Botulinum vs adjustable suture surgery in the treatment of horizontal misalignment in adult patients lacking fusion. Thirty patients were treated with either botulinum toxin or adjustable suture surgery in a prospective, randomized clinical trial. All patients had horizontal deviations greater than 10 prism diopters and absent fusion. Seventeen patients were assigned to toxin treatment, and 13 were assigned to surgical treatment. Follow-up at 6 months after either procedure indicated that surgery was superior, with patient alignment showing a 92.7% average net change, compared with a 50.50% net change in the botulinum-treated group. There was no difference in response between those patients with a starting deviation of 20 PD or less and greater than 20 PD in the surgery group. However, in the botulinum-treated group, those patients with a starting deviation of 20 PD or less seemed to show better responses than those patients with greater than 20 PD. Patients with esotropia showed an 88.89% change with surgery and a 51.55% change with toxin treatment. Patients with exotropia had a 95.83% change with surgery but a 50.3% change with toxin treatment. Since we had 20 patients with exotropia and 10 patients with esotropia, a more formal comparison would require larger numbers. 