Seven perfect chakras are a rarity. If you’re all upper and no lower you’ll be relatively away with the fairies, but relatively pleasant with it. If you add root to this combo then kundalini activation is a possibility – keep your governor and main meridians connected (ie. tip of tongue to front of palate) to avoid energetic spikies if you actively pursue this.
Visions derive from pulses from a full upper dan tian dosing your sixth chakra. If you notice any brilliant metallic light strobing during them, that’s your 6th and 7th temporarily fusing together.