Wales and Ireland face each other in the Six Nations clash wearing their traditional red and green shirts for the last time on Saturday – with the rules stepping in to help colour-blind fans.
Color vision deficiency (CVD) is a particular problem for men – one in 12 people have the condition – while globally one in 200 women are also affected.
The combination of red and green is especially problematic for those who watch this situation, but the world Football Regulations that will come into effect from January next year will address this issue.
All teams in the Six Nations will be asked to avoid clashes that could negatively impact spectators and TV viewers with cardiovascular disease.
Abbey Tierney, chief executive of the Welsh Rugby Union, said: “Kits’ color clashes are changing the way you watch the match, and I completely sympathize with those whose enjoyment is affected as a result.”
Six Nations guidelines will stipulate that visiting teams must wear change kits where a color match has been specified.
This means Ireland will wear the change strip in Cardiff next year, if both kits remain the same.
Wales' current change strip is black, which would not have avoided the issue at Dublin's Aviva Stadium on Saturday.
“Our current away kit is black, we have used green in the recent past,” Ms Tierney said.
“None of these examples are particularly helpful in solving this problem, and in addition, the color red in Wales is not only traditional, it is part of our culture.”
There are other ways around these problems, she added, and kits with “significantly different designs” can help avoid the problem.
If one team wears jerseys and the other wears stripes, for example, colors become “largely irrelevant,” she said.
“But we are thinking carefully about a solution that suits everyone,” she added.
Read more:
The Six Nations free rule could have a 'devastating impact' on rugby
Six Nations backer CVC is in talks to buy Runescape Maker for £900m
“We realize that this is a serious issue for many fans, and we take it very seriously ourselves.
“It is unfortunate that we did not reach a decision that works for everyone this season, but I can confirm that we are fully committed to correcting this in the next equipment cycle.”