Effect of ongoing treatment of amblyopia on surgical outcome in esotropia

Classic teaching recommends completion of amblyopia therapy prior to surgical correction of esotropia. Recent reports, however, suggest that incomplete treatment does not adversely affect surgical outcome. This study assesses the effect of incompletely treated amblyopia on the success rate of bimedial rectus recession in infantile and acquired esotropia.

All patients (n = 102) with esotropia undergoing bimedial rectus recession in 1994 who met inclusion criteria were reviewed. Subjects were classified as having infantile; acquired, partially accommodative; or acquired, nonaccommodative esotropia for comparison. Amblyopia was classified as none, mild, moderate, or severe. Surgical success was defined as orthophoria +/- 8 prism diopters and was assessed at the second postoperative visit (4 to 6 weeks after surgery). Other variables studied included mean surgical age, preoperative deviation, millimeters of surgery, and amount of follow up.

For all patients, surgical success rates were as follows: no amblyopia, 84.3% (43/51); mild amblyopia, 81.6% (31/38); and moderate amblyopia, 61.5% (8/13). All patients with severe amblyopia underwent unilateral recess/resect procedures and were excluded. Of the esotropia subgroups, a statistically significant decrease in surgical success was noted only in the infantile esotropia group with moderate amblyopia. For this group, success rates were as follows: no amblyopia, 77.1% (27/35); mild amblyopia, 81.0% (17/21); and moderate amblyopia, 16.7% (1/6), P = 0.005.

Performing corrective surgery on patients with infantile esotropia leads to poorer surgical outcome if moderate amblyopia is present at the time of surgery. Mild amblyopia, however, does not adversely affect surgical outcome in patients with infantile esotropia. Furthermore, the presence of mild or moderate amblyopia does not appear to have an influence on surgical outcome for patients with acquired esotropia. The effect of amblyopia on sensory outcome was not studied as most patients were too young for reliable sensory testing.