Surgical weakening of the inferior oblique

1. The inferior oblique may be weakened effectively by recession, disinsertion, or myectomy, disrupting the muscle continuity between Lockwood's ligament and the muscle's insertion. 2. A successful unilateral inferior oblique weakening produces 20 prism diopters less hypertropia or more hypotropia in the field of action and has less effect away from the muscle's field of action; a bilateral weakening of the inferior oblique produces 20 prism diopters less exotropia or more esotropia in upgaze. 3. Complications of inferior oblique weakening are persistent overaction, operation on the wrong muscle, and the adherence syndrome. 4. The adherence syndrome is not related to the myectomy procedure specifically but is probably related to (or caused by) fat rupture with hemorrhage, which may accompany any type of inferior oblique weakening. 5. The adherence syndrome can be avoided by careful surgical technique.