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Blind man sees after two decades - 7th June 2021

The vision of a completely blind man has been partially restored using light-sensing proteins first found in aquatic plants called algae.

The man was treated with optogenetics therapy, which relies on algal proteins to stimulate cell growth in the retina, located at the back of the eye.

The initial realization that the treatment was successful occurred when the man was able to make out painted road markings. Although limited, this newly found sight is sufficient to allow him to grab and add up items close to hand.

The patient, who remains anonymous, resides in northern France and travelled to the capital for the ground-breaking treatment.

Diagnosed with retinitis pigmentosa 40 years ago, the individual concerned has had no vision for the past two decades. It’s a disorder which leads to the death of light-sensing cells on the retinal surface. It affects more than two million people, although such complete blindness is uncommon.

The patient underwent treatment with optogenetics, a process which uses light to precisely control the activity of brain cells. The technique is based on proteins, produced in algae, which alter their behaviour in response to light. The waterborne microbes use the proteins to move towards the light.

This behaviour was exploited by scientists to restore one of the patient's eyes with the ability to see light. The first clear indication of success was when the man suddenly became aware of the stripes of a pedestrian crossing when out walking.

Commenting on the incident, Dr José-Alain Sahel, from the Institute of Vision, in Paris, said the patient had initially been "a bit frustrated" by the apparent lack of progress. However, Sahel reported that "when he was able to see the white stripes... you can imagine he was very excited. We were all excited."

While a return to full vision will not be an option, the contrast between having no sight and having partial sight can be life-changing.