Models of myopia: the effect of accommodation, lenses and atropine.

Abstract

Two quantitative models for myopia have been proposed and used for myopic intervention, one derived from feedback theory, and the other from physiological and mechanical considerations. This paper shows that they both predict the same results indicating that they are valid and reliable. These models are the only ones that can make predictions about the effect of atropine and lenses on myopia, explain multiple observations heretofore unexplained and offer possible interventions. Using their predictive power we test the models by calculating and comparing the effect of accommodation, lenses or atropine. The models offer a rationale that makes atropine equivalent to a positive lens for purposes of refractive development. This report includes thought experiments, actual experiments and trials, as well as an analysis of clinical data and integrates and tests results from all of them for far-reaching conclusions. Both models accurately predict the same myopia progression caused by near work. These models are simple but powerful enough to suggest what treatments are indicated. Interventions for prevention and control of myopia are evaluated analytically, in particular atropine and optical treatments, such as positive lenses and under correction. Optical treatments have enormous potential; atropine is of questionable value since there are ways to get the same or superior effect with lenses of power calculated as described here.