To compare the long-term follow-up surgical success rate of adjustable and non-adjustable surgery in horizontal strabismus.

A retrospective analysis was performed. The patients aged 15 years or older who were diagnosed with horizontal strabismus between September 2004 and August 2007 and who underwent at least 6 months of follow-up after surgery were reviewed. Eleven patients (Group A) underwent adjustable surgery, and 20 patients (Group B) underwent non-adjustable surgery. The surgical success rate of 31 patients with 6 months of follow-up were compared. After 2 years, the long-term follow-up surgical success rates of 10 patients in Group A and 12 patients in Group B were compared. Additionally, the changes between deviation angle on postoperative day 1 and final follow-up were compared.

The success rates 6 months after surgery was 81.8% in Group A and 85.0% in Group B, a difference that was not statistically significant ( p = 0.82). The success rate over 2 years of follow-up after surgery was 80.0% in Group A and 58.3% in Group B, and the difference was not statistically significant ( p = 0.28). However, the change in deviation angle was more stable in Group A than in Group B, and standard deviation, skewness, and kurtosis were lower in Group A.

After 2 years of follow-up, the success rate of adjustable surgery was higher than the non-adjustable surgery (Group A 80%, Group B 58.3%, p = 0.28). Moreover, in adjustable surgery, the changes in deviation angle were smaller and more stable.