Prevalence and associated factors of myopia in children and adolescents in Russia: the Ural Children Eye Study.

BACKGROUND: To assess the prevalence of myopia and the distribution of ocular axial length as surrogate for myopic refractive error in school children in a population in Russia. METHODS: The Ural Children Eye Study, a school-based case-control study, was conducted in Ufa/Bashkortostan/Russia from 2019 to 2022 and included 4933 children (age: 9.7±2.6 years; range: 6.2-18.8 years). The parents underwent a detailed interview and the children an ophthalmological and general examination. RESULTS: Prevalence of any myopia (≤-0.50 dioptres (D)), minor myopia (-0.50 D to -1.0 D), moderate myopia (-1.01 D to -5.99 D) and high myopia (≤-6.0D) was 2187/3737 (46.2%; 95% CI 44.8% to 48.6%), 693/4737 (14.6%; 95% CI 13.6% to 15.6%), 1430/4737 (30.2%; 95% CI 28.9% to 31.5%) and 64/4737 (1.4%; 95% CI 1.0% to 1.7%), respectively. In the children aged 17+ years, prevalence of any, minor, moderate and high myopia was 170/259 (65.6%; 95% CI 59.8% to 71.5%), 130/259 (50.2%; 95% CI 44.1% to 56.3%), 28/259 (10.8%; 95% CI 7.0% to 14.6%) and 12/259 (4.6%; 95% CI 2.1% to 7.2%), respectively. After adjusting for corneal refractive power (beta: 0.09) and lens thickness (beta: -0.08), larger myopic refractive error was associated (r2=0.19) with older age (beta: 0.33), female sex (beta: 0.04), higher prevalence of maternal (beta: 0.15) and paternal (beta: 0.12) myopia, more time spent in school, with reading books or playing with the cell phone (beta: 0.05) and less total time spent outdoors (beta: 0.05). Axial length and myopic refractive error increased by 0.12 mm (95% CI 0.11 to 0.13) and -0.18 D (95% CI 0.17 to 0.20), respectively, per year of age. CONCLUSIONS: In this ethnically mixed urban school children population from Russia, prevalence of any myopia (65.6%) and high myopia (4.6%) in children aged 17+ years was higher than in adult populations in the same region and it was lower than in East Asian school children, with similar associated factors.

Associations between axial length, corneal refractive power and lens thickness in children and adolescents: The Ural Children Eye Study.

PURPOSE: To assess relationships between ocular biometric parameters in dependence of age and sex in children and adolescents. METHODS: In the Ural Children Eye Study, a school-based cohort study, 4933 children underwent an ophthalmological and general examination. RESULTS: Complete biometric measurements were available for 4406 (89.3%) children. Cycloplegic refractive error (mean: -0.87 ± 1.73 diopters (D); median: -0.38 D; range: -19.75 D to +11.25 D) increased (multivariable analysis; r2 = 0.73) with shorter axial length (ß: -0.99; non-standardized regression coefficient B: -1.64; 95% CI: -1.68, -1.59) and lower corneal refractive power (ß: -0.55; B: -0.67; 95% CI: -0.70, -0.64), in addition to higher cylindrical refractive error (ß: 0.10; B: 0.34; 95% CI: 0.27, 0.41), thinner lens (ß: -0.11; -0.85; 95% CI: -1.02, -0.69) and male sex (ß: 0.15; B: 0.50; 95% CI: 0.42, 0.57). In univariate analysis, decrease in refractive error with older age was more significant (ß: -0.38 vs. ß: -0.25) and steeper (B: -0.22 (95% CI: -0.24, -0.20) vs. B: -0.13 (95% CI: -0.15, -0.11)) in girls than boys, particularly for an age of 11+ years. Axial length increased with older age (steeper for age <11 years) (B: 0.22 (95% CI: 0.18, 0.25) vs. 0.07 (95% CI: 0.05, 0.09)). In multivariable analysis, axial length increased with lower refractive error (ß: -0.77; B: -0.42; 95% CI: -0.43, -0.40) and lower corneal refractive power (ß: -0.54; B: -0.39; 95% CI: -0.41, -0.38), in addition to older age (ß: 0.04; B: 0.02; 95% CI: 0.01, 0.03), male sex (ß: 0.13; B: 0.23; 95% CI: 0.21, 0.32), higher cylindrical refractive error (ß: 0.05; B: 0.09; 95% CI: 0.05, 0.14) and thinner lens (ß: -0.14; B: -0.62; 95% CI: -0.72, -0.51). The axial length/corneal curvature (AL/CR) ratio increased until the age of 14 years (ß: 0.34; B: 0.017; 95% CI: 0.016, 0.019; p < 0001), and then became independent of age. The AL/CR ratio increased (r2 = 0.78) mostly with higher corneal refractive power (ß: 0.25; B: 0.02; 95% CI: 0.02, 0.02; p < 0.001), lower refractive error (ß: -0.75; B: -0.05; 95% CI: -0.05, -0.05; p < 0.001), thinner lens thickness (ß: -01.6; B: -0.09; 95% CI: -0.10, -0.08; p < 0.001) and older age (ß: 0.16; B: 0.006; 95% CI: 0.005, 0.007; p < 0.001). CONCLUSIONS: In this multiethnic group of school children in Russia, the age-related increase in myopic refractive error was more significant and steeper in girls, particularly for the age group of 11+ years. Determinants of higher myopic refractive error were longer axial length, higher corneal refractive power, lower cylindrical refractive error, thicker lens and female sex.

Anterior chamber depth and angle and associations in a pediatric and adult population in Russia.

Purpose: To investigate the normative data of anterior chamber depth (ACD) and angle (ACA) and their associations in multiethnic cohorts spanning three generations in Russia. Methods: The study cohort included the participants of three population-based studies performed in urban and rural Bashkortostan/Russia: The Ural Eye and Medical Study (UEMS; age:40+ years), Ural Children Eye Study (UCES; age:6-18 years), and Ural Very Old Study (UVOS; age:85+ years). Using Scheimflug camera-based anterior chamber imaging, we measured ACD and ACA as part of a comprehensive ophthalmological and systemic examination. Exclusion criterion was previous cataract surgery. Results: The study included 4869 (98.7 %) children out of 4933 children of the UCES, 5426 (92.0 %) out of 5899 UEMS participants, and 268 (16.3 %) out of 1526 UVOS participants. In the UEMS, shallower ACD (mean:3.14 ± 0.37 mm) correlated (multivariable analysis; r[2] = 0.57) with older age (beta: 0.08;P < 0.001), shorter body height (beta:0.03;P = 0.003), shorter axial length (beta:0.34;P < 0.001), lower corneal volume (beta:0.06;P < 0.001) and corneal refractive power (beta:0.12;P < 0.001), thicker lens (beta: 0.09;P < 0.001), higher IOP (beta: 0.03;P = 0.02), higher prevalence of angle-closure glaucoma (beta: 0.03;P = 0.003) and lower prevalence of open-angle glaucoma (beta:0.03;P = 0.007). Similar associations were found in the UCES (ACD mean:3.70 ± 0.27 mm) and UVOS (ACD mean:2.96 ± 0.56 mm). Conclusions: In this population-based cohort of three generations from rural and urban Bashkortostan, ACD decreased from the children cohort (mean:3.70 ± 0.27 mm) to the adult cohort (mean:3.14 ± 0.37 mm) and to the very old cohort (2.96 ± 0.56 mm). Determinants of shallow ACD were older age and lower body height, in addition to the ocular biometric parameters of shorter axial length, lower corneal volume, corneal refractive power, and thinner lens thickness.