The Chosen

The film takes place in Brooklyn, beginning near the conclusion of the Second World War. Reuven Malter is a middle-class Modern Orthodox Jewish teenager, and the son of David Malter, a college professor and dedicated Zionist. At a baseball game between their schools, Reuven meets Danny Saunders, another Jewish teenage boy. At first, the meeting is one of enmity since Danny accidentally injures Reuven's eye during the game; this results in Reuven wearing an eye patch for a good portion of the movie. Danny goes to visit Reuven at the hospital to apologize--both boys are surprised to learn that Danny already knows David Malter from the library--and the teens gradually become friends, despite their differing backgrounds. Danny is the eldest son of a Hasidic Rebbe, the dynastic leader of the Hasidic Jews in that neighborhood. However, Danny is somewhat distant from him. Danny has also been going to the nearby public library and reading books on psychology. He amazes Reuven with his ability to remember word-for-word what he has read. It turns out that David Malter has been showing him these books. Reuven and Danny also go to a Sabbath service in Danny's Hasidic community as Danny is eager for Reuven to meet his father. Danny's father approves of their friendship - however, Rebbe Saunders disapproves of Prof. Malter's writings, which doesn't surprise anyone. Rebbe Saunders also wishes for Danny to become a rabbi and to eventually succeed him in leading his Hasidic community in keeping with the tradition of several generations but Danny doesn't seem very eager to pursue this.
Some time later, the boys begin attending Hirsch College, a Jewish university. While Reuven finds college life exciting and challenging, Danny finds it harder to adjust, especially in one of his psychology courses where his professor denounces Sigmund Freud whom Danny was fascinated by. During this time, World War II ends and Reuven takes Danny to his first movie. After the movie, a newsreel begins and broadcasts the horrors of the concentration camps and the genocide of over six million Jews in Europe; Rebbe Saunders is horror-stricken by this too. Shortly after this, the question arises of whether a Jewish state should be formed in Palestine, as many European Jews have emigrated there. This results in Prof. Malter heading to Chicago for a conference to debate the issue and Reuven goes to stay with Danny's family. He meets the rest of the family, including Danny's sister Shaindel, whom he begins to have feelings for. Reuven is eventually accepted by the family and attends many services and ceremonies, including a Hasidic wedding. However, during the reception, Danny gently breaks the news to Reuven that he can't pursue a relationship with Shaindel, because her future marriage has already been arranged.
After Prof. Malter returns, he becomes engrossed in the creation of Israel and writes several articles and speeches about it. This controversial issue, however, causes friction between Hasidic and Modern Orthodox Jews. While the Modern Orthodox Jews believe that creating a Jewish state in Palestine is the right thing to do, the Hasidic Jews believe that only the Messiah will grant them Palestine. This results in Rebbe Saunders excommunicating Reuven from the family and thus causes growing friction between Danny and Reuven. Eventually, the United Nations passes a resolution that partitions the Palestine Mandate territory, creating Israel. Rebbe Saunders allows Reuven to come back and the two friends reconcile. It is also revealed that Danny plans to transfer to Columbia University to pursue a psychology degree and Reuven plans to be a rabbi. Rebbe Saunders approves of Danny's plans and finally reveals why he was so distant from Danny: when Danny was younger, his father was impressed by how much Danny remembered when he had read something; however, blessed with this great ability, Danny became a know-it-all who felt indifferent towards other people and their troubles. As a result, Rebbe Saunders had to teach him empathy and the wisdom and pain of being alone by distancing himself from Danny and thus "teaching through silence", just as Rebbe Saunders' own father had taught him. Rebbe Saunders also tells Danny to keep his Jewish faith. This results in a tearful Danny reconciling with his father. In the end, Danny and his father now have a good relationship again, although Danny changes his appearance, such as shaving his beard, which had been an important part of his Hasidic tradition, and adopting more modern-style clothing rather than the traditional black-colored suits and robes that he had worn up till then. Danny and Reuven part ways as Danny prepares for his new life.

Question: Why does Reuven have to wear an eye patch for most of the movie?
Answer: Danny accidentally injured her during the game