Interventions for preventing posterior capsule opacification

Novel Technique of Pneumatic Posterior Capsulorhexis for Treatment and Prevention of Posterior Capsular Opacification

PURPOSE

To evaluate a new technique of posterior capsulorhexis using air support to treat primary posterior capsular opacification (PCO) during cataract extraction surgery or to prevent postoperative PCO.

SETTING

(1) Ophthalmology department, Faculty of Medicine, Minia University, 61519, El-Minia, Egypt. (2) Security Forces Hospital, Ophthalmology Department, Riyadh, Kingdom of Saudi Arabia.

DESIGN

Prospective, randomized, consecutive case comparative non controlled study.

METHODS

One hundred eyes of 100 patients with a mean age of 63.3 years with dense cataract were enrolled in the study. Fifty of them (group (1)) were with primary PCO (discovered during the operations) and fifty (group (2)) with clear posterior capsule. All of the patients underwent phacoemulsification and posterior capsulorhexis using the air to support the posterior capsule. Then, IOL implantations were done between the anterior and posterior capsular rims. Postoperatively, each patient was evaluated for the following: visual acuity (UCVA and BCVA), manifest refractive spherical equivalent (MRSE), intraocular pressure, intraocular lens (IOL) stability, visual axis opacification, and posterior segment complications as retinal breaks, retinal detachment, or cystoid macular edema (CME).

RESULTS

There were no significant differences in UCVA, BCVA, and MRSE. All cases had a clear visual axis, with stable IOL and normal IOP during the follow-up period without posterior segment complications. The VA improved significantly throughout the follow-up periods in both groups without significant clinical difference.

CONCLUSION

Pneumatic posterior capsulorhexis is a new effective technique for the treatment of primary PCO in dense cataract and for prevention of postoperative PCO with the good visual outcomes and minimal complications. This trial is registered with NCT04007965.

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.

Influence of super-hydrophobic silicone rubber substrate on the growth and differentiation of human lens epithelial cells

Materials with low cell adhesion are advantageous for production of replacement intraocular lens (IOL) to prevent posterior capsular opacification (PCO). We evaluated the feasibility of compression molding for manufacture of silicone rubber with super-hydrophobic surface and low cell infiltrative characteristics compared to ordinary hydrophobic silicone rubber. Silicone specimens with complex surface topology (super-hydrophobic) or smooth surfaces (hydrophobic) were manufactured by vacuum deforming and molding. Contact angle, microscopic surface structure, and transparency were evaluated. Super-hydrophobic and smooth samples were compared for effects on proliferation, adhesion, and morphology of human lens epithelial cells (hLECs). Epithelial-mesenchymal transition (EMT) was examined by immunofluorescence expression of fibronectin (Fn), Alpha-smooth muscle actin (α-SMA), and vimentin. The surface contact angle of super-hydrophobic silicone was greater than that of smooth silicone (153.8° vs. 116°). The super-hydrophobic surface exhibited a micron-scale palisade structure under scanning electron microscopy (unit length, width, and height of 80, 25, and 25 μm, respectively). However, cell number per 50 × microscopic field on super-hydrophobic surfaces was markedly reduced 24 and 72 h post-seeding compared to smooth surfaces (p < 0.01). Cells were cuboidal or spherical after 72h on super-hydrophobic surfaces, and exhibited numerous surface microvilli with fluff-base polarity, while cells on smooth surfaces exhibited morphological characteristics of EMT. Expression levels of the α-SMA and vimentin were reduced on super-hydrophobic surfaces compared to smooth surfaces. Super-hydrophobic silicon inhibits proliferation, adhesion, and EMT of hLECs, properties that may prevent fibrosis following cataract surgery.

German claims data analysis to assess impact of different intraocular lenses on posterior capsule opacification and related healthcare costs

Aim

Cataract extraction is one of the most frequent surgeries in Germany. In most cases, the clouded natural lens is replaced by a hydrophobic or hydrophilic acrylic intraocular lens (IOL) implant. The most common long-term complication after cataract surgery is the development of a posterior capsule opacification (PCO). Although no precise real world data are available, published evidence suggests a lower risk for PCO development for hydrophobic acrylic IOLs compared to hydrophilic acrylic IOLs. Therefore, in the present study we assessed real world data on the impact of different IOL material types on the incidence of post-operative PCO treatment.

Subject and methods

In this retrospective study, we included 3,025 patients who underwent cataract extraction and implantation of either an acrylic hydrophobic or hydrophilic IOL in 2010. We assessed clinical outcomes and direct costs in a 4-year follow-up period after cataract surgery from a statutory health insurance (SHI) perspective in Germany.

Results

PCO that required capsulotomies occurred significantly (p < 0.0001) less frequent in patients who had received a hydrophobic IOL (31.57% of 2,078 patients) compared to the group with hydrophilic IOL implants (56.6% of 947 patients) and costs per patient for postoperative treatment in a 4-year follow-up were 50.03 € vs. 87.81 € (i.e. 75% higher in the latter group, p < 0.0001).

Conclusion

Considering the high prevalence of cataract, the economic burden associated with adverse effects of cataract extraction is of great relevance for the German SHI. Hydrophobic lenses seem to be superior regarding both medical and economic results.

Predictors of Successful Laser Capsulotomy for Significant Posterior Capsule Opacification after Phacoemulsification

Purpose:

This study aimed to determine the reasons behind the failure of laser capsulotomy (LC) performed for significant posterior capsular opacification (PCO).

Methods:

Eighty-eight eyes of 88 patients referred for LC at a tertiary care center were retrospectively analyzed. The data recorded included the cause of cataract, visual acuity, duration of PCO, location of PCO, intraocular lens (IOL) position, IOL type, and lens capsule status. These data were later analyzed for determining the requirement of high pulse energy during LC and the success rate of primary LC.

Results:

The mean age of the participants was 55.77 ± 18.60 years with 58 (65.9%) male patients. The mean duration between cataract and LC surgeries was 45.58 ± 37.33 months. Senile (n=58), uveitic (n=12), post-pars plana vitrectomy (PPV) (n=12), and traumatic (n=6) cataracts were the common causes. Late-presenting PCO, trauma, uveitis, sulcus placement of IOLs, irregular capsulorhexis shape, and polymethyl methacrylate (PMMA) IOLs were significantly associated with unsuccessful LC and/or higher pulse energy settings during LC.

Conclusion:

Significant PCO is often associated with cataract caused by uveitis or trauma, and after PPV. PCO associated with trauma, sulcus placement of IOLs, and PMMA IOLs may need multiple LCs.

Cochrane systematic reviews and co-publication: dissemination of evidence on interventions for ophthalmic conditions

BACKGROUND

Systematic reviews of interventions provide a summary of the evidence available on intervention effectiveness and harm. Cochrane systematic reviews (CSRs) have been published electronically in the Cochrane Database of Systematic Reviews (CDSR) since 1994, and co-publication (publication of a Cochrane review in another journal) has been allowed since that time, as long as the co-publishing journal has agreed to the arrangement. Although standards for co-publication were established in 2008, the frequency of co-publication and adherence to the standards have remained largely unexamined. Our objective was to examine the frequency of co-publication of Cochrane Eyes and Vision Group (CEVG) reviews, adherence to the co-publication policy, the relative numbers of citations of the two modes of publishing, and differences in times cited in CSRs with and without a co-publication.

METHODS

We identified all CEVG reviews published by May 30, 2014 in The Cochrane Library. Using keywords from the title, author names, and "Cochrane Eyes and Vision Group", we searched Google Scholar, Web of Science, Scopus, and PubMed databases to identify possible co-publications. We also emailed contact authors of all identified CEVG reviews to ask them whether they had published their CSR elsewhere. We compared each co-publication to the corresponding CEVG review for adherence to the Cochrane Policy Manual (dated June 10, 2014). We recorded the number of times each CEVG review and each co-publication had been cited by others according to Google Scholar, Web of Science, and Scopus, as of June 11, 2014.

RESULTS

We identified 117 CEVG reviews;19 had been co-published in 22 articles. Adherence to Cochrane policy on co-publication was moderate, with all authors complying with at least one of four requirements we addressed. Co-publications were cited more often than the corresponding CEVG reviews; CEVG reviews with at least one co-publication were cited approximately twice as often as CEVG reviews without a co-publication. The number of citations varied considerably depending on whether the CEVG review had a co-publication or not.

CONCLUSIONS

The findings support encouraging co-publication while maintaining the primacy of the Cochrane systematic review. Support for co-publication may be tempered by other factors such as the possibility that CEVG reviews with a co-publication covered more clinically important and timely topics than those without a co-publication. Assuming that citations are a valid measure of dissemination effectiveness, the 15-year CEVG experience with co-publication of systematic reviews suggests that Cochrane authors should be encouraged to co-publish in traditional medical journals.

Does Posterior Capsule Opacification Affect the Results of Diagnostic Technologies to Evaluate the Retina and the Optic Disc?

The visual outcome obtained after cataract removal may progressively decline because of posterior capsular opacification (PCO). This condition can be treated by creating an opening in the posterior lens capsule by Nd:YAG laser capsulotomy. PCO optical imperfections cause several light reflection, refraction, and diffraction phenomena, which may interfere with the functional and structural tests performed in different ocular locations for the diagnosis and follow-up of ocular disease, like macular and optic nerve diseases. Some parameters measured by visual field examinations, scanning laser polarimetry, and optical coherence tomography (OCT) have changed after PCO removal. Imaging quality also changes following capsulotomy. Consequently, the results of ancillary tests in pseudophakic eyes for studying ocular diseases like glaucoma or maculopathies should be correlated with other clinical examinations, for example, slit-lamp biomicroscopy or funduscopy. If PCO is clinically significant, a new baseline should be set for future comparisons following capsulotomy when using automated perimetry and scanning laser polarimetry. To perform OCT in the presence of PCO, reliable examinations (considering signal strength) apparently guarantee that measurements are not influenced by PCO.

[Posterior capsule opacification, capsular bag distension syndrome, and anterior capsular phimosis: A retrospective cohort study]

OBJECTIVE

To determine the incidence and the risk factors involved in the development of the three main postoperative capsular complications: posterior capsule opacification (PCO), capsular bag distension syndrome (CBDS), and anterior capsular phimosis syndrome (ACP).

SUBJECTS, MATERIAL AND METHODS

A retrospective cohort study was conducted on 801 patients submitted to cataract surgery in the ophthalmology unit of Hospital del Henares (Madrid) from March 2, 2009 to February 28, 2010. Computerized clinical charts were reviewed during July 2012. PCO was studied using the Kaplan-Meier method (log rank test).

RESULTS

A total of 167 patients developed PCO. No association could be demonstrated between PCO and age, sex, diabetes mellitus, phaco technique, IOL model, tamsulosin intake, glaucoma, and age-related macular degeneration. Three patients developed CBDS, all of them have received and Akreos Adapt AO(®) (Bausch & Lomb). Two of them were young men who had received surgery for posterior subcapsular cataracts. Three patients developed ACP, 2 of whom had received a MicroSlim(®) IOL (PhysIOL).

CONCLUSIONS

No association was found between PCO and any of the studied variables. Male gender, young age, subcapsular cataract and large non-angulated lens such as Akreos Adapt AO(®) could be associated with CBDS. ACP could be more frequent when microincision IOLs (like MicroSlim(®)) are implanted.

In vitro growth of lens epithelial cells from cataract patients - association with possible risk factors for posterior capsule opacification

AIM

Inter-individual differences in intrinsic proliferative capacity of lens epithelial cells may have importance for the risk of developing posterior capsule opacification (PCO) after cataract surgery. The purpose of the present study was to determine growth of human lens epithelial cells (HLEC) in culture and investigate possible associations with clinical characteristics of the donors, such as age, sex, pseudoexfoliation, uveitis and diabetes.

METHODS

Pieces of lens capsule and adhering lens epithelial cells were obtained through capsulorhexis at cataract surgery. Specimens were cultured in a humidified CO2-incubator using standard culture medium and 5% fetal calf serum for two weeks after which cultured cells were stained with carboxy-fluorescein diacetate succinimidyl ester. Image processing software was used to determine the area of the confluent epithelial cell layer in relation to the size of the original capsule specimen.

RESULTS

The increase in area of confluent HLEC showed a negative correlation with diabetes at the first week after surgery. Lower age and female sex showed border-line significant associations with a higher rate of cell proliferation. The presence of pseudoexfoliation in vivo did not significantly affect cell growth in culture postoperatively. Nor did installation of xylocain in the anterior chamber during surgery.

CONCLUSION

Diabetes is associated with lower rate of proliferation of lens epithelial cells in culture. The lack of strong correlations between in vitro growth and known risk factors for PCO in the donors suggest that other factors than the proliferative capacity of the cells per se are important for PCO formation.

Myo/Nog cells: targets for preventing the accumulation of skeletal muscle-like cells in the human lens

Posterior capsule opacification (PCO) is a vision impairing condition that arises in some patients following cataract surgery. The fibrotic form of PCO is caused by myofibroblasts that may emerge in the lens years after surgery. In the chick embryo lens, myofibroblasts are derived from Myo/Nog cells that are identified by their expression of the skeletal muscle specific transcription factor MyoD, the bone morphogenetic protein inhibitor Noggin, and the epitope recognized by the G8 monoclonal antibody. The goal of this study was to test the hypothesis that depletion of Myo/Nog cells will prevent the accumulation of myofibroblasts in human lens tissue. Myo/Nog cells were present in anterior, equatorial and bow regions of the human lens, cornea and ciliary processes. In anterior lens tissue removed by capsulorhexis, Myo/Nog cells had synthesized myofibroblast and skeletal muscle proteins, including vimentin, MyoD and sarcomeric myosin. Alpha smooth muscle actin (α-SMA) was detected in a subpopulation of Myo/Nog cells. Areas of the capsule denuded of epithelial cells were surrounded by Myo/Nog cells. Some of these cell free areas contained a wrinkle in the capsule. Depletion of Myo/Nog cells eliminated cells expressing skeletal muscle proteins in 5-day cultures but did not affect cells immunoreactive for beaded filament proteins that accumulate in differentiating lens epithelial cells. Transforming growth factor-betas 1 and 2 that mediate an epithelial-mesenchymal transition, did not induce the expression of skeletal muscle proteins in lens cells following Myo/Nog cell depletion. This study demonstrates that Myo/Nog cells in anterior lens tissue removed from cataract patients have undergone a partial differentiation to skeletal muscle. Myo/Nog cells appear to be the source of skeletal muscle-like cells in explants of human lens tissue. Targeting Myo/Nog cells with the G8 antibody during cataract surgery may reduce the incidence of PCO.

Comparison of clinical efficacy: Nd:YAG laser rates after implantation of AcrySof® SN60WF, Akreos® AO-MI60 and Hoya® YA-60BB

PURPOSE

To compare Nd:YAG laser rates following implantation of AcrySof(®) SN60WF (Alcon), Akreos(®) AO-MI60 (Baush & Lomb), and Hoya(®) YA-60BB (Hoya) intraocular lenses.

METHODS

This retrospective study was conducted at three French centers with each implanting at least two of the three implants. Included patients had undergone uncomplicated cataract surgery with at least 3 years of follow-up. Records of patients implanted with one of the three IOL's were drawn randomly from the surgical logs. Postoperative data were obtained from the medical records of either the surgeon or the referring physician. Time elapsing until Nd:YAG laser was analysed using Kaplan-Meier survival curves.

RESULTS

Three hundred eyes were implanted (AcrySof(®) 126, Akreos(®) 89, and Hoya(®) 85). AcrySof(®) recipients were the youngest (AcrySof(®) 72.1, Akreos(®) 76.4, and Hoya(®) 75.2 years of age: P=0.0007). The sex ratio was 4:6 male:female. Follow-up was longest for Hoya eyes (AcrySof(®) 29.4, Akreos(®) 24.6 and Hoya(®) 34.6 months; P=0.0002). Eyes implanted with AcrySof(®) had 1.74 times less chance of Nd:YAG laser treatment than Hoya eyes (P=0.0327) and 3.50 times less than Akreos(®) eyes (P<0.0001). The results remained unchanged when the analysis was restricted to events in the first 24 months (Risk Ratios: Hoya(®)=2.64: P=0.02; and Akreos(®)=4.22: P=0.0001). Adjustment on unbalanced confounding variables did not alter the results.

CONCLUSIONS

Eyes with AcrySof(®) implants required significantly fewer Nd:YAG laser capsulotomies than those with Hoya(®) and Akreos(®) implants and were therefore less subject to Nd:YAG laser treatment complications, thus ensuring better vision at the lowest cost.

Clinical consequences of acrylic intraocular lens material and design: Nd:YAG-laser capsulotomy rates in 3 x 300 eyes 5 years after phacoemulsification

Background/aims

To investigate the incidence of Nd:YAG-laser treatment for posterior capsular opacification (PCO) over a period of 5 years from phacoemulsification in an unselected population, comparing outcomes for three acrylic intraocular lenses (IOLs).

Methods

Retrospective longitudinal cohort study comprising 900 eyes. Three subgroups of 300 eyes, receiving the AR40, AR40e (Abbott Medical Optics, Santa Ana, California), or BL27 (Bausch & Lomb, Rochester, New York) IOL respectively, were compared. Data on patient age, gender, IOL type, dates of cataract surgery, Nd:YAG-laser treatment and/or death, and visual acuities before/after cataract surgery/Nd:YAG-laser treatment were collected from five sources: cataract operation register, patient administration system, quality control system for cataract operations, Nd:YAG-laser treatment register and clinical patient records.

Results

216 eyes (24%) received Nd:YAG-laser treatment over a 5-year period. Statistically significant differences (p<0.001, χ² test) were found between treatment rates for the three IOLs: AR40 73 eyes (24%), BL27 91 eyes (30%) and AR40e 52 eyes (17%). Eyes of patients who died during the follow-up period had fewer treatments (23/266, 8.6%) than eyes of patients living (193/634, 30%) at the end of the follow-up period.

Conclusion

In comparison with a hydrophobic acrylic IOL with sharp posterior optic edge, a hydrophilic acrylic IOL was associated with almost twice the number of Nd:YAG-laser treatments over the 5-year period. The results are useful for discussing the economic long-term consequences of choosing an IOL with a design that makes PCO development more or less likely. Caution is advised when applying data from post-mortem PCO studies on living populations.

Modelling lifetime cost consequences of ReSTOR in cataract surgery in four European countries

BACKGROUND

To compare the lifetime costs of liberating patients from spectacles after cataract surgery by implanting the multifocal intraocular lens (IOL) 'ReSTOR' versus monofocal IOLs in France, Italy, Germany and Spain.

METHODS

A Markov model was created to follow patient cohorts from cataract surgery until death. Prevalence rates of patients not needing spectacles after cataract surgery were obtained from clinical trials. Resource utilisation included implant surgery, IOLs, spectacles, visits to ophthalmologists and eye centres, transport, and time lost by patients. Economic perspectives were those of Society and Sickness Funds (SFs).

RESULTS

The mean number of spectacles purchased after ReSTOR was 1.34-1.61 and after monofocal IOLs 6.05-7.27. From the societal perspective, total cost estimates discounted by 3% were between 3,551 euros and 4,052 euros with ReSTOR compared to 3,989 euros and 5,548 euros with monofocal IOLs. Undiscounted savings related to ReSTOR ranged from 815 euros to 2,164 euros. From the SFs' perspective total cost estimates discounted by 3% were between 2,150 euros and 2,524 euros with ReSTOR compared to 2,324 euros and 2,610 euros with monofocal IOLs. Savings related to ReSTOR, once costs discounted, ranged from 61 euros to 219 euros. Discount and spectacle freedom prevalence rates were the most sensitive parameters.

CONCLUSION

The bulk of the savings related to ReSTOR were realized outside the SF. From both a societal and SF perspective, savings, after a 3% discounting, achieved by liberating patients from spectacles counterbalanced the initially higher cost of ReSTOR. ReSTOR is a cost saving alternative to spectacles for patients requiring cataract surgery.