Ortho C is most effective when the patient’s myopia is within the myopic model. An important characteristic that differentiates myopia within the myopic model from myopia outside the model is that the crystalline lens can still change its curvature (within the limits imposed by the tension of the oblique muscles). The tension induced by the oblique muscles places a limitation on how much the ciliary muscle can relax, but it does not compromise the muscle’s flexibility. It is an indication that spastic tension was not induced. It allows a “focal point draw” to flatten the myopic crystalline lens before the elongated eyeball can retract—according to the theory behind the treatment for myopia.