What constitutes “normal” changes from one era to the next.

What constitutes a disability has depended on who was judging and who was being judged. A lot depends on things such as where you are, what you are doing, and whether you feel safe or excluded.
For example, a beggar, a war veteran, a baby, and a musician may all have shared the experiences of being blind, but stigma, discrimination, and access to resources would be different for each.
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