Jason Smyth has been reclassified from the T13 class to the T12 class ahead of the commencement of the Paralympic Athletics European Championships in Swansea.
The decision to reclassify the reigning double Paralympic and world champion, and world record holder at T13 100m and 200m comes as a result of the deterioration of his Stargardts disease.
Classification is an integral part of Paralympic sport but can often prove confusing.
It provides the structure to separate athletes with similar levels of impairments into groups or classes as they are commonly known, so they can compete in fair and equal competitions against one another.
IPC Athletics recently advised all athletes whose classification was confirmed prior to September 2011 (Smyth's classification was confirmed in 2006) that their classification would be reviewed in order to ensure that all athletes were assessed against the same standard.
Speaking about the reclassification Smyth said: "It was not what I was expecting. I have found it hard to get my head around the fact that a few days before my competition everything has changed; the days I am competing, who I compete against...everything.
"It also means since the last time I was classified my eyesight has got worse which is never what you want to hear."
As a T13 athlete, Smyth was facing the prospect of only being in a position to defend one of his titles at the next Paralympic Games in Rio as the T13 200m event had been removed from the list of Rio medal events published by the International Paralympic Committee (IPC) last year.
Smyth will now be in a position to contest both sprint events on the the programme.
The 27-year-old will be one of an eight-strong Irish team in Swansea at the European Championships.
Alongside him is fellow double Paralympic and world champion Michael McKillop, Orla Barry, Catherine O’Neill, John McCarthy, Heather Jameson, Lorraine Regan, and Andrew Flynn.