Manual small incision cataract surgery (MSICS) with posterior chamber intraocular lens versus phacoemulsification with posterior chamber intraocular lens for age-related cataract

  • Review
  • Intervention

Authors


Abstract

Background

Age-related cataract is a major cause of blindness and visual morbidity worldwide. It is therefore important to establish the optimal technique of lens removal in cataract surgery.

Objectives

To compare manual small incision cataract surgery (MSICS) and phacoemulsification techniques.

Search methods

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to July 2013), EMBASE (January 1980 to July 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to July 2013), Web of Science Conference Proceedings Citation Index - Science (CPCI-S) (January 1970 to July 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 23 July 2013.

Selection criteria

We included randomised controlled trials (RCTs) for age-related cataract that compared MSICS and phacoemulsification.

Data collection and analysis

Two authors independently assessed all studies. We defined two primary outcomes: 'good functional vision' (presenting visual acuity of 6/12 or better) and 'poor visual outcome' (best corrected visual acuity of less than 6/60). We collected data on these outcomes at three and 12 months after surgery. Complications such as posterior capsule rupture rates and other intra- and postoperative complications were also assessed. In addition, we examined cost effectiveness of the two techniques. Where appropriate, we pooled data using a random-effects model.

Main results

We included eight trials in this review with a total of 1708 participants. Trials were conducted in India, Nepal and South Africa. Follow-up ranged from one day to six months, but most trials reported at six to eight weeks after surgery. Overall the trials were judged to be at risk of bias due to unclear reporting of masking and follow-up. No studies reported presenting visual acuity so data were collected on both best-corrected (BCVA) and uncorrected (UCVA) visual acuity. Most studies reported visual acuity of 6/18 or better (rather than 6/12 or better) so this was used as an indicator of good functional vision. Seven studies (1223 participants) reported BCVA of 6/18 or better at six to eight weeks (pooled risk ratio (RR) 0.99 95% confidence interval (CI) 0.98 to 1.01) indicating no difference between the MSICS and phacoemulsification groups. Three studies (767 participants) reported UCVA of 6/18 or better at six to eight weeks, with a pooled RR indicating a more favourable outcome with phacoemulsification (0.90, 95% CI 0.84 to 0.96). One trial (96 participants) reported UCVA at six months with a RR of 1.07 (95% CI 0.91 to 1.26).

Regarding BCVA of less than 6/60: there were only 11/1223 events reported. The pooled Peto odds ratio was 2.48 indicating a more favourable outcome using phacoemulsification but with wide confidence intervals (0.74 to 8.28) which means that we are uncertain as to the true effect.

The number of complications reported were also low for both techniques. Again this means the review is underpowered to detect a difference between the two techniques with respect to these complications. One study reported on cost which was more than four times higher using phacoemulsification than MSICS.

Authors' conclusions

On the basis of this review, removing cataract by phacoemulsification may result in better UCVA in the short term (up to three months after surgery) compared to MSICS, but similar BCVA. There is a lack of data on long-term visual outcome. The review is currently underpowered to detect differences for rarer outcomes, including poor visual outcome. In view of the lower cost of MSICS, this may be a favourable technique in the patient populations examined in these studies, where high volume surgery is a priority. Further studies are required with longer-term follow-up to better assess visual outcomes and complications which may develop over time such as posterior capsule opacification.

Résumé scientifique

Comparaison de la chirurgie de la cataracte par petite incision manuelle (CCPI manuelle) avec lentille intraoculaire en chambre postérieure et de la phacoémulsification avec lentille intraoculaire en chambre postérieure pour la cataracte liée à l’âge

Contexte

La cataracte liée à l’âge est la principale cause de cécité et de morbidité visuelle dans le monde. Il est donc important de déterminer la meilleure technique de retrait du cristallin en chirurgie de la cataracte.

Objectifs

Comparer les techniques de chirurgie de la cataracte par petite incision manuelle (CCPI manuelle) et de phacoémulsification.

Stratégie de recherche documentaire

Nous avons effectué des recherches dans CENTRAL (qui contient le Registre des essais du groupe Cochrane sur l’ophtalmologie) ( Bibliothèque Cochrane 2013, numéro 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (de janvier 1946 à juillet 2013), EMBASE (de janvier 1980 à juillet 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (de janvier 1982 à juillet 2013), Web of Science Conference Proceedings Citation Index - Science (CPCI-S) (de janvier 1970 à juillet 2013), le Méta-registre des essais contrôlés (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) et la Plate-forme internationale des registres d’essais cliniques de l’OMS (ICTRP) (www.who.int/ictrp/search/en). Nous n’avons appliqué aucune restriction concernant la langue ou la date dans les recherches électroniques d’essais. Nous avons effectué les dernières recherches dans les bases de données électroniques le 23 juillet 2013.

Critères de sélection

Nous avons inclus des essais contrôlés randomisés (ECR) sur la cataracte liée à l’âge qui comparaient la CCPI manuelle et la phacoémulsification.

Recueil et analyse des données

Deux auteurs ont évalué indépendamment toutes les études. Nous avons défini deux critères de jugement principaux : « bonne vision fonctionnelle » (acuité visuelle de 6/12 ou plus) et « résultat visuel médiocre » (meilleure acuité visuelle corrigée inférieure à 6/60). Nous avons recueilli les donnés sur ces critères de jugement à trois mois et 12 mois après la chirurgie. Les complications telles que les taux de rupture de la capsule postérieure et autres complications per- et postopératoires ont également été évaluées. En outre, nous avons examiné la rentabilité des deux techniques. Lorsque cela était approprié, nous avons regroupé les données en utilisant un modèle à effets aléatoires.

Résultats principaux

Nous avons inclus huit essais dans cette revue, avec un total de 1 708 participants. Les essais ont été réalisés en Inde, au Népal et en Afrique du Sud. La durée du suivi allait de un jour à six mois, mais la plupart des essais étaient rapportés au bout de six à huit semaines après la chirurgie. Dans l’ensemble, les essais étaient considérés à risque incertain de biais en raison du manque de clarté de la mise en aveugle et du suivi. Aucune étude ne rapportait de présentation de l’acuité visuelle, de sorte que les données ont été recueillies sur l’acuité visuelle à la fois corrigée (MAVC) et non corrigée (AVNC). La plupart des études rapportaient une acuité visuelle de 6/18 ou plus (plutôt que 6/12 ou plus), que nous avons donc utilisée comme indicateur d’une bonne vision fonctionnelle. Sept études (1 223 participants) rapportaient une MAVC de 6/18 ou plus à six-huit semaines (risque relatif (RR) groupé de 0,99, intervalle de confiance (IC) à 95 % de 0,98 à 1,01), sans différence entre les groupes de CCPI manuelle et de phacoémulsification groupes. Trois études (767 participants) rapportaient une UCVA de 6/18 ou mieux au bout de six-huit semaines, avec un RR combiné indiquant des résultats plus favorables avec la phacoémulsification (0,90, IC à 95 % de 0,84 à 0,96). Un essai (96 participants) rapportait l’UCVA à six mois avec un RR de 1,07 (IC à 95 % de 0,91 à 1,26).

Concernant les MAVC inférieures à 6/60 : il n’y a eu que 11/1223 événements rapportés. Le rapport des cotes de Peto global était de 2,48, ce qui indique des résultats plus favorables avec la phacoémulsification, mais avec de larges intervalles de confiance (0,74 à 8,28), ce qui signifie que nous ne sommes pas certains de l’effet réel.

Le nombre de complications signalés étaient également faible pour les deux techniques. Ici encore, cela signifie que la revue n’est pas assez puissants pour déceler une différence entre les deux techniques en termes de complications. Une étude a rendu compte du coût, qui était plus de quatre fois plus élevé avec la phacoémulsification qu’avec la CCPI manuelle.

Conclusions des auteurs

Sur la base de cette revue, l’élimination de la cataracte par phacoémulsification peut donner une meilleure UCVA à court terme (jusqu’à trois mois après l’opération) par rapport à la CCPI manuelle, mais une MAVC similaire. On manque de données sur le résultat visuel à long terme. À l’heure actuelle, la revue n’est pas assez puissante pour déceler des différences dans les résultats plus rares, notamment les mauvais résultat visuels. Compte tenu du coût plus faible de la CCPI manuelle, cette technique pourrait être intéressante favorable dans les populations examinées dans ces études, où il faut en priorité opérer un grand nombre de patients. D’autres études sont nécessaires, avec un suivi à plus long terme afin de mieux évaluer les résultats sur la vision et les complications qui peuvent se développer au fil du temps, telles que l’opacification de la capsule postérieure.

Plain language summary

Comparing two different techniques of removing cataracts

Cataract is a clouding of the lens in the eye, which most commonly occurs due to increasing age. This can only be treated with an operation, and the aim of this review was to assess two different surgical methods. The first, called manual small incision cataract surgery (MSICS) involves using instruments to remove the lens from the eye through a small incision. The second, phacoemulsification, involves using a high frequency ultrasound probe to fragment the lens, and this machine also removes the lens fragments from the eye.

We searched the literature in July 2013 and identified eight randomised controlled trials that compared these two techniques. These included a total of 1708 participants randomly allocated to MSICS or phacoemulsification. The studies were carried out in India, Nepal and South Africa.

Not all studies reported the outcomes of visual acuity that we aimed to assess, making it difficult to draw definite conclusions. Better uncorrected visual acuity was seen in the short term with phacoemulsification; however, there were no differences in best-corrected visual acuity (i.e. after correction with spectacles). There appeared to be no significant difference regarding uncorrected visual acuity between the two techniques at six months in the one trial that reported at that time point. There was a lack of long-term data (one year or more after surgery). Very few participants were reported to have poor visual outcomes or complications (such as posterior capsule rupture) from the surgery. The cost of phacoemulsification was documented in one study only, and this was more than four times the cost of MSICS.

In this setting, the two techniques appear to be comparable in terms of visual acuity outcomes and complications. However further studies with a longer follow-up period are needed to better assess these outcomes.

Résumé simplifié

Comparaison de deux différentes techniques d’ablation de la cataracte

La cataracte est une opacification du cristallin de l’œil, qui est le plus souvent due au vieillissement. Elle ne peut être traitée que par la chirurgie. L’objectif de cette revue était d’évaluer deux méthodes chirurgicales différentes. La première, appelée chirurgie de la cataracte par petite incision manuelle (CCPI manuelle), consiste à utiliser des instruments pour retirer le cristallin à travers une petite incision. La seconde, la phacoémulsification, consiste à fragmenter le cristallin à l’aide d’une sonde à ultrasons à haute fréquence ; cette machine enlève également les fragments de cristallin de l’œil.

Nous avons effectué des recherches dans la littérature en juillet 2013 et identifié huit essais contrôlés randomisés comparant ces deux techniques. Ces études portaient sur un total de 1 708 participants assignés à la CCPI manuelle ou à la phacoémulsification. Les études ont été réalisés en Inde, au Népal et en Afrique du Sud.

Les études ne rapportaient pas toutes les résultats d’acuité visuelle que nous cherchions à évaluer, ce qui rend difficile de tirer de conclusions définitives. Une meilleure acuité visuelle non corrigée était observée à court terme avec la phacoémulsification ; cependant, il n’y avait aucune différence en termes d’acuité visuelle corrigée (par ex. après correction avec des lunettes de vue). Il ne semble y avoir aucune différence significative concernant l’acuité visuelle non corrigée entre les deux techniques au bout de six mois dans le seul essai rapportant les résultats avec ce recul. Il manque des données à long terme (un an ou plus après la chirurgie). Le nombre rapporté de patients ayant obtenu de mauvais résultats visuels ou ayant eu des complications (telles que la rupture de la capsule postérieure) après la chirurgie est faible. Le coût de la phacoémulsification est documenté dans une seule étude ; il était plus de quatre fois supérieur à celui de la CCPI manuelle.

Dans ce contexte, les deux techniques semblent être comparable en termes de résultats d’acuité visuelle et de complications. Pour autant, des études avec des suivis plus longs sont nécessaires pour mieux évaluer ces critères de jugement.

Notes de traduction

Traduit par: French Cochrane Centre 9th January, 2014
Traduction financée par: Financeurs pour le Canada : Instituts de Recherche en Sant� du Canada, Minist�re de la Sant� et des Services Sociaux du Qu�bec, Fonds de recherche du Qu�bec-Sant� et Institut National d'Excellence en Sant� et en Services Sociaux; pour la France : Minist�re en charge de la Sant�

Summary of findings(Explanation)

Summary of findings for the main comparison. 
  1. 1 Risk in phacoemulsification group ranged from 0 per 1000 to 25 per 1000 in the included studies; the median risk was 0. We have therefore estimated a low risk in the phacoemulsification group at 1 per 1000.
    2 Downgraded for risk of bias: several items on risk of bias assessment not clearly reported.
    3 Downgraded for imprecision: wide confidence intervals.
    4 Downgraded for indirectness (not measured at 12 months).
    5 Downgraded for inconsistency: only one study reported so not possible to assess.

Manual small incision cataract surgery (MSICS) compared with phacoemulsification for age-related cataract

Patient or population: people with age-related cataract

Settings: hospital

Intervention: manual small incision surgery

Comparison: phacoemulsification

OutcomesIllustrative comparative risks* (95% CI)Relative effect
(95% CI)
No of Participants
(studies)
Quality of the evidence
(GRADE)
Comments
Assumed riskCorresponding risk
PhacoemulsificationMSICS
Good functional vision (presenting visual acuity 6/12 or better) 12 months after surgerySee comment

No study reported presenting visual acuity; few studies reported 6/12 outcomes; only one study reported at 12 months.

Seven studies reported best-corrected visual acuity (BCVA) of 6/18 or better at three months (pooled RR 0.99 (95% CI 0.98 to 1.01)) and three studies reported uncorrected visual acuity (UCVA) of 6/18 or better at three months (pooled RR in favour of phacoemulsification 0.90 (95% CI 0.84 to 0.96).

Poor visual outcome (best-corrected visual acuity worse than 6/60) 12 months after surgery1 per 10001

2 per 1000

(1 to 8)

OR: 2.48 (95% CI 0.74 to 8.28)1250
(6)
⊕⊝⊝⊝
very low2,3,4
No data available at 12 months so data from three months follow-up used.
Posterior capsule opacification 12 months after surgerySee comments

494

(2)

⊕⊝⊝⊝
very low4,5,6
Posterior capsule opacification was reported in two studies. At six weeks no cases were observed in Gogate 2005a and at six months 20/46 MSICS versus 7/48 phacoemulsification cases were observed in Ruit 2007 (OR 2.98, 95% CI 1.39 to 6.37).
Other complicationsSee commentsNo data on retinal detachment, glaucoma, cystoid macular oedema or corneal decompensation.
Quality of lifeSee commentsNo data reported
CostsSee commentsIn the Ruit 2007 study, phacoemulsification cost USD 70 per case and MSICS cost USD 15 per case.
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: Confidence interval; RR: Risk Ratio; OR: Odds Ratio
GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

Background

Description of the condition

Cataract is the opacification of the normally transparent lens of the eye and occurs as a result of denaturation of lens proteins. This cloudiness can cause a decrease in vision and may lead to eventual blindness. Most cataracts are age-related. The density and location of the cataract determines the amount of vision affected. Initially, cataracts may not affect vision and if the cataract remains small or at the periphery of the lens, the visual changes may be minor. If the cataract forms in the area of the lens directly behind the pupil, vision may be significantly impaired. It is not thought to be reversible and surgery is currently the only treatment option. In the months or years after cataract surgery a small percentage of people will develop a condition called posterior capsular thickening which can be treated. A laser treatment, YAG laser capsulotomy, makes a small opening in the back of the lens capsule, which restores vision.

The World Health Organization (WHO) estimated from a recent global review of surveys that there are 37 million people worldwide who were blind in 2002 (Passolini 2004; Resnikoff 2004) and that age-related cataract remained the leading cause of blindness globally in 2002, as it was in 1990. Fifty per cent of total world blindness is thought to be due to cataract, with the majority of blinding cataract found in developing countries. The contribution of cataracts to blindness globally is likely to grow due to an ageing population and unsuccessful attempts to control this blinding condition in low- and middle-income countries (WHO 2005).

Description of the intervention

Phacoemulsification was first described in 1967 by Charles D. Kelman, an American ophthalmologist (1930 to 2004). It is the most commonly performed method of cataract extraction in the developed world and involves ultrasonic fragmentation of the crystalline lens. The incision is small (with a standard size of around 2.75 mm, but may range from 2.2 mm to 3.2 mm) which allows rapid visual rehabilitation postoperatively and low induced astigmatism. This technique requires a phacoemulsification machine which may cost GBP 20,000 to GBP 45,000 and has high disposable and maintenance costs. Phacoemulsification requires extensive surgical training, particularly the necessity to carry out a continuous capsulorhexis.

Manual small incision cataract surgery (MSICS) was first described by Blumenthal 1992. In Asia and Africa there has been a renewal of interest in this technique (Ruit 2000) as an alternative to phacoemulsification, because it is considerably less costly but has similar benefits of rapid visual recovery and reduced astigmatism (Yorston 2005). It involves a 6 mm to 6.5 mm scleral incision, just large enough to allow insertion of a 6 mm intraocular lens (IOL). There are various different techniques described for performing the capsulotomy in MSICS, for example, the can-opener method (Gogate 2005b), the continuous curvilinear capsulorhexis (Gogate 2003) and the endocapsular technique where the incision is from pupil margin to pupil margin. The lens is delivered into the anterior chamber, hydroextracted and aspirated. The posterior capsule of the lens is left intact. This technique is technically more difficult than a standard manual extracapsular extraction (ECCE).

Figure 1 summarises the different types of cataract surgery.

Figure 1.

Types of cataract surgery

How the intervention might work

Cataract surgery consists of removing the lens of the eye and replacing it with an artificial lens called an intraocular lens. IOLs can be made from a range of materials, and can be of varying size, shape and refracting power. Before cataract surgery the eye to be operated on is measured so that an IOL of the correct power (strength) can be inserted after the cataract has been removed. The IOL is usually placed inside the 'bag' of the lens capsule inside the eye. Other options for lens replacement include contact lenses and cataract glasses.

Why it is important to do this review

Although phacoemulsification is the most technologically advanced method providing small-incision, sutureless surgery it requires considerable resources in the form of the initial capital outlay for the phacoemulsification machine, and there are considerable ongoing costs due to consumables, maintenance and training of surgeons. It is the procedure of choice for cataract surgery in high-income countries.

From a global perspective phacoemulsification is too costly for many developing countries where there is the highest incidence of cataract blindness. Manual small incision cataract surgery and ECCE are alternative techniques available at a lower cost. A key question is whether the resources required for phacoemulsification are justified in a lower-income setting.

This review in its original form ‘Surgical interventions for age-related cataract’ (Riaz 2006) compared the outcomes of different cataract surgical techniques. The techniques included initially were intracapsular extraction (ICCE), ECCE and phacoemulsification. In 2006 it was revised and a fourth surgical technique, MSICS, was added to the review.

Following consultation with the authors and the Cochrane Eyes and Vision Group this update has been divided into three smaller reviews each using the same outcome measures but only comparing two surgical methods within each review. The ICCE technique is no longer included as this method is no longer used as a primary procedure.

The cataract surgical techniques compared in these three reviews are:

1. MSICS and ECCE (Ang 2012);
2. Phacoemulsification and ECCE (Riaz 2010a);
3. MSICS and phacoemulsification (current review, published protocol Riaz 2010b).

Objectives

The aim of this review is to compare the effects of two types of cataract surgery: manual small incision cataract surgery (MSICS) and phacoemulsification.

Our secondary objective is to compare the costs of the two procedures as reported in included trials.

Methods

Criteria for considering studies for this review

Types of studies

We include randomised controlled trials (RCTs) only in this review.

Types of participants

We include trials where participants were people with age-related cataract.

Types of interventions

We include trials that compared MSICS with phacoemulsification, followed by implantation of a posterior chamber intraocular lens (IOL) in both techniques.

Types of outcome measures

Primary outcomes

Postoperative visual acuity

  • proportion of people achieving good functional vision, defined as presenting* visual acuity better than or equal to 6/12 in the operated eye.

  • proportion of people with a poor outcome after surgery, defined as best-corrected visual acuity (BCVA) worse than 6/60 in the operated eye.

* 'Presenting visual acuity' is vision that the person uses in normal life, i.e. with or without glasses, if worn.

Secondary outcomes
  • Intraoperative complications

    • capsular rupture with or without vitreous loss

    • iris prolapse

    • postoperative inflammation

    • other complications as reported

  • Long-term complications (one year or more after surgery)

    • posterior capsule opacification

    • retinal detachment

    • glaucoma

    • cystoid macular oedema

    • corneal endothelial cell loss

    • corneal decompensation

    • other complications as recorded

  • Quality of life (self care, mobility, social and mental function) as reported

  • Cost effectiveness

Follow-up

Outcomes were measured at three months and one year after surgery. As studies may not report outcomes exactly at these time points, data collection was considered within the following time periods:

  • three months: from four weeks to less than six months

  • 12 months: from six months to less than 18 months

Search methods for identification of studies

Electronic searches

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) 2013, Issue 6, part of The Cochrane Library. www.thecochranelibrary.com (accessed 23 July 2013), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to July 2013), EMBASE (January 1980 to July 2013), Latin American and Caribbean Health Sciences (LILACS) (January 1982 to July 2013), Web of Science Conference Proceedings Citation Index - Science (CPCI-S) (January 1970 to July 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 23 July 2013.

See: Appendices for details of search strategies for CENTRAL (Appendix 1), MEDLINE (Appendix 2), EMBASE (Appendix 3), LILACS (Appendix 4), CPCI-S (Appendix 5), mRCT (Appendix 6), ClinicalTrials.gov (Appendix 7) and the ICTRP (Appendix 8).

Searching other resources

We searched the reference lists of identified included studies. We contacted study authors and other experts in the field to identify unpublished studies or studies sent for publication or in press.

Data collection and analysis

Selection of studies

Two review authors independently screened the titles and abstracts resulting from the electronic searches. Duplicate records were removed, as were obviously irrelevant titles and abstracts. We obtained full-text copies of any report referring to definitely or possibly relevant trials. Multiple reports of the same study were linked together. We assessed these full-text reports for compliance of studies with eligibility criteria, and then assessed trials that met these criteria for methodological quality.

All studies that were excluded at this stage were documented and reasons for exclusion provided.

Data extraction and management

We extracted data using a form developed by the Cochrane Eyes and Vision Group. Two authors extracted data and compared the results for differences. We resolved discrepancies by discussion. Any disagreements which could not be resolved were initially addressed by contacting the study authors, and if this was unsuccessful were reported in the review. Data were entered onto a spreadsheet, checked for accuracy by all review authors, and then cut and pasted into Review Manager 5 (RevMan 2012).

Assessment of risk of bias in included studies

We assessed the risk of bias in each study using The Cochrane Collaboration's tool for assessing the risk of bias as detailed in Chapter 8 of the Cochrane Handbook for Systematic Reviews of interventions (Higgins 2011). We considered the following parameters: sequence generation, allocation sequence concealment, masking (blinding), incomplete outcome data, selective outcome reporting and other potential sources of bias. We judged whether they were at high risk of bias, low risk of bias or unclear. Two review authors independently assessed the risk of bias and disagreement was resolved by discussion. Authors were not masked to the report authors and trial results during the assessment.

Measures of treatment effect

The outcomes for this review were largely dichotomous (i.e. postoperative visual acuity and complications). Our measure of treatment effect was the risk ratio. For outcomes that occurred rarely (in less than 10% of the cohort), we used the Peto odds ratio. Corneal endothelial cell loss was reported as a continuous variable and was analysed using the mean difference. Currently the review does not include data on quality of life. In future updates this may become available. It may be reported as a continuous variable, in which case the mean difference will be used.

Unit of analysis issues

In all studies included in this review, data were reported for one eye per person, although it was not always clear how the study eye was selected.

Dealing with missing data

We collected information on follow-up by treatment groups, and the reasons for missing data, although this was not always reported. The analyses in this review are based on available data and therefore assume that missing data are missing at random. We originally planned to investigate how reasonable this assumption is by doing a series of sensitivity analyses with different assumptions about the missing data using methods as set out by White 2008. However, data currently included in the review are sparse and we have therefore not done these sensitivity analyses for this initial version of the review.

Assessment of heterogeneity

We assessed heterogeneity in several ways. Firstly, by documenting clinical and methodological differences between the studies. Secondly by examining the forest plots to see whether the estimates of effect are consistent, and thirdly by considering the I² value and Chi² test for heterogeneity (bearing in mind that the Chi² test has low power when the number of trials is small) (Higgins 2003).

Assessment of reporting biases

The main reporting biases that we planned to consider were publication bias and outcome reporting bias. Currently there are not enough trials included in the review to assess publication bias. In order to assess the possibility of outcome reporting bias we did a review outcome matrix using the ORBIT classification (Kirkham 2010).

Data synthesis

Where data were available, we pooled the results using a random-effects model if there were more than three studies, and a fixed-effect model if there were three or fewer studies. For data on complications, as the number of events was small, we used the Peto odds ratio (fixed-effect model). As a general rule, if there was substantial heterogeneity as defined above (Assessment of heterogeneity), we planned not to report a pooled estimate, depending on the size of studies and consistency of the effect estimates.

Subgroup analysis and investigation of heterogeneity

We did not plan or conduct any subgroup analyses.

Sensitivity analysis

We planned to do a sensitivity analysis excluding trials at high risk of bias and investigating the impact of missing data (see Dealing with missing data). However, currently there are not enough data to enable this.

Summary of findings table

We prepared a 'Summary of findings' table and assessed the quality of the body of evidence for each outcome using the GRADE approach as described in Chapter 12 of the Cochrane Handbook for Systematic Reviews of interventions (Schünemann 2011). This was done by one author (JE) and checked by the other authors.

Results

Description of studies

Results of the search

The electronic searches yielded a total of 748 records (Figure 2). After deduplication we screened the title and abstract of 541 records. We excluded 523 records as not relevant to the scope of the review. We obtained full-text copies of 17 records for further investigation. We excluded eight studies, see Characteristics of excluded studies and included eight studies (nine reports) see Characteristics of included studies.

Figure 2.

Results from searching for studies for inclusion in the review.

Included studies

We included eight randomised controlled trials (RCTs) for analysis in this review (Cook 2012; George 2005; Ghosh 2010; Gogate 2005a; Gogate 2010; Ruit 2007; Singh 2009; Venkatesh 2010). See Characteristics of included studies for further details. All studies compared manual small incision cataract surgery (MSICS) with phacoemulsification. One trial had an additional extracapsular extraction (ECCE) arm (George 2005).

Participants: A total of 1708 people were included in these studies: 200 (Cook 2012); 124 (George 2005); 224 (Ghosh 2010); 400 (Gogate 2005a);  200 (Gogate 2010); 108 (Ruit 2007); 182 (Singh 2009); 270 (Venkatesh 2010).

Demographics: The average age of participants ranged from 56 to 68. Approximately equal numbers of women and men were enrolled (range percentage of women from 44.2% to 61%).

Location: Five of the included studies were conducted in India (George 2005; Ghosh 2010; Gogate 2005a; Gogate 2010; Venkatesh 2010), two in Nepal (Ruit 2007; Singh 2009) and one in South Africa (Cook 2012).

Outcomes: All eight studies evaluated Snellen visual acuity outcomes. Six studies reported visual acuity as their main outcome whereas George 2005 reported endothelial cell loss and surgery-induced astigmatism as their main outcome, and Ghosh 2010 reported macular thickness as the primary outcome. Postoperative complications were recorded in all studies.

Follow-up: Singh 2009 reported results on the first postoperative day only; George 2005; Gogate 2005a; Gogate 2010 and Venkatesh 2010 reported results at six weeks, Cook 2012 reported results at eight weeks; Ghosh 2010 and Ruit 2007 reported data up to six months postoperatively.

Excluded studies

See Characteristics of excluded studies table.

Risk of bias in included studies

Risk of bias is summarised in Figure 3 and Figure 4. See individual 'Risk of bias' tables for more detailed information on each study.

Figure 3.

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

Figure 4.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Allocation

All eight trials clearly stated how participants were allocated to each arm of the study. Five trials described using picking a ball or ‘ballots’ for assignment of treatment and surgeon (Cook 2012; Ghosh 2010; Gogate 2005a; Gogate 2010; Ruit 2007). Two studies used computer-generated random numbers (George 2005; Venkatesh 2010) and another study used a random number table (Singh 2009). Allocation concealment was described in five studies (Cook 2012; Ghosh 2010; Gogate 2005a; Gogate 2010; Venkatesh 2010).

Blinding

Performance bias

Five studies (Cook 2012; Ghosh 2010; Gogate 2005a; Gogate 2010; Venkatesh 2010) reported masking of participants to the nature of surgery.

Detection bias

Four studies reported that masking was carried out and that postoperative assessors were masked to the nature of surgery (Cook 2012; Ruit 2007; Singh 2009; Venkatesh 2010). However, obvious differences in postoperative appearance of the eye in each group may influence the ability to mask assessors.

Incomplete outcome data

Follow-up rates were variable between the included studies: 82.5% (Cook 2012); 91% (George 2005); 86% (Ghosh 2010); 93% (Gogate 2005a); 73% (Gogate 2010); 87% (Ruit 2007);100% (Singh 2009); 85% (Venkatesh 2010) respectively. Only Cook 2012 stated the reason for attrition, which was the distance needed to travel by participants living in rural areas.

Selective reporting

The only intraoperative complication described in George 2005 was posterior capsular rupture. Otherwise, a range of outcomes were reported in all other studies. Without access to the protocols for the studies it was difficult to assess this bias formally. However, we compiled an 'outcome reporting matrix' (Table 1) using the ORBIT classification (Kirkham 2010). We did not identify any cause for concern.

Table 1. Outcome reporting matrix
  1. ✔ Reported and included in review
    F: Clear that outcome was measured but not necessarily analysed. Judgment says unlikely to have been analysed but not reported because of non-significant results (low risk of bias)
    H: Not mentioned but clinical judgment says unlikely to have been measured at all (low risk of bias)
    I: Clear that outcome was not measured (no risk)
    For other categories see Kirkham 2010

 George 2005Gogate 2005Gogate 2010Ruit 2007Singh 2009Cook 2012Venkatesh 2011

Ghosh

2010

Review outcomes        
Presenting VA ≥ 6/12HHIH
BCVA < 6/60FFI
Capsular rupture with or without vitreous loss
Iris prolapseHHHHHHH
Postoperative inflammationHHHH
Posterior capsule opacificationHHHHHH
Retinal detachmentHHHHHHHH
GlaucomaFHHHHHHH
Cystoid macular oedemaHHHHHHH
Corneal endothelial cell lossHHHHHH
Corneal decompensationHHHHHHHH
Quality of lifeIIIIIIII

Other outcomes

(list other outcomes reported)

AstigmatismCapsulorhexis extended, Iridodialysis, zonule dialysis, Descemet tear, conversion to MSICS, AstigmatismCapsulorhexis extended, Conversion to MSICS, Iridodialysis, retained cortex, decentred IOLCapsulorhexis extended, Minor hyphaema, cost effectiveness, AstigmatismZonule dialysis, surgical time, Astigmatism“Other complications”, corneal oedema at day 1, median astigmatismCorneal oedema at day 1 and 6 weeks, astigmatism, surgical timeMacular thickness

Other potential sources of bias

The level of surgical experience for each technique performed may be a source of bias. However, this would only be the case if there were imbalance between study groups in level of experience of the surgeon. In Cook 2012, 35% of phacoemulsification surgeries and 58% of MSICS surgeries were done by a team of five consultants. The remainder of surgery was done by 10 registrars, who were reported to be competent in the technique but had varying levels of experience. If the assumption is made that consultants were more experienced, this may be a potential source of bias in favour of MSICS outcomes.

In George 2005; Gogate 2005a; Ruit 2007 and Venkatesh 2010, all surgeons had comparable levels of experience. In Singh 2009 there was only one surgeon and it is not stated whether he had equal surgical experience of both techniques. In Ghosh 2010 there were two surgeons who performed equal amounts of surgery. In Gogate 2010 neither the number of surgeons nor the level of surgical experience is stated.

Effects of interventions

See: Summary of findings for the main comparison

Primary outcomes

Visual outcomes
Good functional vision

We defined 'good functional vision' as presenting visual acuity of 6/12 or better. No studies reported presenting visual acuity so we report both uncorrected (UCVA) and best-corrected visual acuity (BCVA). Most studies reported outcomes of 6/18 or better, rather than 6/12 or better, so this outcome has been used as an indicator of good functional vision.

Uncorrected visual acuity (UCVA)

Five studies reported UCVA of 6/18 or better, with one study reporting this outcome at one day only (Singh 2009), two studies at six weeks (Gogate 2005a; Venkatesh 2010), one study at eight weeks (Cook 2012) and one study at six months (Ruit 2007).

At one day postoperatively, UCVA of 6/18 or better was found in 77.7% of participants in the MSCIS group and 68% of participants in the phacoemulsification group (P = 0.0655) (Singh 2009).

At six weeks, Gogate 2005a reported UCVA of 6/18 or better in 133/187 (71%) of MSICS participants compared to 150/185 (81%) of phacoemulsification participants (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.78 to 0.98). Venkatesh 2010 reported this outcome in 96/117 (82%) MSICS participants and 99/113 (88%) phacoemulsification participants (RR 0.94, 95% CI 0.84 to 1.04). At eight weeks, Cook 2012 reported this outcome in 63/85 (74%) MSICS participants and 69/80 (86%) phacoemulsification participants (RR 0.86, 95% CI 0.74 to 1.00). The pooled RR for this outcome was 0.90, (95% CI 0.84 to 0.96) which favours phacoemulsification (Analysis 1.1).

At six months, Ruit 2007 reported 41/46 (89%) of the MSICS group had UCVA of 6/18 or better compared with 40/48 (83%) of the phacoemulsification group (RR 1.07, 95% CI 0.91 to 1.26) (Analysis 1.2).

Best-corrected visual acuity (BCVA)

More studies reported BCVA (Analysis 1.3). At three months there was no difference between MSICS and phacoemulsification groups (pooled RR 0.99, 95% CI 0.98 to 1.01) (Analysis 1.3). One trial only reported at six months (Ruit 2007) with a RR of 1.0 (95% CI 0.94 to 1.06) (Analysis 1.4).

Poor visual outcome after surgery

We defined a poor outcome after surgery as BCVA of less than 6/60.

Six studies reported poor visual outcome data within three months postoperatively, with no cases in either group in three out of six studies. In total 8/617 MSICS cases and 3/606 phacoemulsification cases had BCVA worse than 6/60. With low numbers of events, the true estimate of effect is uncertain with a pooled Peto OR of 2.48 in favour of phacoemulsification and wide confidence intervals (95% CI 0.74 to 8.28; Analysis 1.5).

Ruit 2007 reported 1.9% of cases in both MSICS and phacoemulsification groups had BCVA worse than 6/18 at six months (Analysis 1.6).

Secondary outcomes

Intraoperative surgical complications

Posterior capsule rupture (PCR) was reported in all studies (Analysis 1.7). In most studies few cases of PCR were reported. The number of cases reported varied between studies from no events in either group (George 2005) to 10/100 in the MSICS and 4/100 in the phacoemulsification group (Cook 2012). Overall there was little evidence of any difference between the two intervention groups (Peto OR 1.07, 95% CI 0.63 to 1.83).

Five studies reported iridodialysis (Analysis 1.8). There were too few cases (seven) to detect any difference between MSICS and phacoemulsification (Peto OR 2.37, 95% CI 0.54 to 10.45). Two studies reported zonule dialysis (Gogate 2005a; Singh 2009) but again the number of cases (three) was low.

Three studies (Gogate 2005a; Gogate 2010; Ruit 2007) reported extension of capsulorrhexis during surgery (Analysis 1.9). This appeared to occur more commonly in the phacoemulsification group, but again the number of cases was low (six); Peto OR 0.26 (95% CI 0.05 to 1.30).

In Gogate 2005a, 2/199 cases allocated to the phacoemulsification groups were converted to MSICS; in Gogate 2010 this was 5/100 cases (three due to zonular dialysis and two due to posterior capsule tears), in Cook 2012 8/100 cases (due to hard nucleus) and in Venkatesh 2010 3/137 cases.

Postoperative inflammation was reported in three studies (11 cases in total) (Analysis 1.10). In the Ruit 2007 study, no events occurred in either group.

Postoperative complications

Early postoperative corneal oedema (occurring at day 1 to day 7) was reported in six studies (Analysis 1.11) with a total of 60/739 cases in the MSICS group and 93/737 cases in the phacoemulsification group. Overall there appeared to be more cases of early postoperative corneal oedema in the phacoemulsification group (Peto OR 0.58, 95% (CI) 0.41 to 0.83). In four studies, no events of corneal oedema were reported at three to six weeks (Analysis 1.12).

Posterior capsule opacification was reported in two studies (Analysis 1.13). At six weeks no cases were observed in Gogate 2005a, and at six months 20/46 MSICS versus 7/48 phacoemulsification cases were observed in Ruit 2007 (RR 2.98, 95% CI 1.39 to 6.37).

No significant difference between percentage endothelial cell loss was found between the two techniques (Analysis 1.14). George 2005 reported a 5.41% endothelial cell loss at six weeks in the phacoemulsification group, and 4.21% in the MSICS group (P = 0.855). Gogate 2010 reported a mean endothelial cell loss at one week of 16.1% in the phacoemulsification group, and 12.2% in the MSICS group (P = 0.06). At six weeks the percentage loss was 18.4% in the phacoemulsification group, and 17.7% in the MSICS group (P = 0.44).

Other reported findings
Surgically induced astigmatism (SIA)

This was reported in six studies (George 2005; Ghosh 2010; Gogate 2005a; Ruit 2007; Singh 2009; Venkatesh 2010).

At one day postoperatively, Singh 2009 reported a mean induced astigmatism of 0.11 dioptre (D) (SD 0.74) for the phacoemulsification group and 0.09 (SD 0.82) for the MSICs group.

At six to eight weeks postoperatively, three studies reported a greater SIA in the MSICS groups: George 2005 (mean SIA 1.1 ± 0.95 D MSICS versus 0.77 ± 0.65 D phacoemulsification); Venkatesh 2010 (mean SIA 1.20 ± 0.36 D MSICS versus 0.8 ± 0.24 D phacoemulsification) and Cook 2012 (median SIA -1.50 D MSICS versus -1.00 D phacoemulsification). At this time point, Gogate 2005a found mean astigmatism was almost equal in the two groups (1.1 D phacoemulsification group versus 1.2 D MSICs group). They also found that 47/185 participants in the phacoemulsification group and 40/187 in the small incision group had no astigmatism at all.

At six months postoperatively, Ruit 2007 did not show any significant difference in keratometric astigmatism between the MSICS group (0.88 D) and the phacoemulsification group (0.70 D) (P = 0.12).

Cost evaluation and surgical time

In Ruit 2007, phacoemulsification cases took 15.5 minutes each on average (cost USD 70 per case), whereas MSICS cases took nine minutes per case on average (cost USD 15 per case). Surgical time was reported in two studies, and was shorter in the MSICS group in both. Singh 2009 reported surgical time was less than six minutes in 11.2% of phacoemulsification and 84.9% of MSICS cases. Venkatesh 2010 reported mean surgical time of 8.8 +/- 3.4 minutes in the MSICS group and 12.2 +/- 4.6 minutes in the phacoemulsification group.

Discussion

Summary of main results

The results are summarised in Summary of findings for the main comparison.

We defined a good visual outcome as presenting acuity of 6/12 or better. Presenting acuity was not reported by any trial and we have reported both best-corrected (BCVA) and uncorrected (UCVA) visual acuity. There was some evidence of a better visual outcome regarding UCVA at six weeks in participants in the phacoemulsification group versus the manual small incision cataract surgery (MSICS) group based on the results of three studies (Cook 2012; Gogate 2005a; Venkatesh 2010). However, there was no evidence of any difference in BCVA. Only one trial reported at longer time periods (six months), and found no difference in either corrected or uncorrected acuity.

We defined poor visual outcome as BCVA of less than 6/60. There were a small number of events reported in either group in any study, so it is uncertain as to whether there are differences between the two groups with respect to poor visual outcome.

The number of complications reported were also low for both techniques. Again this means the review is currently underpowered to detect a difference between the two techniques with respect to these complications. Although most studies did not report postoperative corneal oedema, in the two studies that did there was some evidence that phacoemulsification caused more immediate postoperative oedema than MSICS. Further investigation is required to assess whether this effect is dependent on the setting in which the studies were conducted: for example, levels of cataract severity and degree of surgical experience may be possible explanations of this effect

No data were reported on quality of life. The cost of phacoemulsification was more than four times greater per case than MSICS (Ruit 2007).

Overall completeness and applicability of evidence

The outcomes reported by the included studies differed widely, making it difficult to collate evidence from all studies. Any conclusions must therefore be treated with caution due to the small numbers involved. The majority of studies were performed in India and Nepal in high output surgical units, and thus these results can not easily be applied to other settings, such as in developed countries. The one study carried out in South Africa concluded that the outcomes of phacoemulsification were better for UCVA, BCVA and astigmatism. However, this study involved 15 surgeons of varying experience, so the results may reflect surgical expertise rather than surgical technique.

We considered quite a number of secondary outcomes, and it is possible that some significant findings might have arisen due to chance. As the number of events was low we did not observe many statistically significant findings and we think it unlikely that the overall conclusions of the review are based on chance findings.

Quality of the evidence

Overall we graded the quality of the evidence as low or very low. All studies included were randomised controlled trials (RCTs). However, the level of evidence for many outcomes was downgraded due to lack of data reported in assessing risk of bias, imprecision (wide confidence intervals) and inconsistency (for example, if only one study reported the outcome and consistency could therefore not be assessed). The main risk of bias was a lack of reporting of the cause of incomplete outcome data in many studies. Also, most of the studies had a short follow-up period with the longest follow-up time of six months only reported in one study. Therefore more data regarding long-term visual outcomes are needed to draw conclusions about the two surgical techniques.

Potential biases in the review process

We did not identify any obvious biases in the review process, although we did not have enough included studies (10 or more) to assess publication bias.

Agreements and disagreements with other studies or reviews

This review agrees with a recently published meta-analysis of six RCTs (Zhang 2013). Phacoemulsification was associated with improved uncorrected visual acuity compared to MSCIS, but both procedures resulted in similar best-corrected visual acuity.

A study comparing the cost of the two procedures (Muralikrishnan 2004) found MSICS to cost on average USD 17.03 per case, whereas phacoemulsification cost USD 25.55 per case. This study supports the finding that MSICS is less costly; however, their analyses included costs such as equipment, utilities, labour and materials in a very high volume setting, so the conclusions drawn are not directly comparable to the Ruit 2007 study.

Authors' conclusions

Implications for practice

On the basis of eight RCTs included in this review the only significant difference found was in UCVA at three months which favoured phacoemulsification, but there were no differences in BCVA at three months or in either outcome at six months. There was no difference found in poor visual outcomes and complications between these two techniques for cataract surgery. However, due to a lack of available data the review is currently underpowered to detect differences for rarer complications. The major advantage of MSICS over phacoemulsification was the lower cost of this technique .

Implications for research

To be able to draw more comprehensive conclusions, more studies comparing MSICS and phacoemulsification are required. These need to have standardised reporting of outcomes enabling data from different studies to be pooled. In the absence of a formal core outcome set for such trials, we suggest that the primary outcomes we have included in this review (presenting visual acuity 6/12 or better and best corrected visual acuity worse than 6/60) should be reported as a minimum. However, as this review suggests that there may not be big differences in terms of visual outcome between these two interventions, future trials should collect information on vision-related quality of life and cost utility. Most of the trials included in this review had a relatively short follow-up period. We recommend a longer follow-up period ideally 12 months or more. We recognise that this may be difficult in some populations but it is important especially with regard to complications such as posterior capsule opacification which may become visually significant over a longer time course.

Acknowledgements

Iris Gordon at the Cochrane Eyes and Vision Group editorial base created and executed the electronic searches. We thank Clare Gilbert, Catey Bunce, Daniel Gore and Richard Wormald for their comments and Anupa Shah for editorial support. We would also like to thank Aeesha Malik for her work on the published protocol and earlier drafts of the review.

Richard Wormald (Co-ordinating Editor for CEVG) acknowledges financial support for his CEVG 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 views expressed in this publication are those of the authors and not necessarily those of the NIHR, NHS or the Department of Health.

Data and analyses

Download statistical data

Comparison 1. MSICS versus phacoemulsification
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Good functional vision at 3 months (uncorrected acuity)3767Risk Ratio (M-H, Random, 95% CI)0.90 [0.84, 0.96]
2 Good functional vision at 12 months (uncorrected acuity)  Other dataNo numeric data
3 Good functional vision at 3 months (best-corrected acuity)61223Risk Ratio (M-H, Random, 95% CI)0.99 [0.98, 1.01]
4 Good functional vision at 12 months (best-corrected acuity)  Other dataNo numeric data
5 Poor visual outcome at 3 months (best-corrected acuity worse than 6/60)61223Peto Odds Ratio (Peto, Fixed, 95% CI)2.48 [0.74, 8.28]
6 Poor visual outcome at 12 months (best-corrected acuity worse than 6/60)  Other dataNo numeric data
7 Posterior capsular rupture81708Peto Odds Ratio (Peto, Fixed, 95% CI)1.07 [0.63, 1.83]
8 Iridodialysis51114Peto Odds Ratio (Peto, Fixed, 95% CI)2.37 [0.54, 10.45]
9 Capsulorhesis extended3708Peto Odds Ratio (Peto, Fixed, 95% CI)0.26 [0.05, 1.30]
10 Postoperative inflammation3732Peto Odds Ratio (Peto, Fixed, 95% CI)1.19 [0.36, 3.93]
11 Corneal oedema postoperatively61476Peto Odds Ratio (Peto, Fixed, 95% CI)0.58 [0.41, 0.83]
12 Corneal oedema 3 to 6 weeks4 Peto Odds Ratio (Peto, Fixed, 95% CI)Totals not selected
13 Posterior capsule opacification2 Risk Ratio (M-H, Fixed, 95% CI)Totals not selected
14 Endothelial cell loss2 Mean Difference (IV, Fixed, 95% CI)Totals not selected
Analysis 1.1.

Comparison 1 MSICS versus phacoemulsification, Outcome 1 Good functional vision at 3 months (uncorrected acuity).

Analysis 1.2.

Comparison 1 MSICS versus phacoemulsification, Outcome 2 Good functional vision at 12 months (uncorrected acuity).

Good functional vision at 12 months (uncorrected acuity)
Study 
Ruit 2007At 6 months: MSICS: 41/46 Phacoemulsification: 40/48 Risk ratio: 1.07 (95% CI 0.91 to 1.26)
Analysis 1.3.

Comparison 1 MSICS versus phacoemulsification, Outcome 3 Good functional vision at 3 months (best-corrected acuity).

Analysis 1.4.

Comparison 1 MSICS versus phacoemulsification, Outcome 4 Good functional vision at 12 months (best-corrected acuity).

Good functional vision at 12 months (best-corrected acuity)
Study 
Ruit 2007At 6 months: MSICS: 45/46 Phacoemulsification: 47/48 Risk ratio: 1.0 (95% CI 0.94 to 1.06)
Analysis 1.5.

Comparison 1 MSICS versus phacoemulsification, Outcome 5 Poor visual outcome at 3 months (best-corrected acuity worse than 6/60).

Analysis 1.6.

Comparison 1 MSICS versus phacoemulsification, Outcome 6 Poor visual outcome at 12 months (best-corrected acuity worse than 6/60).

Poor visual outcome at 12 months (best-corrected acuity worse than 6/60)
Study 
Ruit 2007At six months: BCVA < 6/18 1.9% participants in both groups
Analysis 1.7.

Comparison 1 MSICS versus phacoemulsification, Outcome 7 Posterior capsular rupture.

Analysis 1.8.

Comparison 1 MSICS versus phacoemulsification, Outcome 8 Iridodialysis.

Analysis 1.9.

Comparison 1 MSICS versus phacoemulsification, Outcome 9 Capsulorhesis extended.

Analysis 1.10.

Comparison 1 MSICS versus phacoemulsification, Outcome 10 Postoperative inflammation.

Analysis 1.11.

Comparison 1 MSICS versus phacoemulsification, Outcome 11 Corneal oedema postoperatively.

Analysis 1.12.

Comparison 1 MSICS versus phacoemulsification, Outcome 12 Corneal oedema 3 to 6 weeks.

Analysis 1.13.

Comparison 1 MSICS versus phacoemulsification, Outcome 13 Posterior capsule opacification.

Analysis 1.14.

Comparison 1 MSICS versus phacoemulsification, Outcome 14 Endothelial cell loss.

Appendices

Appendix 1. CENTRAL search strategy

#1 MeSH descriptor Cataract
#2 MeSH descriptor Cataract Extraction
#3 MeSH descriptor Lens, Crystalline
#4 MeSH descriptor Lenses, Intraocular
#5 MeSH descriptor Lens Implantation, Intraocular
#6 intraocular lens* or intra ocular lens* or IOL*
#7 (#1 OR #2 OR #3 OR #4 OR #5 OR #6)
#8 MeSH descriptor Phacoemulsification
#9 pha?oemulsif*
#10 phaco or phako
#11 (#8 OR #9 OR #10)
#12 manual near/3 small near/3 incision near/3 cataract*
#13 MISICS or SICS
#14 MeSH descriptor Capsulorhexis explode all trees
#15 continuous near/3 curvilinear near/3 capsulor*hexis
#16 continuous near/3 circular near/3 capsulor*hexis
#17 CCC or CCS
#18 can opener near/5 capsulotom*
#19 endocapsular
#20 (#12 OR #13 OR #14 OR #15 OR #16 OR #17 OR #18 OR #19)
#21 (#7 AND #11 AND #20)

Appendix 2. MEDLINE (OvidSP) 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/
14. cataract extraction/
15. exp lens crystalline/
16. exp lenses intraocular/
17. lens implantation intraocular/
18. (intraocular lens$ or intra ocular lens$ or IOL$).tw.
19. or/13-18
20. phacoemulsification/
21. pha?oemulsif$.tw.
22. (phaco or phako).tw.
23. or/20-22
24. (manual adj3 small adj3 incision adj3 cataract$).tw.
25. (MISICS or SICS).tw.
26. capsulorhexis/
27. (continuous adj3 curvilinear adj3 capsulorhexis).tw.
28. (continuous adj3 circular adj3 capsulorhexis).tw.
29. (continuous adj3 curvilinear adj3 capsulor?hexis).tw.
30. (CCC or CCS).tw.
31. (can opener adj5 capsulotom$).tw.
32. endocapsular.tw.
33. or/24-32
34. 19 and 23 and 33
35. 12 and 34

The search filter for trials at the beginning of the MEDLINE strategy is from the published paper by Glanville et al (Glanville 2006).

Appendix 3. EMBASE (OvidSP) 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$).tw.
29. or/25-28
30. 29 not 10
31. 30 not (11 or 23)
32. 11 or 24 or 31
33. exp cataract/
34. exp cataract extraction/
35. exp lens/
36. exp lens implant/
37. exp lens implantation/
38. (intraocular lens$ or intra ocular lens$ or IOLS).tw.
39. or/33-38
40. exp phacoemulsification/
41. pha?oemulsif$.tw.
42. (phaco or phako).tw.
43. or/40-42
44. (manual adj3 small adj3 incision adj3 cataract$).tw.
45. (MISICS or SICS).tw.
46. capsulorhexis/
47. (continuous adj3 curvilinear adj3 capsulorhexis).tw.
48. (continuous adj3 circular adj3 capsulorhexis).tw.
49. (continuous adj3 curvilinear adj3 capsulor?hexis).tw.
50. (CCC or CCS).tw.
51. (can opener adj5 capsulotom$).tw.
52. endocapsular.tw.
53. or/45-52
54. 39 and 43 and 53
55. 32 and 54

Appendix 4. LILACS search strategy

cataract$ and phaco$ or phako$ and manual small incis$ or MISICS or SICS or capsulorhexis or capsulorrhexis

Appendix 5. Web of Science CPCI-S search strategy

#17 #3 and #6 and #16
#16 #7 or #8 or #9 or #10 or #11 or #12 or #13 or #14 or #15
#15 TS=can opener capsulotom*
#14 TS=(CCC or CCS)
#13 TS=(continuous circular capsulorrhexis)
#12 TS=(continuous circular capsulorhexis)
#11 TS=(continuous curvilinear capsulorrhexis)
#10 TS=(continuous curvilinear capsulorhexis)
#9 TS=capsulorhexis
#8 TS=(MISICS or SICS)
#7 TS=(manual small incision)
#6 #4 or #5
#5 TS=(phaco or phako)
#4 TS=(phacoemulsification or phakoemulsification)
#3 #1 OR #2
#2 TS=(intraocular lens* or intra ocular lens* or IOL*)
#1 TS=cataract*

Appendix 6. metaRegister of Controlled Trials search strategy

cataract AND phacoemulsification

Appendix 7. ClinicalTrials.gov search strategy

cataract AND phacoemulsification

Appendix 8. ICTRP search strategy

phacoemulsification = Condition AND manual or MISICS or SICS or capsulorhexis or capsulorrhexis = Intervention

Contributions of authors

Conceiving the review: YR
Designing the review: YR, JE
Co-ordinating the review: YR, JE
Data collection for the review:
- Designing electronic search strategies: Cochrane Eyes and Vision Group editorial base
- Undertaking manual searches:
- Screening search results: YR, JE, SdeS
- Organising retrieval of papers:
- Screening retrieved papers against inclusion criteria: YR, SdeS
- Appraising quality of papers: YR, SdeS, JE
- Extracting data from papers: YR, SdeS, JE
- Writing to authors of papers for additional information: YR
- Providing additional data about papers: SdeS, YR
- Obtaining and screening data on unpublished studies: SdeS, YR
Data management for the review:
- Entering data into Review Manager 5: JE, YR, SdeS
- Checking data entered into Review Manager 5: YR, JE, SdeS
Analysis of data: JE
Interpretation of data:
- Providing a methodological perspective: JE
- Providing a clinical perspective: YR, SdeS
- Providing a policy perspective: YR, SdeS
Writing the review: YR, SdeS, JE
Performing previous work that was the foundation of the current study: YR, JE

Declarations of interest

None known.

Sources of support

Internal sources

  • No sources of support supplied

External sources

  • Sightsavers, UK.

Differences between protocol and review

Primary outcome "presenting visual acuity 6/12 or better"

No study reported presenting visual acuity so we report both uncorrected and best-corrected acuity. Most studies reported 6/18 or better outcomes and we have used this to indicate 'good functional vision'.

Unit of analysis

The main unit of analysis issue is how the trial investigators dealt with two eyes. There were several options here: a trial may randomise people to the intervention groups and then apply the intervention and/or measure the outcome in one eye (study eye) or both eyes. However, if the intervention had been applied to both eyes, it would have been incorrect to analyse eyes without taking into account the fact that the eyes for a person are not independent. Alternatively a trial may randomly allocate eyes to an intervention so each person had a different intervention in each eye. In this case, the pairing would have to be taken into account in the analysis. In the protocol for this review, if the trial had been incorrectly analysed, we planned to contact the trial investigators for further information to enable calculation of a design effect (Perera 2007). However, in the event this was not necessary.

Assessment of reporting biases

The main reporting biases that we planned to consider were publication bias and outcome reporting bias. Currently there are not enough trials included in the review to assess publication bias.When there are enough trials (10 or more) we will do a funnel plot to see if small studies report different effects, one explanation for which could be publication bias

Sensitivity analysis

We planned to do a sensitivity analysis excluding trials at high risk of bias and investigating the impact of missing data. However, currently there are not enough data to enable this.

'Summary of findings' tables

This was not specified in the protocol.

Notes

The original published Cochrane review 'Riaz Y, Mehta JS, Wormald R, Evans JR, Foster A, Ravilla T, Snellingen T. Surgical interventions for age-related cataract. Cochrane Database of Systematic Reviews 2006, Issue 4. Art. No.: CD001323. DOI: 10.1002/14651858.CD001323.pub2' has been divided into three smaller reviews each using the same outcome measures as the original review but only comparing two surgical methods within each review. The interventions being compared are ECCE, MSICS and phacoemulsification. Intracapsular extraction (ICCE) is no longer included in the reviews as this technique is no longer used as a primary procedure.

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Cook 2012

Methods

Parallel group randomised controlled trial

200 participants (200 eyes) randomised

Follow-up: eight weeks

Participants

Age-related cataract in participants over 50 years

Exclusion criteria:

1. People with early cataract (visual acuity better than 6/36)

2. People with coexistent glaucoma

3. People with corneal scar

Demographics:

M:F phacoemulsification 39:61; MSICS 33:67

Mean age: phacoemulsification 66.9 years, MSICS 68.8 years

Black, coloured and white participants

Setting:

Groote Schuur Hospital, University of Cape Town, South Africa

InterventionsMSICS n = 100; phacoemulsification n = 100
Outcomes
  1. UCVA at day 1 and week 8

  2. BCVA at week 8

  3. Refraction

  4. Intraoperative and postoperative complication

Notes

Published data only

Date conducted: not reported

Funding sources: "Nil"

Declarations of interest among the primary researchers: "Nil"

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risk"Randomisation to the two arms of the study was done using opaque sequentially numbered envelopes. The randomisation sequence allocation was generated by a research assistant who randomly selected and numbered sequential envelopes containing an instruction on the type of surgery to be done".
Allocation concealment (selection bias)Low risk"The envelopes were kept in the operating room, and the next numbered envelope was opened by the surgeon immediately prior to the surgery".
Blinding of participants and personnel (performance bias)
All outcomes
Low risk"The patients were not informed about the method of surgery that was used"
Blinding of outcome assessment (detection bias)
All outcomes
Low risk"The ophthalmic assistants and nurses who tested and recorded the post operative visual acuities were also masked to the surgery that was done"
Incomplete outcome data (attrition bias)
All outcomes
Unclear risk80 participants in the phacoemulsification group, 85 participants in the MSICS group completed 8-week follow-up. "Eighteen per cent of our patients were lost to follow-up at eight weeks. Our patients are indigent people living both within the Cape Town Metropole and in more distant rural areas, and this loss to follow-up is difficult to control".
Selective reporting (reporting bias)Low riskNone obvious.

George 2005

Methods

Parallel group randomised controlled trial

124 participants (124 eyes) randomised by computer-generated random numbers

Follow-up: six weeks

Participants

Primary diagnosis of nuclear sclerosis grade III or less

Exclusion criteria:

1. Persons with other potential causes of decreased vision

2. Non-age-related cataracts

3. Cataract associated with glaucoma or retinal pathology

4. Phacodenesis

Demographics:

Gender M:F ratio 24:29 for MSICS, 27:33 for phacoemulsification groups. Mean age 58.75 years for MSICs and 59.63 for phacoemulsification groups (no significant difference in the age or gender of all three groups)

Study setting:

Community ophthalmic care centre of a tertiary care eye hospital, Tamil Nadu, India

InterventionsMSICS n = 62; phacoemulsification n = 62 (ECCE group n = 62, not included in this review)
Outcomes
  1. Mean endothelial cell loss

  2. Cell density recorded as no of cells per square millimetre and as a percentage reduction

  3. Mean surgically induced astigmatism (dioptres)

  4. Mean prescribed cylindrical correction (dioptres)

  5. Postoperative BCVA < 6/18

Participants were reviewed preoperatively, at one day, one week and six weeks postoperatively. Only results from the preoperative and six weeks postoperative visits were reported

At six weeks all participants had visual acuity measured, refraction, slit lamp examination, keratometry, applanation tonometry, specular microscopy and dilated fundus examination

The six-week follow-up was completed on 52/62 cases in the ECCE group, 53/62 cases in the MSICS group and 60/62 cases in the phacoemulsification group

No subgroup analyses were performed.

Notes

Published data only

Date conducted: not reported

Funding sources: none specified

Declarations of interest among the primary researchers: not mentioned

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risk

"Cases were randomized into three groups based on computer-generated random numbers. Randomization was carried out at the time of admission and used the hospital numbers (which were allotted at the time of the first hospital visit) for allocation into different groups". (Page 294)

"Cases were separately randomized for each surgeon so that equal numbers of each technique were performed by each surgeon". (Page 294)

Allocation concealment (selection bias)Unclear riskNot reported
Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskStudy does not document whether participants were aware/ informed of which intervention they were assigned to
Blinding of outcome assessment (detection bias)
All outcomes
Unclear risk

"Independent observers performed refraction and keratometry in order to minimize bias". (Page 295)

No mention of masking of outcome assessment

Incomplete outcome data (attrition bias)
All outcomes
Unclear risk

The six-week follow-up was completed by 53/62 cases of MSICS and 60/62 cases of phacoemulsification

The reasons for attrition were not stated

Selective reporting (reporting bias)Unclear riskPrimary outcomes implicit but neither outcomes or protocol clearly stated.

Ghosh 2010

Methods

Parallel group randomised controlled trial

224 participants (224 eyes) randomised. “In each patient, the eye with more advanced cataract was included as study eye” (Page 103).

Follow-up: six months

Participants

Inclusion criteria:

Age 50 - 75 with age-related cataract

Exclusion criteria:

Fasting plasma glucose more than 126 mg/dl

Any treatment history of diabetes

History of previous eye surgery

Present or past history of uveitis
Ocular disease other than cataract
History of significant eye trauma
Axial length more than 26.5 mm

People with 3+ or more flare (Standardization of Uveitis Nomenclature Working Group) on the 1st postoperative day were also excluded from study.

Demographics:

Mean age: 62 +/- 6 SD years MSICS group; 61 +/- 6 SD Phacoemulsification group

Males: 125 participants (55.8%)

Study setting:

Tertiary care hospital, Kolkata, West Bengal, India

InterventionsMSICS n = 112; phacoemulsification n = 112
Outcomes
  1. BCVA

  2. Mean macular thickness

Notes

Published data only

Date conducted: April 2007 to April 2008

Funding sources: none specified

Declarations of interest among the primary researchers: not mentioned

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risk"Each patient was allocated to either MSICS or phacoemulsification group by drawing ballots from a sealed envelope". (Page 103)
Allocation concealment (selection bias)Low risk"Allocation to each surgeon was also performed during drawing of ballots, the two procedures being equally distributed among two surgeons (PNB, SG)". (Page 103)
Blinding of participants and personnel (performance bias)
All outcomes
Low risk"The participating surgeons were not involved with the allocation procedure and were masked concerning the method of surgery until the patients were prepared on the table. The patients were masked to the allocation code until surgery was performed". (Page 103)
Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskDetails not stated in paper
Incomplete outcome data (attrition bias)
All outcomes
Unclear risk

"All patients completed the 1st-day and the 7th-day follow-up. In phacoemulsification group, 97 patients came for the 42nd-day follow-up and 94 patients completed the 180th-day follow-up. In MSICS group, 100 patients completed the 42nd-day follow-up and 99 came for the 180th-day follow-up". (Page 103).

Reason for attrition not stated.

Selective reporting (reporting bias)High risk

"Five patients in MSICS group (corneal oedema 1, iridodialysis 1, posterior capsular rupture 1, sulcus fixation IOL 1, 3+ flare 1) and nine patients in phacoemulsification group (corneal oedema 4, posterior capsular rupture 4, 3+ flare 1) were further excluded from the study because of various preoperative and postoperative complications necessitating alteration in management protocol". (Page 103)

"The macular thickness of the five cases that were excluded for corneal oedema was evaluated on the 42nd and the 180th day after clearance of oedema. When these values along with the values of two patients with 3+ flare and five patients with capsular rupture were included in the analysis, the difference in CSMT between the two groups was still statistically significant". (Page 104).

Gogate 2005a

Methods

Parallel group randomised controlled trial

400 participants (400 eyes) randomised

Follow-up: six weeks

Participants

Primary diagnosis: age-related cataract

Inclusion criteria:

Resident in region, willing and able to attend regular follow-up for one year

Exclusion criteria:

Combined surgical procedure

Other causes of compromised vision (e.g. amblyopia, glaucoma, diabetic retinopathy, age-related macular degeneration)

Axial length > 26.5 mm

Age < 40 or > 90

Age/mobility would hinder follow-up

Could not give informed consent

Demographics: age 40 - 90, average age 68.1 phacoemulsification, and 60.7 for MSICs.

Study setting:

HV Desai Eye hospital, Pune, India

InterventionsMSICS n = 201; phacoemulsification n = 199
Outcomes

Relevant outcomes:

  1. VA at one week and six weeks

  2. Intraoperative and postoperative complications

  3. Final astigmatism at six weeks postoperative

Adverse events: two phacoemulsification converted to MSICs

Intervals of outcomes: one and six weeks

Number of participants included in analysis:

Phacoemulsification at one week follow-up = 192, at six weeks follow-up = 185

MSICs at one week follow-up = 191, at six weeks follow-up = 187

Notes

Published data only

Date conducted: July 2002 to December 2003.

Funding sources: HV Desai hospital and Lakhani Trust

Declarations of interest among the primary researchers: not mentioned

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskAllocation of participants: "Each patient was randomly allocated to 1 of the 2 groups by drawing ballots (from sealed envelopes) at the beginning of surgery, after the patient was placed on the operating table". (Page 870)
Allocation concealment (selection bias)Low riskThe allocation codes were sealed in sequentially numbered opaque envelopes and placed in the care of the trial manager. The participating surgeons were not involved in the care of or the opening of the envelopes and were informed of the treatment assignment in the operating room immediately before surgery. The trial statistician who generated the allocation schedule in Hyderabad was not involved in the execution of the assignment. The trial manager opened the envelope in Pune and was not involved in the generation of the allocation schedule." (Page 870)
Blinding of participants and personnel (performance bias)
All outcomes
Low risk"The patients were masked before, during, and after (during the follow-up) the surgical intervention regarding the surgical technique. The patients and the ophthalmologists in charge of the follow-up outcome assessment were masked to the treatment allocation code.". (Page 870)
Blinding of outcome assessment (detection bias)
All outcomes
Unclear risk"The patients and the ophthalmologists in charge of the follow-up outcome assessment were masked to the treatment allocation code. However, the ophthalmologist examining the patient on follow-up would be able to determine the type of surgery". (Page 870)
Incomplete outcome data (attrition bias)
All outcomes
Unclear riskNo reasons for attrition were reported. 185/199 completed follow-up in the phacoemulsification group and 187/201 completed follow-up in the MSICs group.
Selective reporting (reporting bias)Unclear riskNone obvious.

Gogate 2010

Methods

Parallel group randomised controlled trial

200 participants randomised: it is most likely that one eye per person was enrolled in the trial; it was unclear how this eye may have been selected

Follow-up: six weeks

Participants

Primary diagnosis: age-related cataract

Inclusion criteria:

Mature cataract

Cataract up to grade 4 hardness

Exclusion criteria:

Ocular comorbidity e.g. acute infection, severe inflammation, pre-existing corneal opacity, black cataract, non-age-related or complicated cataract, glaucoma, pseudoexfoliation, retinal pathology

Pre-operative endothelial cell count < 2000 cells/mm2

Unable to consent

Demographics:

Gender 47.5% male, mean age 63.7 years for phacoemulsification and 62.7 for MSICs

Study setting:

Tertiary care centre, India

InterventionsMSICS n = 100; phacoemulsification n = 100
Outcomes

1. Endothelial cell count - Preoperatively, one week, and six weeks postoperatively

2. Difference in ECCE over time

3. Corrected distance VA at one and six weeks

4. Intra- and postoperative complications up to six weeks

5. Postoperative astigmatism

Number of participants included in the analysis:
at one week, phacoemulsification 92/100, MSICs 94/100.
at six weeks phacoemulsification 71/100, MSICs 75/100

Adverse events were reported for both groups

Notes

Published data only

Date conducted: not reported

Funding sources: none specified

Declarations of interest among the primary researchers: "no author has a financial or proprietary interest in any material or method mentioned"

No correspondence with authors

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risk"Ballots drawn from sealed envelopes at beginning of surgery used to randomly allocate each patient to phacoemulsification or SICS. There were 50 ballots for each of 4 surgeons; 25 ballots were for SICS and 25 for phacoemulsification. The randomization (allocation) schedule for each surgeon was generated using the EpiTable application (Epi Info, Centers for disease control) at the International Centre for Advancement and Rural Eye Care, L.V. Prasad Eye Institute, Hyderabad, India." (Page 248)
Allocation concealment (selection bias)Low risk"The allocation codes were sealed in sequentially numbered, opaque envelopes and kept by the study coordinator. The envelopes were opened 10 minutes before surgery. The participating surgeons were not involved in the care or opening the envelopes. If the surgeons performed a different technique or converted from phacoemulsification to SICS, the patients were analyzed on an intent to treat basis". (Page 248)
Blinding of participants and personnel (performance bias)
All outcomes
Low risk"To minimize bias, patients were masked to the type of surgery". (Page 248)
Blinding of outcome assessment (detection bias)
All outcomes
Unclear risk"Health workers interviewing patients were also unaware of the type of surgery the patients were to have. Surgeons were masked to the technique until 10 minutes before surgery. Optometrists and ophthalmologists examining the patient postoperatively were not masked to the type of surgery.A different set of ophthalmologists performed the postoperative follow-up and refractions". Page 248
Incomplete outcome data (attrition bias)
All outcomes
Unclear risk

No explanation is given of why the attrition rate was relatively high.

"However, patients whose data were not available (lost to follow-up, data lost) did not differ from those whose data were available in preoperative variables (age, sex, preoperative acuity, cataract type, operating surgeon), intraoperative variables (type of surgery, surgery time, complications), or 1-week follow-up outcome measures". (Page 251)

Missing data balanced in numbers across intervention groups. 71/100 participants analysed for phacoemulsification group and 75/100 analysed for MSICs group.

Selective reporting (reporting bias)Unclear riskNone obvious

Ruit 2007

Methods

Parallel group randomised controlled trial

108 participants randomised: it is most likely that one eye per person was enrolled in the trial; it was unclear how this eye may have been selected

Follow-up: six months

Participants

Primary diagnosis: decreased visual acuity due to cataract

Exclusion criteria:

Other ocular disease

Demographics:

Median age 65.8 years (phacoemulsification) 63.8 years (MSICS)

Study setting:

Outreach microsurgical eye clinic, Nepal

InterventionsMSICS n = 54; phacoemulsification n = 54
Outcomes

Outcomes:

  1. Operation time

  2. Surgical complications intraoperatively and postoperatively

  3. UCVA and BCVA

  4. Astigmatism

  5. Central corneal thickness and keratometry

  6. Cost of equipment and consumables

Intervals at which outcomes assessed:

Postoperative days one and five, three and six weeks, three and six months

Adverse events were reported for each intervention

Number of participants included in analysis:

100% follow-up for each intervention at day one postoperatively

phacoemulsification 86%; MSICs 85% follow-up at six months

Notes

Published data only

Date conducted: May 2005

Funding sources: none specified

Declarations of interest among the primary researchers: "The authors indicate no source of funding or financial conflict of interest"

No correspondence with investigators

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risk"Patients who were cleared for cataract surgery were assigned randomly by picking a ball from a bag that contained one white ball and one black ball. A white ball assigned the patient to phacoemulsification with a foldable IOL, which was performed by one of the authors (D.C.), who is a clinical professor at the University of California, San Francisco. A black ball assigned the patient to sutureless manual SICS, which was performed by another author (S.R.), director of the Tilganga Eye Center in Nepal. After each random assignment, the following patient was assigned automatically to the alter- native procedure". (Page 33)
Allocation concealment (selection bias)Unclear riskNot reported
Blinding of participants and personnel (performance bias)
All outcomes
Unclear risk

Surgeons were not masked since each surgeon performed a different technique

Not mentioned if participants were masked

Blinding of outcome assessment (detection bias)
All outcomes
Low risk"All postoperative visual acuities and refractions were obtained by ophthalmic assistants who were masked to the treatment group and had not been involved in the preoperative portion of the study." (Page 34)
Incomplete outcome data (attrition bias)
All outcomes
Unclear risk

Cause of attrition rate not known:

"Because of the nature of the outreach cataract screening process and the poor and remote setting where most patients reside, we were unable to determine the reasons that eight patients in the manual SICS group and six patients in the phacoemulsification group were lost to follow-up". (Page 35). 48/54 patients analysed for phacoemulsification group and 46/54 analysed for MSICS group

Selective reporting (reporting bias)Unclear riskNone obvious

Singh 2009

Methods

Parallel group randomised controlled trial

182 participants randomised: it is most likely that one eye per person was enrolled in the trial; it was unclear how this eye may have been selected

Follow-up: immediate postoperative (before discharge) only

Participants

Inclusions criteria:

People with immature senile cataracts (defined as nucleus sclerosis up to 2+, cortical cataract 2+ and posterior sub-capsular cataract of any grade).

Exclusion criteria:

All other types of cataracts were excluded.

Demographics:

Mean age 58.2 years (phacoemulsification), 58.7 years (MSICS)

Study setting:

Biratnagar Eye Hospital, Nepal

InterventionsMSICS n = 89; phacoemulsification n = 93
Outcomes
  1. Postoperative uncorrected visual acuity on the first postoperative day

  2. Surgery-induced astigmatism

  3. Intraoperative and postoperative complications

  4. Surgical time

Notes

Published data only

Date conducted: May 2007 to June 2007

Funding sources: none

Declarations of interest among the primary researchers: "none"

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risk"Randomization was done with the help of random number tables". (Page 96)
Allocation concealment (selection bias)Unclear riskNot reported
Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskNot reported
Blinding of outcome assessment (detection bias)
All outcomes
Low risk"However, the visual acuity recording person was not aware of the study and masking could be achieved". (Page 96)
Incomplete outcome data (attrition bias)
All outcomes
Low riskThere is no indication in the paper that any participant did not complete the follow-up period (one day)
Selective reporting (reporting bias)Low riskNone obvious

Venkatesh 2010

  1. a

    BCVA: best-corrected visual acuity
    ECCE: extracapsular extraction
    MSICS: manual small incision cataract surgery
    UCVA: uncorrected visual acuity
    VA: visual acuity

Methods

Parallel group randomised controlled trial

270 participants randomised: it is most likely that one eye per person was enrolled in the trial; it was unclear how this eye may have been selected

Follow-up: six weeks

Participants

Inclusion criteria:

Participants between 35 years and 70 years of age with white cataract that obscured fundus visualisation and whose pupils dilated to at least 5.0 mm.

Exclusion criteria:

Subluxated cataracts and cataracts clearly caused by trauma
Additional exclusion criteria
Coexisting glaucoma

Corneal pathology

Uveitis

Poor pupil dilation (!5.0 mm)

Other known pathology that could impair visual potential

People that were unable to attend the follow-up visits or give informed consent

Demographics:

M:F phacoemulsification group 57:76; 51:86 MSICS group

Mean age: 56 +/- 9.3 years phacoemulsification group; 56.6 +/- 9.5 years MSICS group

Setting:

Aravind Eye Hospital, Pondicherry, India

InterventionsMSICS n = 137; phacoemulsification n = 133
Outcomes
  1. Rate of intraoperative and postoperative complications

  2. BCVA

  3. Corneal astigmatism 6 weeks postoperatively

  4. Surgical time

Notes

Published data only

Date conducted: September 2007 to April 2008

Funding sources: none specified

Declarations of interest among the primary researchers: "no author has a financial or proprietary interest in any material or method mentioned"

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risk"The randomization (allocation) schedule was generated by a DOS-based software program at Lions Aravind Institute for Community Ophthalmology". (Page 1850)
Allocation concealment (selection bias)Low risk"The allocation codes were sealed in opaque numbered envelopes that were opened by the operating room staff". (Page 1850)
Blinding of participants and personnel (performance bias)
All outcomes
Low risk"Patients were not informed about the method of surgery to which they were assigned". (Page 1850)
Blinding of outcome assessment (detection bias)
All outcomes
Low risk"The evaluating independent investigator (an ophthalmologist who was not a study surgeon) and the examining refractionist who assessed uncorrected (UDVA) and corrected (CDVA) distance visual acuities were also masked to the identity of the operating surgeon and the method of surgery". (Page 1850)
Incomplete outcome data (attrition bias)
All outcomes
Unclear risk"Two hundred thirty of 270 patients (85.2%) completed the 6-week follow-up". (Page 1851).
No explanation given for attrition rate
Selective reporting (reporting bias)Low riskNone obvious

Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion
Cai 2008Participants were not randomised to interventions
Centurion 1999All participants underwent phacoemulsification
Centurion 2005Retrospective study
Chanis 1993No direct comparison
Elkady 2009The study reported on microincision cataract surgery (MICS) versus microcoaxial phacoemulsification
Goel 2012Cataract surgery with implantation of endocapsular supporting devices.
Parmar 2006This was a study of per-operative contamination of the anterior chamber
Reddy 2007Non-standard interventions were used

Ancillary