Can an eye doctor detect if you have diabetes?

Yes may be: But the diagnosis still depends on the fasting level of blood glucose. When the eyes start showing complications of diabetes that means that an uncontrolled diabetes is present for some years.

Occasionally: Diabetes can lead to leaking blood vessels in the body. The easiest place to spot the small vessels (which are first affected) is the retina in the back of the eye. Retinal blood vessel disease (retinopathy) usually does not show up until after one has been diabetic for several years, so looking for it is not a useful early detection method, but it certainly can be picked up by an eye doctor.

Possibly: If you have had uncontrolled diabetes for a number of years, you are at risk for developing diabetic retinopathy. An eye doctor can see this retinopathy on examination.