Some optical illusions are funny and others pretty challenging, but there is one that is downright serious.
It's called the Amsler grid and the National Eye Institute suggests people try it out because it checks for problems with your optic nerve.
While it's best to print it out, you can also look at the one above. To use it, cover up one eye and stare at the dot in the middle. If any lines are missing or wavy, or if you see any dark areas, weird shaped boxes or blurry edges, then something might be up with your vision and you should go to a doctor.
Be sure to do the test for each eye and remember - the earlier you diagnose a problem, the easier it should be to address.
Photo Credit: Getty