The phrase "eye-opening" is often used to describe something that is surprising, enlightening or revealing. However, there are several antonyms that can be used to describe the opposite of an eye-opening experience. For instance, "dull" can describe a situation that is boring, uninteresting, or lacking in excitement. "Unremarkable" refers to something that is ordinary, unexceptional or typical. "Unsurprising" describes an outcome or event that was predictable and lacked the element of surprise. Similarly, "uninspiring" refers to something that fails to capture the imagination or motivate action. Overall, antonyms for "eye-opening" can range from mundane to unimpressive, but they all lack the ability to captivate the audience's attention.