Nathalie Fex has been blind for most of her life.

The 42-year-old woman has Leber congenital amaurosis, a form of inherited blindness that left her unable to see colours, faces, and letters from a very early age.

The disease often strikes in an infant’s first few months of life.

However, a group of McGill University medical doctors and researchers have found a way to partially restore the vision of thousands of people with the disease, which had been untreatable until now.

Fex has been a patient of the study’s lead doctor Robert Koenekoop since 1997.

One day, he told her he had some medication he wanted to try on her to see if it would help her vision. She agreed, becoming one of 14 patients recruited to the study between 2009 and 2011.

The medication was a replacement for 11-cis, a key molecule for vision that people with Leber congenital amaurosis are missing.

She received her first treatment in 2010, and said she noticed a difference by the second or third dose.

“After the medication, I could recognize some letters,” Fex said. She said being able to do otherwise impossible tasks was “amazing.”

“You feel incredible because you never thought it would happen,” she said.

Rapid results

Koenekoop said the new treatment has had very rapid results, with many patients in the study reporting a difference in seven to 10 days. He said this initial study is just the first phase, but that the research so far has been very rewarding and shows a lot of promise.

He recalled a conversation with a nine-year-old patient.

"She said, 'Dr. Koenekoop, you've known me for nine years and you know that I needed a cane to go to school. I just want you to know I'm not using the cane anymore.' It was one of the most remarkable experiences of my life," he said.

Of the 14 study participants, 11 returned to their baseline vision two years after receiving the week-long treatment. However, three sustained improvements.

Fex is one of them. She thanks the treatment for being able to enjoy some of life’s simplest pleasures, especially cooking.

“Just being able to read your bill, to cook and not have the danger of burning yourself,” she said.

Sharon Colle of the Foundation Fighting Blindness of Canada said the results were more than they had ever hoped for.

"Seeing your children graduate, you know. Seeing the faces of your grandchildren. These are monumental in terms of giving people back a very wholesome life," Colle said.

Koenekoop said he hopes this new approach will also work in curing other causes of blindness, though extensive testing is required. However, he said, it sends a "clear new message" that some forms of blindness are treatable.