The phrase "hard on the eyes" can be used to describe something that is visually unappealing or difficult to look at. There are many synonyms for this phrase such as unattractive, unsightly, unpleasant, ugly, repulsive, ghastly, hideous, unappealing and distasteful. These words can be used to convey the message that something is not easy to watch or look at without causing discomfort or disgust to the viewers. Whether it's a person, object, or place, using a more descriptive synonym can help to better communicate exactly what it is about the subject matter that makes it so difficult to look at.