Why was Rachael Scdoris refused entry into the Iditarod race in 2004?

Rachel Scdoris was born with an uncorrectable vision defect known as congenital achromatopsia. She was denied entry into the Iditarod until 2005, when the Iditarod Trail Committee allowed her to race with the aid of a visual interpreter after she waged a two year battle with them to compete.