I get dizzy and the room twists when on a computer or phone. what can cause dizziness/vertigo when looking at a computer or phone screen?

Visual vertigo: I have answered this question before. But the symptoms have been labeled as visual vertigo and is caused by moving the eyes back and forth for long periods of time. It is worse in the dark. You also may be benign positional vertigo which is caused by loose stones in the inner ear. Visual vertigo is more central (brain). See an neuro-otologist for a more specific diagnosis.

See neurologist: Visual stimuli seems to bring it on but needs to be worked up by a neurologist.