There is more than meets the eye.
There is more to reading than meets the eye.
more (to something) than meets the eyeFig. [there are] hidden values or facts regarding something. There is more to that problem than meets the eye. What makes you think that there is more than meets the eye?
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
more (to somebody/something) than meets the eyemore interesting or complicated than someone or something appears at first There is more to her death than meets the eye – she was probably murdered. There must be more to him than meets the eye, or else why would she be interested in him?Usage notes: also used in the form less than meets the eye (not as interesting or complicated as it appears): Unfortunately, with her boyfriend, there is less than meets the eye.
Cambridge Dictionary of American Idioms Copyright © Cambridge University Press 2006. Reproduced with permission.