Terminology in orthokeratology: conceptual systematization, semantics, and practical application

Background. Orthokeratology is one of the most rapidly developing approaches to refractive error correction and myopia control worldwide. Different terminological traditions have emerged, often varying considerably between national ophthalmological schools. As orthokeratology continues to develop, this terminological heterogeneity has become a significant issue. It complicates the comparison of research findings, the conduct of meta-analyses, and the translation of evidence into routine clinical practice. Purpose: To systematize the terminology used in orthokeratology, clarify semantic differences between Russian-language and international concepts, identify controversial definitions, and propose recommendations for the appropriate use of terms in clinical practice and scientific communication. Materials and methods. A targeted search of PubMed/MEDLINE and eLIBRARY.RU was conducted for publications from 1962 to 2025 using the following search terms: orthokeratology, ortho-k, corneal reshaping, reverse geometry, myopia control, ортокератология, and ОК-терапия. The analysis included consensus documents, including BCLA CLEAR Orthokeratology 2021 and the IMI Clinical Management Guidelines 2019, randomized clinical trials, systematic reviews, Russian clinical guidelines, and regulatory documents. Thirty-four peer-reviewed sources that met the inclusion criteria were selected. Results. At least six English-language terms or near-synonyms for the core concept were identified: orthokeratology, ortho-k, corneal refractive therapy, vision shaping treatment, accelerated orthokeratology, and overnight vision correction. Four Russian-language equivalents were also identified: ортокератология, ОК-терапия, ночные линзы and корнеорефракционная терапия. The term orthokeratologist was found to be absent from professional standards in the United States, the European Union, and the Russian Federation and should therefore be regarded as professional jargon used to refer to ophthalmologists and optometrists who practice orthokeratology. The terms open design and closed design were not found in English-language consensus sources. Instead, lens designs are classified by geometric configuration, such as toric or spherical design, and by manufacturing approach, such as stock or custom-designed lenses. Several concepts were found to be insufficiently structured from a semantic standpoint, including the Jessen factor, compression factor, and myopia control efficacy. Conclusion. Standardization of orthokeratology terminology is necessary for the accurate interpretation of clinical studies, transparent communication with patients, and appropriate delineation of professional competencies. In the Russian Federation, the term ophthalmologist specializing in orthokeratology is recommended for use in official documents instead of orthokeratologist. The terms open design and closed design should be replaced with descriptive characteristics of lens design.

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