In 5e, Blindness is described in the PHB as:
A blinded creature can't see and automatically fails any ability check that requires sight. Attack rolls against the creature have advantage, and the creature's attack rolls have disadvantage
Grappling is described as a special Melee attack that requires an ability check (STR vs STR or DEX).
Does defending against a Grapple require sight and thus automatically fail if you are blind?