The progression of corrected myopia
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This study seeks to demonstrate the existence of a feedback loop controlling myopia by comparing the prediction of a feedback model to the actual progression of corrected myopia. In addition to theoretical results, confirming clinical data are presented.
The refraction of 13 continuously corrected myopic eyes was collected over a period of time ranging from 4 to 9 years from the time of their first correction. Refractive data was collected in an optometry office from myopic young subjects from the general population in Boston. Subjects were myopes, ages 2 to 22 at the time of first correction selected randomly from a larger population. All individuals were fully corrected with lenses; new lenses were prescribed every time that their myopia increased by 0.25 diopters or more. Subjects wore their spectacle lenses during the followed period.
Subjects exhibit a linear time course of myopia progression when corrected with lenses. The observed rate of myopia increase is 0.2 to 1.0 diopters/year, with a mean correlation coefficient r = −0.971, p < 0.005.
This report establishes that feedback control theory applies to the clinical phenomenon of progressive myopia. Continuous correction of myopia results in a linear progression that increases myopia. The Laplace transformation of temporal refractive data to the s-domain simplifies the study of myopia and emmetropia. The feedback transfer function predicts that continuous correction of myopia results in a linear progression because continuous correction opens the feedback loop. This prediction is confirmed with all subjects.
KeywordsEmmetropia Emmetropization Refraction Laplace transform Feedback Myopia
Conflict of interest statement
The author certifies that he has NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.
- 5.Medina A, Fariza E (1993) Emmetropization as a first-order feedback system. Vis Res 33(1):21–26Google Scholar
- 10.Ray WA, O'Day DM (1985) Statistical analysis of multi-eye data in ophthalmic research. Inv Ophthalmol Vis Sci 26:1186–1188Google Scholar
- 17.Vasudevana B, Esposito C, Petersona C, Coronado C, Ciuffreda K (2014) Under-correction of human myopia – is it myopigenic?: a retrospective analysis of clinical refraction data. J Optom 07:147–152Google Scholar