Comparison of surgical dose response between divergence insufficiency esotropia and non-accommodative esotropia without divergence insufficiency

BACKGROUND: The study compared the surgical dose-response relationship for divergence insufficiency esotropia (DIE) and non-accommodative esotropia without divergence insufficiency (non-DIE). METHODS: We carried out a retrospective review of a group of patients with DIE and non-DIE who underwent recession surgery of the medial rectus muscle in both eyes. Linear regression analysis compared surgical dose–response between the two groups. RESULTS: In the 15 patients with DIE, the mean preoperative ocular deviation at distant fixation was 25 prism diopters (PD), compared with 3 PD postoperatively. In the 38 non-DIE patients, the mean preoperative ocular deviation was 28 PD, compared with 3 PD postoperatively. The average surgical dose–response was 1.56 PD/mm in the DIE group and 2.91 PD/mm in the non-DIE group (p < 0.001). CONCLUSIONS: Surgical dose–response was significantly lower in DIE patients than in non-DIE patients. Augmented MR recession surgery could be regarded as an effective treatment option for patients with DIE. Further study with a larger sample and long-term follow-up is needed to seek the proper extent of surgery in these patients.