The AFL umpires wear blue uniforms primarily to support the charity OneSight, which provides essential eye care to Australians in need. The blue color represents the OneSight Foundation logo, and AFL umpires wear these blue uniforms during specific rounds as part of a campaign in partnership with OPSM, the official eye care partner of the AFL. This initiative aims to raise awareness and funds to help people with vision problems, especially children, across Australia. The use of blue uniforms for this cause marks a charitable and symbolic change from their usual attire in the AFL.

In addition, AFL umpires sometimes wear blue uniforms when there might be a clash with teams wearing yellow or green, making blue an alternative to avoid jersey conflicts.