LAKE LUZERNE -- Corey Haas, 9, likes to ride his bicycle and watch television. In school, he often smiles and tries to make classmates laugh. He likes to have fun.

But Corey uses a walking cane to maneuver through the hallways of the Stuart M. Townsend Middle School in rural Lake Luzerne. When he reads, he keeps his face inches from the book.

Corey, a fourth-grader, has Leber's congenital amaurosis, a rare eye disorder that is inherited and, over time, can lead to blindness.

The disorder made it difficult for him to see in low light. At one point, he could stare into the sun without discomfort.

The condition is caused when the retina, a transparent tissue over the inner surface of the eye, is unable to detect light.

For years, no cure existed. But in 2007, a team of doctors in Philadelphia began a treatment on humans after getting positive results with animals.

The surgery involved taking a manufactured gene and using a virus to spread it over the retina, allowing cells to produce a protein needed for the retina to capture light.

In September 2008, Corey became the youngest of 12 people to undergo the experimental treatment, done at the Children's Hospital of Philadelphia.

The procedure was performed on his left eye, the worst of the two.

His life has since changed for the better and has brought hope to other people with the same condition.

"It was kind of dark, darker than it would normally be," Corey said of his vision before the treatment. "Now things are a lot brighter.

"I felt excited that my vision had changed," he said.

Now, the sun is bright enough to hurt his eyes. He can ride his bicycle on his own, unlike before, when his father had to be by his side.

His life at school has also changed. He still uses a walking cane, but he no longer needs an aide to follow him around.

Before the surgery, Corey used a large magnifying device to see in the classroom. He needed a lamp positioned inches from a book to help him read.

Now, the lamp and the magnifier are collecting dust in a storage room.

"His independence, his attitude has become better," said his father, Ethan Haas. "He is just about a normal 9-year-old."

Taking a chance Corey's parents knew he had vision problems when he was a toddler. Light attracted him. He did not make eye contact. When he started walking, he kept bumping into things.

He began wearing glasses when he was 10 months old, but it wasn't until he was six that a doctor in Boston discovered he had Leber's congenital amaurosis.

His parents were told he would go blind. But they were also told about an experiment going on in Philadelphia, one that showed promise for reversing the progress of the disease.

It was good enough for Corey and his parents.

"I decided that any kind of improvement was better than none at all. There are no regrets," said Ethan Haas.

After the surgery, Corey has returned to Philadelphia for exams with a team of doctors. His visits will taper off over time and, eventually, he'll only be required to check in with doctors by phone.

Dr. Jean Bennett, director of the research team that spent nine years and almost $2 million to create the treatment, said Corey and his parents are pioneers for participating in the experiment.

"We are totally grateful to the core for his contributions because it is going to help other people," she said.

The treatment was done on one eye for the people involved in the experiment. The results were positive enough that subjects asked if the surgery could be performed on their other eye, Bennett said.

Tests are being done on animals to find out if surgery on the second eye is safe, she said.

At school, Corey has gained popularity among his peers. His story was featured on ABC's "Good Morning America," and on other network shows and in newspapers in Boston and Philadelphia.

"The kids are like, ‘He is a celebrity,' " said Susan Ostrander, Corey's teacher last year.

Corey's eye disorder has never affected his grades in school. Even last year, as he was adjusting to his improved vision, his grades were excellent, said the school principal, Patrick Cronin.

Corey still holds a book inches from his face to read. A board on his desk lifts his books and papers close.

The school provides him with large-print textbooks and exams. He still learns Braille a few times a week.

On tests, he is given all the time he needs.

Last week, Corey was the last student in his class to finish a science test. He was also the only one who earned a perfect score, said his teacher, Diane Camardello.

"He is doing excellent in all his schoolwork. That's what is amazing to me," she said.

And he has not lost his sense of humor.

"I like him because he is funny. He talks to everyone. He is friendly," said classmate Logan Thompson.