Cataract is the leading cause of blindness in low- and middle-income countries (LMICs), and the prevalence is inequitably distributed between and within countries. Interventions have been undertaken to improve cataract surgical services, however, the effectiveness of these interventions on promoting equity is not known.
To assess the effects on equity of interventions to improve access to cataract services for populations with cataract blindness (and visual impairment) in LMICs.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2017, Issue 3), MEDLINE Ovid (1946 to 12 April 2017), Embase Ovid (1980 to 12 April 2017), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to 12 April 2017), the ISRCTN registry (www.isrctn.com/editAdvancedSearch); searched 12 April 2017, ClinicalTrials.gov (www.clinicaltrials.gov); searched 12 April 2017 and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 12 April 2017. We did not use any date or language restrictions in the electronic searches for trials.
We included studies that reported on strategies to improve access to cataract services in LMICs using the following study designs: randomised and quasi-randomised controlled trials (RCTs), controlled before-and-after studies, and interrupted time series studies. Included studies were conducted in LMICs, and were targeted at disadvantaged populations, or disaggregated outcome data by 'PROGRESS-Plus' factors (Place of residence; Race/ethnicity/ culture/ language; Occupation; Gender/sex; Religion; Education; Socio-economic status; Social capital/networks. The 'Plus' component includes disability, sexual orientation and age).
Two authors (JR and JP) independently selected studies, extracted data and assessed them for risk of bias. Meta-analysis was not possible, so included studies were synthesised in table and text.
From a total of 2865 studies identified in the search, two met our eligibility criteria, both of which were cluster-RCTs conducted in rural China. The way in which the trials were conducted means that the risk of bias is unclear. In both studies, villages were randomised to be either an intervention or control group. Adults identified with vision-impairing cataract, following village-based vision and eye health assessment, either received an intervention to increase uptake of cataract surgery (if their village was an intervention group), or to receive 'standard care' (if their village was a control group).One study (n = 434), randomly allocated 26 villages or townships to the intervention, which involved watching an informational video and receiving counselling about cataract and cataract surgery, while the control group were advised that they had decreased vision due to cataract and it could be treated, without being shown the video or receiving counselling. There was low-certainty evidence that providing information and counselling had no effect on uptake of referral to the hospital (OR 1.03, 95% CI 0.63 to 1.67, 1 RCT, 434 participants) and little or no effect on the uptake of surgery (OR 1.11, 95% CI 0.67 to 1.84, 1 RCT, 434 participants). We assessed the level of evidence to be of low-certainty for both outcomes, due to indirectness of evidence and imprecision of results.The other study (n = 355, 24 towns randomised) included three intervention arms: free surgery; free surgery plus reimbursement of transport costs; and free surgery plus free transport to and from the hospital. These were compared to the control group, which was reminded to use the "low-cost" (˜USD 38) surgical service. There was low-certainty evidence that surgical fee waiver with/without transport provision or reimbursement increased uptake of surgery (RR 1.94, 95% CI 1.14 to 3.31, 1 RCT, 355 participants). We assessed the level of evidence to be of low-certainty due to indirectness of evidence and imprecision of results.Neither of the studies reported our primary outcome of change in prevalence of cataract blindness, or other outcomes such as cataract surgical coverage, surgical outcome, or adverse effects. Neither study disaggregated outcomes by social subgroups to enable further assessment of equity effects. We sought data from both studies and obtained data from one; the information video and counselling intervention did not have a differential effect across the PROGRESS-Plus categories with available data (place of residence, gender, education level, socioeconomic status and social capital).
Current evidence on the effect on equity of interventions to improve access to cataract services in LMICs is limited. We identified only two studies, both conducted in rural China. Assessment of equity effects will be improved if future studies disaggregate outcomes by relevant social subgroups. To assist with assessing generalisability of findings to other settings, robust data on contextual factors are also needed.