98th Annual Meeting DOG 2000

V 87

The correlation coefficient between the glucose content of the aqueous humour of the eye and that of capillary blood is higher in diabetic than in non-diabetic human subjects

R. Grajewski1, P. Meuer1,2, W. Schrader1

Purpose: To determine changes of the correlation between the content of glucose in aqueous humour and in the plasma of capillary blood depending on the underlying illness.

Patients and methods: Capillary blood and aqueous humor were sampled from 36 fasting patients with diabetes mellitus (type I or II) and from 64 non diabetics scheduled for cataract surgery (CS) or pars plana vitrectomy (PPV) to measure glucose concentrations (hexokinase-method). The patients had no inflammatory eye disease or impurities of aqueous humor. 50µl of capillary blood from earlobes at 30, 20, 10 and 5 minutes before intraocular surgery and 100µl of aqueous humour at the beginning of surgery were drawn. The coefficient of correlation (r) between glucose content of aqueous humour (aq) and capillary blood (pl) was calculated.

Results: Mean r was 0.72 for all patients. Plasma glucose level remained constant within sampling periods. Results for subgroups are shown below:

Group

No.

r

glucose (aq) [mg/dl]

glucose (pl) [mg/dl]

Alter (mean)

Non diabetic PPV

34

0.42

32.5-80.5

61-114

67.0

Non diabetic Cat surg

30

0.67

44.5-145.5

61-151

69.5

Diabetic PPV

33

0.81

44-268.

62-234

63.1

Diabetic Cat surg

14

0.98

77-282

54-234

74.1

Conclusions: Diabetic patients showed a better correlation between the glucose contents of aqueous humour and capillary blood than non diabetic subjects. The reason for this observation is unknown so far but may depend on disturbed autoregulation of the glucose content in the aqueous humour of diabetics, therefore correlating higher with blood glucose levels.

(1) Universitätsaugenklinik, Josef-Schneider-Str. 11, Würzburg, Germany;
(2) Institut für Physikalische Chemie, University of Würzburg, Germany

Acknowledgements: Dr. Weishaupt , Neurologische Universitätsklinik, and his technicals assistants for the detemination of the glucose levels.
Support: Erweiterte Forschungsförderung Universität Würzburg, Grant 2c/1998, DFG Grant Schr 598/2-1



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