Comparing Inferior Oblique Muscle Myectomy with and without Displacement of Bilateral Rectus Muscles in Correction of Exotropia V Pattern with Severe Inferior Oblique Muscle Overreaction: A Pilot Study

Purpose: To evaluate a new method of inferior oblique muscle myectomy with displacement of the external rectus muscles on both sides for correction of exotropia V pattern with severe inferior oblique muscle overaction. Patients and Methods: In a pilot study, 9 patients with exotropia V pattern strabismus who were referred to Al-Zahra Ophthalmology Hospital, Tehran, Iran, in 2011 were studied in two randomly divided groups: group A underwent conventional surgical treatment including external rectus resection and inferior oblique weakening and in addition received external rectus displacement upwards while group B only received the conventional treatment. Results: The mean V pattern before surgery in group A was 41 ± 16.7 prism diopters which changed to 6 ± 10.7 prism diopters after surgery. The mean V pattern before surgery in group B was 37.2 ± 4.3 prism diopters which changed to 19.5 ± 3.1 prism diopters after surgery. In group A, V-pattern correction was 35.0 ± 11.6 prism diopters while it was 20.2 ± 1.2 prism diopters in group B, which indicated a statistically significant difference between the two groups (P = 0.04). Conclusion: Our results suggest that the mean V Pattern correction among patients undergoing our modified surgical method was significantly higher than the conventional method. Further comparative studies with a higher number of participants are suggested to confirm our results.