Myopia and defocus: the current understanding

Authors

  • Mhairi Day Glasgow Caledonian University
  • Lorraine A Duffy Glasgow Caledonian University

DOI:

https://doi.org/10.5384/sjovs.vol1i4p1-14

Keywords:

Myopia, defocus, near work, accommodation

Abstract

The current theories relating to the development and progression of myopia are related to exposure of the eye to hyperopic defocus. This paper discusses these theories and the large body of recent research investigating the evidence behind them. As both human and animal studies demonstrate, when considering the potential influence of defocus on eye growth, the duration of exposure as well as the type and magnitude of the blur are important. In addition, we must understand the defocus threshold over which an eye growth signal can be made. Investigations with respect to central defocus alone have been unable to find a unified theory due to (1) insufficient evidence showing refractive group differences in the amount of central defocus actually present and (2) unsuccessful attempts to wholely reduce myopia progression using corrective lenses. Recent research measuring peripheral blur is summarised in this paper and modelled together with previous measurements of peripheral defocus thresholds, providing an up-to-date perspective on myopia.

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Author Biographies

Mhairi Day, Glasgow Caledonian University

Lecturer

Department of Vision Sciences

Lorraine A Duffy, Glasgow Caledonian University

PhD student

Department of Vision Sciences

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Published

2011-06-29

How to Cite

Day, M., & Duffy, L. A. (2011). Myopia and defocus: the current understanding. Scandinavian Journal of Optometry and Visual Science, 4(1), 1–14. https://doi.org/10.5384/sjovs.vol1i4p1-14

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Review Article