THE EFFECT OF ANTERIOR TRANSPOSITION OF THE INFERIOR OBLIQUE MUSCLE

The effect of anterior transposition of the insertion of the inferior oblique muscle.was compared with the results from conventional inferio r oblique muscle recession in 50 patients. Even though both groups of patients had a similar degree of overaction preoperatively, postoperat ive inferior oblique muscle action was weaker (P < .01) and upgaze mor e limited P < .01) in the anterior transposition group. These data sug gest that anterior transposition serves to convert the inferior obliqu e muscle from an elevator to a depressor on attempted elevation. Becau se anterior transposition is such a powerful weakening operation, we s uggest that it be reserved for patients with moderate to severe inferi or oblique muscle overaction. To avoid postoperative hypotropia in upg aze, anterior transposition should be performed in both eyes for bilat eral inferior oblique muscle overaction and not unilaterally.