Tragic reason little girl's eyes turned black after she got trapped in volcanic mudflow where she died

A 13-year-old girl tragically became the symbol of a devastating volcanic tragedy.

Columbian teenager Omayra Sánchez Garzón died along with tens of thousands of others when the Nevado del Ruiz volcano erupted on 13 November, 1985.

20,000 of the 29,000 residents in Armero died after the eruption caused a massive landslide which engulfed the entire town, leaving a helpless Omayra trapped under the debris.

With her legs submerged in the water and mud, she was stuck there for three agonising days.

While rescue teams tried to set her free, they lacked the necessary equipment to get her out.

Omayra Sánchez Garzón, 13, was the victim of a volcano eruption in Columbia after being trapped for three days. (Frank Fournier)

Amid the hopeless circumstances, Omayra showed such bravery and courage as the media shared her tragic story with the world.

In a now-famous image, photojournalist Frank Fournier captured Omayra's dark eyes, as the picture went on to win the World Press Photo of the Year in 1986.

And the heartbreaking reason why her eyes were so dark was due to prolonged submersion in the water, combined with the pressure of the debris pinning her.

This resulted in intensely bloodshot eyes, giving them the black appearance seen in the photo.

Fournier told the BBC: "She was in a large puddle, trapped from the waist down by concrete and other debris from the collapsed houses.

"She had been there for almost three days. Dawn was just breaking and the poor girl was in pain and very confused.

"All around, hundreds of people were trapped. Rescuers were having difficulty reaching them.

"I could hear people screaming for help and then silence - an eerie silence. It was very haunting.

Rescue efforts were made, but they were unsuccessful. (Frank Fournier)

"There were a few helicopters, some that had been loaned by an oil company, trying to rescue people.

"Then there was this little girl and people were powerless to help her. The rescuers kept coming back to her, local farmers and some people who had some medical aid. They tried to comfort her.

"When I took the pictures I felt totally powerless in front of this little girl, who was facing death with courage and dignity. She could sense that her life was going.

"I felt that the only thing I could do was to report properly on the courage and the suffering and the dignity of the little girl and hope that it would mobilise people to help the ones that had been rescued and had been saved.

"I felt I had to report what this little girl had to go through."

Omayra Sánchez passed away on November 16, 1985, after spending nearly 60 hours trapped.