‘Little House on the Prairie:’ Here’s the Reason Why the Real Mary Ingalls Went Blind

Of all the hardships on Little House on the Prairie, this Mary Ingalls (Melissa Sue Anderson) going blind was one of the saddest. When it comes to how the real Mary Ingalls went bind, though, the story is still a little bit muddled.

Here’s what we know about the differences between Mary Ingalls’ blindness in the television series, the novel, and real life.

Mary Ingalls goes blind in the television series ‘Little House on the Prairie’ 

She’s the eldest of the Ingalls girls. Although she’s smart and beautiful, Mary doesn’t have it easy. On the television series, Little House on the Prairie, Mary Ingalls falls deathly ill in a two-part episode, needing surgery (“To Live With Fear.”) 

As she got older, this character had dreams of becoming a teacher. After studying for hours by candlelight for the state teacher’s exam, and complaining that her eyes are tired, Mary gets a shocking piece of news — she’s going blind. 

She completely loses her sight in the two-part episode, “I’ll Be Waving as You Drive Away.” The reason for this, Charles Ingalls is told, is her scarlet fever. After that, Mary Ingalls attends a school for the blind, where she meets her husband, a teacher named Adam. 

According to Little House on the Prairie’s website, though, in real life, Mary Ingalls never married or taught at this school. The reason for her blindness, however, may also different from the television series.

'Pilot' Episode of 'Little House on the Prairie'
‘Pilot’ Episode of ‘Little House on the Prairie’ | NBCU Photo Bank

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What is the real reason Mary Ingalls went blind?

In real life, Mary Ingalls went blind at the age of 14, her parents then sending her to the Iowa School for the Blind. The character’s blindness was somewhat delayed in the television series, according to one website, “for fear it would limit storyline options.” 

Even the reason behind Mary Ingall’s blindness might’ve been altered in different tellings of her story. One scientific journal states that the reason behind permanent blindness caused by scarlet fever is uncertain. It could be “a postinfectious autoimmune phenomenon.” It’s more likely, however, that Mary Ingalls went blind for another reason.

CNN reports that Wilder wrote letters to her daughter, Rose, making reference to “some sort of spinal sickness.” The letter also mentions that Mary saw a specialist in Chicago who said “the nerves of her eyes were paralyzed and there was no hope.”

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What is the reason Mary Ingalls goes blind in Wilder’s novel?

Similar to the television series, in the Little House on the Prairie novel, the author tweaks Mary Ingall’s illness, making it scarlet fever. This change could be because of the common illnesses of the time period.

According to CNN, “it could be because Wilder and her editors thought scarlet fever would be more relatable to her readers. Scarlet fever is mentioned in other books from the period, including Little Women and Frankenstein.”