Abstract
Purpose :
To investigate the association between the vessel diameter measured by adaptive optics (AO) imaging and the ocular blood flow assessed by laser speckle flowgraphy (LSFG) in diabetic retinopathy (DR).
Methods :
This was a cross sectional study of 161 eyes from 137 patients with type 2 diabetes (none DR (NDR) ; 47 eyes, mild nonproliferative DR (M-NPDR) ; 36 eyes, severe nonproliferative DR (S-NPDR) ; 22 eyes, proliferative DR (PDR) with pan retinal photocoagulation (PRP) ; 32 eyes) and 24 control patients without diabetes. An AO camera (rtx1) was used to obtain images of retinal artery, and we measured external diameter (ED), lumen diameter (LD), wall thickness (WT), and wall to lumen ratio (WLR). The ocular blood flow of optic nerve head (ONH) in the vessel was assessed as mean blur rate (MBR) by LSFG. Vascular measurements, ONH-MBR, and systemic or blood data was used for statistical analysis.
Results :
The mean ED, LD, WLR, ONH MBR-vessel was 120.12±14.67 µm, 94.62±11.95 µm, 0.27±0.03, 43.83±8.22(arbitrary unit; AU) in the control group, 93.21±15.37μm, 122.57±18.60μm, 0.31±0.04, 42.30±7.17 AU in the NDR group, 122.93±13.20μm, 91.60±11.37μm, 0.34±0.07, 40.64±7.74 AU in the M-NPDR group, 119.06±11.16μm, 89.35±9.64μm, 0.33±0.03, 41.44±6.30 AU in the S-NPDR group, 122.69±11.07μm, 82.31±11.74μm, 0.50±0.11, 30.50±11.09 AU in the PDR group.There was no significant difference in the mean ED among the groups (p=0.714). The mean LD in the PDR group was significantly lower than the control, the NDR, and the M-NPDR groups (p=0.001). The mean WLR in the PDR group was significantly higher than the other groups (p<0.001). The ONH MBR in the vessel in the PDR group was significantly lower than the other groups (p<0.001). The ONH MBR in the vessel had a significant positive correlation with LD (r=0.185, p=0.024) and significant negative correlation with WLR (r=-0.331, p<0.001). Stepwise multiple regression analysis demonstrated that DR stage (β=0.043, p<0.001) and ONH MBR in the vessel (β=-0.03, p=0.012) was independent factors associated with WLR.
Conclusions :
We found that diabetic retinopathy has hyperplasia of arterial vessel wall, lumen diameter narrowing and decreased ocular blood flow when retinopathy progress. The results also suggest the association between retinal vessel wall or lumen diameter and retinal microcirculation.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.