Methodological quality of the review: Medium confidence
Author: Zhang JY, Feng YF, Cai JQ.
Region: Details not provided
Sector: Cataract surgery, age-related cataract
Sub-sector: Phacoemulsification, manual small-incision cataract surgery.
Type of cataract: Age-related cataract
Equity focus: None Specified
Review type: Effectiveness review
Quantitative synthesis method: Meta-analysis
Qualitative synthesis methods: Not Applicable
Phacoemulsification (Phaco) has become a leading cataract extraction procedure in developed countries, although its usage in developing countries is limited due to its high cost and requirement of more advanced surgical training. As an alternative to Phaco, ophthalmologists in low-income countries are performing manual small-incision cataract surgery (MSICS) in order to achieve similar outcomes to those of Phaco. This review built on a review performed in 2006 (Riaz et al 2006), questioning the efficacy of these two surgical techniques.
‘To compare outcomes of phacoemulsification [Phaco] with manual small incision cataract surgery (MSICS) for age-related cataract.’
Six randomized controlled trials (RCTs) that compared Phaco with MSICS were included in the review. The geographical location of the studies was not addressed by the review.
Analysis of the six RCTs found that out of a total of 1,315 eyes included in the studies as a whole, there were no significant differences between Phaco and MSICS when looking at best corrected vision acuity 6/9 or better (P= 0.69) and less than 6/18 (P= 0.68) percent of ECC loss (P=0.45), intraoperative or postoperative complications (P=0.44 and P= 0.87 respectively). However, more patients receiving Phaco had a final uncorrected visual acuity (UCVA) greater than 6/9 (P= 0.03) and a greater proportion of patients receiving MSICS had final UCVA less than 6/18 (P=0.03). Furthermore, surgically induced astigmatism was less prevalent in Phaco than MSICS.
Based on findings, authors concluded that Phaco is superior to MSICS in (UCVA) and causes less surgically induced astigmatism (SIA), but there were no significant differences in visual rehabilitation, endothelial cell count (ECC) loss and complication rates between the two techniques.
Authors noted that the review was limited by the short follow up time data used in the meta-analysis (which was 6 months or less) and that longer follow up is needed for better observation of surgery induced astigmatism and other complications or adverse effects.
Only RCTs that compared Phaco and MSICS followed by implantation of a posterior chamber intraocular lens (IOL) in both techniques were included in the review. Participants were people with decreased visual acuity because of cataracts and no other known eye disorders. Primary outcomes of this study were: (1) The proportion of people achieving best corrected vision acuity (BCVA) better than or equal to 6/9 and (2) The proportion of people with poor visual outcome, BCVA worse than 6/18. Secondary outcomes also included (1) Complications resulting from surgery, (2) Corneal endothelial cell count (ECC) and (3) Surgery induced astigmatism.
The authors conducted a search of the literature on various databases including PUBMED, EMBASE and the Cochrane Controlled Trials Register, although dates searched were not reported. No language restriction was used. The reference lists of original reports and review articles retrieved were reviewed for additional studies. Two independent reviewers initially screened texts for inclusion and extracted data for subsequent analysis.
The review included a meta-analysis. For results showing significant heterogeneity, a random effects meta-analysis was performed. Otherwise, a fixed effects method was performed.
The review does not specifically discuss how generalizable the results are.
The geographical location of the studies was not addressed by the review.
Overall, there is medium confidence in the conclusions about the effects of this study. Authors conducted a partially comprehensive search of the literature, however, search parameters were not reported and it was not clear if authors contacted experts for potentially relevant studies. It was noted that authors did not search for unpublished studies or original data, which may induce publication bias within the report.
The likelihood of bias of the included studies was addressed and the methodological quality of the included randomized control trials was appropriately assessed. Using this scale, all six studies were rated as ‘fairly good’, meaning methodologically sound. Authors clearly described the method of analysis and addressed issues of heterogeneity in the review.
Zhang J, Feng Y, Cai J. Phacoemulsification versus manual small incision cataract surgery for age-related cataract: meta-analysis of randomised control trials. Clinical and Experimental Ophthalmology. 2013;vol 41:issue 4.