Media playback is unsupported on your device Media caption The moment of truth as Rhian Lewis tries her new 'bionic' eye implant

A blind woman from Cardiff has had some of her sight restored with an electronic "bionic" eye implant.

Rhian Lewis, 49, has described her joy as she could make out the time on a clock face.

Surgeons at Oxford Eye Hospital implanted a tiny light-sensitive microchip at the back of her right eye in an eight-hour operation.

An inherited disorder meant she lost her sight in the eye 16 years ago.

She has had the condition retinitis pigmentosa since she was age five, with her eyesight deteriorating as she got older - until she was completely blind in her right eye, with very limited vision in her left eye.

Image copyright University of Oxford Image caption Implant in place

She underwent surgery in June, when surgeons implanted the chip as part of a trial at Oxford's John Radcliffe Hospital.

During follow-up tests, Mrs Lewis was asked to look closely at a large cardboard clock to see if she could tell the time correctly.

She was able to tell it was three o'clock.

"Honest to God, that felt like Christmas Day," she said.

Mrs Lewis was then taken to the cloisters of New College, Oxford, to see if she could make out its features.

She said: "I walked up the street, and the lady from social services said to me to point out anything I thought might or might not be there.

"And the first thing I thought 'there might be something there,' there was a car, a silver car, and I couldn't believe it, because the signal was really strong, and that was the sun shining on the silver car.

"And I was just, well, I was just so excited, I was quite teary."

Mrs Lewis is the first patient outside of Germany to be fitted with the latest generation of the light-sensitive chip.

Image copyright University of Oxford

How does it work?

The implant - a 3mm sq array of about 1,500 light sensors which sends pulsed electrical signals to nerve cells - is connected to a tiny computer that sits underneath the skin behind the ear.

This is powered by a magnetic coil on the skin. From the outside, it looks like a hearing aid.

When the device is first switched on, patients see flashes of light, but over a few weeks the brain learns to convert those flashes into meaningful shapes and objects.

Media playback is unsupported on your device Media caption Rhian Lewis: 'Honest to God, that felt like Christmas Day'

The images can be black and white and grainy but still have the power to transform lives.

"The problem with having no sight is that you also lose your confidence because you lose your mobility," explained Mrs Lewis.

"It's simple things like shopping, clothes shopping, you don't know what you look like.

"It's been maybe eight years that I've had any sort of idea of what my children look like.

"Now, when I locate something, especially like a spoon or a fork on the table, it's pure elation. I just get so excited that I've got something right."

You can see more on how the technology has changed Mrs Lewis's life on Wednesday's episode of 'Trust Me, I'm a Doctor' on BBC2 Wales at 20:00 GMT.