Results in 50 cases of strabismus after graduated surgery designed by A scan ultrasonography.

Of 50 cases of strabismus having surgical operations designed on the basis of A scan ultrasonography 45 (90%) had less than 10 dioptres eso- or exodeviation two months postoperatively; 22 eso-, 25 exo-, and 3 vertical deviations were included in the series. A scan ultrasonography is done preoperatively to find the diameter and thus the circumference of the globe. This is used with the angle of deviation to estimate the amount of recession and/or resection necessary to correct the deviation. Attention is drawn to the oculomotor axis, which is 10-12 degrees divergent to the anteroposterior axis and around which the recti muscles act. The oculomotor equator is at right angles to this axis and is closer to the limbus medially than laterally, so that excessive recession of the medial rectus is more likely than of the lateral rectus.