[Surgical treatment of myopic strabismus fixus by modified Yokoyama's surgery]

To evaluate the surgical results of modified Yokoyama's procedure for treating myopic strabismus fixus.

Retrospective analysis of records of 5 patients (7 eyes) with high myopic strabismus. Pre- and postoperative orthoptic measurements were recorded and analyzed. Anatomic relationships between the muscle cone and globe were analyzed using MRI or CT scan. The surgical procedure is a modification of Yokoyama's technique and medial rectus muscle was also recessed.

The average axis length of 7 eyes was 32.62 mm (SD1.84). The mean preoperative horizontal deviation was 82.86 PD (SD 37.62) esotropia and mean vertical deviation was 20 PD (SD 7.91) hypotropia. All patients had marked limitation of elevation and abduction. Displacement of the lateral rectus inferiorly and superior rectus medially was demonstrated in each patient by CT or MRI scan of the orbits and by observation during surgery. After surgery, the supertemporal dislocation of globe was improved. Both the horizontal and vertical deviations decreased significantly, and the abduction and sursumduction motility were also improved gradually. The average follow-up was 5 months, all patients achieved satisfactory results and remained stable.

In high myopic patients, if the deviant paths of the LR and SR muscles were demonstrated by MRI or CT scan, the surgical procedure to restore the dislocated globe back into the muscle cone by uniting muscle bellies of the superior rectus and lateral rectus muscles is effective and recommended.