conjugate prisms

Also known as yoked prisms, conjugate prismss are prisms with the bases oriented in the same direction before both eyes. They are sometimes used to treat A- or V-pattern deviations, where the angle of strabismus varies in upgaze and downgaze. For example, in V-pattern esotropia, where the eyes turn inward more in downgaze, base-down yoked prisms can be used to shift the eyes upward, away from the area of lost binocular vision.