ABSTRACT
OBJECTIVE: This article evaluates the effects of unilateral and bilateral inferior oblique myectomy (IOM) on fundus torsion in primary and secondary inferior oblique overaction (IOOA). METHODS: This study analyzed 230 OCT images of 53 eyes of 32 patients who had undergone IOM by a single surgeon in the last two years. The disc-foveal angle (DFA) was calculated by digitally measuring the angle between the horizontal line passing through the geometric center of the optic disc and the curved line connecting the fovea to the geometric center of the optic disc. DFA was classified into intorsion, normal torsion, and extortion. The DFA was measured from the OCT images before the operation in the first week, first month, third month, and sixth month. RESULTS: When all the patients in our study were evaluated together, IOM statistically reduced the mean DFA in the third month (p=0.00). The DFA was higher in the secondary IOOA group than in the primary IOOA group (p=0.24). Bilateral IOM statistically significantly reduced DFA in the third month (p=0.00) and decreased the DFA difference between the two eyes in the third month (p=0.583). Unilateral IOM increased the DFA, rather than decreasing it, in the first week in operated eyes (p=0594) and increased the DFA difference between the two eyes after surgery (p=0.477). When we evaluated the localization of the macula as an intorsion, normal intorsion, or extortion, the extortion decreased from 36 to nine in the third month after bilateral IOM, and intorsion was seen in only two. Unilateral surgery did not significantly change fundus torsion in primary IOOA, and it caused intorsion in 3 of 6 (50%) operated eyes in secondary IOOA. CONCLUSION: Although unilateral IOM provides a clinical improvement in secondary IOOA, it increases the difference in DFA between both eyes and causes intorsion in 50% of patients. Masked IOOA was detected in 3 of 11 (27.3%) patients who underwent unilateral IOM. When deciding on unilateral surgery, the possibility of increased DFA difference between both eyes, intorsion in the operated eye, and masked IOOA in the other eye should be considered.
ABSTRACT
PURPOSE: To evaluate the amount of excyclotorsion according to degree of inferior oblique overaction (IOOA) in patients with primary IOOA. METHODS: Fifty-nine primary IOOA patients who underwent inferior oblique muscle surgery were evaluated. Visual acuity, ocular movement test, prism cover test, Bielschowsky head tilt test, fundus photograph and photographic examination for excyclotorsion were performed. The correlation analysis was performed for the excyclotorsion according to the amount of IOOA (Control group; IOOA < 1, Group 1; 1 < or = IOOA < 2, Group 2; 2 < or = IOOA < 3, Group 3; 3 < or = IOOA < 4, Group 4; IOOA = 4). RESULTS: Excyclotorsion was 7.37 +/- 2.36degrees in the Control group, 9.29 +/- 3.79degrees in Group 1, 10.04 +/- 4.39degrees in Group 2, 17.98 +/- 4.62degrees in Group 3, and 24.70 +/- 4.61degrees in Group 4. The amount of IOOA and excyclotorsion showed a positive correlation (Pearson's correlation coefficient r = 0.675). Asymmetric IOOA was observed in 35 patients (59.3%) and symmetric IOOA was observed in 24 patients (40.7%). Asymmetric IOOA combined with hypertropia was presented in 9 patients (37.5%) and symmetric IOOA combined with hypertropia was presented in 3 patients (8.6%). Therefore, patients with asymmetric IOOA have a higher incidence of vertical diplopia. The amounts of IOOA and excyclotorsion were greater in primary IOOA with esotropia than in subjects with exotropia (p = 0.001). CONCLUSIONS: The excyclotorsion was proportional to the amount of IOOA in Group 3 and Group 4. The aspect of excyclotorsion was widely distributed in Group 1 and Group 2 compared to that in the Control group.
