As Shakespeare painted, blindness is not only visible to the body, it is also a psychological defect in the emergence of several characters in this tragedy.
King Lear and Count Gloucester are the two men who make up the "double conspiracy" of the tragedy due to lack of sight and mental blindness.
True vision is not the product of properly functioning optic nerves - it is the ability to keenly observe one's situation and to deduce, interpret, and decipher. A clinically blind man walking down the street with a cane may, in this definition of "sight," be able to "see" more than a person with 20/20 vision.
In this definition of "sight," a Fool may be sagacious and a King may be foolish.
This is exactly the case in William Shakespeare's famed play, King Lear.
Two characters, King Lear and the Fool, represent the juxtaposition of the two contrasting qualities of blindness and the ability to perceive, in their interactions with one another, with others, and their general behavior.
Throughout the text there are many references both to literal and metaphorical vision and blindness.
Nowhere is this more true than when it comes to fathers seeing (or rather not seeing) the true worth of their children.
Fundamentally, he does not discern how ill-judged is his staging of the public love-test as a basis on which the division of his kingdom will occur.
Meanwhile, Gloucester is so blind to the truth that he immediately believes the lies of a son who ‘hath been out nine years’ against one whose honesty and loyalty he has witnessed every day.