Is Doctor Faustus misled by the devil or is he willfully blind to his situation in Marlowe's Doctor Faustus?
As to whether Faustus is misled about or willfully self-blinded to his situation, it is difficult to argue either of these points from the text. Marlowe's text makes it rather clear that Faustus is deliberate and precise in his calculations, considerations and estimations that lead to his choices. He knows precisely what he does not want and why. He knows precisely what he does want and why. He knows precisely what his end objectives are and why.
First, he is a distinguished scholar of every academic field there was. He has come to a juncture where he is to choose one field to devote his professorship to, to choose what to profess. He evaluates the essential foundations of each field and rejects them based upon disagreement with or flaws in the fundamental logic or premise of each.
Next, he examines the thus untried field of magic, necromancy, and enumerates its various strong points. Marlowe shows here that (1) Faustus craves further and deeper knowledge: he is still at heart a scholar, though an insatiable one; and (2) Faustus craves earthly rewards that he has previously set aside in the pursuit of knowledge: he now wants unlimited power and wealth to accompany his unlimited knowledge.
One thing that Faustus is is that he is deluded. He is deluded about what kind of and what degree of authority he has over the forces of Hell that he calls upon with his chants and incantations. He believes he can command according to his fancy. This deluded belief is strengthened by the apparent ease with which he confines Mephistophilis to his will on their first encounters. What Faustus does not understand is that it is Mephistophilis who confines Faustus and that it is Lucifer who confines Mephisto. This is where the mistaken flaw in Faustus's plan lies: he does not understand the powers that he is calling upon.
Another reason it is hard to argue either position is that Marlowe includes the Bad and the Good Angels and the Old Man who describe his situation quite well from both perspectives.
Faustus, repent; yet God will pity thee.
Thou art a spirit; God cannot pity thee.
Who buzzeth in mine ears I am a spirit?
Be I a devil, yet God may pity me;
Ay, God will pity me, if I repent.
Assuming that the question really relates to why Faustus refuses salvation in the end, the real reason he fails to accept salvation is that he has a mortal fear of suffering. Once Mephisto begins to threaten violence, Faustus quails with fear and succumbs to Mephisto's power over him. So while it is difficult to argue that he was blinded or misled, it is textually arguable that he was deluded about who would hold power over whom once his contract with the devil was signed: they had power over him, he was to find.
Thou traitor, Faustus, I arrest thy soul
For disobedience to my sovereign lord:
Revolt, or I'll in piece-meal tear thy flesh.
One comes to know through the chorus that Faustus became puffed up with pride for hisvast knowledge and scholarship and started indulging in black art of magic to attain super human powers. So in the very first scene of the drama we come to know that Faustus is dissapointed with all the branches of knowledge that he had so far mastered.Where knowledge should be a strength it turns out to be a weaknes for him.So herein liess the great tragic flaw in his character. with a craze to attain super human powers and supreme sensuos pleasures he utters ....divinity Adieu..These Metaphysics of magicians, And necromantic books are heavenly . He has no response to what the good angel has to tell him but he is carried away by the evil....he is easily glutted with conceit with the words of the Evil Angel. Curiously enouggh Mephostophilis, the champion of the christian heterodoxy begins to teach him the vices...which leads Faustus only to damnation.
My reading of the play suggests, in Christopher Marlowe's Doctor Faustus, Faustus is "willfully blind to the reality of his situation", as you said.
Dr. Faustus who is a profound scholar of Germany, famous and skillful physician, acts solely according to his own will. He, as the chorus comments in the prologue, is like Icarus who, because of his ambition, faces a disastrous downfall. This renowned scholar misuses his power being fascinated towards necromancy or black art. He seems not to be satisfied with what he has gained through his knowledge till now and tends to cross the limit. Here, for the first time, a signal alarms that something destructive he is going to call upon himself. It is his own choice, not the devils, which misleads him. He willingly brought more danger for himself by contracting with Lucifer and his companions and selling his soul to them, since he wanted to gain more power. He abuses his knowledge for the sake of power, and at the end, he has to pay a huge toll. This is why, in the epilogue, we see the chorus to say: "Whose deepness doth entice such forward wits/ To practise more than heavenly power permits."
In Mephostophilis' speeches there are alarming signs when he says: "Fools that will laugh on earth must weep in hell." or when he describes his own pathos by uttering : "Am not tormented with ten thousand hells,/ In being depriv'd of everlasting bliss?" Faustus, if thought carefully, should have come back from the hellish path he chose. But, he is blind by his gluttony and ambition. That is why, when the old man and the good angel alert him, he just ignores. Even if he tries to repent, again, he gets distracted by his crave for worldly pleasures offered by Lucifer and his companions. He lacks the moral strength to protest against them. He creates his own fate choosing the wrong path. Here, Faustus and Macbeth are much alike. Macbeth's cruelty can not be ignored by condemning the witches and Lady Macbeth, and Faustus' wrongdoing and tragic consequnce does not take place only because of the devils. Faustus starts first, then the devils work as spurs. It is simple that a person who does not pay heed to his well-wishers, becomes responsible for his own sufferings. Faustus, like Macbeth, chooses the evil path self-willingly to lead his life, and this results in a terrible ending.