Prevalence and associations of keratokonus among children, adults and elderly in the population‐based ural eye studies

Abstract

Aims/Purpose: To estimate prevalence and associations of keratoconus in populations in Russia with an age from childhood to seniority.Methods: The study population consisted of the cohorts of three population‐based studies performed in urban and rural areas within the same geographical region in Bashkortostan/Russia: The Ural Children Eye Study (UCES; age: 6–18 years; n = 4890), Ural Eye and Medical Study (UEMS; age: 40+ years; n = 5314) and Ural Very Old Study (UVOS; age: 85+ years; n = 651). Based upon Scheimflug imaging, keratoconus was defined by a keratometric reading of ≥48 D in any eye.Results: The mean maximal and minimal corneal refractive power increased from the UCES (43.58 ± 1.50 dioptres (D) and 42.70 ± 1.42D, respectively) to the UEMS (44.26 ± 1.70 D and 43.61 ± 1.76D, resp.) and to the UVOS (45.1 ± 1.72D and 43.98 ± 1.68D, resp.). Correspondingly, keratoconus prevalence increased from the UCES (42/4890; 0.086%; 95% CI: 0.060, 0.112) to the UEMS (112/5314; 2.11%; 95% CI: 1.72, 2.49) and to the UVOS (42/651; 6.45%; 95% CI: 4.56, 8.34). In the UCES, higher keratoconus prevalence was associated (multivariable analysis) with higher birth order (OR: 2.34; 95% CI: 1.32, 4.15; p = 0.004), lower birthweight (OR: 0.99; 95% CI: 0.99, 0.99; p < 0.001), and shorter axial length (OR: 0.15;9 5% CI: 0.08, 0.30; p < 0.001). In the UEMS, keratoconus prevalence correlated with shorter axial length (OR: 0.15; 95% CI: 0.10, 0.23; p < 0.001), larger corneal volume (OR: 1.17; 95% CI: 1.09, 1.25; p = 0.001), thicker lens (OR: 2.27; 95% CI:1.06, 5.28; p = 0.04), cortical cataract degree (OR: 1.02; 95% CI:1.01, 1.04; p = 0.01), and higher stage of age‐related macular degeneration (OR: 1.65; 95% CI: 1.09, 2.51; p = 0.02). In the UVOS, keratoconus prevalence correlated with lower educational level (OR: 0.84; 95% CI:0.71, 0.99; p = 0 0.04) and lower dynamometric hand grip force (OR: 0.92; 95% CI: 0.88, 0.97; p = 0.003).Conclusions: In this study on multiethnic groups from Russia, keratokonus prevalence increased from the paediatric group (0.09%) to the adult group (2.11%) and seniority group (6.45%), correlated mostly with biometric ocular parameters, and was in all age groups statistically independent of most systemic parameters.