CommanderBond.net tem comentários de Mads Mikkelsen de uma entrevista.
Mikkelsen also talks about the distinguishing feature of Le Chiffre–the scar above his eye. ‘The weeping blood is a disease. It is rare, but it’s like high blood pressure in certain situations will make people start bleeding from their nose, and occasionally through their eyes, which is kind of scary.’
He explains that it worked especially well in Casino Royale‘s poker sequences between Bond and his character. ‘We liked the look of it because I was playing a lot of poker in this film and there is nothing more annoying than looking at a person that is unreadable because they only use one eye. It becomes blurry and unfocused and we really liked that detail.’
Wikipedia é um pouco mais específico
He suffers from haemolacria, which causes him to weep blood out of a damaged vessel in his left eye.