So you are trying to see if a student has opened a document you shared or created with them right? Perhaps the student struggled but did not make any edits to the doc. Well there is a way to do this for any Google product (slides, docs, sheets, etc.) using a new button: the squiggly arrow.
It allows you to see everyone in your domain that has looked at a particular document/slide/sheet. It is quite helpful and something I had forgotten about until I had a staff request. So thank you so much for asking! It looks like below but I have blocked out the names for privacy. You will notice that you can see those in our domain and the other selection being those that it has been shared with. Then under view trend you can see the dates it has been opened which is helpful for seeing how long (days) a student might have worked on a particular document.