Botulinum toxin type A in treating early-stage patients with small-angle acute acquired comitant esotropia.

AIM: To investigate botulinum toxin A (BTXA) efficacy on small-angle (≤25Δ) acute acquired concomitant esotropia (AACE) in early-stage patients. METHODS: The electronic medical record data of AACE patients during March 2019 and June 2023 were collected in this retrospective and hospital-based cohort study. A total of 72 small-angle AACE patients received BTXA extraocular muscle injection. Patients were grouped by onset-to-treatment time (Group A: ≤6mo, Group B: >6mo). Deviation of esotropia, eye alignment and stereopsis were analyzed at the period of pre/post-injection (1wk, 1, 3, and 6mo). Orthophoria rate at 6mo (horizontal deviation <10Δ and binocular single vision) were considered as outcome index. RESULTS: There were no significant baseline differences (P>0.05) between two groups except onset-to-treatment time (2mo vs 11mo, P<0.001). Higher orthophoria rates were in Group A at last follow-up (94.74% vs 73.53%, P=0.013). Post-BTXA deviations of two groups at 1mo showed no difference (P>0.05); while in 3 and 6mo Group A was significantly smaller than group B (all P<0.001). No statistically significant differences were observed among all post-BTXA deviations of near and distance in Group A. In Group B, deviation at 3mo (near: 2Δ vs 0, P<0.001; distance: 4Δ vs 0, P<0.001) and 6mo (near: 6Δ vs 0, P<0.001; distance: 6Δ vs 0, P<0.001) was significant increased compared to deviation at 1wk after treatment. Group A showed better stereopsis recovery in last follow-up compared to Group B (80″ vs 200″, P=0.002). Both groups obtained improved stereopsis after treatment (Group A: 80″ vs 300″, P<0.001; Group B: 200″ vs 300″, P=0.037). CONCLUSION: BTXA is effective for AACE with small deviation (≤25Δ) in early stage. Delayed treatment (>6mo) may reduce BTXA efficacy. Early BTXA intervention benefits long-term eye alignment and stereopsis recovery.

Clinical efficacy of botulinum toxin type A on acute acquired comitant esotropia.

AIM: To investigate the effects of micro-injection of botulinum toxin A (BTXA) on acute acquired comitant esotropia (AACE). METHODS: A total of 33 AACE patients who underwent BTXA micro-injection at Renmin Hospital of Wuhan University from September 1st, 2019 to July 1st, 2021 were retrospective analyzed. Esotropia, eye alignment, stereopsis, and complications were examined at baseline (except complications), 1wk, 1, 3, and 6mo after injection. RESULTS: The average angle of deviation before injection was (+20.24±6.80)Δ at near and (+24.76±6.43)Δ at distance, while (+5.15±5.85)Δ at near and (+7.30±6.17)Δ at distance 6mo after treatment (P<0.05). Six months after injection, the stereopsis of patients had improved. The number of patients having no stereopsis (>800 seconds of arc) decreased from 11 to 3. The number of patients having peripheral stereopsis (300-800 seconds of arc), macular stereopsis (70-200 seconds of arc) and central concave stereopsis (≤60 seconds of arc) increased from 10 to 11, 10 to 12, and 2 to 7, respectively. At the follow-ups at 1wk, 1, 3, and 6mo after injection, success rates were 96.97%, 96.97%, 93.94% and 87.88%, respectively. One week after injection, two patients (6.07%) showed subconjunctival hemorrhage; three patients (9.09%) showed limited eye movement and one patient (3.03%) showed mild vertical strabismus. All the symptoms disappeared by the final follow-up. CONCLUSION: Micro-injection of BTXA can reduce diplopia and improve binocular vision function of AACE patients. Furthermore, the operation is relatively safe with few complications, making it an ideal treatment modality for AACE.