Midoperative Forced Duction Test as a Guide to Titrate the Surgery for Consecutive Exotropia

Abstract

This is a retrospective study of the outcome of all consecutive exotropia surgery performed between the years 1999 and 2007. Excluded were cases of slipped muscles, muscle transpositions, and concurrent cyclovertical procedures. A total of 135 patients of mean age 40 years (range 6–72) were operated with a mean preoperative angle of deviation −40Δ (range −12 to −90). Five were treated with fixed sutures and the rest with adjustables. The surgery included preplanned lateral rectus recessions of mean 6 mm (range 2–9) and maximal possible medial rectus advancements with or without resections of mean 5.6 mm (range 2–11), intraoperatively adjusted to give a resistance of +1 to +2 for abduction on forced duction test (FDT). Adjustable suture patients were seen 4 to 6 hours after surgery and underwent further adjustment, if needed, to achieve the target angle. A further review took place at 2 weeks and 2 months. Children remained under follow-up till 8 years of age. Forty percent needed postoperative adjustment. The mean postoperative angle at final measurement was −2Δ (range +25 to −45). Eighty percent achieved an angle within 10Δ of orthotropia. No gross restrictions of ductions were present postoperatively.