Methodological quality of the review: Medium confidence

Author: Subzwari S, Desapriya E, Scime G, Babul S, Jivani K, Pike I.

Region: United States of America (USA), Europe, Australia and India.

Sector: Cataract surgery

Sub-sector: Driving, driving related difficulties.

Type of cataract: Age-related cataract

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

Numerous studies have made associations between visual problems and increased motor vehicle crash involvement or worsening driving ability and drivers with cataracts report increased driving difficulty. The elderly, who tend to experience reduced visual acuity, impaired vision including the onset of cataracts, will be particularly prone to experiencing driving related difficulties. Authors note that people who reduce their exposure to driving or stop driving altogether may experience a negative impact on their independence and quality of life.

This study hypothesized that cataract surgery would improve vision and driving and driving performance as well as reduce driving-related difficulties including motor vehicle (MV) crashes.

Research objectives

To assess the effects of cataract surgery in improving vision and driving performance while reducing driving-related difficulties.

Main findings

The authors included seven studies in the systematic review, of which six studies used a prospective cohort design and one was a retrospective cohort study. In the meta-analysis a total of five studies were included, four used a prospective cohort design and one a retrospective cohort design. These examined driving-related indicators in patients undergoing cataract surgery and were conducted in the USA (two), India (one), Europe (three) and Australia (one).

The pooled analysis of the five studies showed a significant reduction in driving-related difficulties following cataract surgery (OR 0.12, 95% CI 0.10 to 0.16), and associated with an 88% reduction in the risk of driving-related difficulties.

Authors concluded that following cataract surgery, improvements were made in day and night time vision and fewer driving related difficulties are seen when compared to pre-surgery. Authors also noted that there is a need for further research that examines ‘the relationship between cataract surgery and direct driving outcomes such as motor vehicle crashes and injury’.

Methodology

Authors searched 12 databases including MEDLINE, EMBASE and Cochrane Register of Controlled Trials with no date restriction. Reference lists in the included articles were reviewed and authors of included studies were contacted for additional information. Eligibility in regards to study designs included randomized controlled trials, non-randomized controlled trials, quasi-experimental, case-control, controlled before and after studies, and cohort studies. Studies were included if:

• The study was in English only
• The study population involved older drivers with cataracts
• Intervention included any type of cataract surgery
• Comparison group included older drivers who did not undergo cataract surgery, or older drivers compared before and after surgery
• Outcome measures included any type of driving-related indicator
• Secondary outcome measure included MV crash involvement.

Authors included relevant observational studies, following the guidelines and recommendations of the ‘meta-analysis of observational studies in epidemiology (MOOSE)’ group to ensure quality assessment methods were properly conducted.

Applicability/external validity

Authors noted that, as external validity of using observational studies is higher than randomized controlled trials, results from this review would be generalizable to a wider population.

Geographic focus

The review included studies from both high- and middle-income countries and presents results from India as well as Europe, the US and Australia.

Quality assessment

The systematic review was based on a comprehensive search of the literature. Although no date restriction was applied, language bias was not avoided. Screening of full text and data extraction was appropriately conducted by the authors, minimising selection bias. The likelihood of bias and an assessment of quality were reported in the review, as well as an assessment of heterogeneity between the included studies.

Authors acknowledged the limitations of the review, including the inclusion of observational studies which consist of a weaker study design. However, it is noted that they did adhere to strict protocols for the meta-analysis of observational studies in epidemiology (MOOSE) in order to ensure quality and robustness. Authors also note that data included self-reported information and can as a result include untruthful responses. Therefore, medium confidence was attributed in the conclusions about the effects of this study.