Light is Judgment

35 Jesus heard that they had cast him out; and when he had found him, he said unto him, Dost thou believe on the Son of God?
36 He answered and said, Who is he, Lord, that I might believe on him?
37 And Jesus said unto him, Thou hast both seen him, and it is he that talketh with thee.
38 And he said, Lord, I believe. And he worshipped him.
39 And Jesus said, For judgment I am come into this world, that they which see not might see; and that they which see might be made blind.

Light is judgment. That is because when God brings light and I see, I cannot go back. I cannot say I have not seen. I am now accountable.
Jesus is pointing out that once a person sees, he will either be changed to fit the Truth, or he will change the Truth to fit him. He will ultimately do one or the other.
There cannot be neutrality because though he try to be neutral, he HAS seen. If I love light rather than darkness, I will be set free. But if I love darkness rather than the light God has given me, I will close my eyes to the light and live in a self-created darkness. My blindness will no longer be because I could not see. It will be because I refused to see.