Measuring Retinal Vessel Caliber in Relation to Dark Adaptation and Blood Glucose Level
The overall objective is to investigate, whether retinal blood vessel diameter change during the energy consuming dark adaptation process and if responses vary between low and high blood glucose.
|Study Design:||Observational Model: Case-Only
Time Perspective: Prospective
|Official Title:||Measuring Retinal Vessel Caliber in Relation to Dark Adaptation and Blood Glucose Level|
- Vessel caliber [ Time Frame: 1 day ] [ Designated as safety issue: No ]
- Blood glucose level [ Time Frame: 1 day ] [ Designated as safety issue: No ]Capillary samples.
Biospecimen Retention: Samples Without DNA
Venous blood sample. Na+, K+, Crea, HbA1c. Capillary glucose measurement. Samples will be analysed and destructed according to normal laboratory practice at the Glostrup Hospital.
|Study Start Date:||August 2009|
|Study Completion Date:||September 2010|
|Primary Completion Date:||June 2010 (Final data collection date for primary outcome measure)|
Type 2 DM
This group includes subjects diagnosed with type 2 diabetes mellitus with none or minimal diabetic retinopathy.
Dietary Supplement: Oral Glucose Tolerance Test (OGTT)
75 g of glucose dissolved in 250 mL water.
Other Name: OGTT
All subjects are being studied using the same procedure. The study schedule takes place from 8 a.m. to 12 a.m. every time. Each subject shows up on one single day. Subjects are to show up fasting overnight with a break in insulin and/or oral antidiabetic treatment.
The study eye of each subject will be selected by randomisation. We seek to have an equal distribution of right and left eyes overall.
A first set of images will be taken after 5 minutes in "standardised daylight", in a room without light from outside, which eliminates any concerns about weather variations. After this the room is completely darkened. 2 set of images will be taken in the dark adapted state after 20 and 40 minutes. Subsequently the patient ingests the OGTT and will reach maximum blood glucose level after about 60-90 minutes. At this time, the subjects undergo the same "photo session" as above with high blood glucose levels.
|Copenhagen University Hospital at Glostrup|
|Copenhagen, Denmark, DK-2600|
|Principal Investigator:||Stig K Holfort, MD||Glostrup University Hospital, Copenhagen|