If you're here I'm assuming you're either looking for a guide to find all the eyes which you can find here:
or you found a similar problem to me which is that you've already collected every eye and now there are none in the game so you can't earn the challenge. As far as I know it is impossible to earn the challenge at the moment if you already collected all the eyes prior to these new challenges being added unless you delete your save game and restart. If you don't feel like waiting then that should work but I haven't tried it so do so at your own risk. Other than that there isn't much you can do so I sent an email to the developers and will update this if I get a response. I hope as was able to help in someway and will hopefully return later with good news.
Edit: I just came back to tell everyone that I haven't gotten a response yet and it's been so long that I probably won't get one. I would like to thank the people in the comments for trying out some of the solutions and if you would like this challenge you can head down there and see what people have done.