Since about 8 years ago I have been occasionally experiencing the sudden appearance of a bright blue dot in my vision. The frequency with wich it occurs also varies: sometimes I see them a few times a day, sometimes not for weeks. It is not longer present than 2 seconds and is not moving, even if my visionfield changes (= even if I look at something else). Also, they appear in different surroundings: regardless of lightintensity and coloursetting. They can appear with a background of a white wall in daylight, as well as in dark with different coloured background. I've never experienced a pressure on my eyes or head when it happens. In other words, I haven't discovered a common denominator when a blue dot appears.
Is there anyone with similar experiences or with a logical explanation for this phenomenon?