Little House on the Prairie S05 E16 Blind Man's Bluff

"Together, a pioneering family faces a crucial test of its courage and its love!"

After a boy is in an accident, he pretends to be blind to keep his parents from getting divorced. Laura discovers that the boy isn't blind, but doesn't tell his parents because the boy pleads with her not to. The boy is involved in another accident and has a concussion. The concussion causes him to not remember his pretending to be blind.