Understanding the chemical messages between sclera and choroid linked to myopia progression

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 in later life and could lead to permanent sight loss. 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. One of the reasons why this usually only happens in children is that the tough white coat of the eye (the sclera) is softer in children than in adults. In people in whom myopia gets worse even in adulthood, the sclera may be softer and more stretchable than usual.

We do not know how this happens, but we know that spending more time outdoors and getting plenty of natural light can slow down the worsening of myopia. Sunlight releases chemical messengers in the eye. These messengers are thought to send signals to the soft, spongy layer in front of the sclera (the choroid), which, in turn sends messenger chemicals to the cells in the sclera. Understanding this biological process could pave the way to new therapies to stop the progression of myopia. 

What is the aim of the project?

This project proposes to test the hypothesis that signals from the choroid are crucial to the regulation of scleral biomechanics and, as a result, may contribute to the development and progression of myopia. The main focus of the research is to better understand the interaction between the cells in the choroid and the sclera by assessing samples from children, teenagers, and adults. 

How will this research help to beat sight loss faster? 

In the UK alone, today, over a quarter of all teenagers have myopia. Once the eyeball has become too long, it is impossible to shrink it. We therefore need to find ways to slow down the lengthening of the eyeball to prevent myopia from happening in the first place. We hope that this research will help to lead to new treatments, which could slow down myopia progression and avoid sight loss in later life.

Further information

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 other research in myopia and high myopia and you can read more here.

Not everyone who is severely short-sighted will develop other eye conditions, and for most people, their eyes will be healthy. The best way for everyone to look after their eyes is to have regular eye tests. An optician can spot early signs of eye conditions before you experience any symptoms, many of which can be treated if detected early enough. You can read about what’s involved in having an eye test here.

You can find more about the causes and symptoms of myopia and pathological myopia here.