Large consecutive esotropia after uneventful surgical correction of infantile exotropia: A post-operative surprise

The incidence of consecutive esotropia developing after exotropia surgery has been reported to be 6%–20%. Consecutive esotropia with limited abduction requires reoperation on the muscles that were operated during the first surgery. It is difficult to predict the result of the second surgery because it may convert to exodeviation after the advancement of lateral rectus (LR) muscle, the contracture of the previously recessed muscle, or hypertrophy of resected medial rectus (MR). We present a case of 20-year-old woman with infantile exotropia who underwent bilateral lateral rectus recession and left MR resection in view of a large primary position deviation of 55 prism diopter (PD) at a 6-meter distance. But the patient developed large consecutive esotropia of 50 PD within 3 weeks of surgery with abduction limitation in the left eye, which was highly suspicious of slippage of the left LR. But when the LR was explored, it was found at 16 mm from the limbus without any evidence of slippage. In view of the abnormal response after the first surgery, the LR was advanced by 9 mm, and was inserted at 7 mm from limbus. The patient was orthophoric on the first postoperative day, and the alignment was maintained till 6 months of follow-up. This case is unique in terms of unexpected large consecutive esotropia of 50 PD after uncomplicated routine strabismus surgery, which was corrected by advancement of one LR only. This event could be possibly due to lack of binocularity and fusion in these patients with an associated component of dissociated horizontal deviation. This report emphasizes the possibility of some unusual postoperative outcomes in spite of careful and meticulous preoperative workup, and uneventful squint surgery in patients with infantile deviation.