Why FDA panel's vote on gene therapy to treat form of blindness is such a big deal

An experimental treatment for blindness is one step closer to getting approval. 

On Thursday, an FDA advisory panel recommended the agency give a green light for the therapy, which can improve the vision of people with a rare genetic disorder called Leber's congenital amaurosis (LCA).  

"This is the first time that a genetic therapy has been used to treat an inherited disease in the United States," CBS News medical contributor Dr. Tara Narula told "CBS Evening News" anchor Anthony Mason. "This disorder we are talking about, LCA is a disorder that has no treatment. It has no cure."  

"People can really only see in very bright lights," she continued. "They have blurry vision and eventually lose their vision and become extremely visually impaired over time."   

What this does, when you talk to children who got the treatment, they say they are able to see the moon, the stars, snow falling and their mother's face, Narula said. "It's priceless." 

For 16-year-old Christian Guardino, most of his life has been a blur. He was born with LCA, which left his mother, Beth, feeling hopeless. 

"It is the most horrifying feeling just seeing everything fade away over time," Guardino told CBS News correspondent Errol Barnett. 

"He was my first born, so ... it was devastating," Beth added. "We were alone, we were completely alone in this." 

That is until four years ago, when Beth found Dr. Jean Bennett and her husband, Dr. Albert Maguire. The couple has been dedicated to reversing hereditary blindness for two decades. They say this new treatment could be a turning point. 

Researchers have found that their 41 patients' visual ability to complete an obstacle course improved after receiving treatment. Guardino nailed it.  

Some patients have even reported being able to lead more fulfilling lives. 

"What this really does is open the door for treatment of other inherited retinal disorders in terms of progressive scientific development and research," Narula said.  "Bottom line, it gives independence to people -- it allows them to go to school, to work." 

The Guardino's shared their story at the FDA hearing, encouraging the agency to take the historic step of approving the experimental therapy — a treatment that breaks new medical ground and improves lives.