Factors influencing the therapeutic effect of hyperopic correction on esotropia in patients with partially accommodative esotropia.

Objectives: To collate data on partially accommodative esotropia (PAET) to better understand this condition's aetiology and to evaluate and predict the therapeutic effect of a hyperopic correction on PAET.

Methods: Eighty-nine consecutive patients diagnosed with PAET with a spherical equivalent (SE) refractive error >+2.50 D were included in this retrospective review. Clinical characteristics, including gender, age, SE, angle of esodeviation, accommodative convergence/accommodation (AC/A) ratio, near-distance disparity (NDD) and anatomical features of the rectus muscles were compared among different PAET subgroups. Multiple linear regression was used to identify independent factors that influenced the therapeutic effect of a hyperopic correction on esotropia.

Results: No significant differences were observed for the angle of esodeviation as a function of age in individuals with PAET. The incidence of SE in PAET participants >9 years old was significantly greater than in those <5 and 6-8 years of age. The therapeutic effect of hyperopic correction on esotropia was positively associated with SE both at distance and near. In addition, the limbus insertion distance (LID) of the lateral rectus (LR) muscle was positively associated with NDD at distance, but negatively associated at near.

Conclusion: A greater incidence of hyperopia was observed in older (>9 years old) PAET patients. A hyperopic correction had a greater effect on esotropia in individuals with a higher SE, larger LID of the LR muscle and a smaller NDD.