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A handheld gaming device designed by UK and Auckland-based researchers to rebalance amblyopic children’s vision has been approved as a medical device in the UK.

The device, developed and trialled collaboratively by Auckland University, University College London (UCL) and Moorfields Eye Hospital in London, shows modified 3D movies, engaging children and increasing their therapeutic compliance. Visual acuity improvement after two to six months was similar to that achieved in two years with patching, said Professor Steven Dakin, one of the research leaders and head of Auckland University’s School of Optometry and Vision Science (SOVS).

The device works by employing a 3D movie’s unique technology which relies on two separate but nearly identical images being seen, one by each eye. In trials of the device an optometrist assessed each patient at the start of treatment. The patient was then given a handheld Nintendo 3DS to view the movies, while a researcher added a customised amount of blur to the image seen by the “good” eye to promote binocular vision and force the patient to use their weaker eye to view the unblurred image.

Prof Dakin said it was initially thought the treatment needed to focus on breaking interocular suppression (IS), but an earlier SOVS study showed IS remained despite improvements in visual acuity. “This therapy does not work by breaking IS. The suppression is still in place, which is strange because their vision is improving but they’re still suppressing, so we don’t really understand the mechanism.”

It’s believed it works because it improves compliance, he said, reporting 95% of patients complied with the treatment. Afterall, what’s not to like about watching 3D movies, especially when compared with current amblyopia therapies such as patching or atropine drops.

Being portable made the device particularly versatile as it could be used anywhere, such as in a car or at home. Critically, it was fun and easy for both child and parent, and cost was not a barrier, said Prof Dakin, adding the Nintendo 3DS technology was ideal. “That little game is tracking the position of your head and your eyes. And it’s constantly adjusting the position of the 3D image-pair so each eye sees the correct image.”

Sadly, as that Nintendo model is being discontinued, a new delivery platform needs to be found for future development, he said. “We need to leverage consumer technology. We’re agnostic about the platform but we don’t like glasses.” Virtual reality (VR) may seem a logical next step, but kids wouldn’t wear the headsets an hour a day, said Prof Dakin, so until issues such as headset weight and wearer nausea were solved, other solutions are more attractive. Top of these is currently an iPhone with a clear 3D lenticular screen cover.

A phase II clinical trial is underway at Moorfields Eye Hospital in London, funded through Action Medical Research, under the supervision of consultant paediatric ophthalmologist Dr Annegret Dahlmann-Noor.

Prof Dakin said SOVS was also seeking funding, so researchers could delve into brain imaging to better understand the mechanisms behind amblyopia and how the eye and brain worked together to interpret images. “The mechanism is still quite mysterious. We would like to understand that better. We want to use brain imaging to see how the brain’s rewired after therapy.”