For participants in the IXT group, there was a moderate and borderline significant correlation between the vergence change due to the −2D lens and the difference in clinical deviation angle at near and distance ( r S = 0.51, p = 0.04), indicating a tendency for those with a greater exo-deviation at near than at distance to exhibit smaller vergence changes.
For control participants, the borderline non-significant correlations between the difference in heterophoria at distance and near and vergence and refractive state changes were r S = 0.42 ( p = 0.053) and r S = 0.42 ( p = 0.052), respectively.
On the other hand, there was an overall trend towards smaller vergence responses to the −2D lens in those with greater increase (or less decrease) in strabismic deviation at near compared with distance, and although the AC/A ratio was not correlated with the distance-near difference, our participants with CI-type IXT had low AC/A ratios, consi