The Crystal Glasses were a Shen Gong Wu that allowed the user to peer into the future. They first appeared in "The Crystal Glasses," where they were discovered in Russia. Jack had grabbed them but were later stolen by Vlad and returned to the Monks as a trap. Clay found out that he had Jack's Reversing Mirror and got suspicious. It was later used it to make Omi see his false future causing him to run away.
When activated, the Crystal Glasses allowed the user to peer into the future. However, with knowledge of this, the user could change the future by their reaction to their knowledge. The limits of how far into the future one can see with this Shen Gong Wu was unknown, for when Omi saw the future (although false) he saw one more distant, while Raimundo used the Wu for seeing the immediate future. When combined with the Reversing Mirror, they could reveal a false future.
These special glasses were first secretly used by Raimundo to annoy Omi during training, for he could see Omi's every move before he made it. Later, Omi used the glasses to see his future life, but was tricked by Vlad, who used the Reversing Mirror to show Omi a false outcome of his future.