An evaluation of the prevalence of refractive error and the relationship between relative peripheral refraction and eye growth in children

Abstract

Introduction: Myopia is a refractive error associated with an increased risk of sight threatening ocular pathology. Its aetiology is heterogenous in nature, with a combination of genetic and environmental factors, such as less time spent outdoors, intensive education and increased near work (Rudnicka et al., 2016; Xiong, Sankaridurg, et al., 2017), shown to play a role in its development and progression (Morgan and Rose, 2019). Animal studies and some clinical observations suggest that relative peripheral hyperopia also promotes the development and progression of myopia (Nathan, 1985; Smith and Hung, 1998; Mutti et al., 2007; Sankaridurg et al., 2011; Santodomingo-Rubido et al., 2016; Chamberlain et al., 2019; Lam et al., 2019). The Northern Ireland Childhood Errors of Refraction 1.0 (NICER 1.0) Study, an epidemiological study of the prevalence of refractive error in white UK school children (Lisa O’Donoghue et al., 2010), commenced in 2006/2008. Since 2008 electronic devices have dramatically risen in popularity among UK children (Ofcom, 2011, 2020), which some researchers have implicated in the global surge in childhood myopia prevalence (Holden et al., 2016; Lanca
and Saw, 2020).

Aims: The overall aim of this thesis was to re-evaluate the prevalence of refractive error among white UK school children to determine trends in the prevalence and age of onset of myopia over the last decade. The present work also evaluated the relationship between relative peripheral refraction and changes in central refraction and axial length over one year in children.

Methods: The present study employed identical sampling methodology and cycloplegic examination procedures to The NICER 1.0 Study (Lisa O’Donoghue et al., 2010). Comparisons were drawn between contemporary refractive data and data from age- and ethnicity-matched children in 2006/2008. Baseline measures of spherical equivalent refraction (SER) in the central and peripheral horizontal retina and axial length were recorded, and measurements were repeated after 12-months on a sub-group of children.

Results and conclusions: This thesis established that the prevalence of childhood myopia has remained relatively unchanged in the UK over the last 12 years. There is no evidence that the age of onset of myopia has decreased in this time. The present work found that a hyperopic relative peripheral refraction in the nasal retina is a statistically significant predictor for accelerated eye growth in teenage myopes. Eye care clinicians should consider myopia control options that reduce relative peripheral hyperopia in cases of established myopes to slow further axial elongation.

Date of Award	Jun 2022
Original language	English
Sponsors	Department for the Economy
Supervisor	Kathryn Saunders (Supervisor), Sara Mc Cullough (Supervisor) & Karen Breslin (Supervisor)