Quantification (grading) of inferior oblique muscle recession for V-pattern strabismus.

PURPOSE: To determine the effectiveness of grading such surgery according to the magnitude of the V pattern and inferior oblique muscle overaction (IOOA).

METHODS: We retrospectively reviewed all 53 cases we operated since 1984 for V pattern with IOOA, who had undergone graded inferior oblique recession, recessed according to the anatomical recession table of Apt and Call, ranging from 8mm for V pattern of 12 PD with +1 IOOA to 12mm for 30+ PD with +3 IOOA.

RESULTS: A "satisfactory outcome" (defined as = V pattern of 8 PD or less) was observed in 75% of the cases with a preoperative V pattern less than 20 PD, in 70% of those with a preop' V pattern between 20 PD and 29 PD, and in 57% of those with a preop' V pattern greater than 29 PD. There were no overcorrections. All unsatisfactory outcomes were undercorrections.

CONCLUSIONS: The principle of grading this surgery is supported and affirmed by these results. However, the results also suggest a need to increase the amount of surgery for all categories and add anterior transposition for larger V patterns.