Two-time Olympic champion Nicola Adams, regarded as the pathfinder for women's boxing, is to retire because of fears about her sight, the Briton announced on Wednesday.

The 37-year-old, who became the first ever women's Olympic boxing champion at London 2012 when she took the flyweight crown, said she was abandoning her hopes of winning a third gold next year in Tokyo.

In an open letter to her local newspaper the Yorkshire Evening Post, Adams said she had decided to hang up her gloves because doctors had warned her sight would be permanently damaged if she continued to box.

Adams, who successfully defended her title in Rio, had embarked on a successful professional career and in 2018, within 18 months of doing so, had won a world title - the vacant WBO flyweight belt.

"I've been advised that any further impact to my eye would most likely lead to irreparable damage and permanent vision loss," said Adams.

"I'm immensely honoured to have represented our country - to win double Olympic gold medals and then the WBO championship belt is a dream come true... But it's not without taking its toll on my body.

"To my wonderful team, I would not be the fighter I am today without your encouragement and understanding - what you have taught me goes beyond the ring."

Copyright Agence France-Presse, 2019