Inequality in cataract blindness and services: moving beyond unidimensional analyses of social position

Cost-effectiveness and cost-utility of a digital technology-driven hierarchical healthcare screening pattern in China

Utilization of digital technologies for cataract screening in primary care is a potential solution for addressing the dilemma between the growing aging population and unequally distributed resources. Here, we propose a digital technology-driven hierarchical screening (DH screening) pattern implemented in China to promote the equity and accessibility of healthcare. It consists of home-based mobile artificial intelligence (AI) screening, community-based AI diagnosis, and referral to hospitals. We utilize decision-analytic Markov models to evaluate the cost-effectiveness and cost-utility of different cataract screening strategies (no screening, telescreening, AI screening and DH screening). A simulated cohort of 100,000 individuals from age 50 is built through a total of 30 1-year Markov cycles. The primary outcomes are incremental cost-effectiveness ratio and incremental cost-utility ratio. The results show that DH screening dominates no screening, telescreening and AI screening in urban and rural China. Annual DH screening emerges as the most economically effective strategy with 341 (338 to 344) and 1326 (1312 to 1340) years of blindness avoided compared with telescreening, and 37 (35 to 39) and 140 (131 to 148) years compared with AI screening in urban and rural settings, respectively. The findings remain robust across all sensitivity analyses conducted. Here, we report that DH screening is cost-effective in urban and rural China, and the annual screening proves to be the most cost-effective option, providing an economic rationale for policymakers promoting public eye health in low- and middle-income countries.

Efficacy of cataract surgeries performed during blindness prevention programs in Chongqing, China: a multicenter prospective study

OBJECTIVE

To determine the efficacy of cataract surgeries in blindness prevention programs in Chongqing.

METHODS

During February-December 2019, we prospectively enrolled 487 patients (592 eyes) undergoing cataract surgery during blindness prevention programs in 6 Chongqing district/county hospitals (experimental group) and 481 patients (609 eyes) undergoing cataract surgery in the First Affiliated Hospital of Chongqing Medical University (controls). Uncorrected visual acuity (UCVA), refractive status, best corrected visual acuity (BCVA), slit lamp examination, and visual function/quality of life (VF-QOL) questionnaire scores were evaluated preoperatively, and at 1 and 6 months postoperatively.

RESULTS

In the experimental group, UCVA, BCVA, and VF-QOL scores at 1 and 6 months were better than the preoperative values (P < 0.05), but lower than the control-group values (P < 0.05). Rates of good UCVA and BCVA outcomes (≤ 0.5 logMAR) in the experimental group were 76.2% and 87.6%, respectively, at 1 month and 68.9% and 83.1%, respectively, at 6 months. Most eyes in the experimental (82.1%) and control (89.5%) groups had refractive errors within ± 1 D at 1 month. At 6 months, posterior capsule opacification (PCO) was more common in the experimental group (20.9% vs. 15.0%, P < 0.05). At 6 months, the main causes of visual impairment (UCVA > 0.5 logMAR) in the experimental group were uncorrected refractive errors (33.0%), PCO (29.5%), and fundus diseases (33.9%).

CONCLUSION

Cataract surgeries in blindness prevention programs in Chongqing significantly improved visual acuity, VF, and QOL, but underperformed compared to surgeries in the tertiary teaching hospital.

Cataract services for all: Strategies for equitable access from a global modified Delphi process

Vision loss from cataract is unequally distributed, and there is very little evidence on how to overcome this inequity. This project aimed to engage multiple stakeholder groups to identify and prioritise (1) delivery strategies that improve access to cataract services for under-served groups and (2) population groups to target with these strategies across world regions. We recruited panellists knowledgeable about cataract services from eight world regions to complete a two-round online modified Delphi process. In Round 1, panellists answered open-ended questions about strategies to improve access to screening and surgery for cataract, and which population groups to target with these strategies. In Round 2, panellists ranked the strategies and groups to arrive at the final lists regionally and globally. 183 people completed both rounds (46% women). In total, 22 distinct population groups were identified. At the global level the priority groups for improving access to cataract services were people in rural/remote areas, with low socioeconomic status and low social support. South Asia and Sub-Saharan Africa were the only regions in which panellists ranked women in the top 5 priority groups. Panellists identified 16 and 19 discreet strategies to improve access to screening and surgical services, respectively. These mostly addressed health system/supply side factors, including policy, human resources, financing and service delivery. We believe these results can serve eye health decision-makers, researchers and funders as a starting point for coordinated action to improve access to cataract services, particularly among population groups who have historically been left behind.

Effectiveness of community outreach screening for glaucoma in improving equity and access to eye care in Nigeria

PURPOSE

To determine the effectiveness of community outreach screening for glaucoma in improving equity and access to eye care in Nigeria.

METHODOLOGY

This was a prospective study in which two cohort of participants were recruited in Nigeria: 1 from 24 outreach screenings and another from consecutive patients presenting spontaneously to a tertiary eye clinic in Nigeria. Sociodemographic and clinical data were obtained from participants and compared.

RESULTS

Our sample consisted of 120 patients with glaucoma or suspected glaucoma (6.38% of 1881 screenees) recruited from the 24 outreach screenings, and another 123 patients with glaucoma who presented spontaneously at the eye clinic. Participants from the screenings were significantly older (p=0.012), less educated (p<0.001), had lower incomes (p<0.001), lower glaucoma knowledge scores and were less aware of their glaucoma (both p<0.001) and were more likely to be dependent on relations and children (p=0.002) compared with clinic participants. Of the 120 patients identified at the screenings and referred to the clinic for definitive care, 39 (32.5%) presented at the clinic within 3 months. Reasons for poor uptake of referral services were lack of a felt need and lack of money for transportation. Considering only patients who accepted referral, they were still less educated (p<0.001), poorer (p=0.001) and less knowledgeable about glaucoma (p=0.003) than spontaneous clinic presenters.

CONCLUSION

Outreach screening improved equity of access but its effects were somewhat reduced by poor uptake of referral care. Interventions such as free transportation and educational efforts may improve the uptake of referral services and maximise equity gains.

Artificial Intelligence Model for Antiinterference Cataract Automatic Diagnosis: A Diagnostic Accuracy Study

Background: Cataract is the leading cause of blindness worldwide. In order to achieve large-scale cataract screening and remarkable performance, several studies have applied artificial intelligence (AI) to cataract detection based on fundus images. However, the fundus images they used are original from normal optical circumstances, which is less impractical due to the existence of poor-quality fundus images for inappropriate optical conditions in actual scenarios. Furthermore, these poor-quality images are easily mistaken as cataracts because both show fuzzy imaging characteristics, which may decline the performance of cataract detection. Therefore, we aimed to develop and validate an antiinterference AI model for rapid and efficient diagnosis based on fundus images.

Materials and Methods: The datasets (including both cataract and noncataract labels) were derived from the Chinese PLA general hospital. The antiinterference AI model consisted of two AI submodules, a quality recognition model for cataract labeling and a convolutional neural networks-based model for cataract classification. The quality recognition model was performed to distinguish poor-quality images from normal-quality images and further generate the pseudo labels related to image quality for noncataract. Through this, the original binary-class label (cataract and noncataract) was adjusted to three categories (cataract, noncataract with normal-quality images, and noncataract with poor-quality images), which could be used to guide the model to distinguish cataract from suspected cataract fundus images. In the cataract classification stage, the convolutional-neural-network-based model was proposed to classify cataracts based on the label of the previous stage. The performance of the model was internally validated and externally tested in real-world settings, and the evaluation indicators included area under the receiver operating curve (AUC), accuracy (ACC), sensitivity (SEN), and specificity (SPE).

Results: In the internal and external validation, the antiinterference AI model showed robust performance in cataract diagnosis (three classifications with AUCs >91%, ACCs >84%, SENs >71%, and SPEs >89%). Compared with the model that was trained on the binary-class label, the antiinterference cataract model improved its performance by 10%.

Conclusion: We proposed an efficient antiinterference AI model for cataract diagnosis, which could achieve accurate cataract screening even with the interference of poor-quality images and help the government formulate a more accurate aid policy.

Exploring eye care pathways, patient priorities and economics in Pakistan: A scoping review and expert consultation study with thematic analysis

Purpose

As the prevalence of eye diseases increases, demand for effective, accessible and equitable eye care grows worldwide. This is especially true in lower and middle‐income countries, which have variable levels of infrastructure and economic resources to meet this increased demand. In the present study we aimed to review the literature on eye care in Pakistan comprehensively, with a particular focus on eye care pathways, patient priorities and economics.

Methods

A systematic scoping review was performed to identify literature relating to eye care in Pakistan. Searches of relevant electronic databases and grey literature were carried out. The results were analysed through a mixed methods approach encompassing descriptive numerical summary and thematic analysis. To consolidate results and define priority areas for future study, expert consultation exercises with key stakeholders were conducted using qualitative semi‐structured interviews.

Results

One hundred and thirty‐two papers (published and unpublished) were included in the final review. The majority (n = 93) of studies utilised a quantitative design. Seven interlinked themes were identified: eye care pathways, burden of eye disease, public views on eye‐related issues, workforce, barriers to uptake of eye care services, quality of eye care services and economic impact of blindness. Research priorities included investigating the eye care workforce, the quality and efficiency of current eye care services, eye care services available in rural Pakistan and the costs and benefits related to eye care provision and sustaining eye care programmes.

Conclusions

To the best of our knowledge, this is the first review to synthesise evidence from papers across the field relating to eye care in Pakistan. As such, this work provides new insights into the achievements of the national eye health programme, challenges in eye care in Pakistan and priority areas for future research.

How can we improve the quality of cataract services for all? A global scoping review

BACKGROUND

Cataract is a leading cause of blindness and vision impairment globally. Cataract surgery is one of the most frequently performed operations worldwide, but good quality services are not universally available. This scoping review aims to summarise the nature and extent of published literature on interventions to improve the quality of services for age-related cataract globally.

METHODS

We used the dimensions of quality adopted by WHO-effectiveness, safety, people-centredness, timeliness, equity, integration and efficiency-to which we added planetary health. On 17 November 2019, we searched MEDLINE, Embase and Global Health for manuscripts published since 1990, without language or geographic restrictions. We included studies that reported quality-relevant interventions and excluded studies focused on technical aspects of surgery or that only involved children (younger than 18 years). Screening of titles/abstracts, full-text review and data extraction were performed by two reviewers independently. Studies were grouped thematically and results synthesised narratively.

RESULTS

Most of the 143 included studies were undertaken in high-income countries (n = 93, 65%); 29 intervention groups were identified, most commonly preoperative education (n = 17, 12%) and pain/anxiety management (n = 16, 11%). Efficiency was the quality element most often assessed (n = 58, 41%) followed by people-centredness (n = 40, 28%), while integration (n = 4) and timeliness (n = 3) were infrequently reported, and no study reported outcomes related to planetary health.

CONCLUSION

Evidence on interventions to improve quality of cataract services shows unequal regional distribution. There is an urgent need for more evidence relevant to low- and middle-income countries as well as across all quality elements, including planetary health.

Cataract as a Cause of Blindness and Vision Impairment in Latin America: Progress Made and Challenges Beyond 2020

PURPOSE

To provide an update of cataract as a cause of vision loss in Latin America and to analyze sex inequalities in cataract surgical coverage (CSC) and effective CSC (eCSC) in the region.

DESIGN

Population-based systematic review with longitudinal comparisons.

METHODS

The Latin American and Caribbean Health Sciences Literature (LILACS) and PubMed databased were searched for population-based studies reporting cataract blindness, surgical coverage, and outcomes published between January 2014 and December 2019. Information on the number of surgeries performed from the 2014-2016 period was obtained from ministries of health and was used for calculation of the cataract surgical rate (CSR). Sources such as Rapid Assessment of Avoidable Blindness (RAAB) and Rapid Assessment of Cataract Surgical Services data were reanalyzed to calculate sex inequality in CSC and eCSC by subtracting the rate in women from the rate in men.

RESULTS

Cataract was the cause of 29.8%-77.6% of cases of blindness in the included studies; the CSR improved in 10 countries. The CSC pinhole visual acuity of 3/60 varied from 24.1% in Peru to 97.1% in Argentina, and the median absolute gender inequality CSC pinhole visual acuity 3/60 was -0.7%. The eCSC pinhole visual acuity 3/60 varied from 14.8% in Guatemala to 92.1% in Argentina, and the median absolute gender inequality eCSC pinhole visual acuity 3/60 was -0.8%.

CONCLUSIONS

Cataract remains a leading cause of blindness in Latin America. Coverage is suboptimal, and surgical results are also below target levels in many countries. Incentives for a better distribution of human resources, adequate training of ophthalmologists, and the inclusion of vision services in universal health care coverage could reduce the burden of cataract in Latin America.

Efficacy, safety and visual outcomes of cataract surgeries performed during blindness prevention programs in different locations in Kenya

PURPOSE

To determine the visual outcomes achieved in terms of efficacy and safety during high-volume cataract surgery programs in different locations in Kenya.

METHODS

Eight hundred eighty-one eyes of 849 patients underwent extracapsular cataract extraction with intraocular lens implantation in a retrospective, observational, consecutive cohort study on patients who underwent cataract surgery in five programs that a Spanish non-governmental organization conducted between 2013 and 2019 for the prevention of blindness in different geographical areas of Kenya: Thika, Athi River, Kissi, Bagavathi, and Nakuru. The programs were carried out by Spanish and Kenyan surgeons working together.

RESULTS

Mean age was 66.81 ± 14.47 years. Fifty-one percent of the operated eyes (447 eyes) were women. 94% of patients belonged to six ethnic groups. The mean uncorrected distance visual acuity (UDVA) before surgery was 1.98 ± 0.98 logMAR (20/2000), which changed to 0.82 ± 0.68 logMAR (20/150) 3 months after surgeries. The corrected distance visual acuity (CDVA) was 0.4 ± 0.53 logMAR (20/50) 3 months after surgery, 77.5% of the patients had good visual outcomes, and 6.3% had poor outcomes. Preoperative UDVAs were significantly different with respect to the different geographical areas (Kruskal-Wallis; p < 0.001). The most common intraoperative complication was posterior capsule rupture (incidence, 4.2%, 37 of 881), and the most serious complication was expulsive hemorrhage (incidence, 0.1%, 1 of 881).

CONCLUSIONS

Cataract programs performed in a middle-income country with the proper technique and standardized protocols of action improved the visual outcome of the patients. Dissimilar baseline status was found in different areas regarding preoperative visual acuities. Training programs of local surgeons should be reinforced.

Interventions to improve the quality of cataract services: protocol for a global scoping review

INTRODUCTION

Cataract is the leading cause of blindness globally and a major cause of vision impairment. Cataract surgery is an efficacious intervention that usually restores vision. Although it is one of the most commonly conducted surgical interventions worldwide, good quality services (from being detected with operable cataract to undergoing surgery and receiving postoperative care) are not universally accessible. Poor quality understandably reduces the willingness of people with operable cataract to undergo surgery. Therefore, it is critical to improve the quality of care to subsequently reduce vision loss from cataract. This scoping review aims to summarise the nature and extent of the published literature on interventions to improve the quality of services for primary age-related cataract globally.

METHODS AND ANALYSIS

We will search MEDLINE, Embase and Global Health for peer-reviewed manuscripts published since 1990, with no language, geographic or study design restrictions. To define quality, we have used the elements adopted by the WHO-effectiveness, safety, people-centredness, timeliness, equity, integration and efficiency-to which we have added the element of planetary health. We will exclude studies focused on the technical aspects of the surgical procedure and studies that only involve children (<18 years). Two reviewers will screen all titles/abstracts independently, followed by a full-text review of potentially relevant articles. For included articles, data regarding publication characteristics, study details and quality-related outcomes will be extracted by two reviewers independently. Results will be synthesised narratively and presented visually using a spider chart.

ETHICS AND DISSEMINATION

Ethical approval was not sought, as our review will only include published and publicly accessible information. We will publish our findings in an open-access peer-reviewed journal and develop an accessible summary of the results for website posting. A summary of the results will be included in the ongoing Lancet Global Health Commission on Global Eye Health.

REGISTRATION DETAILS

Open Science Framework (https://osf.io/8gktz).

Incidence and characteristics of cataract surgery in South Korea from 2011 to 2015: A nationwide population-based study

IMPORTANCE

Detailed incidence data for cataract surgery in the general population are limited, yet important for determining the surgical needs of the community and formulation of healthcare policies.

BACKGROUND

To report incidence rates of cataract surgery in South Korea.

DESIGN

Nationwide, retrospective population-based study.

PARTICIPANTS

This study involved the entire population of South Korea (n = 47 990 761); 2 236 107 eyes of 1 591 176 patients confirmed as having cataract surgery from 1 January 2011 to 31 December 2015 were included.

METHODS

Data for all patients who underwent primary cataract surgery in South Korea were retrieved using Korean Electronic Data Interchange and Korean Standard Classification of Diseases-7 codes. Annual incidence rates were calculated and adjusted to the national population data for the corresponding year.

MAIN OUTCOME MEASURES

The average incidence of cataract surgery during the 5-year study period was estimated using population data from the 2010 Korean census.

RESULTS

The incidence of cataract surgery increased from 8.54/1000 person-years in 2011 to 9.67/1000 person-years in 2015. The probability of second-eye surgery within 12 months after the first-eye surgery increased from 42.98% in 2011 to 48.01% in 2015. In total, 85.72% of surgeries were performed in non-rural areas: 43.18% in individuals with a higher household income and 76.65% in primary healthcare centres. The rate of vitrectomy for posterior capsular rupture was 0.72%.

CONCLUSIONS AND RELEVANCE

The incidence of cataract surgery in South Korea is increasing over time. Our findings are expected to aid in the formulation of future healthcare policies concerning cataract surgery in South Korea.

Horizontal inequity in the utilization of cataract surgery in Iran: Shahroud Eye Cohort Study, 2009-2014

Background: Since there was no evidence about economic inequity in utilization of cataract surgery in developing countries, such as Iran, this study was designed to measure horizontal inequity in the utilization of cataract surgery and its changes in an Iranian middleaged population in 2009 and 2014. Methods: Using data from the first and second phases of Shahroud Eye Cohort Study (2009-2014), the economic inequity in the utilization of cataract surgery in an Iranian middle-aged population aged 40-64 years in 2009 and 2014 was evaluated. The horizontal inequity index (HI) was determined using the indirect standardization method based on a nonlinear (probit) model and the concentration index (C) was decomposed into the contribution of each factor. The analyses were performed using STATA software version 12/SE, and significance level was set at less than 0.05. Results: The HI in the utilization of cataract surgery increased from 0.080 (95% CI: 0.011-0.098) in 2009 to 0.166 (95% CI: 0.0821- 0.228) in 2014. Decomposition of changes in the concentration index showed that among need and non-need variables, older age and economic status (being among the wealthiest 20%) were the greatest contributors, with shares of 67.5% and 57.5%%, respectively, which led to pro-rich inequity during the study periods. Conclusion: The present study demonstrated that utilization of cataract surgery did not have an equal distribution among economic quintiles, despite considering equal needs based on cataract severity. Results demonstrated that older age and economic status were the greatest contributors to HI increase in 2009 and 2014.

Cataract Services are Leaving Widows Behind: Examples from National Cross-Sectional Surveys in Nigeria and Sri Lanka

The Sustainable Development Goals aim to leave no one behind. We explored the hypothesis that women without a living spouse—including those who are widowed, divorced, separated, and never married—are a vulnerable group being left behind by cataract services. Using national cross-sectional blindness surveys from Nigeria (2005–2007; n = 13,591) and Sri Lanka (2012–2014; n = 5779) we categorized women and men by marital status (married/not-married) and place of residence (urban/rural) concurrently. For each of the eight subgroups we calculated cataract blindness, cataract surgical coverage (CSC), and effective cataract surgical coverage (eCSC). Not-married women, who were predominantly widows, experienced disproportionate cataract blindness—in Nigeria they were 19% of the population yet represented 56% of those with cataract blindness; in Sri Lanka they were 18% of the population and accounted for 54% of those with cataract blindness. Not-married rural women fared worst in access to services—in Nigeria their CSC of 25.2% (95% confidence interval, CI 17.8–33.8%) was far lower than the best-off subgroup (married urban men, CSC 80.0% 95% CI 56.3–94.3); in Sri Lanka they also lagged behind (CSC 68.5% 95% CI 56.6–78.9 compared to 100% in the best-off subgroup). Service quality was also comparably poor for rural not-married women—eCSC was 8.9% (95% CI 4.5–15.4) in Nigeria and 37.0% (95% CI 26.0–49.1) in Sri Lanka. Women who are not married are a vulnerable group who experience poor access to cataract services and high cataract blindness. To “leave no one behind”, multi-faceted strategies are needed to address their needs.

Universal artificial intelligence platform for collaborative management of cataracts

Purpose

To establish and validate a universal artificial intelligence (AI) platform for collaborative management of cataracts involving multilevel clinical scenarios and explored an AI-based medical referral pattern to improve collaborative efficiency and resource coverage.

Methods

The training and validation datasets were derived from the Chinese Medical Alliance for Artificial Intelligence, covering multilevel healthcare facilities and capture modes. The datasets were labelled using a three-step strategy: (1) capture mode recognition; (2) cataract diagnosis as a normal lens, cataract or a postoperative eye and (3) detection of referable cataracts with respect to aetiology and severity. Moreover, we integrated the cataract AI agent with a real-world multilevel referral pattern involving self-monitoring at home, primary healthcare and specialised hospital services.

Results

The universal AI platform and multilevel collaborative pattern showed robust diagnostic performance in three-step tasks: (1) capture mode recognition (area under the curve (AUC) 99.28%–99.71%), (2) cataract diagnosis (normal lens, cataract or postoperative eye with AUCs of 99.82%, 99.96% and 99.93% for mydriatic-slit lamp mode and AUCs >99% for other capture modes) and (3) detection of referable cataracts (AUCs >91% in all tests). In the real-world tertiary referral pattern, the agent suggested 30.3% of people be ‘referred’, substantially increasing the ophthalmologist-to-population service ratio by 10.2-fold compared with the traditional pattern.

Conclusions

The universal AI platform and multilevel collaborative pattern showed robust diagnostic performance and effective service for cataracts. The context of our AI-based medical referral pattern will be extended to other common disease conditions and resource-intensive situations.

Disability-Disaggregated Data Collection: Hospital-Based Application of the Washington Group Questions in an Eye Hospital in Paraguay

Disability-disaggregated data are increasingly considered important to monitor progress in Universal Eye Health Care. Hospital-based data are still elusive because of the cultural ambiguities of the term disability, especially in under-resourced Health Information Systems in low-and middle-income countries. The aim of this study was to estimate the hospital-based rate of disability in patients presenting at an eye department of a rural hospital in Paraguay and to discuss implications for the management of access barriers. Therefore, we introduced two standardized sets of the Washington Group (WG) Questions as a pilot project. In total, 999 patients answered the self-report WG short set (WG-SS) questionnaire with six functional domains, and 501 of these patients answered an extended set, which included additional domains for "anxiety" and "depression" (WG-ES3). Overall, 27.7% (95% Confidence Interval (CI) 24.9-30.3) were categorized as having a disability. A total of 9.6% (95% CI 7.9-11.6) were categorized as having a disability because of communication difficulties, which was second only to visual difficulties. The odds ratio for disability for patients aged 70 years and older was 8.5 (95% CI 5.0-14.4) and for male patients, it was 0.83 (95% CI 0.62-1.1). Of those patients who answered the WG-ES3, 3.4% were categorized as having a disability because of being worried, nervous or anxious and 1.4% because of feeling depressed. An analysis of the questions of the "depression" domain was impeded by a high rate of measurement errors. The results of the different domains can now be used to inform the identification and mitigation of potential access barriers to eye health services for different types of impairments.

Gender differences in blindness, cataract blindness and cataract surgical coverage in India: a systematic review and meta-analysis

BACKGROUND

The magnitude of blindness is unevenly distributed worldwide. This systematic review aimed to study gender differences in the prevalence of blindness, cataract blindness and cataract surgical coverage in India among persons aged 50 years and above.

METHODS

Literature search was carried out in the Medline, Web of Science, Google Scholar, EMBASE and Trip databases. Data were abstracted and risk of bias was assessed for the selected full-text articles. Pooled prevalence, ORs and risk differences were synthesised by meta-analyses.

RESULTS

22 studies were included in the systematic review. The pooled prevalence of blindness obtained for men was 4.17% and that for women was 5.68%. Women had 35% higher odds of being blind (OR 1.35, 95% CI 1.08 to 1.62) and 69% higher odds of being cataract blind (OR 1.69, 95% CI 1.44 to 1.95). Women had a 27% lower odds of getting cataract surgery (OR 0.73, 95% CI 0.45 to 1.01). In women, around 35% of the prevalence of blindness and 33% of the prevalence of cataract blindness are attributable to their gender.

CONCLUSION

Marked gender differences in blindness, cataract blindness and cataract surgical coverage were seen in India, with the odds being unfavourable for women. Interventions implemented for reduction of blindness, including cataract blindness, need to consider these gender differentials in the Indian context. Further research is needed to ascertain the reasons for these differences and devise interventions to reduce these differences in order to tackle the magnitude of avoidable blindness in India.

Reducing inequity of cataract blindness and vision impairment is a global priority, but where is the evidence?

Throughout the world, people who are socially or economically disadvantaged disproportionately experience blindness and vision impairment caused by cataract. Reducing vision loss from cataract and its unequal distribution must be a priority if the WHO's aim of 'universal eye health' is to be realised. To help achieve this, decision-makers and service planners need evidence on which strategies improve access to cataract services among disadvantaged populations, and under what circumstances. Unfortunately, despite many strategies to improve cataract services being implemented in recent decades, evidence of what works, for who and in what circumstances is not readily available. This paper summarises the extent of the evidence on interventions to reduce inequity of vision loss from cataract and makes suggestions for how the evidence base can be strengthened.

Interventions to improve access to cataract surgical services and their impact on equity in low- and middle-income countries

BACKGROUND

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.

OBJECTIVES

To assess the effects on equity of interventions to improve access to cataract services for populations with cataract blindness (and visual impairment) in LMICs.

SEARCH METHODS

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.

SELECTION CRITERIA

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).

DATA COLLECTION AND ANALYSIS

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.

MAIN RESULTS

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).

AUTHORS' CONCLUSIONS

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.