Its like a plastic film with the prism correction built it. The doctor had a woman cut the film and put on my left eyeglass. So light is bent to correct strabismus. I never had binocular vision. I can trip and fall because depth perception off because of strabismus. So now we are waiting to see what my brain does with the prism. Will I develop 3d vision? This is actually a big question if someone my age can still develop 3d or binocular vision. Its something that develops in childhood. But I never had it. I couldn't play softball because I couldn't track ball in 3d space. But I could bowl and play kickball because the ball is rolling on the ground so I could track it.