Intermittent Exotropia, Overcorrecting Minus Lenses, and the Newcastle Scoring System

Purpose: We sought to determine whether the Newcastle Control Score (NCS) could be used to indicate a successful outcome in patients with intermittent exotropia that were treated with minus lenses. Methods: We studied patients with an intermittent exotropia who were prescribed minus lens therapy in an effort to manage their strabismus conservatively. The NCS, which quantitatively estimates the control of an intermittent exotropia, was applied before treatment and 4 months after treatment. The results of minus lens therapy with a pretreatment NCS of ≥5 (group 1) were compared with those with a NCS of ≤4 (group 2). Results: There were 24 patients (13 girls, 11 boys) treated with minus lenses. The mean age of the patients was 6.8 ± 3.8 years (range, 2-17 years; median, 5). The mean pretreatment distance angle was 28.5 ± 10 prism diopters (range, 6-45; median, 30) and the mean post-treatment distance angle was 18.3 ± 8.9 prism diopters (range, 0-35; median, 18) P = 0.001. Using the NCS minus lenses significantly (P = 0.041) improved control of exotropia. In group 2 (n = 16) 75% had improved scores post-treatment compared with 62.5% in group 1 (n = 8), P = 0.68. Conclusions: These data suggest that the NCS is a useful method to indicate the success in the control of intermittent exotropia with conservative treatment with minus lens therapy.