Methodological quality of the review: High confidence

Author: Desapriya E, Subzwari S, Scime-Beltrano G, Samayawardhena LA, Pike I.

Region: Details not provided

Sector: Cataract surgery

Sub-sector: Vision improvement, falls, reduction in injury

Type of cataract: Age-related cataract

Equity focus: None specified

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis methods: Not applicable

Background

The deterioration in vision that accompanies the normal aging process and eye disease, including cataract, are likely major factors contributing to the increased incidence of injuries in the elderly population; in addition to other sensory impairments, poor vision is a predictor of falls in older women. Worldwide, injuries are a significant cause of death.

Evidence shows that vision impairment and overall quality of life are direct benefits of cataract surgery. Therefore, evidence of quality-of-life improvement due to improved vision could be a suitable factor in prioritizing patients for cataract surgery.

Research objectives

To quantify the benefits of expedited cataract surgery in improving visual acuity and reducing fall-related injuries in the older population through a systematic review and meta-analysis.

Main findings

In total, three randomized controlled trials (RCTs) were included for meta-analysis, which described and analysed to establish correlation between expedited cataract surgery and vision, two of which described and analysed the correlation between expedited cataract surgery and injury reduction.

The meta-analysis showed that expedited cataract surgery was associated with significantly enhanced visual acuity (OR, 7.22; 95% CI, 3.15-16.55; P = .001). The combined results in the three studies that analysed expedited cataract surgery showed that expedited surgery group had a seven-fold improvement in vision over vision in the routine surgery group.

The meta-analysis including two studies that examined falls as an injury outcome showed a decline in the incidence of falls; however, this was not statistically significant (OR, 0.81; 95% CI, 0.55-1.17).

Authors concluded that the gathered evidence indicates that expedited cataract surgery was effective in significantly enhancing vision but is inconclusive in preventing falls.

Authors mentioned the need for future high-quality RCTs. ‘An adequately powered trial is required to detect clinically important effects on the rate of fall-related injuries. The lack of diversified research stresses the need for research in countries with different demographics and ethnicities and in developing countries.’

Methodology

Studies were included if (1) patients were diagnosed and required cataract surgery and any type of intraocular lens implantation, (2) cataract surgery was performed within 4 weeks of diagnosis or expedited, (3) the intervention was designed to enhance vision, (4) there was a comparison group of routine cataract surgery, (5) primary outcome measures included vision improvement, (6) a secondary outcome measure was the incidence of falls. Eligible study designs included RCTs; non-RCTs; quasi-experimental case-control before and after studies; and cohort studies.

Authors conducted a search on MEDLINE (1950-2007), EMBASE (1982-2007), the Cochrane Controlled Trials Register, American College of Physicians Journal Club (1967-2007), the CINAHL (1982-2007), Educational Resource Information Centre (1966-2007), EBM Reviews (1980-2007), International Road Research Documentation (1972-2007), Transdoc (1972-2007), Transportation Research Information Services (1968-2007), International Bibliography of the Social Sciences (1961-2007), and the Database of Abstracts of Review of Effects (1982-2007). Authors also reviewed reference lists of included studies, contacted national and international agencies for information about unpublished studies, and requested authors of relevant trials for additional published or unpublished trials.

Two reviewers independently reviewed the title and abstract of all identified studies and extracted data of relevant studies. Quality assessment was conducted using the quality assessment tool developed by the Effective Public Health Practice Project.

Data analysis consisted of two meta-analyses using the Mantel-Haenszel pooling methods; one analysis examined the correlation between expedited cataract surgery with vision improvement and the second meta-analysis examined the correlation between injuries and vision improvement. To determine heterogeneity between studies, a chi-square test or Q test was performed, and a funnel plot was used to detect the presence of publication bias within the review.

Applicability/external validity

Authors noted that the studies included focussed on narrow patient age groups or excluded important segments of the population; therefore it might be difficult to generalize the results.

Geographic focus

Authors did not report the geographic focus of the included studies, but they mentioned that this study was based mostly on the UK and lacked studies from other parts of the world.

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.

Authors noted the limitations of this study appropriately; they acknowledged that due to the limitations of the studies included it was not possible to generalize the results of the meta-analyses conducted. It was also noted that the search strategy may have failed to identify all relevant studies as studies included were mostly from the UK; and that a meta-analysis of two studies may seem inadequate, but they believe that findings of this synthesis contribute to the literature. Results of this study emphasize the importance of cataract surgery in reducing health risks, and authors note that studies have corroborated this finding.  As such, high confidence was attributed in the conclusions about the effects of this study.