The Blindness of Sinners According To The Scriptures.
1. If you have not been born again, then you are lost, dead in trespasses and sin. Blind to your condition before God.
Romans 3:11-13, 15-18 NKJV
There is none who understands; There is none who seeks after God.  They have all turned aside; They have together become unprofitable; There is none who does good, no, not one.”  “Their throat is an open tomb; With their tongues they have practiced deceit”; “The poison of asps is under their lips”;  “Their feet are swift to shed blood;  Destruction and misery are in their ways;  And the way of peace they have not known.”  “There is no fear of God before their eyes.”
2. When a person is lost and unsaved, they are blind to the beauty of Christ.
Isaiah 53:1 NKJV
Who has believed our report? And to whom has the arm of the LORD been revealed?
3. A lost and unsaved person is blind to the grace of God.
Romans 11:8 NKJV
Just as it is written: “God has given them a spirit of stupor, Eyes that they should not see And ears that they should not hear, To this very day.”
4. A lost and unsaved person is blind to the things of the Lord.
1 Corinthians 2:9-14 NKJV
But as it is written: “Eye has not seen, nor ear heard, Nor have entered into the heart of man The things which God has prepared for those who love Him.”  But God has revealed them to us through His Spirit. For the Spirit searches all things, yes, the deep things of God.  For what man knows the things of a man except the spirit of the man which is in him? Even so no one knows the things of God except the Spirit of God.  Now we have received, not the spirit of the world, but the Spirit who is from God, that we might know the things that have been freely given to us by God.  These things we also speak, not in words which man’s wisdom teaches but which the Holy Spirit teaches, comparing spiritual things with spiritual.  But the natural man does not receive the things of the Spirit of God, for they are foolishness to him; nor can he know them, because they are spiritually discerned.
5. If you are lost, then you are blind to the presence of Christ.
Jesus says in,
Revelation 3:18-21 NKJV
I counsel you to buy from Me gold refined in the fire, that you may be rich; and white garments, that you may be clothed, that the shame of your nakedness may not be revealed; and anoint your eyes with eye salve, that you may see.  As many as I love, I rebuke and chasten. Therefore be zealous and repent.  Behold, I stand at the door and knock. If anyone hears My voice and opens the door, I will come in to him and dine with him, and he with Me.  To him who overcomes I will grant to sit with Me on My throne, as I also overcame and sat down with My Father on His throne.
6. A lost person is blind to the need of the new birth.
John 3:3-7 NKJV
Jesus answered and said to him, “Most assuredly, I say to you, unless one is born again, he cannot see the kingdom of God.”  Nicodemus said to Him, “How can a man be born when he is old? Can he enter a second time into his mother’s womb and be born?”  Jesus answered, “Most assuredly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God.  That which is born of the flesh is flesh, and that which is born of the Spirit is spirit.  Do not marvel that I said to you, ‘You must be born again.’
7. The lost are blind to the deception and the evil that surrounds them.
Ephesians 2:2-3 NKJV
in which you once walked according to the course of this world, according to the prince of the power of the air, the spirit who now works in the sons of disobedience,  among whom also we all once conducted ourselves in the lusts of our flesh, fulfilling the desires of the flesh and of the mind, and were by nature children of wrath, just as the others.