From a summer birth to high intelligence: unravelling myopia risk

In 2017, she was awarded a doctorate for her thesis titled Cognitive, behavioural, environmental and genetic associations of myopia. 

Below, Williams speaks with OT about her research and motivation for focusing on the topic of myopia.

Why did you choose to focus on myopia for your research?

Clinically, as an ophthalmologist, my focus has been on paediatric ophthalmology. I chose to focus on myopia for my PhD because it is becoming dramatically more common in some populations. It is related, in part, to changes in lifestyle during modern day childhood. Myopia is associated with many other conditions. There is this notion that you wear a pair of glasses and it is completely fixed, but myopia can lead to a whole host of complications that may bring you along to the eye clinic.

What questions did you explore through your PhD?

I started with the epidemiology of myopia. We know that myopia is becoming substantially more common in urban areas of some Asian countries, but we were keen to look at what was happening in European countries and the UK. I completed a meta-analysis of data on prevalence in European countries and found that prevalence is increasing here too. The second arm of my PhD research was analysing an adolescent twin cohort to disentangle the relative effect of nature and nurture in myopia.

I also worked with consortiums to pool genetic data in an attempt to explore which genes are linked to myopia. Trying to find the genes for myopia is a huge task ­– because it is not just one gene. The genes that contribute to your risk are variable and immense. We still don’t know them all.

I examined the relative effect of environment on the risk of increasing myopia by exploring some of the early life factors among the twin cohort – things that might have set their trajectory in the pre-school years.

Through your research looking at twins, were there any other lifestyle factors that were associated with myopia?

When I looked at the older twins, there were some associations between myopia and education, screen time and other known risk factors. There was a strong association between maternal education and myopia. The other thing that we found is that a summer birth is associated with myopia, which was an intriguing one. Initially, we wondered whether it would have to do with summer babies being taken outside in the pram – but that didn’t quite fit because you would think that the light would have a protective effect. Then what we found is that babies born in summer went into education earlier – they enter that educational environment when they are younger.

Can you tell OT about the association between intelligence and myopia?

If you’re highly intelligent, you’re more likely to be myopic. As part of my research, I looked at whether there is a shared genetic basis for these two things – are the genes for myopia the same as the genes for intelligence? Or is it that one leads to the other? So, for example, if you’re more intelligent, maybe you spend more time reading and become more myopic. Or perhaps it could be the other way around, that because you are myopic, you don’t want to go outside and play sport with glasses on, so you spend more time indoors reading. What I did find is that there does appear to be an element of shared genetic risk for both being myopic and being intelligent. There are genes that can make you both intelligent and myopic.

What are your predictions about how myopia management may evolve in the future?

I think both the optical and pharmaceutical options are going to become more widespread. It's complicated working as I do in the NHS, because neither of these options are funded by the NHS. Atropine eye drops are not licensed for treating myopia progression in the UK.

As an NHS ophthalmologist, I can discuss these ways of managing myopia, but I can't offer or prescribe them. Some families cannot afford these interventions. That’s a very odd position to be in as an NHS clinician, because we like to offer free healthcare at the point of access. It’s tricky, but I think this is a fast-evolving field. In the future, things may change.

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