Purpose
To investigate the changes in fundus excyclotorsion after inferior oblique myectomy or myotomy
Methods
The case files of 21 patients who had undergone strabismus surgery at the hands of a single surgeon during the period from 2009-2012 were examined. Only patients who had undergone an inferior oblique myectomy or myotomy with or without horizontal rectus muscle surgery were evaluated. Digital fundus photographs were obtained, and the angle formed by a horizontal line passing through the geometric centre of the optic nerve head and the line connecting the foveola and optic disc centre was measured. Associated clinical factors, including the age at the time of surgery, presence of a head tilt, degree of preoperative vertical deviation, torsional angle, inferior oblique muscle overaction or superior oblique muscle underaction, laterality of the operation, and combination with horizontal rectus muscle surgery were analysed.
Results
Preoperatively, the mean torsional angle was 12.0 ± 6.4°, which decreased to 6.9 ± 5.7° postoperatively regardless of laterality of the operation or combination with horizontal rectus muscle surgery (p = 0.000, paired t-test). Torsional angle decreased from 15.1 ± 7.0° to 6.2 ± 4.3° in the myectomy group (p = 0.000, paired t-test) but not significantly in the myotomy group (p = 0.093, Wilcoxon signed rank test). Multivariable linear regression analysis showed the preoperative torsional angle, the degree of inferior oblique overaction, and age at surgery were significant independent variables.
Conclusions
Mean torsional angle decreased after the inferior oblique myectomy. The preoperative torsional angle, the degree of inferior oblique overaction, and age at the time of surgery may affect the postoperative torsional angle.
Keywords: 722 strabismus •
725 strabismus: treatment