Often descriptions of vision therapy include the phrase “vision exercises” or “physical therapy for your eyes”, this phrasing, however, is misleading and here is why.
Optometric vision therapy has nothing to do with exercising eye muscles to improve strength. Eye muscles are inherently much stronger than needed to perform their assigned duties, i.e. moving the eye ball left, right, up and down. Each eye weighs only 0.25oz and has six specific eye muscles that point the eyes in different directions of gaze.
The brain sends a signal to the eye muscles in order to move the eyes together in a coordinated manner. If the development of coordination is interfered with, one of the eyes may not efficiently receive the proper signal; resulting in visual complications such as an eye turn, decreased convergence ability or decreased divergence ability.
For example, an individual with an eye that is turned “out”, away from the nose, also called strabismus, can simply cover their opposite eye, straight eye, and immediately notice the eye that was turned “out” previously, will point straight.
Furthermore, with the previously “out” turned eye now pointing straight, that eye will move in all directions without difficulty. If the eye muscle was actually weak, and needed to be strengthened, it would be unable to move the eyeball in the various directions.
When the straight eye is uncovered, the turned “out” eye will resume it’s adapted direction of “out”.
The purpose of this illustration is to demonstrate how optometric vision therapy is utilized to develop coordination between the two eyes. This development promotes an efficient neural signal from brain to eyes. Without adequate coordination, the eyes cannot work together efficiently and the brain will find a way to compensate for the lack of coordination. This compensation can manifest as obvious as an eye turn or as not-so-obvious convergence insufficiency.
Optometric vision therapy develops coordination and does not develop strength of eye muscles. This is also why vision therapy is a long-term solution as apposed to repeated surgery over the course of time.