I used to meditate but no longer do since I'm starting to trip (audial/visual hallucinations) very fast and the trip is usually not a good one. It is a very powerful natural psychedelic experience, comparable to third plateau of DXM at least... but controllable, unlike DXM.
They are just another distraction, like any other thought but visual. Just let them go. The bigger a deal you make of them, the harder that will be. Acknowledge them and let them go.
As you progress in your practice you might have spacial and auditory hallucinations too. The same thing applies here. Just let them go.