First Human Trials Of Pioneering Blindness Treatment

Mid stage retinitis pigmentosa

A groundbreaking trial using optogenetics, is set to begin soon on 15 patients with retinitis pigmentosa

What is retinitis pigmentosa?

An inherited, degenerative disease in which rod photoreceptor cells within the retina slowly deteriorate. This eventually leads to impairment of the cone photoreceptor cells too, reducing peripheral vision and eventually resulting in blindness.

The power of light

Startup RetroSense Therapeutics in Texas is attempting to treat the condition using something called optogenetics. Optogenetics is an innovative technique which involves modification of neurons to make them responsive to a particular wavelength of light. This is done through viral delivery of an altered gene for channelrhodopsin, which is a light-sensitive protein found in algae. The light-sensitivity allows you to tinker with certain neurons, turning them off and on for example - giving you a simplistic form of 'mind' control.

Optogenetics usually involves insertion of fibre optic wires to near the target site, but there is no need in this case because the retina is already exposed through the eye.

What does the trial involve?

A diagram of the layout of a human eye

Participants will undergo an injection of a virus containing the gene for channelrhodopsin, which will transfect ganglion neurons adjacent to the defective photoreceptor cells. These normally help transmit signals, but by making them light sensitive the hope is that this will create electrical signals which will recover some form of sight. Channelrhodopsin is only responsive to blue light however, so the researchers suspect any success will result in black and white vision alone.

Considering these patients are already significantly visually impaired however, even a small improvement would be very welcome and prove the value of the approach. As we await the results, a number of other companies and labs are also exploring optogenetics as a possible therapeutic approach to multiple diseases.

Read more at Science Alert