Emmetropization as a first-order feedback system
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Updated: Nov 7, 2026

An Experimental Platform to Study the Closed-loop Performance of Brain-machine Interfaces
Published on: March 10, 2011
Abstract:
The existence of a regulatory mechanism that controls the growth of the eye toward emmetropia is generally agreed upon, but such an emmetropization mechanism has never been verified experimentally. This report supports the hypothesis that emmetropization can be described as a feedback process with a first-order equation and establishes a theoretical framework for future study, experimentation, and manipulation of this elusive mechanism. The feedback hypothesis has been tested by comparing two models. The first is a first-order feedback system, the second a non-feedback model with an almost identical equation. The feedback model fits data from human subjects significantly better.
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