The role of ocular torsion on the etiology of A and V patterns.

Theoretically, the torsion of the globe produced by primary oblique overaction results in a vertical displacement of the insertions of the horizontal recti and a horizontal displacement of the insertions of the vertical recti. This should alter the vectors of the forces exerted on the globe by the rectus muscles so that the horizontal recti become partial elevators or depressors and the vertical recti become increasing abductors or adductors. This change in force vectors tends to enhance the A or V pattern that results from oblique dysfunction. I propose that the etiology of A and V patterns is the result of a complex interplay between all of the extraocular muscles and present a clinical series to suggest the validity of that theory.