Document Type

Theses, Ph.D

Rights

Available under a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence

Disciplines

Optics

Publication Details

Successfully submitted for the award of PhD.

Abstract

Background: Uncorrected refractive error is an avoidable cause of visual impairment (Naidoo et al., 2016). Currently, there is a lack of adequate data on eye and vision disorders in schoolchildren in Ireland. Accurate prevalence estimates of refractive error and vision disorders are necessary to determine their impact on public health and to assess the need for interventions (McCarty and Taylor, 2000). Purpose: This study reports the prevalence of ametropia, presenting visual impairment, amblyopia and provides population norms for ocular biometric measures in schoolchildren in Ireland. Links between refractive error and demographic and lifestyle factors were investigated. The impact of poor presenting vision, on participants’ educational performance, was also examined. Methods: The Ireland Eye Study examined 1,626 children (881 boys, 745 girls) in two age groups, 6-7 years (728) and 12-13 years (898), in the Republic of Ireland (henceforth Ireland) between June 2016 and January 2018. Participating schools were selected by stratified random sampling, representing a mix of school type (primary/post-primary), location (urban/rural) and socioeconomic status (disadvantaged/advantaged). Parents completed a questionnaire which provided information on participants’ lifestyle and participants’ school performance. Examination included monocular logMAR visual acuity (both presenting with spectacles if worn and through a pinhole), cycloplegic auto-refraction (Cyclopentolate Hydrochloride 1%), non-contact ocular biometry (IOLMaster), and ocular alignment (cover test). Results: The prevalence of myopia (≤-0.50 D), hyperopia (≥+2.00 D), and astigmatism (≥1.00 DC) in 6-7-year-olds was 3.3%, 25.0%, 19.2%, respectively, and amongst 12-13-year-old children, 19.9%, 8.9% and 15.9%, respectively. Astigmatism axes were mostly with-the-rule (80.3%). The prevalence of presenting visual impairment in the “better ii eye” (≥0.3logMAR, with spectacles, if worn) was 3.7% amongst younger and 3.4% amongst older participants and associated with Traveller and non-White ethnicity. Amblyopia prevalence (pin-hole visual acuity ≥0.3logMAR plus an amblyogenic factor), was high (6-7 years 5.5%, 12-13 years 3.7%) compared to other studies. Amblyopia prevalence was primarily due to uncorrected refractive error. Compliance with spectacle wear, socioeconomic disadvantage and sedentary lifestyle were also contributing factors. Factors associated with myopia included age group, ethnicity, screen-time, time spent outdoors during daylight, obesity and sedentary lifestyle. Astigmatism was significantly associated with visual impairment and amblyopia. Time spent outdoors during daylight in summer was associated with a significantly less myopic SER and shorter axial length in White participants. Poor educational performance was associated with presenting visual impairment and amblyopia.

DOI

https://doi.org/10.21427/6ncn-6d73

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