<Li> Almanzo Wilder (brother - in - law) </Li> <P> Mary Amelia Ingalls (January 10, 1865--October 20, 1928) was born near the town of Pepin, Wisconsin . She was the first child of Caroline and Charles Ingalls and older sister of author Laura Ingalls Wilder, known for her Little House on the Prairie book series . </P> <P> At the age of 14, Ingalls suffered an illness--thought to be scarlet fever--at the time believed to have caused her to lose her eyesight . A 2013 study published in the journal Pediatrics, concluded it was actually viral meningoencephalitis that caused Ingalls' blindness, based on evidence from first - hand accounts and newspaper reports of her illness as well as relevant school registries and epidemiologic data on blindness and infectious diseases . Between 1881 and 1889, Ingalls attended the Iowa Braille and Sight Saving School in Vinton, Iowa . </P> <P> The historical record is silent as to why Ingalls did not attend school during one year in that period, but she did finish the seven - year course of study in 1889 and graduated . She then returned home to De Smet, South Dakota, living with her parents . Ingalls contributed to the family income by making fly nets for horses . After her father died in 1902, Ingalls and her mother rented out a room in their home for extra income . Following her mother's death in April 1924, Ingalls lived for a time with her sister, Grace Ingalls Dow in Manchester, South Dakota . </P>

Was mary from little house on the prairie blind in real life