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

Methodological quality of the review: High confidence

Author: Ang M, Evans JR, Mehta JS.

Region: India and Nepal.

Sector: Cataract extraction, MSICS, ECCE, age-related cataract.

Sub-sector: None specified

Type of cataract: Age-related cataract

Equity focus: None specified

Review type: Effectiveness review

Quantitative synthesis method: Narrative analysis

Qualitative synthesis methods: Not applicable

Background

Age-related cataract is the opacification of the lens, which occurs as a result of denaturation of lens proteins and this is not thought to be reversible. Extracapsular cataract extraction (ECCE) consists on the removal of lens content through a large incision leaving the posterior lens capsule intact. A posterior chamber intraocular lens (IOL) can then be placed in the capsular bag. Extracapsular surgery has become the preferred methods of extraction in economically advantaged countries and most surgeons in developing countries have been trained in this technique.

In Asia and Africa there has been a renewal of interest in Manual Small Incision Cataract Surgery (MSICS) as an alternative to phacoemulsification, as it is considerably less costly and has similar benefits of rapid visual recovery and reduced astigmatism.

Research objectives      

To compare two different techniques of lens removal in cataract surgery; manual small incision surgery (MSICS) and extracapsular cataract extraction (ECCE).

Main findings

Three trials randomly allocating people with age-related cataract to MSICS or ECCE were included in the review. Two were conducted in India and one in Nepal.

In two studies, more participants in the MSICS groups achieved unaided visual acuity of 6/12 or 6/18 or better compared to the ECCE group, but overall not more than 50% of people achieved good functional vision in the two studies. 10/806 (1.2%) of people enrolled in two trials had a poor outcome after surgery (best corrected vision less than 6/60) with no evidence of difference in risk between the two techniques (risk ratio (RR) 1.58, 95% confidence interval (CI) 0.45 to 5.55). Surgically induced astigmatism was more common with the ECCE procedure than MSICS in the two trials that reported this outcome. In one study there were more intra- and postoperative complications in the MSICS group. One study reported that the costs of the two procedures were similar.

There were no other studies from other countries other than India and Nepal and there were insufficient data on cost-effectiveness of each procedure. Better evidence was needed before any change may be implemented. Authors suggested that visual outcomes at three and six months are the minimum follow-up time for comparing ECCE and MSICS; an adequately powered randomized controlled trial (RCT) is required to assess cost-effectiveness and the impact on quality of life. Authors mentioned that when executing the RCTs the study participant should be randomized to expert surgeons rather than having the same surgeon performing both procedures.

Methodology

Authors included trials that compared MSICS with a posterior chamber IOL with ECCE with a posterior chamber IOL implant. Primary outcome measure for this review was postoperative visual acuity, considering both presenting visual acuity better than or equal to 6/12 in the operated eye and BCVA worse than 6/60 in the operated eye. Outcomes follow-up was considered at three months and one year after surgery.

Authors searched several databases including CENTRAL (2012), MEDLINE (1950-2012), EMBASE (1980-2012) and LILACS (1982-2012) with no language or date restrictions being applied to trial searches. Reference lists of all included studies and pertinent reviews identified were screened, and reviewers also contacted the authors of the included studies to identify unpublished studies or studies sent for publication or in press. Two reviewers assessed the search results for relevance and inclusion of studies, extracted data and conducted an assessment of risk of bias of included studies.

Authors did not have enough data to include a formal meta-analysis and conducted a descriptive narrative of the results.

Applicability/external validity

Participants of the included studies were either from India and Nepal, and authors acknowledged that the applicability of the review to other populations may be limited in scope. It should also be noted, that within India itself there were major differences in results depending on type of treatment service being studied, that is, treatment offered in hospitals and treatment offered in cataract camps. Authors also noted that an evaluation of cataract surgery should not rely on visual acuity alone, but should include analysis of quality of life and quality of vision measures.

Geographic focus

Two studies were conducted in India and one in Nepal (please see above).

Quality Assessment

This systematic review was based on relatively comprehensive literature searches and appropriate methods to reduce risk of bias in terms of study selection, data extraction, and analysis. Overall, this review was appropriately conducted and therefore, high confidence was attributed to the conclusions about the effects of this study.