. >> plus jean bennett of the university of pennsylvania. once again, eric kandel a howard hughes medical investigator. i began as i always do with my rent air to review our subject tonight. >> the last program we did was a new approach to the treatment of deafness. tonight were going to consider new approaches to the treatment of blindness. as is the case with deafness, blindness is not a life-threatening situation but in some ways is more disabling as deafness because, as you pointed out, there are number of very important blindness conditions for which there is no treatment. why is that so? unlike deafness, the sensory organ for vision, the retina which is evident of the lower

. >> plus jean bennett of the university of pennsylvania. once again, eric kandel, a howard hughes medical investigator. i began as i always do with my friend eric to review our subject tonight. >> the last program we did was a new approach to the treatment of deafness. tonight we are going to consider new approaches to the treatment of blindness. as is the case with deafness blindness is not a life-threatening situation, but in some ways it is more disabling than deafness because, as you pointed out, there are a number of very important blindness conditions for which there is no treatment. why is that so? unlike deafness, the sensory organ for vision, the retina which is evident in the lower image which shows the eye, that is the most complex sense organ that we have. it is not a peripheral organ. it is actually part of the central nervous system that is an extension of the central nervous system and as a result it has a complex structure. it has a small area and the center that is clear in that image which is called the macula. if i turn m

jean bennett pio neared the study of gene therapy. steve pioneered t stem cell therapy. eberhart zrenner is one of the outstanding leaders in developing retinal chips, the microchips that are amazing for people who can't respond to the other treatments. we have the privilege of having two other people here. carla shatz is the leader of the study of the visual system and my friend sandy here is amazing. he as you pointed out, is a college undergraduate, had a severe case of glaucoma for which he became blind and he will tell us what it's like to be blind. but the amazing thing to me about sandy is, despite the fact he has this tremendous handicap, he's a remarkable human being. he's had a rich happy, productive life. he's invented things and now recently has begun to think of how he can help other people who are blind to make their life better. >> charlie: sandy great to have you at the table. talk to us about becoming blind and the whole sense of the journey for you. >> well, even after 50 years i can still feel what it was when i went blind. for many months i had declin