Long-term surgical outcomes of one-muscle vs. two-muscle horizontal strabismus surgery

ABSTRACT

Purpose

While horizontal strabismus surgery is generally considered to have favorable outcomes, success rates can vary by type of procedure. Our purpose is to compare the long-term outcomes of patients who underwent one-muscle vs. two-muscle horizontal strabismus surgery.

Methods

This is a retrospective study comparing one-muscle to two-muscle strabismus surgery for small to moderate angle horizontal strabismus. Demographic data and eye exam parameters were compared at baseline and postoperatively (6 months up to 6 years). Surgical success was defined as a post-operative angle of 10 PD or less. We also compared outcomes by strabismus type: esotropia vs exotropia and adjusted the analysis for previous strabismus surgery.

Results

Out of 89 patients with moderate angle horizontal strabismus (25 PD or less), 17 patients had a one-muscle operation, and 72 patients had two-muscle surgery. The mean age was 14.12 ± 9.30 years and 11.70 ± 11.30 years for the one-muscle and two-muscle groups, respectively (p = .74). The baseline characteristics of both groups were comparable. Follow-up time was 32.82 ± 26.93 months in one-muscle and 37.67 ± 23.81 in two-muscle groups (p = .29). Success rate was 70.6% for the one-muscle group and 68.10% for the two-muscle group (p = .69). Outcomes were similar when divided into esotropia and exotropia. The success rate was not affected by previous strabismus surgeries nor by the initial angle of deviation.

Conclusion

One-muscle and two-muscle horizontal strabismus surgery had similar long-term outcomes and did not differ by strabismus type nor by angle of deviation.

KEYWORDS:

• Esotropia
• exotropia
• one-muscle
• outcomes
• strabismus surgery
• two-muscle

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethical considerations

This retrospective study was approved by the American University of Beirut Institutional Review Board (IRB) (BIO 2020–0347) and abided by the tenets of the Declaration of Helsinki. Informed consent was waived due to the retrospective nature of the study.

Additional information

Funding

The author(s) reported that there is no funding associated with the work featured in this article.