Algae gene therapy helps blind people restore part of their vision

According to MIT Technology Review Journal of the Massachusetts Institute of Technology, in an attempt to treat the man's vision loss, scientists inserted genes that encode a light-sensing protein into a virus that has already been detected, then inject that gene-edited viral vector into the patient's eye. The protein, called ChrimsonR, is a version of the light-sensitive protein found in single-celled algae, which allows the single-celled organism to detect and move toward sunlight.

ChrimsonR belongs to a family of light-sensitive proteins, called channelrhodopsins (subfamily of retinylidene proteins that function as light ion channels; act as sensory receptors in single-celled green algae; control phototaxis in response to light) and has been modified to respond to colors that are in the red end of the color spectrum, specifically amber light.  By injecting the ChrimsonR gene into the retina, specifically into retinal ganglion cells, a type of nerve cell that sends visual signals to the brain, the team hopes to make these cells sensitive to orange-yellow light.

 Meanwhile, special glasses pick up changes in light intensity from the environment and then convert that signal into a high-intensity, amber image that's projected directly onto the patient's retina for the purpose of activating ChrimsonR. 
After several months, a significant amount of ChrimsonR accumulated in the man's eyes and began to change the patient's vision.  Eventually, this man began to perceive different types of light with the help of goggles.

 "Patients recognized, located, counted and touched" various objects with their treated eyes and while wearing the glasses, the researchers said.  For example, the patient can see a notebook and cups placed on the table in front of him, can even give the exact amount.

 Prior to the treatment, the man was unable to detect any objects, with or without goggles.  After injecting the ChrimsonR gene into the retina, the patient could see but only with glasses, because the glasses would convert all light to amber, the researchers said.

 In addition to the notebook and cup, the patient reported seeing white lines on the pedestrian crossing.  According to the team, patients started exercising with goggles about four to five months after the injection and began to notice an improvement in their vision about seven months later.