The axis of vision is often separated, and when looking at distance, the fused scattering amplitude exceeds the fused collecting amplitude, which produces exotropia; while when looking at near vision, it can maintain an orthotropic position, and intermittent exotropia occurs mostly preceded by exotropia. The onset of intermittent exotropia is mainly due to the imbalance of abduction and assembly functions. When the pooling ability is insufficient and the fusion ability is low, it cannot counteract the excessive abduction ability and makes the eye position have a tendency to be outwardly oblique. The appearance of a deviated eye is commonly examined clinically with A. V motion. The following is a detailed description of the method. Purpose of examination The condition of the function of the homonymous muscle can be considered by a large angle up and down movement. Method of examination The up-and-down rotation can exceed 25o movement during the examination, at which time a difference in the up-and-down obliquity gap can be detected. Judgment of the result When both upper rectus muscles are insufficient or both lower oblique muscles are too strong, “V” syndrome may appear, and when both lower rectus muscles are insufficient or both upper oblique muscles are too strong, “A” syndrome may appear.