A controlled outcome study on the effects of behavioral training on several measures of visual performance was conducted. Twenty-nine myopic subjects received complete optometric evaluations before being randomly assigned to one of three experimental groups. One treatment group received a behavioral training program with a feedback and reward component, another group received behavioral training without feedback and reward, and the third group was the no-treatment control group. In addition to measuring the effects of training on visual acuity and refraction, independent measures of axial length and intraocular pressure (IOP) were obtained for all subjects before and after treatment. An analysis of covariance indicated that axial length plays a significant role in mediating the effects of training.