Abstract
Purpose: :
To study refraction changes in eyes from healthy persons during hyperglycemia.
Methods: :
In a randomized, double-blinded cross-over study nine healthy persons were subjected to clamping of blood glucose to either euglycemia (5 mmol/l) or hyperglycemia (15 mmol/l) using somatostatin to control the endogenous insulin secretion. Each person was studied on two days: On one day euglycemia (E) was present throughout the day during two rounds of measurements of optical parameters were performed, including corneal thickness, anterior chamber depth, lens thickness, and axial length were measured using corneal pachymetry and ultrasound biometry. On the other study day similar examinations were performed, but hyperglycemia (H) was induced after the first round of measurements of optical parameters.Cycloplegia was obtained using topical cyclopentolatehydrochloride (Cyclogyl 1%,Alcon,USA) administered to the study eye one hour prior to the first measurement.
Results: :
Hyperglycemia did not induce significant changes in any of the measured optical parameters. A significant increase in lens thickness was observed during euglycemia, from 3.60mm to 3.68mm (p=0.01) on the right eye, and from 3.64mm to 3.67mm (p=0.03) on the left eye. In parallel with this a non-significant decrease in hypermetropia was found, from 0.60DS to 0.39DS (p= 0.13) on the right eye and from 0.68DS to 0.44DS (p=0.12) on the left eye. None of the other measured parameters showed significant changes during the experiment.
Conclusions: :
Diurnal changes in lens thickness are suppressed by hyperglycemia. Refraction changes in diabetic patients may be due to other factors than changes in blood glucose.
Keywords: diabetes • refraction • optical properties