Factors affecting the motor outcome after corrective surgery for acquired comitant esotropia

Prism adaptation response and surgical outcomes of acquired nonaccommodative comitant esotropia

PURPOSE

To investigate the clinical factors influencing the prism adaptation response of acquired non-accommodative comitant esotropia (ANAET) and evaluate the surgical outcomes.

STUDY DESIGN

Retrospective observational study.

METHODS

This study assessed patients with ANAET who underwent strabismus surgery based on the results of a short prism adaptation test (PAT). Patients wore Fresnel trial prisms based on alternate prism cover tests in outpatient clinics. The cover test was then performed after 15-20 minutes; if the deviation increased, the power of the prism was increased to neutralize the angle. The test was repeated until the angle was stable. Patients were classified as either prism builders (angle increased by ≥ 10 prism diopters [PD] compared with the entry angle) or prism non-builders (angle increased by < 10 PD). The following clinical characteristics were noted: age at onset, age at surgery, duration of esotropia, refractive error, angle of deviation, presence or absence of intermittent esotropia at near, and pre- and postoperative sensory status.

RESULTS

A total of 41 patients (median age, 15.4 years) were evaluated. The mean (standard deviation) spherical equivalent refractions were -3.03 (3.33) diopters (D) and -3.05 (3.23) D in the right and left eyes, respectively. Twenty-seven (66%) patients were prism builders. The prism builders had greater myopia (builders vs. non- builders, right eye: -3.97 [2.97] vs. -1.22 [3.33] D, P = .01; left eye: -4.08 [2.78] vs. -1.07 [3.20] D; P = .003), lower angle of deviation at near (median [interquartile range] 30.0 [20.0, 35.0] vs. 42.5 [35.0, 49.4] PD; P = .009), much more preoperative intermittent esotropia or esophoria at near (44% vs. 7%, P = .03) and diplopia (96% vs. 64%, P = .01), and better postoperative stereoacuity (50 [40, 110] vs. 100 [60, 400] arcsec, P = .02) than the prism non-builders. The overall success rate was 83%, without a significant difference between the two groups (builders vs. non-builders, 89% vs. 71%, P = .21).

CONCLUSION

In cases of myopic refractive error, a small entry angle with intermittency at near, and good binocularity, it is recommended that surgery is performed based on prism-adapted angle to prevent under-correction.

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.].

Outcome of surgery for near angle in patient with incomitant distance/near esotropia and without manifest deviation at distance

INTRODUCTION

To investigate how a subset of patients with partially accommodative esotropia, with a manifest deviation <10 Prism Diopters (PD) at distance and an angle of strabismus at near wider than 10 PD, could respond to a surgical approach based on the misalignment at near.

METHODS

Six patients examined from 2015 to 2019 met criteria for inclusion: partially accommodative esotropia, patients compliant to full correction for at least 6 months, angle of esotropia for near larger at least 10 PD, angle of misalignment obtained with the alternate prism cover test and simultaneous prism cover test at distance <10 PD. All patients underwent bilateral medial recti recession. They were examined at 3 weeks and at 6 months.

RESULTS

No significant difference in the angle of esotropia at distance was found at any follow-up (Baseline: 7.17 ± 1.33 PD vs 3 weeks: 7.0 ± 1.01 PD vs 6 months: 7.33 ± 1.03 PD, p = 0.65, and p = 0.36, respectively). No case of consecutive exotropia was described. Considering the angle at near, there was a significant reduction at 3 weeks (Baseline: 41.7 ± 6.83 PD vs 3 weeks: 9.33 ± 1.63 PD, p = 0.027), that remained stable at the final follow-up (9.0 ± 1.1 PD, p = 0.32). All patients were suppressors and had nil stereopsis pre-operatively, all of them developed fusion and a different degree of stereopsis [276 ± 284 arcseconds (Range 80-800)].

CONCLUSIONS

A surgical approach based on the angle of strabismus for near could obtain satisfactory ocular alignment without consecutive exotropia in children with partially accommodative esotropia wearing full refractive correction, with a manifest deviation for distance <10 PD and a higher misalignment for near, at least for 6 months after surgery.