[The Surgical Effects of Medial Rectus Recession on Divergence Insufficiency Esotropia]

To study the surgical effects of medial rectus recession (MRR) on divergence insufficiency esotropia (DIE).

Nine DIE patients who were admitted to and had MRR at Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University between December 2017 and June 2020 were included in this retrospective study. All patients were followed up for 1 year at least. The postoperative esodeviation, near-distant disparity (NDD) and visual function were observed and compared.

The mean age of the 9 patients was 28.8 years old (10-49 yr.), including 3 adolescent patients (≤18 yr.). The mean preoperative esodeviation was (19.8±13.2) PD for near and (32.6±15.3) PD at distance, while, the mean postoperative esodeviation 1 year after MMR was (-0.2±3.5) PD for near and (6.0±2.2) PD at distance, showing significant improvement over the mean preoperative esodeviation ( P=0.012, P=0.007). NDD dropped from (12.8±2.4) PD before the surgery to (6.0±2.2) PD 1 year after the surgery, showing significant improvement ( P=0.008), and remained stable 1 year after the surgery ( F=0.075, P=0.900). There was no significant improvement of near stereopsis ( P=0.306). Binocular function at distance was significantly improved after surgery (Worth 4 dots test : P=0.017; Bagolini striated glasses: P=0.035). The patients were divided into two groups, the adolescent group (age≤18 yr., n=3) and the adult group (age>18 yr., n=6). Prior to the operation, the mean spherical diopter of the adolescent group (OD -1.75 D, OS -1.92 D) was lower than that of the adult group (OD -6.17 D, OS -6.04 D) ( P=0.012). The average value of preoperative AC/A of the adolescent group was 4.33. It was 2.33 in the adult group, which was lower than the normal value, and significantly lower than that of the adolescent group ( P=0.12). There was no significant difference in esodeviation or NDD between the adolescent group and the adult group before and after operation.

Medial rectus muscle recession can effectively improve the NDD and the binocular function at distance of patients with divergence insufficiency esotropia. Postoperative esodeviations both for near and at distance tend to regress after the surgery. Therefore, it is recommended that the amount of MRR be increased in the treatment of DIE.