At 18 years old, there are several life-changing moments that young people look forward to. For some, it involves graduating from high school, starting college, and being able to cast a vote in an election. For others, this momentous occasion symbolizes the official start of adulthood.

For James O’ Brien, this milestone was marked by a rather unfortunate event where ammonia was thrown at his face in a random attack. As a result of this incident, the surface of his right eye was burned and he was left completely blind in his right eye.

Fast forward 25 years and thanks to an experimental stem cell treatment, James is able to see out of his right eye for the first time since the attack.

“Being able to see with both eyes – it’s a small thing that means the world. Basically I went from near-blindness in that eye to being able to see everything.” said O’Brien in a news release from Daily Heralds.

Dr. Sajjad Ahmad and a team of surgeons at the Moorfields Eye Hospital in London removed healthy stem cells from O’Brien’s left eye and grew these cells in a lab for months. After an adequate number of healthy stem cells from O’Briens left eye were grown, the surgeons then cut the scar tissue in his right eye and replaced it with the healthy stem cells.

They then waited a year after the procedure for the cells to settle down before inserting a cornea – which plays a key role in vision and focuses light – from a deceased donor.

“This is going to have a huge impact. A lot of these patients are young men so it affects their work, their lives, those around them. It’s not just the vision that drops, it’s the pain.” said Dr. Ahmad in the news release previously mentioned.

The procedure used took over 20 years to develop and Dr. Ahmad hopes to continue to develop the procedure for patients that have been blinded in both eyes by chemicals or have lost their vision through degenerative conditions.

CIRM has funded three clinical trials in vision loss to date. Two of these trials are being conducted by Dr. Henry Klassen for an eye condition known as retinitis pigmentosa and have shown promising results. The third trial is being conducted by Dr. Mark Humayun for another eye condition known as age-related macular degeneration (AMD) which has also shown promising results.

See video below for a news segment of James O’Brien on BBC News: