The effect of acute hyperglycemia on flow velocity in the macular capillaries.

The effect of acute hyperglycemia on retinal blood flow was measured in 12 diabetic patients (mean blood glucose, 276 mg%) on continuous subcutaneous insulin infusion and six nondiabetic controls (mean blood glucose, 198 mg%). Flow velocity measurements in macular capillaries were made using the blue field entoptic method. Retinal artery and vein diameters were measured using red-free fundus photographs. No significant change in flow velocity or retinal vessel diameter was noted in either group.