The relationship between fetal growth and retinal nerve fibre layer thickness measured in a cohort of young adults

Abstract

Purpose : Retinal nerve fibre layer (RNFL) thinning is an important early marker of glaucoma. It is known that RNFL thickness is associated with birth weight and head circumference at birth, both markers of intrauterine growth. We explored relationships between patterns of fetal anthropometric growth, as reflective of early life influences on fetal wellbeing, and global RNFL thickness measured in young adulthood.

Methods : A subset of Caucasian participants (n = 485) from the Raine Study, a pregnancy cohort study based in Western Australia, were included in the analysis. Participants underwent serial ultrasound scans at 18, 24, 28, 34 and 38 weeks’ gestation, with fetal biometry measured at each scan. An eye examination including measurement of optic disc parameters via spectral-domain optical coherence tomography imaging was undertaken at a 20-year follow-up. Growth trajectories based on measurements of fetal head circumference (FHC), abdominal circumference (FAC), femur length (FFL) and estimated fetal weight (EFW) were explored via group-based trajectory modelling. Generalised estimating equations (GEEs) were used to evaluate differences between groups of participants with similar growth trajectories with respect to global RNFL thickness.

Results : Participants with consistently large FHCs throughout gestation had thicker RNFLs than those with small, moderately small or moderately large FHCs, after adjusting for fetal sex, maternal smoking during pregnancy, gestational age at birth, and intraocular pressure and axial length at the 20-year follow-up (p = 0.005, 0.005 and 0.003, respectively). This model showed better fit according to the quasi-information criterion when compared to similarly adjusted GEE models analysing associations between RNFL thickness and either birth weight or head circumference at birth. There were no significant differences in RNFL thickness between trajectory groups in the FAC, FFL or EFW models, although similar trends to those in the FHC model were demonstrated.

Conclusions : FHC growth is strongly correlated with RNFL thickness in young adulthood and is moreover a better predictor than birth weight or head circumference at birth. This indicates that adverse early life conditions may predispose towards thinning of the RNFL in child and adult life. There may therefore be implications for the long-term risk of glaucoma in individuals with restricted FHC growth.

This is a 2021 ARVO Annual Meeting abstract.