Protocol for a scoping review to map evidence from randomised controlled trials on paediatric eye disease to disease burden.

BACKGROUND Currently, about 2 per 1000 children in the industrialised world are severely visually impaired or blind (SVI/BL) due to diverse uncommon conditions that are usually present from early infancy. The impact of SVI/BL is lifelong and life-changing. Thus, children are a priority in the WHO-led global initiative against avoidable blindness. The aim of this scoping review is to assess the current evidence base on interventions to prevent or treat the major causes of childhood SVI/BL, specifically the degree of alignment between robust interventional research (RCTs) and the burden (relative frequency) of the key causative disorders, identifying gaps in the evidence base for tackling childhood blindness. METHODS/DESIGN We will perform a scoping review of the published literature of randomised controlled trials (RCTs) for clinical interventions that prevent or treat eye and vision diseases in children (<18 years old). Major electronic databases MEDLINE (PUBMED), EMBASE and the Cochrane CENTRAL will be searched to identify published trials using a comprehensive paediatric specific strategy informed by previous searches. The outcome of our study, randomised clinical trial activity, will be measured by the total number of RCTs and total paediatric participants randomised. The quantity and distribution of activity across diseases will be classified in the broad categories of anatomical site affected (per WHO taxonomy). The degree of alignment between paediatric trial activity and burden of SVI/BL disease (relative proportion) will be measured using a test of association (Spearman's correlation coefficient). DISCUSSION Despite the global public health importance of childhood blindness, there has been no assessment of the completeness of the evidence base regarding clinical interventions to prevent or treat the causative disorders. This scoping review will measure the degree of alignment between the published evidence and the burden of disease to identify gaps in current knowledge and consider the underlying reasons, informing clinicians, policy makers and funders about research priorities.