Meditation = deep thought and consideration.
without meditation, we do not have knowledge.
Martial arts requires deep thought, and there are many methods to it: forms, breaking, breathing, silent contemplation.
My guess is, the methods of meditation you were doing were off the wall. Seeing things? That is neither the goal nor the result of meditation. What you were doing was something wholly un-martial.
I have been part of schools whose idea of meditation was to pray. This was a bad experience; I seek religious guidance from my church and pastor, not my martial arts instructor. I do not go to my pastor to pick out parts of the Bible to provide me my self-defense curriculum, and I do not go to my martial arts instructor to provide me my religious instruction. It is hard enough to find the right church and the right martial arts school - why would anyone complicate the search for either by making one a requisite of the other?? So, I soon left these places.
But, I do meditate by practicing my forms, and I meditate by breaking (boards and cinderblocks). Occasionally, I mediate (on the subject of martial arts) by simply sitting under a tree at the fortuitously local arboretum.