Objective: Acute acquired concomitant esotropia (AACE) is a distinct subtype of esotropia. The purpose of this retrospective study was to describe the clinical characteristics and discuss the diagnostic and therapeutic management, and evaluate the effect of prism treatment.Methods: The records of 30 patients who presented with acute-onset diplopia at the General Hospital of Central Theater Command from August 2015 to November 2018 were reviewed. All patients underwent a complete medical history, ophthalmological and orthoptic examinations, and brain and orbital imaging. The patients were followed up between 2 and 8 months (mean 3.9 ± 1.2). Angle of strabismus, refractive error, stereopsis, and results of treatment with prisms were analyzed. Level of stereopsis was assessed before and after prismatic correction. Patient satisfaction was assessed with a telephone follow-up survey.Results: The mean age of the 30 patients was 29.7 ± 10.3 years (range 14-52). All patients complained about uncrossed diplopia, only at distance. The esophoria was concomitant in all cases ranging from 12 to 60 prism diopters (PD) at distance (mean 35.80 ± 14.17) and from 10 to 46 PD at near (mean 26.23 ± 11.46) (t = 6.51, P <.001). Cycloplegic spherical-equivalent refraction averaged -5.25 ± 1.67 D (range -0.50 to -8.13), 28 patients were myopic and 2 were emmetropic, all did not wear glasses for near work. All patients received brain and orbital computed tomography scans and magnetic resonance imaging and, in some cases, neurological examinations were performed. All of these examinations were normal. In 27 out of 30 patients treated with prisms, the diplopia resolved, whereas three patients were not satisfied with prismatic correction and underwent surgery. With prisms the esophoria was concomitant, ranging from 6 to 23 PD at distance fixation and from 4 to 18 PD at near fixation. Out of 30 patients, 23 patients were satisfied, 3 patients were not satisfied because their vision remained uncomfortable and 4 patients had an intermediate score.Conclusion: AACE was characterized by a sudden onset of concomitant non-accommodative esotropia with diplopia or visual confusion. In most cases, prismatic correction had a favorable effect with a resolution of diplopia. It offers a good treatment alternative in the early stage, when the angle of strabismus is unstable and surgery is not without risk.