'Buzzing belt' helps guide people with sight loss

LEO belt_image

A specially designed belt, equipped with a 3D camera and vibrating patches, has helped people with restricted peripheral vision to navigate a maze, and could now become a new visual aid.

The belt aims to help people with retinitis pigmentosa (RP) - the most common inherited eye condition, affecting around one in 4,000 people in the UK.

People with RP lose their peripheral sight over time, leaving them with ‘tunnel vision’, as well as difficulty seeing in low light. A person’s sight loss usually happens gradually, over many years, in some cases leads to complete blindness.

New research, published in the journal PLoS One and led by Professor Andrew Lotery, consultant ophthalmologist at University Hospital Southampton NHS Foundation Trust, has shown that a specially designed belt could become a new discreet aid to help people with this condition find their way around.

Navigating the maze

The Low-vision Enhancement Optoelectronic (LEO) Belt consists of a 3D depth-sensing camera and a portable computer stick attached to the belt, connected via Wi-Fi to vibration transducers on an undershirt and ankle straps. The belt was designed by Prof Lotery’s collaborator Professor Steve Russell from the University of Iowa.

The belt scans the area in front of the person using the 3D camera, and warns the wearer about nearby objects through vibrations – the faster the buzzing, the nearer the object – with the object’s position indicated by which patch is buzzing (left, centre or right).

Ffion Brown, a medical student working with Prof Lotery, assessed six patients with advanced RP and 20 healthy people wearing goggles that restricted their vision in a similar way to the condition were able to use the belt to guide them around four mazes – made from obstacles arranged in different ways.

Those with RP found the belt particularly useful when finding their way around the mazes in low lighting, when their vision is worse.

Discreet option

All participants said they found the belt comfortable, with over 90 % saying it was easy to use and thought it had potential future benefit as a visual aid.

Although participants were slower to complete the maze with the belt, the researchers think people could get faster with practice.

“The belt has the advantage over alternative aids for people with sight loss, such as a white stick or guide dog, in that it can be worn under their clothes and be relatively discreet.

“This could help those who are reluctant to use a visual aid for fear of discrimination,” said Professor Lotery, who is also professor of ophthalmology at the University of Southampton.

“In this pilot study we have shown this belt has great promise, and based on what we have learned from this initial study intend to develop it further to hopefully help patients retain their independence despite sight loss.”

Posted on Friday 1 November 2019