I looked up Hypnagogia and if I'm not mistaken, it describes that period of time between getting ready to sleep and falling asleep, and lots of stuff can happen in there, with one of them hallucinations. But there are causes for those things, and THAT'S the issue for you. You concluded your last post by saying maybe you're just tired, so exercise more regular, get plenty to eat and stay hydrated, and go to bed at certain times and get at least eight hours... if you are less than the age of 25, you'll need to sleep more like ten hours, but only if your body will go that far.
Well, that psych had a mouthful to say there! Does your friend who has the same problems of you, does he have that diagnosis? I'm sorry, Hypnagogia sounds sort of unusual. Do YOU think that's what it is? Did the psych offer any help with that?
Let me go back to something I brought up before. Do you spend time on a computer? When I used to work, I did some overtime, day after day, hours beyond usual time, into the dark, until I about blacked out and nearly fell out of my chair. I became terrified riding home in the car, I was just an anxious wreck. Well, THAT can be helped by of course not doing too much overtime with computers, and when normally working on or enjoying the computer, then every hour or so, getting up and finding a window to look out of for a spell, to rest the eyes, the farther they can see to the horizon, the better they will rest. And like I said, if you and your friend can find something similar you do the same, like certain video games, put those aside and only play regular ones and do not play those ones as long.
As I've been told by a psychologist, I'm most likely experiencing macropsic hallucinations derived from Hypnagogia. Totally harmless, I guess when it happens, I'm just tired.
I don't think I can offer much help, except to tell you my experiences that are similar. I am older and take a lot of medications for different health issues I have, and the medicines can make me see things like you see when you close your eyes. But I don't get them when I go to sleep, just when I close my eyes during regular wakeful times, like in the evening when I pray before bedtime. Once my head hits the pillow, I don't have that. My eyes are very blurry and watery from my meds, so could be that's what does it. So, if you take any medicines at all, and also eating food before bedtime can sometimes cause nightmares so that might have something to do with it, then you might want to change meds and food habits.
But now, I also have a lot of anxiety, I take medicine for that, too, and so there are times when I am filled with fear, especially when I pray and am asking for help, and so when I close my eyes to pray, ordinary visuals with the eyes shut take on a scary appearance...so I wind up sometimes having to pray with my eyes open! Could be if you can work through any fears you may have in general, you won't have as many episodes of it. And then sleeping enough, exercising regularly and finding interests that occupy your mind can release tension that comes from anxiety, we live in a stressful world after all, and also it helps to talk to someone about any fears you have... there are psychology clinics you can go to for a few visits and someone there can talk you thru this process, or just a good friend, or a relative who has time to listen.
One more thing, if you and your friend both do some of the same activities, like video games, for example, especially some that are kind of scary, COULD be if you cut back, you will have less visuals. Also, eye strain from being on a computer without resting your eyes regularly might cause some visuals. Last thing I can think of, one time I was asleep and I woke up with my eyes closed and was listening to some really beautiful music on the TV, and talk about some visuals, but they were beautiful visuals, so makes me think if you put on a little soft music that is pleasant, your visuals might be easier to "look" at.