The effect of post prandial glucose changes on oscillatory potentials in subjects with type 2 diabetes mellitus.
OBJECTIVE
To investigate the effect of elevated plasma glucose levels on oscillatory potentials (OPs) in patients with diabetes mellitus.


METHODS
15 patients with type 2 diabetes mellitus, with no ophthalmoscopically visible signs of diabetic retinopathy (NDR), were recruited, mean (SD) age 65.1 (10.91) years and duration 5.95 (4.95) years. Plasma glucose levels and OPs were recorded before, during and after a meal tolerance test (MTT), at times 0, 90 and 210 min. OPs were recorded following 5 min adaptation to a blue mesopic background (1.17 cd m(-2)), and elicited using a white 5 ms stimulus flickering at 5 Hz frequency over the blue background.


RESULTS
Plasma glucose increased significantly from 0 to 90 min during the MTT. This corresponded with an increase in mean amplitude of OP1-4, and a significant increase in the summed amplitudes. Summed OP amplitudes were 14.52 microv and 18.38 microv at time 0 and 90 min respectively. Between times 90 and 210 min plasma glucose levels decreased significantly back to baseline. OP1 and OP2 amplitudes increased slightly and OP3 and OP4 amplitudes decreased markedly, resulting in a non-significant reduction of the summed amplitudes. No significant changes in latencies were seen.


CONCLUSIONS
Summed OP amplitudes, which are known to reflect the efficiency of the retinal circulation, increased with elevated plasma glucose. This effect was not immediately reversible. Latencies appear not to be affected.
Arlotte
Dominique V
DV
School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
Perrott
Rhianon L
RL
Drasdo
Neville
N
Owens
David R
DR
North
Rachel V
RV
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D004596:Electroretinography; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009991:Oscillometry; D019518:Postprandial Period; D012039:Regional Blood Flow; D012160:Retina / Q000502:physiology*; D012171:Retinal Vessels / Q000502:physiology
D001786:Blood Glucose