The positions of 4 rectus pulleys of both eyes were normal in primary position. The position of the right LR pulley was displaced downward in attempted abduction, supraducted adduction, and supraducted abduction. The position of the right superior rectus (SR) pulley was displaced laterally in attempted supraduction, supraducted adduction, and supraducted abduction (Figure 2). Thus, the patient showed instability of the right LR and SR pulleys in attempted supraduction and abduction. There was no significant displacement of the position of all rectus pulleys in the left eye. For correction of pulley instability in the right eye, the SR was transposed 1 muscle width nasally and fixed 13 mm posterior to the SR insertion. The LR was transposed 1 muscle width superiorly and fixed 15 mm posterior to the LR insertion. Three months after the operation, 40 PD of exotropia in upgaze decreased to 12 PD and primary-position orthophoria remained (Figure 1B).