It’s been a week since we found out my son has type 1 diabetes. Is it common to have blurry vision frequently with glucose levels above 200 mg/dl [11.1 mmol/L]?

Yes. Very common. The process is thought to be that while the glucose levels were getting higher, before diagnosis, sugar and water were fluctuating in and out of the lenses of the eyes. This changes vision and can cause blurred vision. We all have seen children prescribed corrective glasses in the weeks before the child was diagnosed with type�1 diabetes, only to find that the vision improved with insulin and the glasses were then not required or a weaker prescription was needed.

As the insulin levels are adjusted in these first few weeks and as the glucose levels change during this “diabetes honeymoon”, I would not be surprised to hear of blurry vision.

Tell your diabetes team, and once the glucose levels have begun to stabilize in the upcoming couple of weeks, you might want a formal visit with a pediatric ophthalmologist. Certainly, if there is something more acute and worrisome, ask for that referral!

DS
Additional comments from Dr. Donough O’Brien:

This phenomenon used to be quite common in the days before type 1 diabetes usually came to be diagnosed very early. The explanation may be a little difficult; but I will try. First of all there is a difference in the concentration of solutes (salt and glucose) between ‘intracellular’ water and ‘extracellular water). The ‘extracellular’ water in the chambers of the eye is a little different in that it is divided off from the rest of the ‘extracellular’ water by the globe of the eye which is a little more permeable to water that to glucose. This means that as the concentration of glucose in the blood and ‘extracellular’ water in the body as a whole is rapidly reduced by giving insulin there is a temporary tendency for water to move into the eye. This, in turn slightly distorts the shape of the eye and the relationship between the lens and the retina causing some blurring of vision. This should clear up quite soon as the fluid equilibriums are restabilised you should have your son seen by an ophthalmologist.

DOB
Additional comments from Dr. Andrea Scaramuzza:

I think that this could be due to fast excursion of sugar blood levels. In fact in my experience I see that sometimes some adolescents with type 1 diabetes experience these blurry vision problems not only with hypoglycemic levels but also with hyperglycemic ones, and other time also with normal level (that is only a reading of that moment but don’t say anything about before and after the glycemic reading). So I think that is safer to try to maintain the glycemic blood levels within a ‘controlled’ range without too much excursions.

AS