DEC 12, 2012
This study retrospectively compared postoperative drift after bilateral lateral rectus recession for infantile exotropia and for intermittent exotropia, and found that postoperative exotropic drift is clinically similar in these two groups of patients up to three years after surgery. The authors conclude that initial overcorrection within 10Δ to orthophoria during the early postoperative period may be associated with the best long-term ocular alignment over three years in both infantile and intermittent exotropia.
They retrospectively reviewed the records of all patients with infantile or intermittent exotropia who had undergone bilateral lateral rectus muscle recession surgery by one of two surgeons between 1993 and 2008 and had a follow-up longer than three years. The study included 37 infantile exotropia patients and 144 intermittent exotropia patients.
The infantile exotropia group had a larger final postoperative misalignment, poorer stereopsis, and a greater rate of amblyopia. However, three-year primary surgical outcome, three-year final surgical outcome, and the reoperation rate did not differ significantly between the two groups.
The overall mean postoperative exotropic drift at three years was 10.4Δ in the infantile exotropia group and 7.2Δ in the intermittent exotropia group (P = 0.05). Both groups had a low success rate at three years: 41 percent in the infantile exotropia group and 51 percent in the intermittent exotropia group (P = 0.270). For patients with an initial esotropia of 0Δ to 10Δ, the success rate at three years was 86 percent in the infantile exotropia group (12 of 14) and 65 percent in the intermittent exotropia group (28 of 43).
The authors say that their subgroup analysis suggested that exotropic drift at three years may be smaller in patients with pattern deviation. Their results also showed that initial overcorrection does not lead to a higher rate of amblyopia development.