The protestant reformation had a large impact on the Catholic Church, but even know much of the reformers concerns apply to the Eastern Orthodox Church as well, it seems that there never was a reformation in this Church. How so?
I don’t know if the Council of Chalcedon (AD 451) is relevant, but it’s worth mentioning that the at this meeting, equal honour was assigned to the Church of Constantinople and the Church of Rome. The council gave the title “patriarch” to the most prominent bishops and concluded that the church of Constantinople (“New Rome”) held a position of authority similar to that of “Old Rome.” The Pope rejected that particular article, while accepting the rest of the Chalcedonian Creed. Eventually, the rift between Rome and Constantinople led to the Great Schism when the Oriental Orthodox split off from Catholic and Eastern Orthodox alike as a consequence of the Council of Chalcedon.
Perhaps the events of the 16th century are more relevant because they have to do with the events surrounding Luther and the Protestant Reformation. Here is a partial quote from an article I found:
Philipp Melanchthon worked with Demetrios Mysos, a deacon sent by the patriarch of Constantinople to find out about the new religious movement in Germany, to complete a Greek translation/paraphrase of the Augsburg Confession, called the Augustana Graeca. Mysos was supposed to take the document back to Constantinople, but he died on the journey. Some Lutheran theologians at Tubingen tried to establish an even closer connection. The "Eastern Orthodoxy" entry in The Oxford Encyclopedia of the Reformation, edited by Hans J. Hillerbrand, reports: In 1575 the Lutherans sent the Augustana Graeca to Patriarch Jeremias II (d. 1595), asking his opinion. There ensued over the next six years a friendly but candid exchange of extensive doctrinal ... Source: https://www.christianitytoday.com/history/2008/august/what-did-reformers-think-about-eastern-orthodox-church.html
I found this reference to events that took place during the 17th century:
In Eastern Orthodox Church history, the Old Believers or Old Ritualists are Eastern Orthodox Christians who maintain the liturgical and ritual practices of the Eastern Orthodox Church as they existed prior to the reforms of Patriarch Nikon of Moscow between 1652 and 1666. Resisting the accommodation of Russian piety to the contemporary forms of Greek Orthodox worship, these Christians were anathematized, together with their ritual, in a Synod of 1666–1667, producing a division in Eastern Europe between the Old Believers and those who followed the state church in its condemnation of the Old Rite. Source: https://en.wikipedia.org/wiki/Old_Believers
Then we have the Greek Old Calendarist schism within the Greek Orthodox Church which occurred in the early 20th century. Both sides of this schism refused to recognize each other’s baptisms as a consequence of this dogmatization of the calendar. Source: https://www.quora.com/Why-did-the-Orthodox-Church-never-suffer-through-a-Protestant-Reformation-like-the-Catholic-Church
Finally, I found this article, but it must be noted that there are no sources identified to back up the claims being made:
There are four Reformed Orthodox Churches in Eastern Christianity. The term "Reformed Orthodox" is given to an attempted Protestant Reformation of the Orthodox Christian beliefs and practices of the Eastern and Oriental Orthodox Churches. Presently the Ukrainian Lutheran Church, the Malankara Mar Thoma Syrian Church, St. Thomas Evangelical Church of India, Evangelical Baptist Union of Georgia, Ukrainian Reformed Orthodox Church (ru), Evangelical Orthodox Church and the Nihon Christ Kyodan Miyakojima Church (ja) are revised according to Lutheran, Anglican, Baptists and Pentecostal Protestant reforms, respectively. Another term applied primarily to the reformation of Non-Chalcedonianism is Protestant Oriental. Source: https://en.wikipedia.org/wiki/Reformed_Orthodox
I do so hope someone with expertise in this subject will post an answer. I simply did a bit of research because I wanted to find out more about the history of the Eastern Orthodox Church.