Evaluation of graded recession of inferior oblique muscle for correction of different grades of V-pattern strabismus

Abstract Background: V pattern identification is essential for a proper surgical management. Graded recession is a very logical approach to treat inferior oblique overaction (IOOA). The aim is to evaluate the efficacy of graded recession of inferior oblique muscle for correction of different grades of V pattern. Methods: Forty patients from 3 to 18 years old with V pattern strabismus and primary IOOA were evaluated by prism cover test to assess the grade of IOOA and amplitude of V-pattern. Graded recession of IO muscle depends on the amplitude of the V-pattern and degree of IOOA. Eight mm recession for amplitude 7.5° to 10° and mild IOOA (10° or +1) ,10 mm recession for amplitude 11°- 15° and moderate IOOA (11° -15 °or +2) and maximum recession for amplitude more than 15 °and marked IOOA (³ 15 ° or +3). Simultaneous correction of the horizontal deviation was performed. Follow up after I week,1 month ,3 month and 6-month. Results: The mean age of the study patients was 9 ± 4.261. Twenty patients (50%) had V-pattern esotropia, 12 (30%) exotropia, 4 (10%) orthotropic and four (10%) had Dissociated vertical deviation (DVD). Four cases 10% were of grade 1, 20 cases 50% grade 2 and 16 cases 40% were of grade 3. Of eighty eyes, 66 eyes 82.5% were fully corrected with no residual IOOA, and 14 eyes 17.5% were under corrected. V-pattern was corrected in 28 cases 70% and only 12cases 30% had residual V-pattern grade 1. Conclusions: Graded Recession of IO muscle is an effective technique for eliminating IOOA and can be graded according to the grade of IOOA, 8-mm recession for +1 overaction, 10-mm for +2 overaction, and 14-mm (maximum recession) for +3 overaction. The grade of IOOA correlates with the amplitude of V-pattern. The amount of recession correlates with preoperative IOOA and grade of V-pattern with frequent undercorrections obtained by the standard 8 mm recession. A +2 overaction merits a 10-mm recession of the inferior oblique. A +3 or +4 overaction merits a 14-mm maximal recession.