Thanks very much for your comment, it was realy informative.
I hope you manage your diabetes well !!!
I know many people who suffer from hypoglycemia, and some who even will completely pass out if glucose gets low. That is rare, for in most cases, the person feels crummy for a while, but the body eventually regulates the sugar levels. During a hypo episode (as a type 1 diabetic, of course I have occasionally overdosed by accident when my insulin didn't properly match the food carbs I ate), the eyes feel dry and vision CAN change temporarily. The eye muscles and other muscles don't have the glucose they need to perform properly, and so I find that my eyes can get somewhat blurry temporarily because they cannot focus and because they are dry (eyes need the moisture of the tears). But this IS temporary, and when glucose levels return to normal, the vision clears up quickly.
Usually people who are not diabetic, but who suffer from hypoglycemia treat it to try to prevent episodes by altering their diet. You can do a Google search on diet to prevent hypoglycemia and lots of info will come up to educate you.
Thanks for you fast reply!
I was just worried it is a chronic disease.
Your friend needs to get a doctor's advice-- we're not doctors here, and we can't recommend a course of medical action. I'm not aware of hypglycemia affecting vision, but again, I'm not a doctor. You can help him find an endocrinologist who specializes in these issues, and then your questions should all be answered. I'm not sure if it can be cured, but it can certainly be successfully managed, so try not to worry.