Methodological variations in studies reporting normative data for binocular vision parameters: A scoping review protocol

Objective:The objective of this scoping review is to map the methodological variations and population characteristics of the studies that report normative data for accommodation and vergence parameters.Introduction:Accommodation and vergence are the two important parameters required for normal binocular vision. The presence of accommodation and vergence anomalies impairs the quality of life of an individual by interfering with their daily visual activities. Diagnosis of accommodative and vergence anomalies requires a series of test procedures. The test procedure or the tool used could influence the outcome measured. Different study designs and methods have been used to estimate the normative data; therefore, we aim to explore the variation in terms of population characteristics and methods used to measure accommodative and vergence parameters.Inclusion criteria:This scoping review will include published literature that assesses normative function of various binocular vision parameters with a focus on mapping the methodological differences.Methodology:JBI methodological framework for scoping reviews will be followed. The review will also be conducted in accordance with the Preferred Reporting Item for Systematic Review and Meta-analysis Extension for Scoping Reviews (PRISMA-ScR) checklist. Three-phase searches for identifying relevant articles will be conducted in the following electronic databases: PubMed, Scopus, CINAHL, Web of Science, African Journals Online, LILACS, China National Knowledge Infrastructure, and Google Scholar. The review undertakes two stages of screening: i) title/abstract screening and ii) full-text screening. The data will be extracted from the retrieved full text. The results will be tabulated and summarized descriptively.