The phrase "most eye opening" can be replaced with numerous synonyms that convey the same meaning. Some synonyms that come to mind include "enlightening," "revealing," "surprising," and "mind-blowing." Other words that can be used include "astounding, "stunning," "shocking," and "jaw-dropping." These synonyms can be used to describe experiences that broaden one's perspective or change their view of a particular subject matter. For instance, a visit to a new city or a conversation with a person that has a different worldview can be described as "eye-opening" because they expose one to new experiences and ideas. In summary, using synonyms is a great way to add variety to one's writing.