My eyesight seems to be getting worse. I see flashes of light in the forms of 1/2 circles. I have been to eye doctors and they say I have healthy eyes.

What to do?

You must be pretty perceptive if you can see the flashes in l/2 circles. I see flashes at the corner of my eyes but I have 'floaters' and that is the reason. Otherwise my eyes are healthy too. You can certainly have 'healthy' eyes but have certain conditions that warrant correction.

I see flashes when I am about to get a migraine or I am dehydrated. Do you get headaches or days when you just feel blah and nauseated ("migraine in the stomach")?

Have you had your blood pressure checked? This can be a symptom of very high blood pressure.