Red-eye was a condition that the Ood were commonly afflicted with. Its symptoms were bright red eyes, rabid temperament and anti-human sentiment.
When the Beast took control of the Ood working in Sanctuary Base 6 on Krop Tor, it resulted in the Ood becoming subject to red-eye, signifying their possession. (TV: The Impossible Planet [+]Matt Jones, Doctor Who series 2 (BBC One, 2006)., The Satan Pit [+]Matt Jones, Doctor Who series 2 (BBC One, 2006).)
On the Ood Sphere, red-eye was caused by the subconscious of the Ood Brain reemerging amongst the Ood after 200 years of slavery, due mostly to the sabotage of Ood Operations's systems by the Friends of the Ood. It led to the Revolution of the Ood in 4126 and the freedom of the Ood. (TV: Planet of the Ood [+]Keith Temple, Doctor Who series 4 (BBC One, 2008).)
When telepathically mediating through time, members of the Ood Council led by the Ood Elder became afflicted with red-eye upon receiving a vision which they used to warn the Tenth Doctor that the return of the Master was inevitable. (TV: The End of Time [+]Russell T Davies, Doctor Who Christmas Special 2009 and New Year Special 2010 (BBC One, 2009-2010).)
The Eleventh Doctor once encountered an Ood with red-eye. (COMIC: Take a Bow (Tie) [+]Error: Code 2 - no data stored in variables, cache or SMW.)
An Ood with red-eye and a bandaged head appeared on a television advertisement for Lawyers Against Time Lords. (COMIC: No Win, No Fez [+]Error: Code 2 - no data stored in variables, cache or SMW.)