The retinal blood flow in diabetes

Abstract

Summary. Retinal blood flow was studied in 9 normal volunteers and 36 diabetic patients. The method used was based on the measurement of the mean transit time of flourescein in the superior temporal quandrant of the retina and on estimation of the vascular volume by measuring vessels diameters. The results showed that patients with mild or no retinopathy had significantly increased volume flow compared with normals, those with moderate retinopathy had a slight but not significant increase and those with severe retinopathy had blood flow similar to that found in normals. The mean transit time was reduced significantly in those with mild or no retinopathy, but was similar to normals in those with moderate and severe retinopathy. Following succesful pituitary ablation and photocoagulation retinal blood flow was reduced compared with pre-treatment studies.

Quantifying Microvascular Abnormalities With Increasing Severity of Diabetic Retinopathy Using Optical Coherence Tomography Angiography

“…Decorrelation values and blood flow velocity, however, are correlated linearly only within a limited range, which may explain the mild correlation we found in our study. 30 It has been reported previously that in early stages of diabetes retinal blood flow may be increased before the onset of DR. 31 – 34 In later stages of DR, a decrease in blood flow has been reported in the literature, which fits well with the decreasing mean AFI values with increasing DR severity observed in our study ( Table 2 ). 31 Based on these previous reports and the adjusted mixed effects model in our study, we hypothesized that higher flow in the SCP (and the full retina) may be an early sign of diabetic changes in eyes without clinical signs of DR.…”

Quantifying Microvascular Abnormalities With Increasing Severity of Diabetic Retinopathy Using Optical Coherence Tomography Angiography

“…Decorrelation values and blood flow velocity, however, are correlated linearly only within a limited range, which may explain the mild correlation we found in our study. 30 It has been reported previously that in early stages of diabetes retinal blood flow may be increased before the onset of DR. 31 – 34 In later stages of DR, a decrease in blood flow has been reported in the literature, which fits well with the decreasing mean AFI values with increasing DR severity observed in our study ( Table 2 ). 31 Based on these previous reports and the adjusted mixed effects model in our study, we hypothesized that higher flow in the SCP (and the full retina) may be an early sign of diabetic changes in eyes without clinical signs of DR.…”

Diabetic retinopathy: sonographically measured hemodynamic alterations in ocular, carotid, and vertebral arteries

“…Our study showed that the mild circulatory changes appeared as a slight, but statistically nonsignificant increase of flow in patients with mild (grade 2) retinopathy, which is in accordance with other studies (16,17,19,26,28,41). An increase in the retinal blood flow is sufficient to damage endothelial cells (26).…”

Relationship between the morphology of the foveal avascular zone, retinal structure, and macular circulation in patients with diabetes mellitus

“…Regarding the hemodynamic trends, as in previous studies, our results indicated a higher arterial velocity in patients with diabetes mellitus without any evidence of DR pathology in comparison to the healthy group 49 – 51 . However, a higher speed was not observed in the venous compartments as compared to the healthy group.…”

Quantifying Microvascular Abnormalities With Increasing Severity of Diabetic Retinopathy Using Optical Coherence Tomography Angiography

“…Decorrelation values and blood flow velocity, however, are correlated linearly only within a limited range, which may explain the mild correlation we found in our study. 30 It has been reported previously that in early stages of diabetes retinal blood flow may be increased before the onset of DR. 31 – 34 In later stages of DR, a decrease in blood flow has been reported in the literature, which fits well with the decreasing mean AFI values with increasing DR severity observed in our study ( Table 2 ). 31 Based on these previous reports and the adjusted mixed effects model in our study, we hypothesized that higher flow in the SCP (and the full retina) may be an early sign of diabetic changes in eyes without clinical signs of DR.…”

Diabetic retinopathy: sonographically measured hemodynamic alterations in ocular, carotid, and vertebral arteries

“…Our study showed that the mild circulatory changes appeared as a slight, but statistically nonsignificant increase of flow in patients with mild (grade 2) retinopathy, which is in accordance with other studies (16,17,19,26,28,41). An increase in the retinal blood flow is sufficient to damage endothelial cells (26).…”

Relationship between the morphology of the foveal avascular zone, retinal structure, and macular circulation in patients with diabetes mellitus

“…Regarding the hemodynamic trends, as in previous studies, our results indicated a higher arterial velocity in patients with diabetes mellitus without any evidence of DR pathology in comparison to the healthy group 49 – 51 . However, a higher speed was not observed in the venous compartments as compared to the healthy group.…”

Quantifying Microvascular Abnormalities With Increasing Severity of Diabetic Retinopathy Using Optical Coherence Tomography Angiography

“…Decorrelation values and blood flow velocity, however, are correlated linearly only within a limited range, which may explain the mild correlation we found in our study. 30 It has been reported previously that in early stages of diabetes retinal blood flow may be increased before the onset of DR. 31 – 34 In later stages of DR, a decrease in blood flow has been reported in the literature, which fits well with the decreasing mean AFI values with increasing DR severity observed in our study ( Table 2 ). 31 Based on these previous reports and the adjusted mixed effects model in our study, we hypothesized that higher flow in the SCP (and the full retina) may be an early sign of diabetic changes in eyes without clinical signs of DR.…”

Diabetic retinopathy: sonographically measured hemodynamic alterations in ocular, carotid, and vertebral arteries

“…Our study showed that the mild circulatory changes appeared as a slight, but statistically nonsignificant increase of flow in patients with mild (grade 2) retinopathy, which is in accordance with other studies (16,17,19,26,28,41). An increase in the retinal blood flow is sufficient to damage endothelial cells (26).…”

Relationship between the morphology of the foveal avascular zone, retinal structure, and macular circulation in patients with diabetes mellitus

“…Regarding the hemodynamic trends, as in previous studies, our results indicated a higher arterial velocity in patients with diabetes mellitus without any evidence of DR pathology in comparison to the healthy group 49 – 51 . However, a higher speed was not observed in the venous compartments as compared to the healthy group.…”