Blurring of vision is one of the possible symptoms of diabetes, as significant changes in blood glucose levels can affect the shape of the lens of the eye.

If blood glucose levels are responsible for changes in your vision, these changes should subside once sugar levels go back to normal.

What causes blurry vision?

Possible causes of blurred vision include:

  • Diabetes
  • Age-related macular degeneration (AMD)
  • Astigmatism
  • Corneal ulcer
  • Dry eyes
  • Migraine

When to see your doctor

Our eyes can change over time but if there has been a sudden change or a blurring in vision is accompanied by other symptoms, it’s important to see your doctor.

See your doctor if you experience pain in either of your eyes.

Blurred vision is one of the signs of diabetes so find out whether you have any other of the symptoms of diabetes and arrange to see your doctor if you do.

Blurred vision and high sugar levels

When sugar levels are consistently high, your vision may become increasingly blurred. This effect may come on gradually over weeks or months, particularly if type 2 diabetes is present. Alternatively, blurred vision can occur quickly if blood glucose levels become very high in anyone with diabetes.

If blurred vision is related to high blood glucose levels, your vision is likely to return to normal once your glucose levels return to normal.

Blurred vision and low sugar levels

Blurred vision can also occur as a possible symptom of low blood glucose levels, and may become more noticeable if you are reading.

If you take medication that puts you at risk of severe hypoglycemia (such as if you take insulin, sulfonylureas or glinides), it is important to react to any sudden change in vision by taking quick acting carbohydrate.

If there’s any uncertainty over whether you have too high or too low sugar levels, perform a blood test to find out.

After you’ve treated low blood sugar levels, your vision should soon return to normal.