Retinal Nerve Fiber Layer Thickness and Associated Factors in a Russian Population. The Ural Eye and Medical Study

Abstract

Purpose : To assess the peripapillary retinal nerve fiber (RNFL) thickness and its associated factors in a Russian population.

Methods : The population-based Ural Eye and Medical Study (UEMS) was performed in the city of Ufa/Russia and in villages in a distance of 65 km from Ufa and had an inclusion criterion an age of 40+ years. We measured peripapillary RNFL thickness by spectral-domain optical coherence tomography (OCT).

Results : Out of a population of 7328 eligible individuals, 5899 individuals (participation rate:80.5%) participated (mean age:59.0±10.7 years (range:40-94 years)). RNFL measurements were obtained for 5223 (88.6%) individuals with a mean age of 58.3±10.4 years (range:40-94 years) and mean axial length of 23.3±1.1mm (range:19.78-32.87mm). Mean RNFL thickness was 115.0±18 .8µm (OD) and 113.2±18.4µm (OS). In multivariable linear analysis, RNFL thickness increased with younger age (standardized regression coefficient beta:-0.26; non-standardized regression coefficient B:-0.47;95% confidence interval (CI):-0.51,-0.42;P<0.001), shorter axial length (beta:-0.24;B:-4.11;95%CI:-4.55,-3.68;P<0.001), lower prevalence of glaucoma (beta:-0.19;B:-19.2;95%CI:-21.8,-16.6;P<0.001) and higher serum concentration of hemoglobin (beta:0.04;B:0.04;95%CI:0.01,0.08;P<0.001). For each year of ageing, the RNFL thickness decreased by about 0.5 µm or 0.4% out of an original RNFL thickness of 120 µm at the age of 40 years. In that model, RNFL thickness was not significantly related with gender (P=0.34), rural versus urban region of location (P=0.15), arterial blood pressure (P=0.87) and prevalence of diabetes mellitus (P=0.54).

Conclusions : In this typically ethnically mixed population from Russia, RNFL thickness decreased with older age, longer axial length, higher glaucoma prevalence and lower serum hemoglobin concentration. The annual decline in RNFL thickness of 0.4%/year corresponds to an histomorphometrically measured annual loss of optic nerve fibers of 0.3%/year of age. The decrease in RNFL thickness with longer axial length and older age may clinically be taken into account if the RNFL thickness is used as biomarker for optic nerve damage.

This is a 2020 ARVO Annual Meeting abstract.