Vision Changes with BG Fluctuations? Or High BGs?

My daughter seems to be having some vision problems when playing sports. We’ve had her eyes checked & they’re fine. I’m wondering if the higher blood sugars she usually has while playing would affect her vision. She might be 200 or higher going into a game, which the CDE said is fine, because she’s burning it off while playing. But this weekend at softball, she really had problems judging balls in the outfield. This would be a depth perception thing. If your blood sugars are bouncing around a little, does it affect your vision?

Same thing is going on with me right now but when I’m in the 150 range. Went to the eye doc today, have to go back on Friday. Will pry have to add glasses to my reading glasses prescription.

I don’t think you can universally say that it will happen at x blood glucose but for sure blood sugar can transiently effect vision. For me it would not happen until I am >300 mg/dl for at least 2 weeks. During my rebellious teen years it would happen occasionally. Once I went to an eye doc who refused to write me a script for new glasses because their initial paperwork asked whether I had had a blood glucose of >200 mg/dl in the last month. I told him he was being ridiculous as my A1c was less that 7% but he insisted that this could be a problem.

Thanks. I think you guys are right. The more I’ve been thinking about this, the more convinced I am that it’s high BG causing her problems. She had pancakes the other day before a game & then she couldn’t do a thing! Going to try some new things out, keep the BG lower, watch things better. Our doctor’s office here is terrible for recommendations on these things. The opthalmologist said her eye exam was fine, but she continues to have problems with tracking the ball – just some days, like Jackie says. Once she gets on the pump, hopefully control will be tighter & this will ease up. You guys are the best when I’m trying to figure out things like this! SuFu, you might figure it out before we do! You have to see the ball to ump!

Yeah I had this several times. I had glasses before I was diagnosed, but recently my eyes changed and got contacts. If she needs to get glasses o contacts I would recommend her to get contacts, especially if she is very athletic.

I get considerable blurry vision and double vision when my BG’s are either high or sliding around a large amount.



This was my first symptom of diabetes, even before the dry mouth and tinkling. My eye doctor says that the hydrostatic pressure in the eye changes depending on the amount of glucose in the bloodstream. Some are more sensitive to this than others.



When I get the rare experience of having the pressure in my eyes match my glasses prescription, the world is – for a few, heartbreakingly lovely moments – so exquisitely beautiful. I feel like a kid getting a great big Christmas present in July.



Most of the time, I have to make do with some level of blurriness and fuzziness, even with my very expensive glasses.



I really, really, REALLY miss the moon. I have not seen a clear, crisp, in-focus full moon in years.

He was right. I had my prescription re-done three times when I was way out of control. Finally I gave up and stuck with my old glasses until I got under better control for 90 days. I’m sure it was frustrating for my doctor, too.

I have only tried contacts once but am ok without them. I know nothing about it and my current eye doc may not either but he was saying he has a terrible time getting contacts to work in PWD. I wasn’t paying a whole lot of attention but he was saying something about moisture of the eyes or something.

I have a severe visual impairment in addition to diabetes (not related), but high or low or wildly fluctuating blood sugar levels definitely make my vision quite blurry. For me, it can mean the difference between being able to see a curb and not, or being able to read large print or not. For years I didn’t realize it was from diabetes because I use a white cane and know braille and so would just switch over to those things automatically when my vision wasn’t reliable. It wasn’t until I started Lantus and experienced dramatically more stable blood sugars (in comparison to NPH) and suddenly noticed a big improvement in my vision that I realized there might be a connection.

Now one of my biggest symptoms that I might be high or low is that i find myself trying to see things I’d normally be able to. I would say my vision starts to be affected at around 200 mg/dl, probably.

In recent years I’ve developed seasonal and indoor allergies which affect my vision in similar ways (making it blurry/fuzzy when they act up) and so it’s become even more complicated!

High glucose levels would definitely cause changes in vision - it certainly does for me. I am guessing that her eyes were tested by a normal optemotrist and wonder if she needs to be checked by an eye doctor or diabetic retinopathy specialist. There are things that a normal optemotrist cannot detect.

Fluctuations in blood glucose will influence the vision. The higher the amplitude the more pronounced this influence will be. Increasing the BG from normal numbers like 100 to 200 in a short time is a high variation. Here the eye has a very unique problem. All the fluids of the eye are not exchanged via blood vessels. Instead the blood vessels will just feed the retina. So the fluids have to pass through the retina to feed the eye itself.



Now imagine that the BG was normal and then it is increasing rapidly. Now we have an eye with normal BG and blood vessels with higher blood glucose. It is like liquids with different concentrations separated by a membrane. This will lead to osmosis. The fluid with the lower concentration tries to flow to the fluid with the higher concentration. This will lead to a situation were the eye is gradually loosing fluids. This will change the pressure of the eye and this leads to vision changes. This also works the other way around: if you had a higher BG for a longer time the eye will have the BG of the blood. When the BG is lowered the eye will have the higher concentration and this will lead to osmosis into the eye. Thus the pressure of the eye will gradually rise with the effect of vision changes (different focus point etc).



In short: minimize the fluctuations. I recommend quick acting glucose short before sports. Something like glucose tabs and / or juice. The consumption of the carbs and the physical activity need to be orchestrated in a way that the BG will start to rise when the sport starts. This way the sports can consume the rise in BG - keeping the BG below 170. Of course the longer the activity the more unrealistic it is to find the right balance - a classical trade off situation.

As a side note: the osmosis can be very dangerous for newly diagnosed diabetics with very high blood glucose. If the BG is lowered to quickly the retina can be damaged by the osmosis and the change in pressure. This is why the BG should be lowered gradually.

In my case… rapid bg drops can cause me to “see spots”. This is especially likely to happen if I’m in bright sunlight or if I transition to bright sunlight.

I don’t know if this is an eye problem per se, or if it has more to do with the neurological effects of rapid bg drops.

If my bg is actually really low I can have double vision etc. as my eyes don’t point in the right directions anymore. But that’s really really low.

In all the above cases I think my eyes themselves are actually OK. I think it’s the higher level neurological processing that is out of whack.

Absolutely! Once I’m over 200, I have noticeable changes in my vision. It has to do with the sugar getting into the vitreous fluid of the eyes and distorting vision. I notice the change pretty quickly too, like within a couple of hours of being high. For me, it’s one of the first indications that I have of being high. I definitely notice more distortion with my distance vision too when this happens. Just the other day, after lunch, I stepped out to do something and noticed I was having trouble seeing down the street. I checked my BG and it was 242.

Also (and this is just my opinion, I’m not a medical professional at all), 200 seems a bit too high to be starting a game. I know they sometimes like kids to “run a bit higher” but I would really question the advice of starting to play around 200. Also, keep in mind that if she’s doing an activity that involves a lot of adreneline, her BG may go UP, not down. For me, if I am just exercising by myself (i.e., a long run), I do drop. BUT, if I am playing a sports game, running a road race, or doing anything that gives me a surge of adreneline, I GO HIGHER. I think that’s typical for most T1D folks. So, she might not be “burning it off while she’s playing” like the CDE thinks.

Getting her on the pump will definitely help. I would urge you to do that ASAP. If she’s this active, having a pump will allow her to tweak her basal rates so that she can be closer to the 150 mark, which should improve the vision issues.

Hi Holger. Your reply brings up a question for me. When I’m high, I often over-bolus to bring my blood sugar down quickly, planning to follow up with carbs later for the amount over-bolused. This method does bring the blood sugar down quickly, but maybe that’s a bad idea? Maybe it would be advisable to bring it down more slowly to allow one’s eyes to adjust more slowly? Could these quick changes help to bring on retinopathy? ( didn’t have a problem with retinopathy at my last checkup.) Thanks.

I asked that myself actually. But then I realized that these osmotic processes will need time. I think that the concentration in the eye is lagging behind the blood glucose. So if you are at higher BG levels and you were normal before your eye is in the process of getting there. To simplify things I assume I have measured 200 as a spike and the eye is then around 150. If you then correct quickly the osmotic pressure will be reduced quickly and the eye will just go from 150 back to 100. Thus I think normal glucose levels and a reduction in variability is the key - as always. I do not hesitate to correct a high BG because I am used to normal levels and my eyes are too. I even think that I would not hesitate with 300 because coming down from these levels often takes some time (still some carbs to digest, insulin resistance to overcome). It is just that someone with DKA for a month and 570 mg/dl at the hospital should be lowered with caution. At least I hope so because the last thing we need are worries about the healthyness of BG corrections…

Thanks, that’s a relief!

I haven’t noticed this with my type 1 son, but he is little and doesn’t always tell me when something is off with his sugar. However, I had Gestational Diabetes when I was pregnant with both of my boys, and any time my sugar was high (like right after eating lunch), my vision would get very blurry like I was seeing fuzzy dots flying around in front of me. So, I think you hit the nail on the head with the higher blood glucose levels being to blame for her vision problems. I hope that you are able to find a good solution to fixing this. Good Luck!

For me above 150 I have trouble focusing and it will take several hours under 120 to correct

Thank you, thank you, thank you!! Everyone! I’ve been researching this all week. We will definitely have to get her BG lower than we thought for games & practices because it’s definitely affecting her eyes if she gets too high. Pumping starts Aug 5. You guys are great with your info. It really helps me. I think Sam is maybe a little too afraid of going low. We’ll get this figured out somehow.

Last year, I had BGs in the 400-600 range for a month or two before I finally went into a coma, and my vision was absolutely fried. And they DID bring my BGs down slowly (too slowly, because they were using Type 2 protocols to start with, and I didn’t respond!), and my vision got better, but I still notice that if I’m running high, my vision does get blurry. But never so bad as when I was so out of control.