Blurring images is low pass filtering images. An artist’s blunted sight can have the same effects like blurring with computerized image processing. Sometimes you need to get rid of distracting details in order to get the whole picture.
Before computerized image processing was available, artists use simple techniques to blurr images. For example, squinting or looking at an image through a feather did the trick.
Squinting might help you to see things which you wouldn’t see with clear sight. It’s fine to try that with artwork which might have been intentionally created for such an exercise. But better make sure that it was an artist who created the face that is looking at you. I don’t know whether Mars ever has been inhabited by artists.
See also: Susana Martinez-Conde, Dave Conley, Hank Hine, Joan Kropf, Peter Tush, Andrea Ayala and Stephen L. Macknik: Marvels of illusion: illusion and perception in the art of Salvador Dali
2017-12-28, updated: 2021-02-28