Functional acute acquired comitant esotropia: clinical characteristics and efficacy of single Botulinum toxin type A injection

Abstract

Background To examine the clinical features of acute acquired comitant esotropia (AACE) and to evaluate the clinical effectiveness of a single injection of botulinum toxin type A (BTXA) on binocular visual function (BVF). Methods This retrospective, observational case series study enrolled patients with AACE examined from October 2018–May 2019. BTXA was injected into the both medial rectus muscles. The refractive error, best-corrected visual acuity (BCVA), stereoacuity, vergence, accommodation, the horizontal angle of deviation, and the gradient accommodative convergence/accommodation (AC/A) ratio were measured pre- and post-BTXA injection. Data pre- and postinjection were compared by the Wilcoxon signed-rank test. A Spearman correlation coefficient was calculated to explore the relationships between demographic characteristics and BVF. Results Twenty-two AACE cases were included. Compared with preinjection deviation, the postinjection deviation in the primary position was smaller for near (p < 0.001) and distance (p < 0.001) fixation at 3 months after injection (BTXA). Furthermore, convergence was better for near (p = 0.003) and distance (p < 0.001) fixation, divergence was better for near (p = 0.021) and distance (p < 0.001) fixation, accommodation was better in the right (p = 0.011) and left (p = 0.004) eyes, and the gradient AC/A ratio was better at the third month after injection (p = 0.001). Stereoacuity was improved in 11 (50%), unchanged in 5 (22.73%) and decreased in 6 (27.27%) patients. The preinjection stereoacuity (p = 0.013, r = 0.522) and preinjection deviation for near (p = 0.015 r, = − 0.512) and distance (p = 0.009, r = − 0.541) were significantly associated with patient age. Conclusions AACE is characterized by a high AC/A ratio and low accommodation. A single injection of BTXA is effective for AACE. Deviation, stereoacuity, and the therapeutic effect of BTXA may be correlated with patient age.

The Effect of Different Treatment Methods on Acute Acquired Concomitant Esotropia

“…The most frequent side effect caused by extraocular muscle injections of BTXA is ptosis [ 7 ], due to the diffusion of BTXA into the adjacent muscles of the eye, especially the levator muscle, which is relatively sensitive to BTXA. Among the 32 patients who opted for BTXA injections in this study, 29 had an orthotropic eye position at the last follow-up, and 3 patients exceeded the duration of action of BTXA and had a recurrence of deviation.…”

“…Currently, common treatments for AACE include wearing prism, surgery of squint correction, and microscopic medial rectus muscle injection of botulinum toxin type A (BTXA) [ 7 ]. BTXA is a neurotoxin produced by Gram-positive anaerobic bacteria, which has the effect of muscle paralysis [ 8 ].…”

Independent risk factors of type III acute acquired concomitant esotropia: A matched case–control study

“…[ 1 2 3 6 7 8 ] However, the role of uncorrected myopia as a risk factor for type III AACE remains controversial. Previous studies[ 4 9 10 ] proposed that an individual with uncorrected myopia tends to hold objects excessively close to the eyes, resulting in an imbalance between the converging and diverging forces of the eyes. In contrast, Ruatta et al .…”

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

“…However, BTXA injection as a treatment of ACCE still has some finiteness, including the adverse reactions and the limited duration of BTXA action. The most frequent side effect for BTXA injection into extraocular muscles is ptosis [33] , which is caused by the spread of BTXA to the adjacent muscles, especially the elevator palpebrae superioris, which is comparatively sensitive to BTXA. No cases of ptosis occurred in the 33 AACE patients probably because the injection procedure was performed under a microscope, and the medial rectus was fully exposed for injection, ensuring that the vast majority of the drug was accurately injected into the muscle belly or myo-synovial sheath.…”