Botulinum Toxin Injection in Horizontal Rectus Muscles Without Electromyography Using an Open Sky Versus a Closed Sky Technique.

PURPOSE: To ascertain whether electromyographic control when injecting botulinum toxin in the horizontal rectus muscles is necessary, and to compare the open sky and closed sky injection techniques that are used without electromyographic control. METHODS: The records of 135 patients with horizontal strabismus who received botulinum toxin injections were reviewed retrospectively. Sevoflurane or propofol anesthesia was used in children, and topical benoxinate hydrochloride was used in adults. Patients received a bilateral injection of 2.5 to 15 IU of botulinum toxin, without electromyographic control, into the medial or lateral rectus muscles to correct esotropia or exotropia, respectively. An open sky technique was used in 31 patients, and a closed sky technique was used in 104 patients. Postoperative alignment within 10 prism diopters (PD) of orthotropia was considered a successful outcome. RESULTS: A successful outcome at 6 months of follow-up was achieved in 47% of all patients: 59% of patients in the open sky group and 44% of patients in the closed sky group (P = .151). Botulinum toxin injection corrected a mean of 14 ± 9.705 PD in patients in the open sky group and 31 ± 20.589 PD in patients in the closed sky group to obtain mean residual angles of 21 ± 16.692 and 13 ± 11.901 PD, respectively. CONCLUSIONS: The results obtained without electromyographic assistance were not remarkably different from the studies using electromyographic control. Moreover, because the results of the open sky technique were not significantly superior to the closed sky technique, the latter was favored to shorten the operative time and postoperative convalescence, and to reduce the risk of postoperative adhesions and scarring, which made re-operations difficult. [J Pediatr Ophthalmol Strabismus. 2022;59(6):388-395.].

A Comparative Study of Prism Adaptation and the Augmented Surgery Formula in the Management of Acquired Comitant Esotropia.

PURPOSE: To compare two methods of surgical augmentation (prism adaptation and the augmented surgery formula) in the management of acquired comitant esotropia. METHODS: Forty patients were included in this prospective study and assigned to either the prism adaptation (20 patients) or augmented surgery (20 patients) group. After preoperative prism adaptation, patients in the prism adaptation group were classified as prism adaptation responders (fusers) or non-responders (non-fusers). All patients in the prism adaptation group underwent surgery for the prism-adapted angle. Patients in the augmented surgery group underwent surgery based on the augmented surgery formula, defined as the average of the near deviation without correction and the distance deviation with correction. RESULTS: In the prism adaptation group, 6 patients (30%) were prism responders, whereas 14 (70%) were non-responders. The 3-month motor success rate was significantly higher in the prism adaptation group (90%) than the augmented surgery group (55%) (P = .013). The 6-month motor success rate was not significantly higher in the prism adaptation group (95%) than the augmented surgery group (80%) (P = .151). The improvement in the 6-month outcome was mainly attributed to hyperopic spectacle power reduction after 3-month postoperative evaluation to correct consecutive exotropia. CONCLUSIONS: Although prism adaptation is superior in precisely determining the surgical target angle, the success rates were comparable between the two groups after hyperopic spectacle power reduction. This obviates the need for prism adaptation, except in cases of non-accommodative esotropia. To maximize the benefit of prism adaptation, it is recommended that all patients with prism adaptation (responders and non-responders) undergo surgery for the prism-adapted angle. [J Pediatr Ophthalmol Strabismus. 2020;57(2):108-119.].