Denervation and extirpation of the inferior oblique. An improved weakening procedure for marked overaction.

Parks demonstrated that recession was more effective than myectomy at insertion or origin, or disinsertion for eliminating inferior oblique overaction. This study simultaneously compares an improved procedure, an extirpation of the inferior oblique that involves denervating it, to 14 mm recession in a prospective, consecutive series of 16 patients with symmetrical 4+ overaction of the inferior obliques; one technique (extirpation) performed on the right eye, and the other (14 mm recession) on the left. Mean duration of follow-up was 20.8 months (range 17 to 34 months). Extirpation resulted in 100% normal action, without residual overaction or underaction. Recession, however, resulted in 1+ to 3+ residual overaction in 12 cases (75%) and 4+ overaction requiring reoperation in two eyes (13%). It appears that extirpation of the inferior oblique is far superior to 14 mm recession for treatment of marked overaction of the inferior oblique.