In the past 3 y, considerable attention has been paid to the importance of eye health as a global development priority, first by the World Report on Vision launched by the World Health Organization (WHO) in October 2019,1 then by the Lancet Global Health Commission on Global Eye Health, published in February 20212 and most recently by the Vision for Everyone Resolution adopted by the United Nations (UN) General Assembly in July 2021.3 All three documents provide compelling evidence on the magnitude, impact and costs of poor vision and call for coordinated global efforts to improve access to and the quality and equity of eye care services worldwide. The documents argue that the progress towards the Sustainable Development Goals (SDGs)4 will not be sufficient without integrating eye health within universal health coverage (UHC)5 and highlight the role of quality evidence and research in achieving this ambitious global agenda. The Lancet Global Health Commission gives particular attention to contextually relevant solution-focused implementation research and to translating research findings into policy and practice.2

International non-governmental organisations (iNGOs) have been at the forefront of the global efforts to eliminate avoidable vision impairment and improve access to eye care services in low- and middle-income countries (LMICs) for several decades. Their role in mobilising resources, service delivery, building local capacity and advocacy has been well recognised. In recent years, a number of iNGOs have made considerable investments in generating high-quality evidence and have become important players in eye health implementation research.

There are a number of critical strengths that iNGOs bring to international research. First, iNGOs have a good understanding of service delivery realities and frontline knowledge gaps and can help identify research questions that fit local priorities and meet the needs of local governments, healthcare providers and communities. Second, integrating implementation research into ongoing programmatic activities is both practical and cost-effective. Third, iNGOs are closely engaged with national and local decision-making processes and are well positioned to facilitate the uptake and use of research findings.

This special issue clearly illustrates how iNGOs can contribute to generating crucial evidence to answer operational questions they face and to advance global knowledge on eye health. We are delighted to introduce a collection of articles that present evidence from secondary data analysis and implementation research integrated into eye health programmes supported by the iNGO Sightsavers in sub-Saharan Africa and Asia. This is the first of three supplements to be led by Sightsavers in 2022 and 2023. The two later supplements will focus specifically on evidence from our neglected tropical diseases (NTDs) programmes. In this supplement, we present research findings on a range of eye conditions, including cataracts, unaddressed refractive error (URE), glaucoma, trachoma and onchocerciasis. The articles draw on evidence from 12 countries and address a number of topics pertinent to eye health policies and services in LMICs. We are particularly pleased that several articles are based on a secondary analysis of our programmatic data and have been authored by the technical experts and managers supporting our programmes in the field.

The supplement opens with a guest editorial by Keel and Cieza of the WHO, who present the recent UN developments in support of eye health and highlight global priorities for action to facilitate the journey of member states towards universal eye health. The key messages of the guest editorial are echoed in the commentary by Jones, who discusses the state of eye health funding in LMICs and calls for a step change in delivering more and better financing for eye health within UHC.

The substantial impact of vision on other global health priorities is highlighted in the article by Gascoyne et al., who included disability metrics in a visual impairment survey in Kogi State in Nigeria and present new evidence on the intersection of vision impairment and mental health.

In recognition of the multiple health priorities facing populations in LMICs and the finite resources to address them, a number of articles explore questions on how to make the right policy choices and maximise the effectiveness and efficiency of eye care delivery. Hamill et al. report on the results of a pilot study assessing the feasibility and affordability of mapping areas with medium to low transmission of onchocerciasis in Ghana and Nigeria. They argue that as more and more countries approach onchocerciasis elimination thresholds, questions regarding the cost-effectiveness of treatment in hypo-endemic areas become more and more pressing and the role of implementation research generating such evidence should not be underestimated.

Another article in the series addresses questions of efficiency and equity of services in the context of trachoma elimination. Ul Hassan et al. use programmatic data from seven trachoma-endemic countries (Ethiopia, Kenya, Mozambique, Zambia, Tanzania, Uganda and Nigeria) and compare the effectiveness of different community mobilisation and case-finding approaches with a specific focus on gender. The article stresses the importance of routine multicountry service data in developing recommendations and guidance relevant to a variety of settings.

In India, Buttan et al. also analysed programmatic data from a pilot study that integrated targeted glaucoma screening into existing eye care services and assessed the feasibility and benefits of this approach. Glaucoma is a rapidly emerging global eye health priority that is very challenging for resource-poor settings and operational data on how to address it in a pragmatic and cost-effective way are lacking. Integrating implementation research into ongoing eye care programmes provides an excellent opportunity to build the evidence base so urgently needed by the sector.

Another global priority addressed in this supplement is developing an eye health workforce that is able to meet the growing needs for eye care globally. Two articles focus on task shifting, a strategy frequently used in eye health to address the constant shortages of eye care specialists in LMICs. In a commentary on primary eye care, Yasmin and Schmidt review lessons learned from eye care programmes in Tanzania, Sierra Leone and Pakistan. They argue that while the integration of certain eye care tasks into the roles of primary health and community workers is feasible, a system thinking approach is critical to ensure it is done in a coherent and sustainable way. Further, in a study in Liberia, Tobi et al. show that teachers can be trained to conduct vision screening of schoolchildren to an acceptable level of accuracy. However, based on the data generated by the programme, the authors warn that careful considerations should be given to teachers’ supervision and quality assurance systems.

Two further articles focus on patient-centred care, the theme that features centrally in the World Report on Vision1 and the new eye health agenda. Shrestha et al. explore characteristics and perspectives of patients with postoperative trichiasis in the Hadiya Zone of Ethiopia, while Bechange et al. report results of a multicountry qualitative study considering patients’ perspectives on cataract surgery in rural areas of Kenya, Zambia and Uganda. Both articles argue that patients’ perceptions of quality of care are important determinants of their health-seeking behaviour and need to be better understood to maximise the effectiveness and efficiency of surgical outreach.

Two remaining articles address the role of evidence and innovations in eye health. A commentary by Bartlett et al. describes Sighsavers’ experience of working with the Federal Ministry of Health of Nigeria on strengthening national electronic medical records systems and specifically the adaptation of the electronic data collection tool known as the Trachomatis Trichiasis (TT) Tracker commonly used in trachoma programmes to the needs of paediatric cataract services. Finally, Jolley et al. use the evidence gap map approach and present the current state of evidence from cataract-related systematic reviews relevant to LMICs. The authors point to the shortage of evidence on cataract-related health systems, equity and impact—the gaps also highlighted by the World Report on Vision and the Lancet Commission.

We would like to thank all the authors for the time they spent preparing the manuscripts and for sharing their valuable experiences and findings in an open and transparent way. Many thanks to our reviewers for their time and constructive comments and advice.

We are preparing this supplement at the time of the unfolding coronavirus disease 2019 pandemic. While the scale and impact of this unprecedented global crisis is yet to be fully understood, the increasing importance of evidence in decision-making is indisputable and the role of implementation research is becoming more prominent than ever before. We hope you enjoy reading these articles and find them useful in your own programmatic decisions and policy choices.