[Insertion anomalies of the horizontal muscles and dysfunctions of the oblique muscles in the A-V patterns].

Insertion anomalies of the horizontal rectus muscles and dysfunctions of the oblique muscles were studied in 141 cases with A-V patterns of 824 patients with horizontal strabisums. The frequency of insertion anomaly among all cases of A-V pattern studied was 49.6%, there were more V pattern insertion anomalies than in those of A pattern, but the ratio of insertion anomalies in each type of A-V pattern was more in the A pattern than in the V pattern. In the oblique muscles, overaction of the inferior oblique muscle in the V pattern and of the superior oblique muscle in the A pattern were frequently encountered and insufficient action of the oblique muscles occurred more frequently in cases A-V esotropia than in cases of exotropia. In cases of combination of insertion anomaly of the horizontal rectus muscles with dysfunction of the oblique muscles, insertion anomaly was involved in 91.3% of cases of overaction of the superior oblique muscles, but only in 37.4% of cases of overaction of the inferior oblique muscles. The combination of insertion anomalies with dysfunction of the oblique muscles suggests a possible existence of simulated dysfunction of the oblique muscles in some cases of dysfunction of the oblique muscles diagnosed preoperatively. At the choice of a procedure in surgical correction, a confirmation of insertions of the horizontal muscles during operations is needed, and for this purpose the perilimbal incision is more appropriate than the fornix incision.