not more than the acrylic IOL. There was no difference in PCO severity between the HSM PMMA IOL and the other 2 IOLs. The silicone IOL had higher median capsulotomy-free survival (>150 months) than the acrylic IOL (108 months) and the HSM PMMA IOL (53 months). Overall survival without Nd:YAG capsulotomy did not differ between the acrylic and silicone IOLs or between the silicone and HSM PMMA IOLs; however, overall survival was significantly better with the acrylic IOL than with the HSM PMMA IOL (P<.001).

CONCLUSIONS

After 12 years, there was no difference in PCO or overall survival without capsulotomy between the acrylic IOL and the silicone IOL. The HSM PMMA IOL had a significantly higher PCO fraction than the silicone IOL and lower overall survival than the acrylic IOL.

Posterior capsule opacification with the iMics1 NY-60 and AcrySof SN60WF 1-piece hydrophobic acrylic intraocular lenses: 3-year results of a randomized trial

PURPOSE

To compare the intensity of posterior capsule opacification (PCO) 3 years after implantation of 2 different 1-piece foldable hydrophobic acrylic intraocular lenses (IOLs).

DESIGN

Randomized, prospective, patient- and examiner-masked clinical trial with intraindividual comparison.

METHODS

One hundred patients with bilateral age-related cataract (200 eyes) had standard cataract surgery with implantation of an iMics1 NY-60 IOL (Hoya Corp) in one eye and an AcrySof SN60WF IOL (Alcon Laboratories) in the other eye. Follow-up examinations were performed at 1 week and 3 years. Digital retroillumination images were obtained of each eye. The main outcome measure was PCO score (scale, 0 to 10) assessed subjectively at the slit lamp and objectively using automated image analysis software (Automated Quantification of After-Cataract) 3 years after surgery.

RESULTS

The objective PCO score (mean ± standard deviation) was 3.0 ± 2.0 for the iMics1 NY-60 IOL and 1.9 ± 1.4 for the AcrySof SN60WF IOL (P < .001). Three years after surgery, 35.6% of patients underwent a neodymium:yttrium-aluminum-garnet capsulotomy in the iMics1 NY-60 eye and 13.7% underwent a capsulotomy in the AcrySof SN60WF eye (P = .001). There was no statistically significant difference in best-corrected visual acuity, rhexis-IOL overlap, capsular folds, or anterior capsule opacification. Glistening formations were found in no iMics1 NY-60 IOLs, but in 97% of the AcrySof SN60WF IOLs.

CONCLUSIONS

Comparison of 2 sharp-edged single-piece IOLs of similar design and hydrophobic acrylic material indicated a statistically significant difference in PCO and neodymium:yttrium-aluminum-garnet capsulotomy rate 3 years after surgery.

Posterior capsular opacification in patients with pseudoexfoliation syndrome: a long-term perspective

PURPOSE

To compare posterior capsular opacification in patients with and without pseudoexfoliation syndrome 6-7 years following surgery.

METHODS

Forty-four eyes of 44 patients with pseudoexfoliation syndrome who underwent cataract surgery with phacoemulsification in 2001 and 2002 were available for follow-up in 2008. These patients were compared to 86 age- and gender-matched patients (86 eyes) without pseudoexfoliation syndrome who had surgery during the same time period. Posterior capsule opacification was assessed using digital retroillumination photography. The images were analysed with a software program (POCOman) to determine the extent and severity of the capsular opacification.

RESULTS

Percentage and severity of posterior capsular opacification within the central 4.0 and 1.3 mm of the optical zone were compared in eyes with and without pseudoexfoliation syndrome. Neither of these results were statistically significant. Before the re-examination in 2008, neodymium:yttrium-aluminium-garnet laser posterior capsulotomy had been conducted in 16% (n = 7) of eyes with pseudoexfoliation syndrome, as well as in 16% (n = 14) of eyes without pseudoexfoliation syndrome.

CONCLUSION

Our study indicates that, with phacoemulsification, development of long-term posterior capsular opacification is not increased in patients with pseudoexfoliation syndrome after uncomplicated cataract surgery.

Comparison of posterior capsule opacification and glistenings with 2 hydrophobic acrylic intraocular lenses: 5- to 7-year follow-up

PURPOSE

To compare posterior capsule opacification (PCO) and glistenings 5 to 7 years after cataract surgery with implantation of 2 hydrophobic acrylic intraocular lenses (IOLs) and evaluate the effects on corrected distance visual acuity (CDVA) and contrast sensitivity.

SETTING

St. Erik Eye Hospital, Stockholm, Sweden.

DESIGN

Randomized clinical trial.

METHODS

Cataract surgery with standard phacoemulsification was performed in 1 eye of patients. The patients were randomized to an Acrysof SA60AT (1-piece IOL group) or a Sensar AR40e (3-piece IOL group), both hydrophobic acrylic IOLs with a sharp-edged design. Five to 7 years postoperatively, retroillumination images were obtained and the PCO area and severity (area affected within the capsulorhexis and severity) were evaluated using computer software. High-contrast (100%) and low-contrast (2.5%) CDVAs were measured. The neodymium:YAG laser capsulotomy rates were recorded. Scheimpflug images were obtained to evaluate glistenings, which were graded subjectively at the slitlamp and quantified objectively by digital image analysis using computer software.

RESULTS

The study enrolled 80 patients. There were no significant differences in PCO between the 2 groups. The 3-piece IOL group had significantly fewer glistenings (P<.001). There was good correlation between the subjective grading of glistenings and objective computer-processed image grading. The glistenings were not correlated with IOL power, CDVA, or contrast sensitivity.

CONCLUSIONS

There were no significant differences in PCO between the 2 acrylic hydrophobic IOLs 5 to 7 years postoperatively. The 1-piece IOL group developed more glistenings than the 3-piece IOL group.

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.

Pathology of 157 human cadaver eyes with round-edged or modern square-edged silicone intraocular lenses: analyses of capsule bag opacification

PURPOSE

To assess the degree of capsular bag opacification in human cadaver eyes with silicone intraocular lenses (IOLs), specifically comparing the differences between round-edged IOLs and modern square-edged IOLs.

SETTING

John A. Moran Eye Center, University of Utah, USA.

DESIGN

Experimental study.

METHODS

The eyes were immersed in 10% formalin on enucleation. They had anterior segment scanning with a very-high-frequency ultrasound (Artemis). After the eyes were sectioned at the equator, gross examination of the anterior segment was performed from the posterior aspect to assess the degree of capsular bag opacification, coverage of the IOL edge by the anterior capsule, and IOL fixation. Selected eyes also had histopathologic examination.

RESULTS

Eighty-seven eyes with a 3-piece round-edged IOL, 43 with a 3-piece square-edged IOL, 26 with a 1-piece plate IOL, and 1 with an accommodating IOL design were included in the analyses of capsular bag opacification. Comparison between 3-piece round-edged IOLs and square-edged IOLs showed statistically significant differences in central posterior capsule opacification (PCO) (P=.0001687) and peripheral PCO (P<.0001). In eyes with square-edged IOLs, PCO had a tendency to start in areas without capsulorhexis coverage of the optic. Twenty-one of 26 eyes with a silicone plate IOL had a neodymium:YAG posterior capsulotomy for dense PCO.

CONCLUSIONS

This first study using pseudophakic human cadaver eyes that includes a significant number of modern 3-piece silicone IOLs with square optic edges confirmed the role of this design in the prevention of PCO.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Effect of delivery of MMP inhibitors from PDMS as a model IOL material on PCO markers

Posterior capsule opacification (PCO) or secondary cataract formation, following intraocular lens implantation, is a significant complication affecting an estimated 28% of cataract patients. Matrix metalloproteinases (MMPs) have been demonstrated to play a role in the formation of anterior subcapsular cataracts and it has been shown that the presence of MMP inhibitors (MMPI) decreases subcapsular cataract formation ex vivo. Since the mechanisms responsible for anterior subcapsular cataract formation and posterior capsule opacification are similar, it is reasonable to suggest that MMP inhibitors may also mitigate PCO. One of the most effective ways of delivering the inhibitors may be from the implanted intraocular lens (IOL) material itself. In the current work, delivery of three different MMP inhibitors from silicone rubber as a model IOL material was examined. Loading methods were developed which allowed continuous release of active MMPI for periods of over 5 months in some cases. Reduced migration rates were observed in human lens epithelial cells in vitro, suggesting that an effect on PCO may be possible. While further studies are necessary to tune the systems to achieve the desired rates of release, this work demonstrates that delivery of MMPI from silicone IOL materials has the potential to decrease the incidence of PCO.

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.