Background: Fusion and the development of the monofixation syndrome are well recognized after surgical alignment of congenital esotropia to within 8 delta of orthotropia. However, in adults with longstanding strabismus and a history of congenital esotropia who are not surgically aligned within the first few years of life, the prognosis for the development of fusion is believed to be poor.
Methods and results: Twenty-four adults, 12 with a history of congenital esotropia (onset before 6 months age), 1 of congenital exotropia, and 11 with the onset of esotropia between 6 months and 2 years, were included in this study. All patients had longstanding strabismus, and none had been surgically aligned within the first 2 years of life. No patient had visual acuity worse than 20/30 in the worse eye. Preoperatively, no patient demonstrated fusion with the red glass test, Worth four-dot, or Titmus test. Postoperatively, all were aligned to within 8 delta of orthotropia, and all demonstrated peripheral fusion with the Worth four-dot at near. Twelve patients (50%), 8 of whom were in the congenital group, achieved stereopsis of 200 seconds of arc or better using the Titmus stereo test.
Conclusion: These findings suggest that surgery in this group of patients not only eliminates the ocular alignment deformity but can confer the functional benefits of fusion and increased field of binocular vision.