Blindness is the condition of not having physical sight. In the United States those with the disability of blindness are entitled to certain government programs to help them due to the limitations imposed upon them by their disability. The legal definition of blindness in America is not absolute loss of vision, but an inability to see up to an acceptable range even with corrective lenses.
Blindness can be a condition from birth or be caused be a later accident or illness. Proper nutrition is able to prevent many forms of blindness.
Individuals can also be referred to as blind in a figurative sense as result of a failure to observe obvious realities, similar to the inability of the physically blind to see the world around them. Such examples include the blindness of liberals in regards to their own bias or irrationality in approach to political, economic, or social issues.
In the Bible, blindness is seen as a condition that occurs with extreme old age. For instance Isaac loses his sight as he ages leading him to be tricked by his son Jacob pretending to be Esau. In the New Testament, Jesus cured the blind and restored their sight. The blindness of the atheist towards the light of God's glory is an extensive metaphor for blindness apparent throughout the Bible.