Queston About Eye Damage due to sudden/rapid changes in blood sugar averages

I recently started up a very low carb diet. I am feeling great, and my insulin use has dropped dramatically (from about 50 units a day to about 15)and my blood sugars are all really nice looking! But I was thinking that I had read somewhere that your eyes can suffer from such a drastic change. I just had an eye exam and everything looked great, but I am having a harder time than usual with my vision. I realize it fluctuates, and it has been awhile since I have been able to keep BGs this low. Any suggestions?


The feeling is that diabetic retinopathy will get nominally worse as a result of tightening control too rapidly after an extended period of relatively bad control. This is only temporary though and in the long run tightening control will lead to improvements.

Fluctuations in BG will affect vision temporarily when BG is out of normal range. BG level affects the lens and, therefore, the ability of your eyes to focus. The first thing I noticed when I got my BGs back in control after they were out of control for years was that my far vision improved pretty quickly. That was a relief.

My retinopathy, however, did get noticeably worse and progressed for at least a year after my BGs stabilized. My opthomologist is keeping pretty close tabs and it seems to have stabilized for the most part after it looked like I was heading for surgery.

Bottom line is, better BG control is what you want and your eyes will thank you for it in the long run.

After diagnosis I had fluctuations too. Bright objects in the field of vision looked like they were illuminated by a flickering, flourescent light. It was periodical and went away after some months.
The best you can do is keeping Hba1c low and minimizing BG fluctuations. The studies available show it will not help to run the BG higher than you can safely achieve.

I got my blood sugar under control about 5 years ago. My prescription had been the same for 20 years, very nearsighted with astigmatism. For the past five years I've had to get my prescription changed at least once a year because my eyes keep getting better and better. The glasses I used to use for reading, I can now use for driving. When this first happened and I couldn't see out of my glasses, I was sure my eyes were deteriorating. In actuality they were getting better. Hope you have the same experience.

My retina specialist said that the sudden development of "cotton wool spots" in addition to my "stable" retinopathy, was probably due to my rapid changes in glucose control. Which she highly suggested laser treatment of, and which I did. But, I also went low carb and changed my exercise routine drastically. My a1c went from 9 to 7.1 in 3 months. It's hard to think that doing something good could also be bad.

I think FHS has said it all. The fact that you are noticing fluctuations is great. I have been on low carb for 10 years with no vision changes during that time, no retinopathy.
I give myself LESS insulin, rather than more, when I am dealing with a dose that might drop me into the less than 100 range. One unit can drop me 60-70. My averages are at 100-115 with tight standard deviation, less than 20. The drop that one unit of insulin results in gets larger when you keep good control over time.

I have wondered about that! It seems that when I am high, it takes a couple of different tries with the insulin pump to get me back down where I need to be. Whereas these days, my bg goes lower much more easily with less insulin. I have been playing with my basal to try to find the right dosage, but don't have it figured out quite yet. I wake up pretty low, but will get a little high during the day for no particular reason that I can ascertain. Diabetes Mysteries.

I have read that if you have existing retinopathy, you should try to bring your bg average down slowly.
I think one of the crucial points is to stay in close contact with your retinal specialist. Demand extra appointments if you feel you need them.