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. 2017 Jan 19;2017(1):CD012516. doi: 10.1002/14651858.CD012516

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

Sophie Maedel 1,✉, Wolf Buehl 2, Oliver Findl 1
PMCID: PMC6464775

Abstract

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

The aim of this review is to summarise the effects of modifications in intraocular lens optic edge design on PCO after cataract surgery.

Background

Extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens (IOL) implantation is the preferred surgical technique for the treatment of opacification of the crystalline lens (cataract) in developed countries, and most surgeons in developing countries are now being trained in this method (Ang 2014; Riaz 2013). In this technique, the lens contents are removed leaving the posterior lens capsule intact. This forms an anatomical barrier between the anterior and posterior segments of the eye. This is thought to reduce the risk of posterior segment complications following surgery (such as swelling of the central area of the retina (cystoid macular oedema) and retinal detachment) compared to intracapsular cataract extraction (ICCE), in which the whole lens with intact capsule is removed from the eye. Whereas phacoemulsification with implantation of a posterior chamber IOL is standard for cataract treatment in developed countries, this technique represents only 10% of all cataract surgeries in low‐ and middle‐income countries (LMICs) (Khanna 2011). The main reason for such a low percentage may be the high costs of phacoemulsification equipment (Findl 2010; Riaz 2006). However, leaving the capsule intact may result in long‐term complications, mainly that of posterior capsule opacification (PCO) (Apple 1992; Schaumberg 1998). People with PCO experience decreased visual acuity, impaired contrast sensitivity and glare.

Description of the condition

PCO is the most common postoperative complication after cataract surgery and PCO rates of 11.4‐ 43% have been described within the first year after surgery, dependent on surgical technique, IOL design and material and concomitant ocular diseases. (Schaumberg 1998; Wormstone 2002; Findl 2010; Riaz 2013) Clinically, PCO (or after‐cataract) is subdivided into two types: regeneratory and fibrotic PCO. Regeneratory PCO is much more common and is the main cause of a decrease in visual function after cataract surgery. Regeneratory PCO is a result of migration of lens epithelial cells along the posterior capsule, behind the IOL. These cells proliferate to form layers of lens material and Elschnig pearls, leading to opacification of the posterior capsule. In fibrotic PCO, lens epithelial cells of the anterior capsule undergo transformation to myofibroblasts, causing fibrosis and contraction of the capsule bag. This can lead to decentration of the IOL and hinder visualisation of the peripheral retina. If present on the posterior capsule, this may cause vision to deteriorate. Diagnosis is made by slit‐lamp examination by an ophthalmologist. Posterior capsule opacification is usually treated by cutting an opening into the posterior capsule with a neodymium:YAG (Nd:YAG) laser, or rarely by surgical opening (capsulotomy). However, laser treatment may damage the IOL optic, transiently increase intraocular pressure (IOP), induce cystoid macular oedema, increase the incidence of retinal detachment and often does not improve visualisation of the peripheral retina (Javitt 1992). Additionally, Nd:YAG laser treatment is associated with high costs for the health care system. In the United States, Nd:YAG capsulotomy is the second most commonly performed ophthalmic surgical procedure after cataract surgery. The annual cost of Nd:YAG capsulotomy was estimated to be $250 million in the United States alone (Apple 1992). The lack of availability of laser treatment is one of the major reasons why ECCE with IOL implantation is not extensively used in the developing world.

Description of the intervention

To prevent PCO in eyes after cataract surgery with implantation of an IOL, industry and clinicians make efforts to prevent PCO by modifying IOL loops (or haptics) and optics design. The IOL optic edge may be round or sharp, former means that the posterior surface and the lateral edge of the IOL meet at a right angle. Although a round optic edge creates broad contact between the IOL optic and the capsule, it does not create firm linear contact. The firm linear contact with the posterior capsule created by the sharp optic edge seems to be important in the inhibition of cell migration (Kohnen 2008).

How the intervention might work

IOL optics edges with a rectangular cut edge may improve contact between the posterior capsule and the IOL and, therefore, reduce the migration of remnant lens epithelial cells from the equatorial zone of the capsular bag. Lens epithelial cells proliferating from the periphery of the capsule stop when they reach a sharply bent edge of the capsule in contact with the sharp edge of the IOL . As a result, this optic edge design may have reduce progression of PCO towards the centre of the capsule and, therefore, towards the visual axis. Various manufacturers are offering IOLs with sharp optic edges in order to reduce postoperative PCO rate.

The introduction of sharp optic edges appears to reduce the incidence of PCO (Findl 2010). It is unclear whether differences in the style of IOL haptics play a role in PCO inhibition.

Why it is important to do this review

Two Cochrane reviews evaluating different surgical interventions for age‐related cataract have already been published (Ang 2014; Riaz 2006). There is an extensive body of published data on interventions to reduce the incidence of PCO. Besides surgical technique (Khalifa 1992, Hollick 1999), IOL material and biocompatibility (Auffarth 2004, Findl 2010 ), different IOL optic edge designs (Hollick 1999, Findl 2010, Nishi 2004, Nishi 1998) seem to influence interaction of the IOL with the capsule bag and therefore play an important role in the prevention of PCO progression (Findl 2010). Also intraocular pharmaceutical agents (Walker 2008) have been investigated on their influence on lens epithelial cell growth and PCO formation. In order to draw conclusions regarding the different IOL optic edge designs influence on preventing PCO, a systematic review of randomised controlled trials (RCTs) will be undertaken.

Objectives

The aim of this review is to summarise the effects of modifications in intraocular lens optic edge design on PCO after cataract surgery.

Methods

Criteria for considering studies for this review

Types of studies

We will include only RCTs.

Types of participants

Participants in the trials will be people with age‐related cataract including those with ocular comorbidities such as age‐related macular degeneration (AMD), diabetes, glaucoma or uveitis, who underwent cataract surgery (all extracapsular surgical techniques, including femtosecond laser assisted cataract surgery) with implantation of an IOL into the capsule bag. Other sight threatening ocular diseases (corneal disease, traumatic or complicated cataract, other retinal diseases than AMD) will be excluded from the review.

Types of interventions

We will include all clinical trials comparing amount of PCO in eyes with IOLs with sharp optic edge design compared to round optic edges, including IOLs with special optical properties, like toric, multifocal and accommodating IOLs.

Types of outcome measures

Primary outcomes

The primary outcome measure for this review will be proportion (or rate) of people needing Nd:YAG laser capsulotomy 12 months postoperatively

Nd:YAG capsulotomy may depend on the clinician's subjective evaluation, compared to PCO scores, which are objective measurement techniques. However, PCO scores do not incorporate whether PCO is located on the central or peripheral posterior capsule and may not reflect patients subjective visual impairment (Li 2013). Other than Nd:YAG capsulotomy, PCO scores do not reflect at which point patients are affected to such an amount, that they need treatment. Therefore, the capsulotomy proportion or rate will be used as the primary outcome.

The minimum length of follow‐up will be 12 months after surgery.

Secondary outcomes

1. Mean intensity of PCO, as assessed with scoring techniques or quantification by image analysis 12 months and 24 months postoperatively.

Assessment of PCO intensity/severity is complicated by the fact that there is no commonly accepted scoring method for PCO (Findl 2003). There are several well‐known subjective scoring systems such as the EPCO (Evaluation of PCO) computer‐aided scoring system as well as 'semi‐objective' or objective systems such as the POCO (posterior capsule opacification) and AQUA (Automated Quantification of After‐Cataract) systems, both based on automated analysis of retro‐illumination PCO images. Besides, there is a frequently used objective PCO assessment method based on analysis of Scheimpflug images. To facilitate comparability, we will convert the different scoring systems to a “common PCO score” ranging from 0 to 100 (by multiplying the scores, i.e.. scores ranging from 0‐10 will be multiplied by 10), which can therefore also be read as percentages.

It will be presumed that the PCO scoring systems are linear systems. Otherwise, it would not be possible to perform meta‐analyses for the PCO score. Both analysis of PCO scores and of visual acuity data will be additionally complicated by the fact that YAG capsulotomies may lead to a bias in many studies; when PCO scores or visual acuity data or both include eyes after a YAG capsulotomy. The best way to handle this problem will be to estimate the missing PCO scores after a capsulotomy (Buehl 2005; Findl 2005), however, in most studies there will be no information on how the problem of YAG drop‐outs was handled. When there are several follow‐up examinations in a study, we will use data of the last available follow‐up examination for the meta‐analysis in this review.

2. Mean best‐corrected distance visual acuity (BDVA) (logMAR) The minimum length of follow‐up to be included for meta‐analysis will be 12 months. Data of earlier follow‐ups will be mentioned but not included into analysis. Visual acuity data will be converted to the LogMAR scale.

3. Mean quality of life score as measured by any validated questionnaire at 12 months after surgery.

Adverse effects

  • intraoperative surgical complications (e.g. capsule rupture)

  • entopic phenomena (e.g. negative dysphotopsia)

  • clinically relevant IOL tilt and decentration

  • distinctive anterior capsule fibrosis and capsule phimosis

Search methods for identification of studies

Electronic searches

We will search the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision group Trials Register) (latest issue), Ovid MEDLINE, Epub Ahead of Print, In‐Process & Other Non‐Indexed Citations, Ovid MEDLINE Daily (January 1946 to present), Embase (January 1947 to present), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to present), he ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We will not use any date or language restrictions in the electronic search for trials.

See: Appendices for details of search strategies for CENTRAL (Appendix 1), MEDLINE (Appendix 2), Embase (Appendix 3), LILACS (Appendix 4), ISRCTN (Appendix 5), ClinicalTrials.gov (Appendix 6) and the ICTRP (Appendix 7).

Searching other resources

We will manually search reference lists of relevant trial reports. We will not manually search any conference abstracts for this review. If there is no English abstract available in foreign language publications or any doubts whether a trial should be included in the review, we will ask a translator for advice.

Data collection and analysis

Selection of studies

Two review authors (SM, WB) will review the titles and abstracts resulting from the searches. The same authors will obtain full‐text copies of possibly and definitely relevant trials and will assess them according to the criteria set out above. There will be no restrictions concerning publication date. Both authors will work independently from each other, discrepancies will be discussed among the authors.

Data extraction and management

Two review authors (SM, WB) will independently extract data using a pre‐piloted customised data extraction template in Covidence (Covidence 2016). The review authors will compare these and will resolve discrepancies by discussion. Data will be imported directly from Covidence into Review Manager 5 (RevMan 2014). If data are missing, we will try to contact the study authors by email and ask them to provide the missing information within a period of two months. One review author (WB) will check data entered in Review Manager 5 for accuracy. We will not exclude studies with missing standard deviation (SD) values but we will not incorporate them in the meta‐analyses.

Assessment of risk of bias in included studies

We will assess risk of bias according to the methods set out in Chapter 8 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). We will use four components to determine risk of bias: selection bias (sequence generation, allocation concealment), performance bias, detection bias and attrition bias. We will grade each component low risk of bias, high risk of bias or unclear risk of bias. Masking (blinding) of study participants and personnel may reduce the risk of performance bias and masking of outcome assessors reduce risk of detection bias, therefore both measures, if applicable, will be of special interest in our assessment of risk of bias in the studies included for this review. Two review authors (SM, WB) will independently assess the risk of bias and will resolve disagreements by discussion, the use of additional referees or both. The review authors will not be masked to any trial details during the assessment. If we are unable to make a decision about the classification of a study due to lack of information, we will try to contact the study authors.

Measures of treatment effect

We will present dichotomous outcomes like proportion of people needing capsulotomy as risk ratios, and continuous outcomes like BCVA and PCO scores as the mean difference.

Unit of analysis issues

Trials may randomise one or both eyes to the intervention or comparator. If people are randomly allocated to treatment group but only one eye per person is included in the trial then there will not be a unit of analysis issue. In these cases, we will document how the eye was selected. If people are randomly allocated to treatment but both eyes are included and reported, we will analyse as "clustered data" i.e. adjust for within‐person correlation. We may have to contact the trial investigators for further information to do this. If eyes are randomly allocated to treatment (within‐person study) then we will analyse as paired data. We may have to contact the trial investigators for further information to do this.

Dealing with missing data

Most missing data will be due to loss of follow‐up of patients. To assess whether the data are "missing at random" whenever possible, we will try to contact the original investigators to identify reasons for loss of follow‐up and request incomplete data, if available.

Assessment of heterogeneity

We will examine heterogeneity between trial results using a Chi2 test. Due to the fact that it has low power in the situation of a meta‐analysis when studies have small sample size or are few in number, a P value of 0.10 will be used to determine statistical significance. If we detect heterogeneity either by the I2 statistic or clinically within the trials, we will mention this in the results section of the review. According to Chapter 9 of the Cochrane Handbook for Systematic Reviews of Interventions, concerning I2 statistic, values of 30% to 60% may represent moderate heterogeneity, 50% to 90% may represent substantial heterogeneity, whereas values between 75% and 100% may indicate considerable heterogeneity (Deeks 2011).

Assessment of reporting biases

The main reporting biases that we will consider are publication bias and outcome reporting bias. For publication bias, if there are at least ten trials we will do a funnel plot to assess whether small trials have different effects. To assess outcome reporting bias we will complete a review outcome matrix following the ORBIT classification (Kirkham 2010).

Data synthesis

We will summarise data from studies collecting comparable outcome measures with similar follow‐up times. We will use a random‐effects model, unless there are fewer than three trials in a comparison, when we will use a fixed‐effect model.

Subgroup analysis and investigation of heterogeneity

It is possible that the effect of the interventions will vary not only according to the IOL optic edge design, but also to IOL optic material or surgical technique. If there are enough data, we will explore heterogeneity focusing primarily on these subgroups.

Additionally, we will perform subgroup analysis on eyes with and without different ocular comorbidities ‐ e.g. uveitis ‐ if there are enough data.

Sensitivity analysis

We will investigate the effect of excluding poorer quality trials, if there are enough trials contributing to the meta‐analyses. In particular, we will investigate the effect of excluding trials with higher risk of selection bias, performance bias or detection bias.

'Summary of findings' table

We will create a 'Summary of findings' table for YAG capsulotomy , PCO score, BDVA, intraoperative complications, presence of entopic phenomena, presence of IOL tilt/decentration and presence of distinctive anterior capsule fibrosis. We will grade the certainty of the evidence for each outcome using GRADE (GRADEpro 2014).

Acknowledgements

The Cochrane Eyes and Vision editorial team will develop and execute the electronic searches. We thank Catey Bunce and Mayank Nanavaty for comments on this protocol and Jennifer Evans and Anupa Shah for assistance with the protocol process.

Appendices

Appendix 1. CENTRAL search strategy

#1 MeSH descriptor: [Cataract Extraction] explode all trees #2 phacoemulsificat* or capsulorhexis #3 cataract* near/3 (extract* or surg*) #4 MeSH descriptor: [Lenses, Intraocular] explode all trees #5 MeSH descriptor: [Lens Implantation, Intraocular] explode all trees #6 MeSH descriptor: [Lens Capsule, Crystalline] explode all trees #7 MeSH descriptor: [Capsule Opacification] explode all trees #8 posterior near/3 capsul* near/3 opaci* #9 PCO #10 #1 or #2 or #3 or #4 or #5 or #6 or #7 or #8 or #9 #11 round‐edged #12 sharp‐edged #13 square‐edged #14 sharp‐optic* #15 (round* or sharp* or optic* or haptic*) near/6 (edge*) #16 (round* or sharp* or optic* or haptic*) near/6 (design*) #17 #11 or #12 or #13 or #14 or #15 or #16 #18 #10 and #17

Appendix 2. MEDLINE Ovid search strategy

1. randomized controlled trial.pt. 2. (randomized or randomised).ab,ti. 3. placebo.ab,ti. 4. dt.fs. 5. randomly.ab,ti. 6. trial.ab,ti. 7. groups.ab,ti. 8. or/1‐7 9. exp animals/ 10. exp humans/ 11. 9 not (9 and 10) 12. 8 not 11 13. exp cataract extraction/ 14. (phacoemulsificat$ or capsulorhexis).tw. 15. ((extract$ or surg$) adj3 cataract$).tw. 16. exp lenses, intraocular/ 17. exp lens implantation, intraocular/ 18. exp lens capsule crystalline/ 19. Capsule Opacification/ 20. (posterior adj3 capsul$ adj3 opaci$).tw. 21. PCO.tw. 22. or/13‐21 23. round‐edged.tw. 24. sharp‐edged.tw. 25. square‐edged.tw. 26. sharp‐optic$.tw. 27. ((round$ or sharp$ or optic$ or haptic$) adj6 edge$).tw. 28. ((round$ or sharp$ or optic$ or haptic$) adj6 design$).tw. 29. ((lens or lenses) adj3 design$).tw. 30. or/23‐29 31. 22 and 30 32. 12 and 31 33. or/23‐28 34. 22 and 33 35. 12 and 34

The search filter for trials at the beginning of the MEDLINE strategy was from the published paper by Glanville 2006.

Appendix 3. Embase Ovid search strategy

1. exp randomized controlled trial/ 2. exp randomization/ 3. exp double blind procedure/ 4. exp single blind procedure/ 5. random$.tw. 6. or/1‐5 7. (animal or animal experiment).sh. 8. human.sh. 9. 7 and 8 10. 7 not 9 11. 6 not 10 12. exp clinical trial/ 13. (clin$ adj3 trial$).tw. 14. ((singl$ or doubl$ or trebl$ or tripl$) adj3 (blind$ or mask$)).tw. 15. exp placebo/ 16. placebo$.tw. 17. random$.tw. 18. exp experimental design/ 19. exp crossover procedure/ 20. exp control group/ 21. exp latin square design/ 22. or/12‐21 23. 22 not 10 24. 23 not 11 25. exp comparative study/ 26. exp evaluation/ 27. exp prospective study/ 28. (control$ or prospectiv$ or volunteer$).tw. 29. or/25‐28 30. 29 not 10 31. 30 not (11 or 23) 32. 11 or 24 or 31 33. exp cataract extraction/ 34. (phacoemulsificat$ or capsulorhexis).tw. 35. ((extract$ or surg$) adj3 cataract$).tw. 36. lens implantation/ 37. lens implant/ 38. exp lens capsule/ 39. exp aftercataract/ 40. (posterior adj3 capsul$ adj3 opaci$).tw. 41. PCO.tw. 42. or/33‐41 43. round‐edged.tw. 44. sharp‐edged.tw. 45. square‐edged.tw. 46. sharp‐optic$.tw. 47. ((round$ or sharp$ or optic$ or haptic$) adj6 edge$).tw. 48. ((round$ or sharp$ or optic$ or haptic$) adj6 design$).tw. 49. ((lens or lenses) adj3 design$).tw. 50. or/43‐49 51. 42 or 50 52. 32 and 51

Appendix 4. LILACS search strategy

cataract or phacoemulsificat$ or capsule opacification and round$ or sharp$ or optic$ or haptic and lens$ or design$

Appendix 5. ISRCTN search strategy

(sharp or round or square) and lens

Appendix 6. ClinicalTrials.gov search strategy

(Sharp OR Round OR Square) AND Lens

Appendix 7. ICTRP search strategy

Three searches run on basic search screen.

Sharp AND Lens Round AND Lens Square AND Lens

Contributions of authors

OF, SM and WB conceived the review question.

SM and WB wrote drafts of the protocol and responded to peer review comments and comments from the editorial base.

Sources of support

Internal sources

  • No sources of support supplied

External sources

  • National Institute for Health Research (NIHR), UK.

    • Richard Wormald, Co‐ordinating Editor for Cochrane Eyes and Vision (CEV) acknowledges financial support for his CEV research sessions from the Department of Health through the award made by the National Institute for Health Research to Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology for a Specialist Biomedical Research Centre for Ophthalmology.
    • The NIHR also funds the CEV Editorial Base in London.

    The views expressed in this publication are those of the authors and not necessarily those of the NIHR, NHS, or the Department of Health.

Declarations of interest

OF: No financial interest in any of the products and methods mentioned. SM: No financial interest in any of the products and methods mentioned. WB: No financial interest in any of the products and methods mentioned.

New

References

Additional references

  1. Ang M, Evans JR, Mehta JS. Manual small incision cataract surgery (MSICS) with posterior chamber intraocular lens versus extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens for age‐related cataract. Cochrane Database of Systematic Reviews 2014, Issue 11. [DOI: 10.1002/14651858.CD008811.pub3] [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Apple DJ, Solomon KD, Tetz MR, Assia EI, Holland EY, Legler UF, et al. Posterior capsule opacification. Survey of Ophthalmology 1992;37(2):73‐116. [DOI] [PubMed] [Google Scholar]
  3. Auffarth GU, Brezin A, Caporossi A, Lafuma A, Mendicute J, Berdeaux G, et al. Comparison of Nd : YAG capsulotomy rates following phacoemulsification with implantation of PMMA, silicone, or acrylic intra‐ocular lenses in four European countries. Ophthalmic Epidemiology 2004;11(4):319‐29. [DOI] [PubMed] [Google Scholar]
  4. Buehl W, Findl O, Menapace R, Sacu S, Kriechbaum K, Koeppl C, et al. Long‐term effect of optic edge design in an acrylic intraocular lens on posterior capsule opacification. Journal of Cataract and Refractive Surgery 2005;31(5):954‐61. [DOI] [PubMed] [Google Scholar]
  5. Veritas Health Innovation. Covidence systematic review software. Melbourne: Veritas Health Innovation, (accessed 11 January 2017).
  6. Deeks JJ, Higgins JP, Altman DG. Chapter 9: Analysing data and undertaking meta‐analyses. In: Higgins JP, Green S editor(s). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from handbook.cochrane.org.
  7. Findl O, Buehl W, Menapace R, Georgopoulos M, Rainer G, Siegl H, et al. Comparison of 4 methods for quantifying posterior capsule opacification. Journal of Cataract and Refractive Surgery 2003;29(1):106‐11. [DOI] [PubMed] [Google Scholar]
  8. Findl O, Buehl W, Menapace R, Sacu S, Georgopoulos M, Rainer G. Long‐term effect of sharp optic edges of a polymethyl methacrylate intraocular lens on posterior capsule opacification: a randomized trial. Ophthalmology 2005;112(11):2004‐8. [DOI] [PubMed] [Google Scholar]
  9. Glanville JM, Lefebvre C, Miles JN, Camosso‐Stefinovic J. How to identify randomized controlled trials in MEDLINE: ten years on. Journal of the Medical Library Association 2006;94(2):130‐6. [PMC free article] [PubMed] [Google Scholar]
  10. GRADE Working Group, McMaster University. GRADEpro GDT. Version (accessed 2 January 2016). Hamilton (ON): GRADE Working Group, McMaster University, 2014.
  11. Higgins JP, Altman DG. Chapter 8: Assessing risk of bias in included studies. In: Higgins JP, Green S editor(s). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from handbook.cochrane.org.
  12. Hollick EJ, Spalton DJ, Meacock WR. The effect of capsulorhexis size on posterior capsular opacification: one‐year results of a randomized prospective trial. American Journal of Ophthalmology 1999;128(3):271‐9. [DOI] [PubMed] [Google Scholar]
  13. Javitt JC, Tielsch JM, Canner JK, Kolb MM, Sommer A, Steinberg EP, et al. National outcomes of cataract extraction: increased risk of retinal complications associated with Nd:YAG laser capsulotomy. Ophthalmology 1992;99(10):1487‐98. [DOI] [PubMed] [Google Scholar]
  14. Khalifa MA. Polishing the posterior capsule after extracapsular extraction of senile cataract. Journal of Cataract and Refractive Surgery 1992;18(2):170‐3. [DOI] [PubMed] [Google Scholar]
  15. Khanna R, Pujari S, Sangwan V. Cataract surgery in developing countries. Current Opinion in Ophthalmology 2011;22(1):10‐4. [DOI] [PubMed] [Google Scholar]
  16. Kirkham JJ, Dwan KM, Altman DG, Gamble C, Dodd S, Smyth R, et al. The impact of outcome reporting bias in randomised controlled trials on a cohort of systematic reviews. BMJ 2010;340:c365. [DOI] [PubMed] [Google Scholar]
  17. Kohnen T, Fabian E, Gerl R, Hunold W, Hütz W, Strobel J, et al. Optic edge design as long‐term factor for posterior capsular opacification rates. Ophthalmology 2008;115(8):1308‐14. [DOI] [PubMed] [Google Scholar]
  18. Nishi O, Nishi K, Sakanishi K. Inhibition of migrating lens epithelial cells at the capsular bend created by the rectangular optic edge of a posterior chamber intraocular lens. Ophthalmic Surgery and Lasers 1998;29(7):587‐94. [PubMed] [Google Scholar]
  19. Nishi O, Nishi K, Osakabe Y. Effect of intraocular lenses on preventing posterior capsule opacification: design versus material. Journal of Cataract and Refractive Surgery 2004;30(10):2170‐6. [DOI] [PubMed] [Google Scholar]
  20. Nordic Cochrane Centre, The Cochrane Collaboration. Review Manager 5 (RevMan 5). Version 5.3. Copenhagen: Nordic Cochrane Centre, The Cochrane Collaboration, 2014.
  21. Riaz Y, Silva SR, Evans JR. Manual small incision cataract surgery (MSICS) with posterior chamber intraocular lens versus phacoemulsification with posterior chamber intraocular lens for age‐related cataract. Cochrane Database of Systematic Reviews 2013, Issue 10. [DOI: 10.1002/14651858.CD008813.pub2] [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Riaz Y, Mehta JS, Wormald R, Evans JR, Foster A, Ravilla T, et al. Surgical interventions for age‐related cataract. Cochrane Database of Systematic Reviews 2006, Issue 4. [DOI: 10.1002/14651858.CD001323.pub2] [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Schaumberg DA, Dana MR, Christen WG, Glynn RJ. A systematic overview of the incidence of posterior capsule opacification. Ophthalmology 1998;105(7):1213‐21. [DOI] [PubMed] [Google Scholar]
  24. Walker TD. Pharmacological attempts to reduce posterior capsule opacification after cataract surgery‐a review. Clinical and Experimental Ophthalmology 2008;36(9):883‐90. [DOI] [PubMed] [Google Scholar]
  25. Wormstone IM. Posterior capsule opacification: a cell biological perspective. Experimental Eye Research 2002;74(3):337‐47. [DOI] [PubMed] [Google Scholar]

References to other published versions of this review

  1. Findl O, Buehl W, Bauer P, Sycha T. Interventions for preventing posterior capsule opacification. Cochrane Database of Systematic Reviews 2010, Issue 2. [DOI: 10.1002/14651858.CD003738.pub3] [DOI] [PMC free article] [PubMed] [Google Scholar]

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