Table 2.
aVP biometric interindividual variability estimates for aVP volume, length, mCSA and ε morphometrics.
| Metric | Segment | Proportion of aVP % (95%CI) | CV† (%) |
|---|---|---|---|
| aVP volume [mm3]* | iOrb | 35.4 (33.8, 37.0) | 11.0 |
| iCan | 8.0 (7.7, 8.4) | 9.9 | |
| iCran | 22.3 (21.3, 23.2) | 10.3 | |
| OC | 19.3 (18.3, 20.3) | 12.8 | |
| OT | 15.0 (14.3, 15.7) | 11.3 | |
| Total volume ON [mm3] | 65.7 (64.7, 66.7) | 3.8 | |
| Length [mm]* | iOrb | 36.6 (35.5, 37.6) | 7.1 |
| iCan | 11.4 (10.9, 12.0) | 12.3 | |
| iCran | 25.7 (24.7, 26.8) | 10.0 | |
| OC | 10.7 (10.2, 11.2) | 11.3 | |
| OT | 15.6 (15.0, 16.1) | 9.2 | |
| Total ON length [mm] | 73.7 (73.1, 74.4) | 2.2 | |
| Variation from mean aVP % (95%CI) | |||
| mCSA [mm2] | iOrb | 1.4 (− 1.4, 4.2) | 6.9 |
| iCan | − 25.6 (− 28.2, − 22.9) | 8.9 | |
| iCran | − 8.6 (− 12.6, − 4.6) | 10.9 | |
| OC | 90.4 (82.5, 98.3) | 10.3 | |
| OT | 1.3 (− 3.0, 5.7) | 10.7 | |
| Overall ON mCSA [mm2] | − 6.6 (− 7.3, − 5.9) | 1.9 | |
| ε | iOrb | − 56.6 (− 59.5, − 53.8) | 16.6 |
| iCan | − 41.9 (− 47.5, − 36.3) | 24.1 | |
| iCran | 23.4 (19.3, 27.6) | 8.4 | |
| OC | 63.0 (57.9, 68.1) | 7.9 | |
| OT | 12.0 (6.9, 17.2) | 11.5 | |
| Overall ON ε | − 35.4 (− 38.2, − 32.7) | 10.7 | |
aVP anterior visual pathway; ε ellipticity index; iCan intracanalicular segment; iCran intracranial segment; iOrb intraorbital segment; mCSA mean cross section area; OC optic chiasm; ON optic nerve; OT optic tract; SD standard deviation.
*Volume and length estimates are relative to the total aVP while mCSA and Ellipticity to the mean aVP.
†Coefficient of variation represents the proportion of the estimate variability in relation to its mean (using the standard deviation of the fixed effect terms of the segment estimation model).