Methods for Quantification of Interocular Suppression in Amblyopia and Strabismus: A Scoping Review Protocol

This project describes a scoping review that aims to identify, map, and characterize the methods used to quantify interocular suppression in individuals with amblyopia and/or strabismus. Interocular suppression is a key feature of binocular dysfunction in these conditions and reflects an imbalance in the contributions of the two eyes during binocular viewing. Although suppression has traditionally been assessed using qualitative clinical tests, a wide range of clinical and psychophysical paradigms have been developed to provide quantitative estimates of suppression. These methods differ in their underlying measurement principles, stimulus configurations, outcome metrics, and testing conditions. As a result, suppression has been operationalized in multiple ways across the literature, making it difficult to compare findings across studies or to interpret suppression measures consistently in clinical and research contexts. The purpose of this scoping review is to provide a structured overview of suppression quantification methods reported in the literature. Specifically, the review will identify how suppression has been operationally defined, describe the measurement paradigms used to quantify suppression, and document the outcome metrics and clinical or research purposes associated with these methods. A comprehensive search of multiple electronic databases will be conducted to identify relevant studies. Eligible studies will include experimental, psychophysical, observational, and instrument development or validation studies that report measurable suppression outcomes. Two reviewers will independently screen studies for eligibility and extract relevant data using a predefined charting form. The findings will be summarized descriptively and presented in tabular and narrative formats. The review will map the range of suppression quantification approaches, highlight variations in operational definitions and outcome metrics, and provide insight into how these measures have been applied in clinical and research settings. The results are expected to improve understanding of methodological variability in suppression measurement and may inform future research and clinical assessment approaches for binocular vision disorders such as amblyopia and strabismus.