A man from Massachusetts has seen his wife for the first time in 10 years thanks to a bionic eye.
Allen Zderad suffers from a degenerative eye disease affecting the retina for which there is no effective treatment or cure.
He began having serious vision problems about 20 years ago and lost his sight a decade later. The disease, retinitis pigmentosa, ended his career leaving him only able to see very bright lights.
However, scientists at the Mayo Clinic have now treated the 68-year-old by giving him a bionic eye.
The bionic eye implant works by sending light wave signals to the optic nerve, bypassing the damaged retina. A tiny chip was embedded into Zderad's right eye, with electrode wires attached, during an operation in January. Two weeks later, the prosthetic device set into glasses was activated.
Explaining the device, researcher and ophthalmologist Raymond Iezzi Jr said: "It's an array of electrodes that actually have to lay on a curve surface in the back of the eye where the retina is. We place an electronics package around the eye, fixate that electronics package and then we enter through the eyewall, through the white part of the eye with an electrode that's six by ten electrodes.
"So patients have 60 points of stimulation, and that electrode lays upon the retina through a cable that we carefully secure and then we put a patch graft over the incision that allows this device to enter the eye. So there's actually a portion of the device that's outside of the eye and a portion of the device that's inside of the eye on the retinal surface."
The glasses have a camera in the centre of the bridge of the nose. Images from the camera go down a cable to a device worn on the belt. The computer analyses the images then transmits the information into the implant.
He was then able to make out human forms, outlines of objects and doors – he could also see the silhouette of his own reflection in a window. On seeing his wife, he recognised her instantly, reaching out to grab her hand as he broke down into tears.
Iezzi Jr said it was exciting to see a technique they have been working on for years being used on a patient – and for it to work. While more adjustments will be required, along with physical therapy and instruction, Zderad will now be able to use the device to see again.
Explaining Zderad's vision, Iezzi added: "Mr Zderad is experiencing what we call artificial vision. It's not like any form of vision that he's had before. He's receiving pulses of electrical signal that are going on to his retina and those are producing small flashes of light called electro-phosphenes.
"These small flashes of light are sort of like the points of light on a scoreboard at a baseball game. So, Mr Zderad has only 60 of these, but by moving his head and using his visual memory and all of his cognitive skills and his remarkable capacity to get around, Mr Zderad can reconstruct a scene."
In terms of future application, the bionic eyes could be used to treat trauma victims, as well as diabetic patients or those with advanced glaucoma.
"If we could extend the reach of this technology to care for those patients, I think we would really see a true maturation and that would require that we bypass the eyes altogether and go directly into the brain with this kind of technology. I think we're going to see that happen in our lifetime."