Contacts can change polarization of light, lower oxygen levels and alter/block natural frequencies of sunlight hitting the eye which mess up the signals traveling from the retina through central retina pathway to hypothalamus
Discussion
Would glasses do the same thing?
Yes, but light can travel around glasses via the photoelectric effect. And you can easily wear them lower on your nose if for reading only. Plus CR39 polycarbonate lenses permit more UV light than traditional PC.