Oblique Palsy Research Articles

Consequences of unilateral inferior oblique weakening.

What are the indications for unilateral inferior oblique surgery in the face of asymmetrical primary overaction of the inferior oblique pre-operatively? First, in established acquired cases of superior oblique paralysis, one may proceed without concern with unilateral inferior oblique weakening. However, if the cases are congenital in origin, one must be wary of an effect on the unoperated inferior oblique. Secondly, in the monocular horizontal-vertical squint with amblyopia and the primary overacting inferior oblique is in the amblyopic eye, unilateral inferior oblique weakening may be considered, since it is not likely that fixation will be shifted to the operated eye post-operatively, and the surgery is basically for cosmetic reasons. In the latter cases, one must rule out the unusual situation in which there is simultaneous overaction of both the inferior oblique and superior oblique in the same eye. In such cases, unilateral inferior oblique weakening may produce a dramatic hypotropia. In such cases, weakening of both inferior and superior oblique muscles is recommended.

Active force tests in lateral rectus paralysis.

In lateral rectus (LR) paralysis the amount and type of surgical repair is guided by knowledge of the amount of active LR force which has returned and the amount of antagonist medial rectus (MR) contracture which has occurred. Active LR force is assessed directly by holding the eye as it attempts following or saccadic movements and indirectly by observation of horizontal saccadic velocity. These new active force tests are more reliable than electromyography in assessing mechanical paralysis. Medial rectus contracture is a limit of rotation range but is not a general stiffening of the antagonist. Hummelsheim transplantation operations are indicated when severe LR paralysis and little MR contracture exist. Otherwise, horizontal recessresect surgery is preferable. Simultaneous superior oblique paralysis commonly creates a V pattern. Increased horizontal surgery amounts are then indicated.

Bilateral superior oblique paralysis.

BILATERAL paralysis of the superior oblique muscle may be congenital or acquired. The typical symptoms of bilateral superior oblique paralysis following trauma to the skull have been described by Bielschowsky,1Adler,2and Walsh.3The findings are characteristic in that there are diplopia in the lower fields of gaze and fusion in the upper fields. The head is bent, with the chin on the chest, so that the eyes will look into the upper field of single vision. On looking down and to the right there is left hypertropia with diplopia, and on looking down and to the left there is right hypertropia with diplopia. Adler2charted the diplopia fields for this condition, which showed the left image lower on gaze to the right and the right image lower on gaze to the left. In the upper field the images came together. Bielschowsky1figured the findings