None listed
Conditions
Brief summary
Metabolic changes in type 1 diabetes are the underlying cause of diabetic retinopathy. Even before the development of retinopathy, there are disturbances in the functioning of the retinal nervous and vascular tissue. Hypotheses of our study were formed to confirm: 1. the functional vascular disorders of the retina before the formation of diabetic retinopathy in patients with type 1 diabetes, 2. the difference between the mean levels of some biochemical parameters in patients with type 1 diabetes and the control group, 3. the interrelations between the functional vascular disorders of the retina and biochemical parameters in patients with type 1 diabetes. 41 patients with type 1 diabetes clinically do not differ from the 37 participants of the control group in age, sex, systolic and diastolic blood pressure, the incidence of arterial hypertension and smoking, intraocular pressure and visual acuity, but they have a higher body mass index. Patients show higher levels of glucose, fructosamine, 8-hydroxy-2' -deoxyguanosine, high-sensitivity C-reactive protein, interleukin 6 and lower level of asymmetric dimethylarginine. Average levels of cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, plasma nitrate/nitrite and vascular cell adhesion protein 1 do not differ in both groups . Central retinal artery and vein equivalents are calculated from the measured vessel diameters from the fundus photographs, blood flow and volume of the small retinal blood vessels are measured by Scanning laser Doppler flowmeter and mean velocity of blood in the central retinal artery is measured by Doppler ultrasound device in basal conditions and during 8 Hz flickering light stimulation. In basal conditions patients with type 1 diabetes have wider internal diameter of central retinal vein equivalent, greater volume of the retinal small blood vessels and the mean velocity of blood in the central retinal artery in comparison with the control group. There are no differences between groups in the inner diameter of central retinal artery equivalent nor the average blood flow in the retinal small blood vessels. During stimulation of the retina with flickering light there is lower ability of autoregulation of the retinal vasculature in patients with type 1 diabetes. In these conditions, vasodilatation of central retinal artery and vein equivalent are lower than in the control group. Patients with type 1 diabetes have lower ability to change the blood flow and volume of the retinal small blood vessels. In the same conditions they have also lower ability to change the mean velocity in the central retinal artery than the control group. The results interrelations between the functional vascular disorders of the retina and biochemical parameters in the patients with type 1 diabetes and control group will be presented in the scientific articles.
Interventions
All procedures and measurements in 41 patients with diabetes type 1 were made by one doctor of medicine in the ophthalmic clinic from 9.00 to 12.00 o’clock. Patients were treated only once in the study.
The conversation about diabetes, arterial hypertension, dyslipidemia, other diseases and their treatment was made. Medical documentation about diabetes was checked. The corrected visual acuity, visual field by static perimetry and intraocular pressure by non-contact tonometer were measured. Exam
All procedures and measurements in 41 patients with diabetes type 1 were made by one doctor of medicine in the ophthalmic clinic from 9.00 to 12.00 o’clock. Patients were treated only once in the study. The conversation about diabetes, arterial hypertension, dyslipidemia, other diseases and their treatment was made. Medical documentation about diabetes was checked. The corrected visual acuity, visual field by static perimetry and intraocular pressure by non-contact tonometer were measured. Examinations with slit-lamp of anterior and posterior pars of the eye were performed. The body weight and height were measured and body mass index was calculated. Measurements of blood pressure were made on the left arm. The evaluation of functional features of retinal blood vessels in patients with diabetes type 1 was made by: 1. calculation of central retina artery (CRAE) and vein equivalent (CRVE) obtained from measurements of the internal diameters of the retinal blood vessels from the retinal images 2. measurement of mean velocity (MV) in central retinal artery in the optic nerve by Doppler ultrasound device 3. measurement of volume and blood flow in retinal vessels thinner than 30 micrometres by Scanning laser Doppler flowmeter Those three sets of measurements were made in basal conditions and during 8 Hz retinal flickering light stimulation of the eye. Index of mean velocity in the central retinal artery, indexes of volume and blood flow in small retinal vessels and vasodilatation indexes of central retina artery and vein equivalents were calculated from measurements in basal conditions and during light stimulation. 8Hz white pulse light of the time length of 50 ms was used as physiological retinal stimulator. A halogen lamp with a power of 150 watts and 2,500 candelas was built in the special device with which it was possible to regulate the frequency and intensity of light. The colour spectrum of the halogen lamp ranged from 400 to 2500 nm. Distance of the lamp to the eye was 40 centimetres. The lamp was set at 90 degrees to the visual axis of the eye being measured. Between the lamp and the eye prism was placed at an angle of 45 degrees where the intensity of the light reduced for 30.3% to the final luminance of 4800 lux. In each participant one eye was exposed for 45 seconds to 8 Hz flickering light stimulation, after which three repeated measurements with all three devices were made with continued irritation. Blood was taken on an empty stomach in the morning from 8.00 to 10.00 o’clock from the vein in the left arm. It was frozen on -20.0 C and waited for biochemical tests.
Sponsors
Debelic Vladimir
Study design
Allocation
Non-randomised trial
Intervention model
Parallel
Primary purpose
Diagnosis
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 42 Years
Healthy volunteers
Yes
Inclusion criteria
Patients with type 1 diabetes: treatment with insulin normal blood pressure and concentration of blood lipids the use up to 10 cigarettes per day visual acuity more then 0.9 with correction intraocular pressure up to 21 mmHg clear optical media Control group: normal blood pressure and concentration of blood lipids the use up to 10 cigarettes per day visual acuity more then 0.9 with correction intraocular pressure up to 21 mmHg clear optical media
Exclusion criteria
Patients with type 1 diabetes: diabetic retinopathy glaucoma other retinal and optic nerve diseases which affect the results of the study Control group: diabetes glaucoma other retinal and optic nerve diseases which affect the results of the study
Outcome results
None listed