We Are Not Blind Too, Are We?
Blindness can be categorized as natural or spiritual. Naturally, one might be born blind (like the man in John 9). Or a person might become blind in old age/later seasons of life (Isaac - Genesis 27:1, Eli - 1 Samuel 3:2). Blindness can be an inability to see. Blindness can also be an unwillingness to see.
Scripture often treats blindness as a symbol of the human inability or refusal to realize the importance of God and the gospel.
Natural and spiritual blindness cross paths in John chapter 9.