Microchip helps blind woman regain partial sight

A local woman can see again after 15 years of blindness following a groundbreaking operation to implant a microchip into her retina.

The operation - the first of its kind outside Europe, where the procedure was developed - was done by surgeons from the University of Hong Kong and it took nine hours to complete.

'From zero sight ability to being able to see again, the feeling was absolutely amazing,' Tsang Wu Suet-yun, 57, said.

The insertion of the 3mm by 3mm chip allows blind patients with functioning nerve cells in their eyes to regain partial eyesight.

'The electrodes [on the chip] replace degenerated eye cells to stimulate the brain,' said Professor David Wong Sai-hung, director of the university's Eye Institute.

A cable runs under the skin to behind the patient's ear where a magnet is used to connect it to an external battery. The device only works when the power is connected.

The technique could help roughly 80 per cent of blind people, including those suffering retinitis pigmentosa, a group of genetic eye diseases that leads to permanent blindness.

Tsang and three of her six siblings are among the 2,000 Hongkongers with the condition, for which there was previously no treatment.

Tsang, who works as a masseuse, started losing her sight at about the age of 40. She has been legally blind for 15 years. 'She had completely lost the ability to see, so the surgery gave us a glimpse of hope,' her husband Tsang King-wai said. 'Our family thinks it's a miracle. We just want to thank our father in heaven.'

Though Tsang has only regained 5 per cent of her original sight in her right eye, and can only see black and white images within a narrow field of vision about the size of a compact disc, she and her husband are pleased with the results. But she remains blind in her left eye. 'Sometimes I am able to see moving shadows even without the device on. I think some of my eye cells may have come back to life,' she said with a laugh.

Dr Ian Wong Yat-hin, clinical assistant professor at the institute, says stimulation from the chip may have revived some of Tsang's light-sensitive eye cells.

As the technology is still under trial, Tsang says she is prepared for the possibility that the device may fail and she may lose her vision again.

'I hope the study can go faster to help more patients. I'm prepared for failure,' she said.

German firm Retina Implant has been developing the technology since 1995 and has been conducting clinical trials since 2005, says executive vice-president Reinhard Rubow. Some 26 patients worldwide have undergone the surgery, and the second operation in Hong Kong was conducted two weeks ago.

The firm chose HKU as its partner in Asia because of the Eye Institute's reputation for innovation in ophthalmic research. It hopes the technology will be commercially available next year at a price of Euro100,000 (HK$1.02 million), including surgery.

MEDICAL PROGRESS

Retinal microchip

1,500 electrodes

Absorb light and convert it into electrical energy which stimulates nerves within the retina

General set-up

Entirely under the skin

Power

External control box, worn round the neck, has a wire leading to a magnet which fastens to a coil under the skin. Electricity passes between them by induction

Within the eye

Healthy retina

Photoreceptors Translate light into currents that can be delivered to the brain

With retinis pigmentosa

Damaged layer of photoreceptors

Sources: HKU, Retina Implant AG