Colorful cluster in the center of my vision for several years. What could it be?

I have had a small, round cluster of multicolored dots in the middle of my vision for several years now. It hasn't worsened over time and it doesn't interfere with my daily activities so I haven't bothered questioning it until I found this website and thought I might as well ask.

I can't see it ALL the time, but it always fades into view when I stare in one spot for a few seconds, then stays visible for 1 or 2 minutes regardless of how much I look around, then fades out of view. The dots in the cluster are all either lime green, pinkish red, or a very deep blue-violet. The dots move around in a quick random pattern similar to TV static, but they always stay in the exact center of my vision in a relatively circular shape that doesn't change size except when fading into/out of view. The cluster is translucent like an afterimage, so it doesn't create a blind spot.

The cluster is visible in both of my eyes equally and it appears larger/brighter when I'm very tired, which means it probably isn't a physical problem in my eyes. I get migraines a couple times a year and I do experience a visual aura right before the migraine, but it's always just a blind spot in my peripheral vision that disappears after about ten minutes. The appearance of the cluster of dots is never affected by my migraines so I don't think it's related to that either. Any ideas as to what it could be?

The symptoms you're describing sound unique and are not characteristic of common ocular conditions. However, there are some possibilities to consider:

Phosphenes: These are the phenomenon of seeing light without light actually entering the eye. They are often described as spontaneous flashes or "snow" and can be caused by mechanical action on the retina, among other factors.
Visual Snow: This is a neurological condition where individuals see what looks like "static" similar to an untuned TV. The symptoms can be constant or come and go. It's not well-understood, but it's distinct from migraine aura. The fact that you mention it resembles "TV static" and that it's more noticeable when you're tired makes me think of this possibility.
Persistent Afterimage: Sometimes, looking at a bright light source can produce a persistent afterimage. However, these usually don't last very long and are not typically multicolored or static-like.
Optical Migraine: Also known as a retinal migraine, this is a type of migraine that can cause temporary blindness in one eye. Symptoms can last minutes to an hour. However, since you mention this appears in both eyes and isn't associated with your migraines, it seems less likely.
Floaters: These are small specks or strands that drift in one's field of vision. However, they usually aren't multicolored, don't move quickly in a static pattern, and are typically not in both eyes equally.
Central Serous Retinopathy: A condition where fluid builds up under the retina, but it typically causes visual distortion or a blind spot.
Macular Issues: The macula is the part of the retina responsible for central vision. While there are conditions that can affect the macula, they usually don't produce symptoms like what you're describing.

Given the uniqueness of your symptoms, it would be essential to see an ophthalmologist for a comprehensive eye exam. They may also consider referring you to a neurologist or a neuro-ophthalmologist, given the potential neurological implications of your symptoms. Even if it isn't causing any disturbance in your daily activities, it's worth understanding what might be causing it and if there are any associated risks.

I wish you luck!