The prevalence of myopia (shortsightedness) in children is increasing globally with some countries in East Asia reporting 'epidemic' rates of 80-90%*. The last major study in the UK to report on the prevalence of refractive error and associated ocular biometry was conducted over 40 years ago**. Since that time, the demographics of the UK population have changed significantly, so an updated study is required.
Launched in October 2005, the Aston Eye Study is a cross-sectional study to determine the prevalence of refractive error and its associated ocular biometry (measurement of eye dimensions). The study uses a large, multi-racial sample of school children from the metropolitan area of Birmingham (UK).
A target sample of 1700 Year 2 (6-7 years) and 1200 Year 8 (12-13 years) children is being selected, at random, from Birmingham schools based on an area deprivation index (measures of socio-economic status). Sample size calculations account for the likely participation rate and the clustering of individuals within schools. Procedures follow standardised protocols to allow for comparison with international population-based data***/****.
Examination procedures will include:
- Visual acuity assessment (logMAR)
- Oculomotor status
- Cyclocoplegic (0.5% proxymetacaine and 1% cyclopentolate, 1 drop each in both eyes) autorefraction using open-field Shin-Nippon SRW5000 autorefractor, Japan
- Non-contact ocular biometry (i.e. axial length, corneal radius of curvature and anterior chamber depth) using Zeiss IOLMaster, Jena, Germany
- Height and weight measurements
- A 75 item parental questionnaire and 57 item child questionnaire, including sections that address potential risk factors and gene-environment interactions related to myopia, e.g. family history of spectacle wear, education, nutrition, ethnicity and lifestyle.
Data collection is ongoing with protocols being well received by both parents and children. No adverse incidents or effects have been reported to date. Current data indicate that almost 1 in 10 Year 8 children (N=283) and 1 in 17 Year 2 children (N=229) require refractive correction but do not have provision of spectacles.
The design and methodology of this study will allow for the development of a valuable database of the target population, describing the ocular characteristics of approximately 3000 school children from a large metropolitan area of the UK. The association between educational status, ethnic background and other environmental influences on refractive outcome will be determined. The standardised protocols will facilitate the comparison of UK data with other international population-based data.
The Aston Eye Study is supported by a research donation from Johnson & Johnson.
*B.Gilmartin (2004). Clin Experiment Ophthalmol. 32: 305-24
**A.Sorsby et al (1961). Med Res Council Annual Report. London 301 (special): 1-67
***E.Ojalmi et al (2005). Ophthalmic Epidemol. 12: 59-69
**** Negrel et al (2000). Am J Ophthalmol. 129: 421-6.