Cardiff University researcher shares insight into myopia study

Researchers from the University of Bristol and Cardiff University have found that for every additional year spent in education, there is an increased risk of myopia progressing.

Co-leader of the study, Professor Jez Guggenheim, from Cardiff University’s school of optometry and vision sciences, explains to OT that the discovery of this link will hopefully allow more children to receive education without threatening their future eyesight.

How does this study help improve the understanding of the impact of education on myopia?

Numerous studies over several decades have reported an association between more years spent in education and a higher prevalence of myopia. However, interpreting these past studies was difficult because factors such as socioeconomic position are associated with both educational attainment and myopia. Hence, the causal relationships between education, socioeconomic position and myopia were unclear.

The gold-standard method of testing for a causal relationship is a randomised controlled trial (RCT). However, it would be unethical to randomly assign some children to spend more years in school than others. Instead, in the current research we used a method called Mendelian randomisation (MR) to gain insight into the question of whether education causes myopia, or vice versa.

The results strongly supported the hypothesis that education does cause myopia, with negligible evidence to suggest that children predisposed to myopia choose to stay in education for longer. Although the MR technique relies on more assumptions than an RCT, it does provide an independent line of research evidence that is largely resistant to bias from factors like socioeconomic position.

How can educational practices be improved to reduce the impact of myopia progression?

Unfortunately, the current study does not provide any insight into what aspect(s) of education act to increase myopia. Excessive near-work and insufficient time spent outdoors have both been implicated in the development of myopia in previous studies, therefore these factors could well be relevant.

In light of the glass classroom project, what changes should be made to educational environments to reduce myopia progression?

The glass classroom project is an exciting study. However, as the project is still underway we don’t yet know if it will succeed in slowing myopia onset and/or progression. A previous study from China reported that even modestly increasing the light intensity in schools slowed myopia progression in the following year. Indeed, exposure to high intensity lighting is a promising explanation for the beneficial effects of spending time outdoors.

What other areas of myopia must be further investigated?

Education has many health (and wealth) benefits. For example, more years in education is associated with longer life-expectancy. Therefore, discovering the mechanism underlying the link between education and myopia will hopefully allow children to receive a good education without threatening their future eyesight.

Also, despite the evidence that (insufficient) time outdoors and education are risk factors for myopia, refractive error is also highly heritable. Currently, it is not understood how genes and lifestyle factors combine to determine the risk of myopia.