Caroline Casey was 17 when she discovered she was blind.

For the first 17 years of her life, Caroline Casey had always been the clumsy girl. Exceptionally clumsy, but not noticeably more so than her peers.

It wasn’t until a fluke conversation after her 17th birthday that Casey found out she isn’t like everyone else.

“I had no idea that, in fact, I was legally blind. When I was growing up,  I didn’t know there was anything wrong with me. I wore glasses and was exceptionally clumsy, but my grades at school were no different to anyone else’s,” the TED speaker and disability activist wrote in an article for The Daily Telegraph UK.

After casually mentioning her excitement over learning how to drive at an eye specialist appointment, Casey’s parents had no choice but to reveal what they’d known since she was six months old – their daughter suffers from ocular albinism, a genetic eye condition that causes permanent vision loss.

“All I remember is my mum crying as she admitted  the truth. I think she was heartbroken she could no longer protect me from the reality,” wrote the now 46-year-old.

“But my reaction was different: I simply couldn’t take in the news. I’d lived 17 years of my life as a normal kid and couldn’t relate to what I was being told. I wouldn’t be learning to drive – not that year, or ever.”

Still, the question remains – how can one go through life not knowing they’re blind?

For Casey, learning about her condition certainly filled in a number of blanks that helped to explain why she had struggled with certain aspects of life over the years.

"I’d always coped, but over time things started to slot into place. I can still make out shapes and I can see faces up close, but beyond 2ft, even wearing glasses, my world looks like an out-of-focus camera," Casey explained.

"I [then] understood why I’m scared to walk into a room of people (because I can’t see who they are), why I’m so bad at sports and why I’d have my nose against the screen when I’d watch TV."

However, Casey's eyesight never stopped her from continuing to lead a relatively normal life, choosing not to share her diagnosis with school and university friends, then holding down a demanding full-time job as a disability manager before starting her own not-for-profit to promote a positive image of disability.

"I still prefer not to ask for help unless I absolutely can’t do something, and I’ve developed lots of coping mechanisms, such as searching for the bright light that reflects off my husband’s head. But I’ve now found that balance between strength and vulnerability."

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