Prolonged preoperative prismatic treatment in alternating convergent squint

Our 10-year retrospective study includes 178 children below the age of 10 years, operated for alternating convergent squint. Inclusion criteria were: Absence of amblyopia and an angle of squint less than 45 pdpt so that alignment of the eyes in only one operation could be expected. One hundred children received preoperatively a prismatic correction of the distance deviation for a period of 6-15 months; 78 cases were treated with glasses and occlusion. In the prism-treated group a significantly better alignment (p = 0.0001) with a motorial gain of 7-8 pdpt was observed 6 months after surgery; also better sensorial results with significantly (p = 0.0001) more cases of stable NRC or harmonious ARC and improved binocularity were achieved. Unlike the type of esotropia, the preexisting retinal correspondence significantly influenced the motorial outcome (p < 0.05). Fewer reoperations were necessary in the prism-treated group (p = 0.001). Our results indicate that a prolonged prismatic correction is an effective preoperative treatment in patients with alternating convergent squint.