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Bat-like ‘vision’ helping blind people see through sound

Daniel Earle
Daniel Earle uses castanets to make noises that allow him navigate in a manner similar to bats. Photo: ABC
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Seventeen years ago, Daniel Earle’s world turned to black.

“I have difficulty still explaining to people what it was like but it was terrifying,” he said.

“When you wake up in the dark and you know that it’s not going to get any better, it’s frightening.

“It’s emotionally destructive, it presents challenges that you just don’t know where you’re going to get the energy from to deal with them.”

Mr Earle’s life forever changed in 2000 when he went blind after developing diabetic retinopathy, which meant he had to change every part of his lifestyle to move around in the world.

“At the start I had no desire to venture outside my front door,” he said.

“Now I travel on buses, trams, trains if I have to, I walk independently around my environment.”

Like most people who are blind or vision impaired, he learnt how to use a cane and guide dog.

But in recent weeks Mr Earle has been using a new skill known as echolocation, despite at first being sceptical of the technique.

“Everyone that I’d spoken to, except American [trainers], didn’t believe in it, it wasn’t something that people were passionate about,” he said.

“But now that I’m back out in the community I won’t go anywhere without castanets in my pocket.”

Daniel Earle learns echolocation
Echolocation allows users to make judgements about what’s in front of them based on the way sound bounces off surfaces. Photo: ABC

What is echolocation?

It’s also known as ‘flash sonar’ and is used by bats to work their way through different environments.

In a nutshell, a click of the tongue or the sound made from castanets – the small, hand-held percussion instrument – will create different competing sounds, depending on whether it bounces off of a hard object or soft one.

That means people can make out the shape and material of an object or doorway, without actually seeing it.

“You can tell all your overheads, you can tell where the trees and the bushes are … you can tell where the buildings are,” Mr Earle said.

“The trellis is different to the solid wall … you get a picture in your mind of what it is you’re going past.”

‘Echolocation actually lets them see’

The technique has gained popularity with the help of American Daniel Kish, who has been nicknamed “the batman” and went blind when he was 13.

His ability to read sounds has allowed him to ride a bike without any sight, and go bushwalking by himself.

Daniel Kish
Daniel Kish, who lost his sight when he was 13, is popularising echolocation among blind people. Photo: ABC

His training is now being rolled out in Adelaide for the first time by the Royal Society for the Blind, allowing the vision-impaired to see through sound.

Instructor Gayle McPherson admits she was a little sceptical of the technique at first “because it wasn’t really something that our initial training was focused on”.

But as she learnt off Mr Kish when he visited Adelaide, she realised that the bat-like vision could change the world of someone who could not see.

“It actually enables people to engage with the world in a way that you just can’t do with a cane,” Ms McPherson said.

“[The objects] are all varying distances away so it’s the rate with which that comes back, and the quality of the sonar [sound] that comes back, that eventually you build up an encyclopedia back here.

“Echolocation is just as important as a long cane. Long cane is great for somebody who has just lost their vision to help them to stop falling down.

“The echolocation actually let’s them see the world around them.”

Echolocation gaining popularity around Australia

Ms McPherson said a change in culture was needed to ensure blind people were given as much opportunity as possible.

“It’s about actually changing that perception and the culture and saying, ‘if you’re blind it’s not going to stop you anymore’,” she said.

“Often young children are stopped from naturally developing echolocation but you’re actually wanting that child to take risks and explore the world.

“If we just cotton-wool them and hold their hand and guide them everywhere, they will not gain those skills and they will be fearful.”

Echolocation is also being taught in New South Wales and Victoria, but it is still not as prominent as cane use or guide dogs.

Karen Knight from Vision Australia said it is gaining popularity and will be seen more in Australia in the years to come.

“It needs to be absolutely incorporated into orientation and mobility programs,” she said.

“Just as you might be teaching to use a cane and you might be teaching other devices to help with mobility, echolocation is very critical.

“This is another tool that someone who is blind or has low vision can have in their toolbox to ensure that they’re as independent as they possibly can be.

“And live the life that anyone else lives, just doing some things a different way.”

-ABC