IMI - Defining and Classifying Myopia: A Proposed Set of Standards for Clinical and Epidemiologic Studies
Daniel Ian Flitcroft, Mingguang He, Jost B. Jonas, Monica Jong, Kovin Naidoo, Kyoko Ohno-Matsui, Jugnoo Rahi, Serge Resnikoff, Susan Vitale, and Lawrence Yannuzzi
International Myopia Institute, Brien Holden Vision Institute, Carl Zeiss Vision, Coopervision, Essilor, Alcon, and Vision Impact Institute
Investigative Ophthalmology & Visual Science, Arvo Journal
The purpose of this paper is to provide a standardized set of terminology, definitions, and thresholds of myopia and its main ocular complications.
Critical review of current terminology and choice of myopia thresholds was done to ensure that the proposed standards are appropriate for clinical research purposes, relevant to the underlying biology of myopia, acceptable to researchers in the field, and useful for developing health policy.
Several of the recommendations from this white paper are:The many descriptive terms of myopia be consolidated into the following descriptive categories: myopia, secondary myopia, axial myopia, and refractive myopia. To provide a framework for research into myopia prevention, the condition of ‘‘premyopia’’ is defined.
As a quantitative trait, we recommend that myopia be divided into myopia (i.e., all myopia), low myopia, and high myopia. The current consensus threshold value for myopia is a spherical equivalent refractive error 0.50 diopters (D), but this carries significant risks of classification bias.
The current consensus threshold value for high myopia is a spherical equivalent refractive error 6.00 D. ‘‘Pathologic myopia’’ is proposed as the categorical term for the adverse, structural complications of myopia.
A clinical classification is proposed to encompass the scope of such structural complications.
The paper concluded that standardized definitions and consistent choice of thresholds are essential elements of evidence-based medicine. It is hoped that these proposals, or derivations from them, will facilitate rigorous, evidence-based approaches to the study and management of myopia.
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