The light fantastic

An ongoing University of Oxford retinal implant trial has shown positive results so far in retinitis pigmentosa patients


Next week, the fourth retinitis pigmentosa (RP) patient in the University of Oxford trial for a sub-retinal implant system will have the sight-restoring device switched on.

With the fifth patient set to receive the Alpha AMS implant the week after, things are all go for the device, which acts as a replacement to the lost photoreceptors in the person’s eye.

The intraocular device both captures the light signals in the eye and transmits an electrical signal to the remaining nerves in the eye.

A total of six patients will be implanted with the device in the trial, led by Professor Robert MacLaren of the University of Oxford and funded by the National Institute for Health Research. All the study participants had lost their sight completely from RP.

Professor MacLaren explained that when the chips were switched on, the signals sent to the brain allowed his patients to see again.

He added: “They do very well outside when it’s quite bright, for example they can see a bus coming, or the curb of the road … Inside, when the lights are dim, it’s a little more challenging for them.”

The results were very exciting, but Professor MacLaren explained that the patients in his research needed to understand a clinical trial was one step in a long-term project.

“It’s a tough journey. We want to avoid people who are desperate for an improvement. We need to work out the issues around how the device works … [and] need to spend a long time with patients,” he explained.

The trial comes as another retinal implant device has hit the headlines. The NHS is currently considering whether or not to fund the Argus II retinal implant device, which uses a spectacles-mounted camera, to send signals to the retinal implant.

The results Professor MacLaren has seen with the Alpha implants have convinced him that retinal implant devices should be funded for patients with RP, he emphasised.

“We’ve had some very good results, though they are only suitable for some patients,” he said cautiously.

The Alpha AMS used in the current trial is the second-generation design of the retinal implant. The first, the Alpha IMS, was first trialled by Professor MacLaren in six patients in 2012.

“There were problems with long-term survival … so they re-engineered the device to be more robust,” he said.

One of the patients in the current trial, 48-year-old RP patient Nikki Watson, featured last week on the ITV programme What Would Be Your Miracle? Unfortunately for Ms Watson, her device was removed as the wiring became exposed, but she may be able to get a new implant separately from the trial, Professor MacLaren said.

“It worked very well when she had it,” Professor MacLaren emphasised.

Ms Watson’s story is available to watch until June 11 on the ITV website.