The Surgical Correction of Vertical Deviation after Superior Rectus Muscle Recession in Patients with Hypertropia

ABSTRACT

PURPOSE: In general, the amount of vertical rectus surgery is based on achieving 3 prism diopters (PD) of realignment for each millimeter of muscle recession. The study aimed to determine the surgical correction of vertical deviation in patients with hypertropia after superior rectus muscle recession. METHODS: A total of 32 patients with hypertropia underwent 2-8 mm recession of the superior rectus muscle. The average surgical correction for each millimeter of recession was calculated by deducting the post-surgical deviation from the pre-surgical vertical deviation and dividing the remnant by the amount of recession (mm). RESULTS: The average surgical correction was 2.2 +/- 0.7 PD for each millimeter of superior rectus recession. There was no statistical significance in the change in surgical correction in terms of follow-up period, which was categorized as one day, one, two, and six months, and one year (P>0.05). The relationship between surgical correction and age (below and above 11 years old), gender or the amount of recession (below or above 5 mm) was not statistically significant (P>0.05). There was no statistically significant difference in vertical correction between esodeviation and exodeviation (P>0.05). CONCLUSIONS: The study showed an average surgical correction of vertical deviation of 2.2 PD for each millimeter of superior rectus muscle recession. The results suggest that increased recession, within the maximum limit of 8 mm, is an effective approach to prevent undercorrection for children who have hypertropia but cannot undergo adjustable strabismus surgery.