When Karen Mills first met her father, she was 13 and getting off a plane in New York, her first time in America. He came to pick her up at the airport, but she realized right away that he couldn’t see her. He suffered from severe glaucoma. In all the years of their long-distance phone calls, he’d never told her that he was blind.

When she was growing up, Ms. Mills lived with her mother and three siblings in Accra, Ghana. Her mother sold candies to make a living, but it was barely enough to get by. Her mother often bought just enough food for the children, then swore she wasn’t hungry. Ms. Mills was frequently sent home from school because her family couldn’t pay the tuition.

Her father, who had left the family and moved overseas, called one day to say that she and her three siblings should join him in America, where they could get a free education. As Ms. Mills prepared for the trip, she dreamed of the long hours she would spend with the father she’d never really known. They could cook meals and play sports together, she thought, like the families she saw on TV.