Disabled dressage rider Verity Smith has said making competitors wear blindfolds at Rio 2016 is like somebody tying Usain Bolt's shoe laces together.
Smith feels she may not be able to take part at the Paralympics as she has just a few weeks left to adapt.
Rules introduced in January state blind riders must be blindfolded to be able to compete in Brazil, taking away any available light.
But the 42-year-old has just 10% vision that she relies on when riding.
"It's like tying Usain Bolt's laces at the start, it's so destabilising," Smith told BBC Points West.
"The whole ethic of the Paralympics is about breaking down stereotypes which is something I have tried very hard to do my whole life.
"They are about using what you have got, no matter how small it is and it is very sad that this rule is taking it away."
Smith, who started riding at the age of three, started to go blind aged eight and first represented Para Team GB in 1990.
However, when blindfolded, Smith is unable to ride at a beginners level, let alone compete and admits wearing the blindfold is a distressing experience.
"In the blindfold, I am a prisoner frightened of the dark," she added. "To take away the little light and dark that I have is actually very terrifying.
"It's a dangerous sport anyway, but to disable somebody further is very, very treacherous. We rely on every inch that we have to keep us and the horse safe.
"It is the different between having no day and no night."
Smith has been battling with the governing bodies who sanctioned the ruling - the International Paralympic committee (IPC) and the International Equestrian Federation (FEI) - since the rule came into place.
It will be reviewed after next year's Games, but that would be too late for the Cirencester-based athlete, who has just weeks to either adopt the blindfold and dramatically alter her training programme or see her dream of competing disappear.
"I think it is just an oversight that has been rubber-stamped because the rule cannot benefit anybody and I really hope it changes," Smith added.
"It has been a huge ambition for me to ride at the Paralympics because I think we have the best team in the world.
"My love of horses was hoof-printed upon my heart even before my blindness set in."