Dark Victory (1939)

Judith Traherne is at the height of young society when Dr. Frederick Steele diagnoses a brain tumor. After surgery, she falls in love with Steele. The doctor tells her secretary that the tumor will come back and eventually kill her. Learning this, Judith becomes manic and depressive. Her horse trainer Michael, who loves her, tells her to get as much out of life as she can. She marries Steele who intends to find a cure for her illness. As he goes off to a conference in New York failing eyesight indicates to Judith that she is dying.