Why is my vision changing as my blood sugar goes down?

January 20, 2016 1:29 PM

Last week I was diagnosed with type 2 Diabetes. Since then I've lowered my fasting blood glucose by over a hundred. Yay! But all of a sudden I can't see. Boo!

In the last 2 days I've had to start looking over my glasses to see my monitor, my ipad, books etc. My eyes were just dilated and checked and are fine. In face, when I went to see my Dr. to get the dilation, my vision with my glasses on was 20/20. What gives?

posted by Biblio to Health & Fitness (11 answers total)

Blood sugar levels can affect vision, but you should be discussing this with your doctor, especially if you've started new drugs.
posted by Ruthless Bunny at 1:36 PM on January 20, 2016 [2 favorites]

what was your BG and A1c (then and now) ? When those numbers are high for some time (week, two weeks, eg taking prednisone) it really screws with your eyes. You might have adjusted to the screwed-upness, and now that it's coming back down to normal, things seem strange.
posted by k5.user at 1:36 PM on January 20, 2016

Go have a consult with an actual doctor. Yes, it could very well be your changing blood sugar values, but you really should have this checked. I understand that you just had them checked (likely by an optician NOT a doctor) but a retinal specialist or ophthalmologist will do a more complete exam. These are your eyes, don't mess about. You've had sudden vision changes, go see an actual doctor.
posted by PorcineWithMe at 1:47 PM on January 20, 2016

Response by poster: Actually, my eye doctor IS a doctor. I had a complete exam, dilation, photos done, and he looked at the back of my eyes.

My A1C was a scary 11 and my morning level was 320 a week ago. Today it was 205.

Anyway, I won't mess around. I'll call them tomorrow when they reopen.
posted by Biblio at 1:57 PM on January 20, 2016 [1 favorite]

When exactly did you get your eyes checked? Last week when your levels were high or yesterday when they were back down? Are you nearsighted or farsighted? The fact that you are looking over your glasses suggests that your vision might be improving and your glasses are now over correcting. Just an optimistic possibility - you still want to call the doctor in the morning.
posted by metahawk at 2:16 PM on January 20, 2016 [1 favorite]

are you on any other meds? any kind of steroid?
posted by andrewcooke at 2:17 PM on January 20, 2016

Work with your doctor.

My a1c was not as high as yours but I had my eyes examined the day after I started meds and got the glasses three days later. I was a mess for a couple of weeks until I both adjusted to the meds and got a slightly different eyeglass prescription. After all that I was "fine" with my new vision Rx after the usual day to two settling in.
posted by tilde at 2:46 PM on January 20, 2016

Response by poster: I had my eyes checked Saturday. I wear progressive bifocals for near and far.
I have been on Metformin for a week.
I am on a bunch of other meds, but none are new.
posted by Biblio at 3:27 PM on January 20, 2016

Do check with your doctor, but dramatically decreasing the glucose in the blood can cause some transient swelling in the lens of the eye due to water moving in. This process corrects as everything settles down. Here's an article describing the phenomenon. But do talk to either your regular doctor or your eye doctor. (I'm not your doctor, this is not medical advice).
posted by The Elusive Architeuthis at 4:12 PM on January 20, 2016 [4 favorites]

A long period of high blood sugar can affect your vision -- that's a main complication of diabetes -- but that generally takes a while. Your 11 A1c means 3 months, but you'd have to assume it's been longer.
If your eye doc was aware of your new diagnosis, presumably they were looking closely for diabetes complications. And didn't find any.
It could be something not related, or not directly related, to diabetes, e.g. cataracts.
If it were me (20-year-veteran) I'd 1) go right back to the eye doc 2) see an endocrinologist and raise it.
Great news on dropping your BG. In my experience, you can drive it way down with the right diet (low carbs) and a healthy weight. Good luck!
posted by LonnieK at 6:00 PM on January 20, 2016

Biblio, this isn't abnormal, but yes, mention it to your endocrinologist and your ophthalmologist. Upon diagnosis, I was at 515 with an A1C of 15.8. (Yeah, freaky, as I was in the 5's nine months earlier.) I was on Metformin and Lantus (insulin) for eight weeks, and almost immediately, my vision improved so much that I had to stop wearing my glasses for all but driving for the first four weeks. Once my numbers were back in the non-diabetic range, my vision returned to "normal" (for me) and I needed to wear my glasses again.
posted by The Wrong Kind of Cheese at 10:23 PM on January 20, 2016