I haven't had one for a while, but find they happen more often if my sodium and/magnesium levels are low. ( I've had them for years pre-diagnosis) I also get muscle cramp if my sodium is low too. Bit of salt in/on my food and they generally go away. Good luck with the retinopathy/maculopathy, I'm on 9 month monitoring for Mac in my right eye, I've also got (not diabetes related) weak left retina, with the opticians advise is if I get flashers or floaters than don't quickly resolve, do not pass go, do not collect £200 go straight to A&E as it could becoming detached