Some are in subtle ways and some are in the more obvious ways.
It is not a physical flaw, but the inability of the characters to see a person for whom they truly are. Through these three mediums the true nature of the works characters are exposed, by stripping away the innuendo, deceit and superficiality that initially cloaks each character Lear, too, is stripped down: stripped of his sovereignty, his train, and respect from his daughters.
Similarly to Lear, Gloucester was unable to see which of his children truly loved him. When one goes against the natural order, chaos will follow. However even though Lear may not be able to see things completely clear which are close to him.
Yet, although Goneril certainly errs in betraying the very father that bestowed a large dominion upon her, King Lear deserves much of the blame for Goneril's haughtiness. In the tragedy King Lear, written by William Shakespeare and in the novel The Stone Angel, written by Margaret Laurence, the term blindness has an entirely different meaning.
King Lear is in many ways about nothing.
Lear's tragic flaw is the division of his kingdom and his inability to see the true natures of people because of his pride while his scathing anger is also shown to override his judgment Gloucester tells him that sight comes from within.
I am true to my emotions.
Any subject. Look with thine ears: see how yond justice rails upon yond simple thief.