Great question! Fortunately, there are already several posts asking the same, and you may want to read through some of the answers:

https://www.reddit.com/r/AskHistorians/comments/3bqsd7/how_did_the_orthodox_church_respond_to_the/

https://www.reddit.com/r/AskHistorians/comments/29js6e/how_did_the_reformation_affect_the_orthodox_world/

https://www.reddit.com/r/AskHistorians/comments/26jric/how_did_the_eastern_orthodox_church_feel_about/

https://www.reddit.com/r/AskHistorians/comments/1ym04m/to_what_extent_if_at_all_did_the_protestant/

Feel free to ask further questions!