Welcome!
I've experienced that too and I believe it means your 3rd eye is alert and looking around. Have you had other experiences yet of movement, images, etc?

If not and you want to get further you may have to choose better circumstances for it to go further--another time of evening when you can be alone and have the fan turned off, maybe less meat and sweets for meals--all that stuff that forces one to decide if the experience is worth the adjustments.

If that doesn't apply, perhaps it doesn't go further because you haven't established any intent to do so. 
Keep your first intents simple and loving.  Maybe do some reading on what to expect---it's quite an adventure and a few sentences won't fully prepare you.  Enjoy!

You've done more than I have, streamer!
I didn't know for a long time that not everyone saw 'darkness' that way.  If I'm in that 'darkness' and focus my eyes up toward my third eye, a blue light appears slowly behind craggy rocky shapes,--- the 'blue grotto'? If I stay calm the rocky shapes become animated, and a scene or parable develops that turns out to explain something in my future.
After reading your question I had to go to the grocery store and while there I reviewed what those images had led to.  Then I figured one out for which I hadn't realized the meaning before--excuse me while I weep awhile at that lost opportunity.  We're not allowed to cuss here, not that I generally do. Oh....
So, I guess I'd consider it the gateway to the amazing   Void. You do so much with yours, what else are you seeking about it? Thanks tho  for the nudge towards understanding.  Sometimes it hurts.

I think the best way to do it would be as a result of gradual spiritual conditionning, training, experiences. I think it should only be done in dim light as it is so sensitive. My situation is an aberration and seems sci-fi incredible but I'll post it anyway because I know it's true---
My third eye was awakened prematurely by a man staring at me hatefully for a lengthy time 'to put the fear of god' in me. After being awakened and thinking that only the godly could call it up, it/I recognized the hatred that man had, and the third eye/I? 'panicked', started darting around, stretching its stem and getting caught up in its own trail, on and on.
I've had adepts who just met me and knew nothing of that event draw cartoons of me with my third eye dangling out of my forehead that gave me pain to look at.  Others will cover their crystals with their hands or fabric so I don't --?--what? fly off on a colored ray of light? (which has felt like it's almost happened.) One result was a sense of terror which kept me from pursuing any of the spiritual experiences that this extended third-eye condition probably led to.
When I was fearful I hallucinated demons. I had migraines for 40 years that caused me to come close to killing myself. I've had several 'accidents' to the head with baseball bats, etc that Guidance told me were necessary to counteract the effects of what we call the third eye.
So now I am highly respectful of spiritual traditions while always looking for ways I can ease this problem.  Many of the topics discussed here cause areas of my third eye entanglements to relax, lose their fear. It's still overly -active/alert but it's better. I am so grateful to Bruce Moen and this community for the  love they impart to spiritual seeking. Sometimes when I try to thank them they must think I'm some sort of sycophant but I have looked so long for such help.
Aha, you didn't ask for all that, did you? Well, I just wanted to remind you to respect it, not over-use it, , but enjoy and learn from the experiences it brings.
When it's active (when the 3-d blackness is perceived, ask for an answer that affects your spirit, or for a contact with a deceased loved one; it's ready to provide you with ansers, not to vex you. And don't forget to turn off the ceiling fan, as I think it inhibits the necessary energy flows.    
bets

Concerning the 3d-blackness, today I wanted to go there (or at least my version of it) and I couldn't! Some things don't work while you're thinking about it. Usually I often come to a black space, though mostly there are star dots within it so not totally black. It's the "Where do you wanna go today"- place for me.

Spooky

Bets, thanks for the story.  I relate to it because I feel an agitation in the middle of my forhead when hateful energy is directed at me.  I've learned to use it as a defense mechanism.  Whenever I feel the "agitation" I start looking around the room for someone who may have an "issue" with me.  If I find the person I'll try to diffuse the situation before it gets worse.  Sometimes there's no one around and if the feeling continues I'll make phone calls in an attempt to find the source of the agitation.  Sometimes it works sometimes I never find the source.  There are times when I'm about to say something that is harmful or hateful to someone and I feel the same uncomfortable agitation before I say it.  On occasion I have ignored it and spoke my mind but had to pay the price for it afterword.  Needless to say I've learned not to ignore it.  It's real.

Getting back to the topic.  Thanks, Spooky, for your comments.  Someday, I hope, I will get comfortable with the "BLack" and use it like you do.  I think there's a layer of fear that is preventing me from doing that right now.  I'm working on it.

Spooky,
It's those stardots you mentioned that will morph into shapes that eventually become animated, right?  If you just very slightly change the focus of your 2 eyes, the light in the darkness re-organizes itself diffferently. Slowly with pauses, so it can do whatever it 's got a mind to do. (See that's almost a sacrilege to say it that way, because I believe it is attached or tuned in to the higest Mind I can reach.
So now it twists abit to show annoyance and i do apologize,-- and it eases.) Like 'streamer said it is very active on its own, and full control does not seem to be an option for me.

Bets, I don't recall ever having had a forhead injury and I'm not vegetarian.  When I was 8, I had a brain concussion and amnesia for 3 days but I doubt if that has anything to do with  this "agitation" of the middle forhead.  This sensitivity has just slowly developed over the last 20 years or so.  In the early 70's I did experiment with LSD.  The shock of one of those experiences made me do a 180 degree turn in my life.  I've been seeking answers to the mystical ever since.  So i guess you could say this is an indirect cause of the forhead/third eye sensitivity.  But it was years after I stopped experimenting that I started to notice the agitation.