Experiences - Light and dark affecting how Swim trips...

[Lettish]

Last time Swim did ketamine, his trip was massively based on light and dark. He had consumed a more than average amount, and was heavily feeling the effects about an hour in. When his eyes were open, he could communicate with others in the room, he wasn't tripping/hallucinating, and felt fully in control. But when he closed his eyes (to darkness), that's when the tripping and hallucinating came into play. If he then opened his eyes to the light of the room, it was back to normal. Later that night (was morning really), the light was completely switched off, and his trips started again even with eyes open (as it was dark).

Is this normal with ketamine? Can anyone or most users relate to this happening to them?