Little House on the Prairie (1974)

S4E21 I'll Be Waving As You Drive Away (1)

Mary finds herself falling for Seth, but her world takes a turn when her vision begins to deteriorate. Concerned, Charles takes her to see a specialist, only to be heartbroken when he learns that Mary will inevitably lose her sight. Struggling with the weight of this news, Charles keeps it from Mary for some time. When she eventually loses her vision, the entire family is deeply affected, grappling with the emotional turmoil of her condition.