Twin brothers who were left blind by a rare eye condition are gearing up for a 570km cycle ride from London to Amsterdam.

Friends and family will join Daniel and Michael Smith, 20, of Cedar Avenue, East Barnet in April as they tackle the four-day-ride in aid of Blind in Business.

Michael first noticed he was losing his sight in his first week at Barts and The London School of Medicine in 2009. After three weeks he was diagnosed with Leber’s Optic Neuropathy, a rare form of vision loss.

Michael said: “Losing my sight at such an early age and watching my brother lose his as well has been an intensive process of rehabilitation, functionally and emotionally, which has put incredible pressure on the family.

“With sight loss, it’s a mental condition as well as a functional one as it involves a grieving process, mourning a loss that provokes great anger and shock.”

Michael left university and just one year later his brother discovered there was a 60-70 per cent chance he could also lose his vision.

Daniel said: “I used to think about it 10-20 times a day. It was hard to live with this dark cloud over my head.”

While preparing for his second year exams last Easter, he began to struggle to see through his left eye and within two weeks his near perfect vision rapidly deteriorated.

He said: “I can’t dress myself properly, I don’t even know what I look like, cooking is very difficult and if I drop something on the floor I can’t get it. It’s unbelievable the things I took for granted, such menial tasks, I can’t do them anymore.”

But the pair are determined to finish their degrees – Michael has since started studying Geography at King’s College London - and complete their biking challenge.

The Smith brothers will attempt to raise £3,000 for Blind in Business, which provides training and employment services to help blind and partially sighted people into work.

They will cycle on the back of tandems, with the help of friends. The group aims to cover 140km a day, spending up to nine hours in the saddle, and will be followed by Daniel and Michael’s parents Steve and Su-Jan who will drive a support vehicle.

Daniel said: “I’m nervous and there’s a lot of trepidation – I really want to succeed and raise the money.”

Dan Mitchell, training and fundraising manager at Blind in Business, said: “Blind in Business knows that these young men will challenge what visual impairment means and show how a group of people can work together in aid of a small charity to make a real difference to young visually impaired people.”

To sponsor Daniel and Michael visit: http://www.justgiving.com/sevenmenfivebikes