Hi. For 3 weeks now, when I blink, and especially when I look at a white wall, or white background on computer screen I see something like a ring or circle, from my right eye. This only happens on the right eye. The color of the circle and how obvious it is depends on sourrounding light. Most obvious in daylight. I have had visual migraines in the past... I ll get these 3 to 4 times a year, and they last about 20 mins, and then go. I don t actually get a head ache with them. This is different though, because it is constant. No head ache. I have had a thorough eye check at my opticians, who found nothing - but advised that I see my GP if it continues, and if frequency of visual migraines increases.