Table 2.
Univariate Analysis of Quantitative Metrics in Averaged and Single Images
| Variable | Control (SD) Averaged Images |
Control (SD) Single Images |
P | No DR (SD) Averaged Images | No DR (SD) Single Images | P | Mild DR (SD) Averaged Images | Mild DR (SD) Single Images | P | Moderate DR (SD) Averaged Images | Moderate DR (SD) Single Images | P | Severe DR (SD) Averaged Images | Severe DR (SD) Single Images | P | Proliferative DR (SD) Averaged Images | Proliferative DR (SD) Single Images | P |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| FAZ size | 0.29 (0.10) | 0.27 (0.10) | 0.507 | 0.23 (0.10) | 0.22 (0.10) | 0.801 | 0.34 (0.14) | 0.33 (0.14) | 0.888 | 0.39 (0.17) | 0.23 (0.14) | 0.034* | 0.32 (0.16) | 0.28 (0.17) | 0.685 | 0.46 (0.16) | 0.27 (0.14) | <0.001* |
| FAZ circularity | 0.70 (0.07) | 0.69 (0.08) | 0.693 | 0.67 (0.08) | 0.67 (0.07) | 0.830 | 0.60 (0.07) | 0.61 (0.05) | 0.730 | 0.54 (0.12) | 0.54 (0.11) | 0.900 | 0.41 (0.04) | 0.55 (0.08) | 0.010* | 0.55 (0.15) | 0.49 (0.14) | 0.244 |
| SRL superior VLD | 20.03 (0.94) | 21.93 (1.12) | <0.001* | 19.20 (0.73) | 21.22 (0.53) | <0.001* | 18.50 (0.99) | 20.14 (1.14) | 0.005* | 16.95 (1.21) | 18.78 (1.14) | 0.003* | 17.56 (1.80) | 19.42 (1.54) | 0.115 | 16.38 (1.83) | 17.79 (1.67) | 0.013* |
| SRL inferior VLD | 18.69 (1.65) | 21.14 (2.07) | <0.001* | 18.31 (1.43) | 21.15 (1.47) | <0.001* | 17.87 (0.93) | 20.02 (1.06) | <0.001* | 17.30 (1.07) | 19.03 (1.71) | 0.019* | 16.39 (1.40) | 18.39 (1.22) | 0.043* | 16.93 (1.78) | 18.84 (1.88) | 0.002* |
| SRL nasal VLD | 19.57 (0.98) | 22.24 (1.13) | <0.001* | 19.32 (0.87) | 21.95 (0.93) | <0.001* | 18.81 (0.60) | 20.60 (1.08) | 0.001* | 17.84 (1.05) | 19.59 (1.66) | 0.011* | 18.31 (0.69) | 20.23 (0.94) | 0.006* | 16.82 (1.64) | 18.21 (1.91) | 0.016* |
| SRL temporal VLD | 19.49 (1.30) | 21.65 (1.35) | <0.001* | 19.46 (1.20) | 21.65 (0.84) | <0.001* | 18.15 (0.80) | 20.26 (1.17) | <0.001* | 17.81 (1.13) | 19.15 (1.86) | 0.066 | 17.17 (0.96) | 17.89 (1.15) | 0.318 | 16.62 (1.77) | 18.11 (1.86) | 0.012* |
| SRL inner ring VLD | 19.48 (0.83) | 21.75 (1.21) | <0.001* | 19.12 (0.81) | 21.49 (0.69) | <0.001* | 18.35 (0.55) | 20.25 (0.83) | <0.001* | 17.45 (0.59) | 19.15 (1.20) | 0.001* | 17.39 (0.91) | 18.98 (1.08) | 0.036* | 16.67 (1.40) | 18.22 (1.43) | 0.001* |
| SRL total VLD | 18.22 (0.83) | 20.66 (1.20) | <0.001* | 17.88 (0.75) | 20.48 (0.61) | <0.001* | 16.92 (0.69) | 19.16 (0.88) | <0.001* | 16.11 (0.70) | 18.26 (1.15) | <0.001* | 16.07 (0.79) | 18.11 (0.89) | 0.005* | 15.40 (1.26) | 17.39 (1.30) | <0.001* |
| DRL superior VLD | 21.36 (1.15) | 22.39 (1.10) | 0.001* | 20.47 (0.90) | 21.54 (0.53) | 0.003* | 20.08 (1.00) | 20.77 (1.23) | 0.215 | 18.00 (1.08) | 19.46 (1.05) | 0.007* | 18.55 (0.98) | 19.75 (0.40) | 0.036* | 17.63 (2.22) | 19.33 (1.74) | 0.008* |
| DRL inferior VLD | 20.76 (1.28) | 22.45 (1.23) | <0.001* | 19.64 (0.86) | 21.64 (1.13) | <0.001* | 19.15 (0.67) | 21.15 (0.60) | <0.001* | 18.36 (1.28) | 20.05 (0.81) | 0.003* | 17.01 (1.20) | 19.23 (1.79) | 0.051 | 18.14 (1.68) | 19.92 (1.63) | 0.001* |
| DRL nasal VLD | 20.48 (1.36) | 21.75 (1.42) | 0.001* | 20.06 (0.75) | 21.39 (0.82) | 0.001* | 19.38 (1.03) | 20.26 (1.24) | 0.123 | 17.63 (1.65) | 19.35 (1.40) | 0.022* | 18.90 (1.24) | 20.16 (1.11) | 0.130 | 17.37 (1.83) | 18.86 (1.81) | 0.012* |
| DRL temporal VLD | 19.80 (1.64) | 20.95 (1.37) | 0.007* | 19.40 (1.27) | 20.78 (1.03) | 0.011* | 18.21 (1.36) | 19.68 (1.41) | 0.038* | 17.46 (1.29) | 19.28 (1.31) | 0.006* | 15.36 (0.99) | 17.07 (1.32) | 0.049* | 16.72 (1.85) | 18.96 (1.94) | <0.001* |
| DRL inner ring VLD | 20.59 (1.10) | 21.88 (1.10) | <0.001* | 19.90 (0.69) | 21.34 (0.60) | <0.001* | 19.21 (0.79) | 20.47 (0.94) | 0.007* | 17.82 (0.41) | 19.53 (0.67) | <0.001* | 17.43 (0.58) | 19.04 (0.86) | 0.008* | 17.41 (1.42) | 19.25 (1.26) | <0.001* |
| DRL total VLD | 18.55 (1.05) | 20.68 (1.01) | <0.001* | 18.05 (0.74) | 20.32 (0.67) | <0.001* | 17.30 (0.78) | 19.46 (0.85) | <0.001* | 16.31 (0.44) | 18.94 (0.68) | <0.001* | 15.95 (0.44) | 18.45 (0.69) | <0.001* | 15.99 (1.09) | 18.77 (1.21) | <0.001* |
| SRL superior PD | 0.38 (0.02) | 0.41 (0.02) | <0.001* | 0.37 (0.01) | 0.40 (0.01) | <0.001* | 0.36 (0.01) | 0.39 (0.02) | 0.007* | 0.35 (0.02) | 0.38 (0.02) | 0.014* | 0.36 (0.03) | 0.39 (0.02) | 0.155 | 0.34 (0.03) | 0.36 (0.03) | 0.033* |
| SRL inferior PD | 0.35 (0.03) | 0.40 (0.03) | <0.001* | 0.35 (0.02) | 0.40 (0.02) | <0.001* | 0.35 (0.02) | 0.39 (0.02) | <0.001* | 0.35 (0.01) | 0.38 (0.03) | 0.039* | 0.33 (0.02) | 0.37 (0.01) | 0.003* | 0.34 (0.03) | 0.38 (0.03) | <0.001* |
| SRL nasal PD | 0.36 (0.02) | 0.41 (0.01) | <0.001* | 0.37 (0.01) | 0.41 (0.02) | <0.001* | 0.37 (0.01) | 0.40 (0.02) | 0.001* | 0.36 (0.02) | 0.39 (0.03) | 0.030* | 0.37 (0.02) | 0.41 (0.01) | 0.006* | 0.35 (0.02) | 0.37 (0.03) | 0.010* |
| SRL temporal PD | 0.37 (0.02) | 0.40 (0.02) | <0.001* | 0.37 (0.02) | 0.41 (0.02) | 0.002* | 0.36 (0.01) | 0.39 (0.02) | <0.001* | 0.37 (0.01) | 0.39 (0.03) | 0.036* | 0.36 (0.01) | 0.37 (0.02) | 0.433 | 0.35 (0.03) | 0.37 (0.03) | 0.044* |
| SRL inner ring PD | 0.36 (0.01) | 0.40 (0.02) | <0.001* | 0.37 (0.01) | 0.40 (0.01) | <0.001* | 0.36 (0.01) | 0.39 (0.01) | <0.001* | 0.36 (0.01) | 0.38 (0.02) | 0.001* | 0.36 (0.01) | 0.39 (0.01) | 0.007* | 0.35 (0.01) | 0.37 (0.02) | <0.001* |
| SRL total PD | 0.34 (0.01) | 0.39 (0.02) | <0.001* | 0.34 (0.01) | 0.39 (0.01) | <0.001* | 0.33 (0.01) | 0.37 (0.01) | <0.001* | 0.33 (0.01) | 0.36 (0.02) | <0.001* | 0.33 (0.01) | 0.37 (0.01) | 0.001* | 0.32 (0.01) | 0.35 (0.02) | <0.001* |
| DRL superior PD | 0.39 (0.02) | 0.42 (0.02) | <0.001* | 0.39 (0.02) | 0.42 (0.01) | 0.002* | 0.38 (0.02) | 0.40 (0.03) | 0.170 | 0.37 (0.03) | 0.39 (0.03) | 0.151 | 0.37 (0.03) | 0.39 (0.01) | 0.215 | 0.35 (0.04) | 0.37 (0.03) | 0.040* |
| DRL inferior PD | 0.38 (0.02) | 0.42 (0.02) | <0.001* | 0.37 (0.02) | 0.41 (0.02) | <0.001* | 0.37 (0.01) | 0.40 (0.01) | <0.001* | 0.37 (0.03) | 0.39 (0.02) | 0.057 | 0.35 (0.03) | 0.38 (0.03) | 0.092 | 0.36 (0.03) | 0.39 (0.03) | 0.002* |
| DRL nasal PD | 0.38 (0.02) | 0.42 (0.02) | <0.001* | 0.38 (0.02) | 0.41 (0.02) | 0.001* | 0.38 (0.02) | 0.40 (0.02) | 0.076 | 0.35 (0.04) | 0.38 (0.03) | 0.133 | 0.39 (0.03) | 0.41 (0.03) | 0.385 | 0.34 (0.04) | 0.36 (0.04) | 0.121 |
| DRL temporal PD | 0.37 (0.03) | 0.40 (0.02) | <0.001* | 0.37 (0.02) | 0.40 (0.02) | 0.003* | 0.36 (0.03) | 0.39 (0.03) | 0.050* | 0.35 (0.03) | 0.38 (0.03) | 0.033* | 0.31 (0.02) | 0.34 (0.03) | 0.112 | 0.33 (0.03) | 0.36 (0.04) | 0.003* |
| DRL inner ring PD | 0.38 (0.01) | 0.42 (0.02) | <0.001* | 0.38 (0.01) | 0.41 (0.01) | <0.001* | 0.37 (0.01) | 0.40 (0.02) | 0.003* | 0.36 (0.02) | 0.38 (0.01) | 0.001* | 0.35 (0.01) | 0.38 (0.02) | 0.018* | 0.34 (0.02) | 0.37 (0.02) | <0.001* |
| DRL total PD | 0.34 (0.01) | 0.39 (0.01) | <0.001* | 0.34 (0.01) | 0.39 (0.01) | <0.001* | 0.33 (0.01) | 0.38 (0.02) | <0.001* | 0.33 (0.01) | 0.37 (0.01) | <0.001* | 0.32 (0.01) | 0.37 (0.01) | <0.001* | 0.32 (0.01) | 0.36 (0.02) | <0.001* |
T-test comparing means of quantitative variables for single versus averaged images in control eyes and eyes with varying degrees of diabetic retinopathy (DR) severity. Bold (*) values denote significance set at P < 0.05.
PD, perfusion density, is defined as the total area covered by perfused vasculature per unit area (%); VLD, vessel length density, is defined as the total length of perfused vasculature per unit area (mm/mm2).
DRL = deep retinal layer. FAZ = foveal avascular zone. SD = standard deviation. SRL = superficial retinal layer.