Do you have any floaters or flashes of light in your vision?
Do you suffer from migraines?
No floaters or flashers. No migraines. No pain in the eye.
The view thru the eye when this happens reminds me of the way oil on water reflects the light. It breaks it into blue and yellow etc. Only on the side of the eye and faintly but entirely noticeable.
I would advise you to get a dialted eye examination by an ophthalmologist. There could be posterior vitreous detachment which is a normal ageing change in which the vitreous gel in the posterior part of the eye liquifies with age and shrinks. This may be associated with floaters and flashes of light. Another possibility is a vessel occlusion in retina like BRVO. To read more about it you can follow this link - http://emedicine.medscape.com/article/1223498-overview.
Yet another possibility could be an ocular migraine which may or may not be followed by a headache. It is important that you get a dilated fundus examination to confirm the diagnosis. Thanks and best wishes.
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