Two-time Olympics champion Nicola Adams, regarded as the pathfinder for women’s boxing, is to retire because of fears about her sight, the Briton announced today.

The 37-year-old, who became the first ever women’s Olympics 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. “I’ve been advised that any further impact to my eye would most lead to permanent vision loss,” said Adams.