Global myopia epidemic linked to indoor life

"It has happened within one generation, so it is not genetic," University of Newcastle Associate Professor Sally McFadden said.

"It is something to do with visual exposure in our modern world," she said.

"We do spend more time looking at screens that emit light rather than books that reflect light."

Dr McFadden said the condition was "certainly associated with time studying indoors".

"People who live in small houses are more likely to be myopic."

About half the world's population is expected to suffer from myopia [short sightedness] by the year 2050. And about 10 per cent of people are predicted to have high myopia by then.

"About one fifth of myopes go on to develop high myopia," she said.

High myopia - which is defined as a refractive measurement of -6.00 diopters or higher - has reached epidemic levels in many Asian countries and is rising steeply elsewhere. Myopia - also known as being short-sighted - occurs because the eye is too big and grows too rapidly during development.

"The problem is myopia progresses to high myopia and blindness," she said.

"So, to fix myopia, we have to slow down this excessive growth."

This excessive eyeball growth means images "focus in front of the visual photoreceptors [cells in the retina that respond to light] instead of precisely on them".

Traditional glasses, contact lenses and laser treatment of the cornea correct the optics of the eye, but they do nothing to change the length of the eyeball when it has grown too long.

"It is this excessively big eye that causes all the pathological problems," she said.

Dr McFadden is driven to help people who are going blind.

As part of this mission, she aims to stop them from progressing to blindness, "as vision is probably the most important sense for humans".

She has developed a unique animal model of high myopia, drawing the attention of the Dutch Research Council and Netherlands Organisation for Scientific Research.

The Dutch will fund her $388,000 research project, called "Light for Sight: Towards a Novel Therapy for Myopia".

The research will go for three years, but a potential commercial partner has shown interest in progressing the project to clinical trials.

It involves correcting changes in the skin of the eyeball [the sclera], which becomes "very thin and weak in high myopia".

"This weakness causes a bubble-like outpouching [staphyloma] to occur in the back of the eye and leads to blindness," she said.

"There is no treatment except for a few game surgeons who try to sew up the eyeball to keep it from 'exploding'."

The research aims to develop a new treatment that fixes these problems in the damaged skin of the eye through a simple injection and light.

Dr McFadden uses techniques that span molecular biology, genetics, physiology and optical modelling.

She builds novel instruments, using engineering and bioengineering. She was originally drawn to research the eye because she was interested in how humans and animals perceive the world.

She wanted to know more about how humans differ from other creatures.

"For example, birds can see in two places at once. Just like we can see and hear simultaneously - and take this for granted - they see in two different ways simultaneously and with many more colours than us."

She's also working on a $1.8 million myopia study funded by the National Medical Research Council of Singapore.

It aims to understand the "detailed molecular changes in the sclera that drive the changes in high myopia".

The region of the eye where most of these changes occur contains the optic disk, where the optic nerve exits the eyeball.

"The optic disk is strongly affected by glaucoma and these changes are followed by the associated blindness."

Glaucoma patients often have high myopia and vice versa.

"We are interested in finding the common molecular changes in these two diseases. We aim to understand the mechanistic links between glaucoma and high myopia to better understand why one leads to the other."

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