Hitomi no naka no houmonsha (1977)

Komori Tiaki is a budding tennis student, however one day in training her coach hits the ball into her eye accidentally. She is taken to hospital but it advised that she will never regain the sight in her eye. Her coach knows of a mysterious doctor 'Blackjack' who lives in a secluded house, who might be able to help. 'Blackjack' agrees to do the operation, but for a 'substantial reward'! Her sight is regained, but now she starts to see a mysterious man that is invisible to those around her....