Abstract： AIM:To analyze the clinical characteristics of acute acquired concomitant esotropia(AACE)in patients among different age groups.METHODS:Retrospective analysis of clinical data.A total of 112 non-Swan type AACE patients who underwent surgery at Peking University People's Hospital from January 2015 to December 2022 were retrospectively analyzed.Clinical data were collected and the characteristics were compared,including gender,age,diopter,duration of disease,daily time spent on near work,angles of deviation before and after surgery,stereopsis,etc.According to age,patients were divided into three groups:＜18 years old group(22 cases),18-45 years old group(67 cases),and＞45 years old group(23 cases).The clinical characteristics of patients were compared in each group.RESULTS:A total of 112 patients were included in the study,comprising 56 males and 56 females,with a median age of 29.50(19.25,41.75)years old.Among them,97 patients had myopia(86.6％).There were 93 patients(83.0％)who spent more than 8 h on near work.The age group＜18 years old had the shortest duration before surgery,with a median time of 1.00(0.50,1.00)a,the minimum negative diopter,with a median diopter of-0.75(-3.19,-0.56)D in the right eye and the diopter of-1.25(-2.81,-0.75)D in the left eye,and the maximum preoperative near angle of deviation,with a median angle of 30.00(18.50,80.00)PD,and the maximum preoperative distant angle of deviation,with a median angle of 35.00(23.75,80.00)PD.All these differences were statistically significant compared with other two groups(both P＜0.05).For the age group from 18 to 45 years old,the median near angle of deviation was 20.00(14.00,30.00)PD,and the median distant angle of deviation was 25.00(20.00,35.00)PD,both of which were higher than those in the age group＞45 years old(both P＜0.05).For the age group＞45 years old,the median near angle of deviation after surgery was-4.50(-7.50,0)PD,and the median distant angle of deviation after surgery was 4.50(0,9.50)PD,which were smaller than those in other two groups(all P＜0.05).The age group＞45 years old had the hiughest surgical success rate(100％).The preoperative stereopsis was better in age group＞45 years old than the group＜18 years old(P＜0.05).The postoperative stereopsis of the age group of 18 to 45 years old and the age group＞45 years old was better than age group＜18 years old(both P＜0.05).CONCLUSION:Surgical patients with AACE are mainly in the age group from 18 to 45 years old.The characteristic of angle of deviation is that distant angle of deviation is greater than near angle of deviation.The patients＜18 years old have larger preoperative angles of deviation than adults,while their stereoacuity is worse than adults in the early postoperative period.It is recommended that augmented-dose surgery should be performed in AACE patients who are in the age group of 18 to 45 years old(5-10 PD).A conservative surgery should be designed for hyperopia young children without established binocular vision.