Scientific Reports (Sep 2021)

Axial length and its associations in the Ural Very Old Study

  • Mukharram M. Bikbov,
  • Gyulli M. Kazakbaeva,
  • Ellina M. Rakhimova,
  • Iuliia A. Rusakova,
  • Albina A. Fakhretdinova,
  • Azaliia M. Tuliakova,
  • Songhomitra Panda-Jonas,
  • Timur R. Gilmanshin,
  • Rinat M. Zainullin,
  • Natalia I. Bolshakova,
  • Kamilia R. Safiullina,
  • Ainur V. Gizzatov,
  • Ildar P. Ponomarev,
  • Dilya F. Yakupova,
  • Nail E. Baymukhametov,
  • Nikolay A. Nikitin,
  • Jost B. Jonas

DOI
https://doi.org/10.1038/s41598-021-98039-z
Journal volume & issue
Vol. 11, no. 1
pp. 1 – 8

Abstract

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Abstract To assess the distribution of axial length as surrogate for myopia and its determinants in an old population, we performed the Ural Very Old Study as a population-based cohort study. Out of 1882 eligible individuals aged 85 + years, the Ural Very Old Study performed in an urban and rural region in Bashkortostan/Russia included 1526 (81.1%) individuals undergoing ophthalmological and medical examinations with sonographic axial length measurement. Biometric data were available for 717 (47.0%) individuals with a mean age of 88.0 ± 2.6 years (range 85–98 years; 25%). Mean axial length was 23.1 ± 1.1 mm (range 19.37–28.89 mm). Prevalences of moderate myopia (axial length 24.5–< 26.5 mm) and high myopia (axial length ≥ 26.5 mm) were 47/717 (6.6%; 95% CI 4.7, 8.4) and 10/717 (1.4%; 95% CI 0.5, 2.3), respectively. In multivariable analysis, longer axial length was associated (coefficient of determination r2 0.25) with taller body height (standardized regression coefficient beta:0.16;non-standardized regression coefficient B: 0.02; 95% confidence interval (CI) 0.01, 0.03; P < 0.001), higher level of education (beta: 0.12; B: 0.07; 95% CI 0.02, 0.11; P = 0.002), and lower corneal refractive power (beta: − 0.35; B: − 0.23; 95% CI − 0.28, − 0.18; P < 0.001). Higher prevalence of moderate myopia, however not of high myopia, was associated with higher educational level (OR 1.39; 95% CI 1.09, 1.68; P = 0.007) and lower corneal refractive power (OR 0.77; 95% CI 0.63, 0.94; P = 0.01). In this old study population, prevalence of moderate axial myopia (6.6% versus 9.7%) was lower than, and prevalence of high axial myopia (1.4% versus 1.4%) was similar as, in a corresponding study on a younger population from the same Russian region. Both myopia prevalence rates were higher than in rural Central India (1.5% and 0.4%, respectively). As in other, younger, populations, axial length and moderate myopia prevalence increased with higher educational level, while high myopia prevalence was independent of the educational level.