|IPC Athletics World Championships|
|Venue: Qatar Sports Club, Suhaim Bin Hamad Stadium, Doha Dates: 22-31 October|
|Coverage: Daily reports on the BBC Sport website, plus coverage of key races on BBC Radio 5 live and BBC World Service|
Irish Paralympic champion Jason Smyth will only be able to run in one event at next year's Rio Games.
The visually impaired athlete, 28, won T13 100m and 200m gold at both the Beijing and London Paralympics but was reclassified as a T12 athlete in 2014.
However, Smyth has been reinstated to T13 competition following further tests before the IPC World Championships, which start in Doha on Thursday.
The T13 category will only have a 100m in Rio, with T12 having both sprints.
The International Paralympic Committee opted in 2013 to drop the T13 200m, but Smyth's subsequent reclassification to T12 put him in line to double up again in Rio.
A statement from the IPC on Wednesday said that Smyth's classification status was found to be "borderline" when he was tested before last year's IPC European Championships in Swansea.
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"All of the results of the assessment placed him in the T12 class," it said. "He was however placed under review status.
"The review was conducted this week and his results were again borderline but all were in the T13 class so he was moved back.
"Vision impairment tests can be influenced by a number of environmental characteristics.
"As last year's result came as a surprise to all concerned, the IPC acknowledges that in retrospect it should have asked Smyth to undergo a second classification at that time."
Smyth's mixed feelings over latest reclassification
Smyth's latest classification removes any uncertainty over his status, with no further review scheduled until 2019.
The county Londonderry athlete, who narrowly missed out on qualifying for the London Olympics, has mixed feelings.
"It was a surprise to me last year that I had been moved to a T12 and was difficult to deal with, so I'm pleased that my status as a T13 has been clarified," said Smyth, who has the degenerative condition Stargardt disease, which limits his vision to the outlines of shapes.
"However it is disappointing that I definitely won't have the chance to defend two of my Paralympic titles in Rio as the T13 200m has been removed from the list of medal events by the IPC.
"At least I can put all my energies in the 100m and continue to try to run faster and bridge the gap between Paralympic and able-bodied sport."
Smyth, who won double T13 gold at the last IPC World Championships in Lyon two years ago, will only be competing in the 100m in Doha, with the opening heats on Friday.
Immediately after Saturday's 100m final, Smyth will travel home to be with wife Elise, who is due to give birth to the couple's first child on Sunday.
Despite the imminent new arrival, Smyth says he is fully focused on retaining his world 100m title.
"Whether I run T12 or T13, I will still want to achieve what I want to achieve - winning gold here and going on to hopefully compete at next year's Olympics and Paralympics," he said.
"This is a big event for me to set a platform for next year.
"Over the last month or two I have been building on each race and my last race before coming out here was my quickest so hopefully I can go and run quicker here."