The story
The notion of ‘blindness’ comes from the lack of a through passage (the ‘eye’). Attested since 1583, and used figuratively since the mid-19th century.
Etymology from Wiktionary, CC BY-SA 4.0.
blind alley
Today it means: Used other than figuratively or idiomatically: see blind, alley. A street or passageway that leads nowhere. Full definition →