You're talking about 2 different things. Clairvoyance(seeing visions) and photokinesis(manipulating light through will alone by psychokinesis). I would say clairvoyance or any psychic ability does have to do with the third eye. Any of those. You just THINK that it isn't open or you're unsure of it. But if(if you're naturally clairvoyant) you've ever saw things bumping in your mind at night like faces, random places ect. then your third eye is open for sure. To develop it I would say try finding methods online. Master the art of visualization(it's really important), break the wall of doubt, practice psychomentry precognition or postcongition if you wish, practice divination, be creative and accept anything you get even if it's random(they mostly make sense to others or yourself later) and follow your intuition at all times.
Developing photokinesis is a whole other thing but it does have to do with psychics and the third eye. But just so you know the third eye is nothing evil or stuff like that. Hollywood and the medias usually makes that crap.