{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,8,15]],"date-time":"2025-08-15T00:03:40Z","timestamp":1755216220504,"version":"3.43.0"},"reference-count":7,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,8,4]],"date-time":"2025-08-04T00:00:00Z","timestamp":1754265600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Ophthalmol."],"abstract":"<jats:p>Axial myopia is characterized by excessive axial elongation, traditionally quantified by axial length (AL). However, AL conflates the eye\u2019s focal distance (adaptive to refractive power) with defocus distance (excessive axial elongation). In this study, we developed Myopic Strain, defined as the ratio of retinal defocus distance (\u0394AL) to the eye\u2019s focal length, yielding a normalized metric for assessing axial myopia. In an analysis of 242 eyes, \u0394AL and Myopic Strain were derived from Morgan\u2019s optometric model. Subsequently, the correlation between Myopic Strain and optical and biomechanical markers of myopia was analyzed. Finally, we analyzed the distinctive characteristics exhibited by Myopic Strain and the ratio of AL to corneal curvature radius (AL\/CR) as AL increased. Results demonstrated that Myopic Strain showed significant correlations with optical and biomechanical markers of myopia\u2014spherical equivalent refractive error (SER; <jats:italic>r<\/jats:italic> = \u20130.81) and stress-strain index (SSI; <jats:italic>r<\/jats:italic> = \u20130.30) (both <jats:italic>p<\/jats:italic> &amp;lt; 0.001). Correspondingly, Myopic Strain provided superior explanatory power for SER (<jats:italic>R\u00b2<\/jats:italic> = 0.65) and comparable power for SSI (<jats:italic>R\u00b2<\/jats:italic> = 0.09) (both <jats:italic>p<\/jats:italic> &amp;lt; 0.001). Furthermore, our analysis revealed a strong positive correlation between Myopic Strain and AL (<jats:italic>r<\/jats:italic> = 0.82, <jats:italic>p<\/jats:italic> &amp;lt; 0.001), concomitantly with a moderate positive correlation between AL\/CR and AL (<jats:italic>r<\/jats:italic> = 0.64, <jats:italic>p<\/jats:italic> &amp;lt; 0.001). Notably, the theoretical emmetropization baseline of AL\/CR exhibited an inverse relationship with AL. In conclusion, Myopic Strain emerges as a suitable normalized metric for assessing axial myopia severity.<\/jats:p>","DOI":"10.3389\/fopht.2025.1648686","type":"journal-article","created":{"date-parts":[[2025,8,4]],"date-time":"2025-08-04T04:10:20Z","timestamp":1754280620000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Myopic Strain: a normalized metric concept for assessing axial myopia"],"prefix":"10.3389","volume":"5","author":[{"given":"Qi","family":"Ren","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhe","family":"Chu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2025,8,4]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1167\/iovs.18-25957","article-title":"IMI - defining and classifying myopia: A proposed set of standards for clinical and epidemiologic studies","volume":"60","author":"Flitcroft","year":"2019","journal-title":"Invest Ophthalmol Vis Sci"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.3389\/fbioe.2022.939129","article-title":"The relationship between axial length\/corneal radius of curvature ratio and stress-strain index in myopic eyeballs: Using Corvis ST tonometry","volume":"10","author":"Chu","year":"2022","journal-title":"Front Bioeng Biotechnol"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1097\/OPX.0000000000001281","article-title":"The relationship between progression in axial length\/corneal radius of curvature ratio and spherical equivalent refractive error in myopia","volume":"95","author":"Jong","year":"2018","journal-title":"Optom Vis Sci"},{"key":"B4","doi-asserted-by":"publisher","first-page":"18","DOI":"10.1016\/j.clae.2019.11.005","article-title":"Estimation of ocular axial length from conventional optometric measures","volume":"43","author":"Morgan","year":"2020","journal-title":"Cont Lens Anterior Eye"},{"key":"B5","doi-asserted-by":"publisher","first-page":"413","DOI":"10.1016\/j.clae.2020.03.011","article-title":"Corrigendum to \u201cEstimation of ocular axial length from conventional optometric measures\u201d [Cont. Lens Anterior Eye 43 (1) (2020) 18-20","volume":"43","author":"Morgan","year":"2020","journal-title":"Cont Lens Anterior Eye"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.3389\/fbioe.2023.1145032","article-title":"Effect of corneal stiffness decrease on axial length elongation in myopia determined based on a mathematical estimation model","volume":"11","author":"Ren","year":"2023","journal-title":"Front Bioeng Biotechnol"},{"key":"B7","doi-asserted-by":"publisher","first-page":"133","DOI":"10.1038\/s42003-020-0802-y","article-title":"Genome-wide association meta-analysis of corneal curvature identifies novel loci and shared genetic influences across axial length and refractive error","volume":"3","author":"Fan","year":"2020","journal-title":"Commun Biol"}],"container-title":["Frontiers in Ophthalmology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fopht.2025.1648686\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,8,4]],"date-time":"2025-08-04T04:10:20Z","timestamp":1754280620000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fopht.2025.1648686\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,8,4]]},"references-count":7,"alternative-id":["10.3389\/fopht.2025.1648686"],"URL":"https:\/\/doi.org\/10.3389\/fopht.2025.1648686","relation":{},"ISSN":["2674-0826"],"issn-type":[{"type":"electronic","value":"2674-0826"}],"subject":[],"published":{"date-parts":[[2025,8,4]]},"article-number":"1648686"}}