Clinical analysis and surgical treatment of atypical acute acquired concomitant esotropia

Objective: To investigate the clinical characteristics, possible etiology and surgical efficacy of acute acquired concomitant esotropia (AACE) with atypical etiology. Methods: Case-control study. Twelve patients, including 7 males and 5 females, who complained of diplopia and were diagnosed with AACE in Tianjin Eye Hospital from January to December 2019 and underwent surgical treatment were included. The duration of the disease was (8.83±3.71) months. All patients underwent routine ocular examination except amblyopia and ocular organic lesions. MRI examination of the orbits and the brain was performed in all the patients in order to screen orbital and craniocerebral diseases, and patients denied that the existence of common causes of AACE (such as occlusion of one eye, mental or psychological factors, medium to high myopia, etc. during medical examination). The characteristics of the disease, the difference of deviation angle at 33 cm and 5 m, and the changes of deviation angle and stereopsis before and after surgery were analyzed. The forced duction test was performed before operation, and the distance between the sclera margin and the midpoint of the medial rectus muscle attachment was measured and compared with the patients with intermittent exotropia (10 cases) and comitant esotropia (10 cases). Paired sample t-test and one-way analysis of variance were used for statistical analysis. Results: The mean spherical equivalent was (1.70±0.88) D in all AACE patients, and the deviation angle was (22.42±5.82) prism diopter (PD) at 33 cm and (20.00±4.86) PD at 5 m in primary gaze, which were not statistically significant (P=0.371). The force duction test showed no obvious tension or contracture of the medial rectus and no paralysis. In patients with AACE, the horizontal distance from the midpoint of the medial rectus to the limbus was (5.20±0.27) mm, versus (5.30±0.25) mm in intermittent exotropia patients and (5.30±0.31) mm in concomitant esotropia patients. All the differences were not statistically significant (P=0.618). All the patients with AACE had residual esotropia (mean, 3.42 to 6.33 PD) at 6 weeks, 3 months, and 6 months postoperatively, and their stereopsis improved more than before, with no stereopsis in 2 patients before surgery and stereopsis in all 12 patients after surgery. Conclusions: AACE patients with atypical etiology do not have high myopia and hyperopia. There is no significant difference between the distance and near angles. The occurrence of esotropia is related to decompensation of esophoria, which may result in clinical symptoms of diplopia. Conventional surgery can reduce esotropia and restore stereoscopic vision, but there is still a small amount of esophoria after surgery. There is no abnormality in the attachment point of the medial rectus muscle. (Chin J Ophthalmol, 2021, 57: 348-352).