Exploring the relationship between insulin and myopia
- Grant holder: Dr Denize Atan, Consultant Senior Lecturer and Honorary Consultant in Neuro-Ophthalmology
- Institution: University of Bristol, Bristol Eye Hospital
- Grant award: £69,039
- Start: November 2020
- End: October 2023
Why is this research needed?
Myopia, or short-sightedness, is estimated to become a leading cause of permanent blindness worldwide by 2050. For many people, myopia poses a much more serious problem than the inconvenience of having to wear glasses or contact lenses. People who are short-sighted, especially those who are severely so, are at significantly higher risk of developing sight-threatening conditions such as retinal detachment and macular degeneration. The prevalence of myopia is on the rise and it is estimated that by 2050, some 5 billion people – half the world’s population – will be short-sighted, compared to around 1.4 billion today.
Myopia occurs when the eyeball grows too long during childhood. The longer shape of the eyeball means that, as light enters the eye, instead of focusing on the retina at the back of the eye, it focuses in front of it, causing blurred vision. Studies have shown that many of the genes that increase the risk of myopia are also involved in insulin signalling: the process that regulates the body’s uptake and storage of blood sugar, and which also plays a part in growth during puberty.
Myopia is a hugely complex disorder. Its development has been linked to a range of environmental risk factors, and in addition, over 100 genetic variants have been identified that increase susceptibility to the condition.
What is the aim of the project?
Dr Atan’s theory is that myopia in children may be caused, in part, by changes in blood glucose and insulin levels, which in turn send cell growth signals to the eyes. The Western diet, characterised by high consumption of energy-dense foods that raise blood glucose levels, may play a part in this process.
The project’s overarching goal is to discover how both environmental and genetic factors interact with insulin signalling to cause myopia. In order to explore these questions, Professor Atan’s team will analyse data from two key resources: the Avon Longitudinal Study of Parents and Children (ALSPAC), and UK Biobank.
ALSPAC, also known as “Children of the 90s”, contains detailed health and environmental data gathered from over 14,500 participants born in the former county of Avon during 1991 and 1992.
Changes in insulin signalling happen naturally in children around puberty, and ALSPAC’s data set, which contains information on eye growth; glasses prescriptions; and blood levels of glucose and insulin before, during and after puberty; will help to reveal how these changes in insulin signalling affect eye growth. As the data set also includes information relating to residential, school, natural, and physical environments, it will also help to reveal how environmental factors interact with insulin signalling to affect myopia.
Additionally, the project will determine how normal variants in our genes that influence levels of insulin and blood sugar are linked to myopia. To address this question, Dr Atan’s team will analyse data from UK Biobank, a world-leading health research resource containing donated samples (e.g. blood, urine, saliva, DNA) and completed detailed health questionnaires from over 500,000 participants.
How will this research help to beat sight loss faster?
Myopia is becoming more prevalent across the globe. If current trends continue, over the half the world’s population will be myopic by 2050, and one tenth will have high myopia, which carries and increased risk of developing sight-threatening conditions, such as cataracts or myopic macular degeneration.
In the UK, the incidence of myopia in children has more than doubled over the last few decades, and now stands at 20%. A better understanding of the underlying biology of myopia, and how it is affected by genetic and environmental influences, will be key to the development of new treatments and prevention strategies (e.g. lifestyle changes) to help stop both the onset and development of the condition.
Professor Jeremy Guggenheim at the University of Cardiff led another research project, funded by Sight Research UK, that explored the interaction between genetic and environmental risk factors for myopia. You can read about what he discovered here.
We are also supporting Dr Veronique Vitart, at the University of Edinburgh, who is researching the genetic risk factors associated with retinal detachment arising from severe myopia.
You can find more about the causes and symptoms of myopia and pathological myopia here.