High Accommodative Convergence/Accommodation Ratio Consecutive Esotropia Following Surgery for Intermittent Exotropia: Clinical Feature, Diagnosis, and Treatment

Consecutive esotropia is a common and stereopsis-threatening consequence of surgery for intermittent exotropia. However, too little attention has been paid to the accommodative convergence per accommodation (AC/A) ratio in this condition. We aimed to describe the clinical features of patients who developed consecutive esotropia with a high AC/A following surgery for intermittent exotropia, compared to those with normal AC/A. In this retrospective cohort study, we identified 54 patients with consecutive esotropia who remained esotropic at one month after surgery. Patients were divided into two groups: normal AC/A and high AC/A groups. Clinical features and outcomes were compared between the two groups. Fourteen (25.9%) of the 54 were classified as high AC/A consecutive esotropia. Good preoperative control at near was the only significant preoperative factor associated with the development of high AC/A consecutive esotropia. Bifocal glasses were prescribed for all patients with high AC/A consecutive esotropia, and 11 (78.6%) of them achieved satisfactory alignment at distance and near fixations using bifocals. Patients with high AC/A consecutive esotropia had a significantly more successful alignment (0.9 vs. 13.0 prism diopters, p < 0.001) and better stereopsis (67.9 vs. 670.0 arc seconds, p = 0.04) than the normal AC/A counterparts at the final follow-up. We suggest that high AC/A consecutive esotropia could be successfully managed by wearing bifocals in most cases. A high AC/A ratio in patients with consecutive esotropia may be considered as a clinical marker heralding a better prognosis.