A method for estimating and tracking refractive error progression of an individual includes estimating a percentile of Spherical Equivalent Refraction (SPHEQ) as a function of at least the individual's age by comparison to a reference population； estimating an expected SPHEQ trajectory over a future predetermined period of time； comparing the expected SPHEQ trajectory with the reference population； and comparing the expected SPHEQ trajectory with an expected SPHEQ trajectory using an ametropia control treatment, thereby showing a possible treatment benefit over the predetermined period of time.
