The Crimson Forever was a disease caused by the Great Life Jewels.
When the Great Life Jewels were separated, they produced a negative aura. This caused an exotic ailment, which induced a coma in its victims. The first stage of infection was a reddish color in the eyes of the infected, who stared into space while failing to respond to attempts at reviving them, thus providing the affliction with its name. Advanced stages were signaled by the skin of the victim turning entirely red. The only known survivor of Crimson Forever was Luke Skywalker, who, while under the fever, had intense dreams.
- The Complete Star Wars Encyclopedia, Vol. III, p. 211