Purpose: To determine normal values of blood-flow velocities in extraocular vessels.
Methods: In one eye each in 189 healthy adult volunteers, blood-flow velocities in the ophthalmic artery (OA), central retinal artery (CRA), central retinal vein (CRV), short lateral posterior ciliary artery (LPCA), and short medial posterior ciliary artery (MPCA) were measured by color Doppler imaging. In the arteries, peak systolic velocity (PSV), end diastolic velocity (EDV), and resistivity index (RI) were calculated. In the CRV, maximal and minimal blood-flow velocities were measured. Influence of age, gender, blood pressure, and heart rate on blood-flow velocities and the resistivity index were analyzed.
Results: Mean outcomes +/- S.D. cm/sec were as follows: in the OA, PSV was 39.2 +/- 5.3, EDV was 9.1 +/- 2.5, and RI was 0.77 +/- 0.05. In the CRA, PSV was 11.0 +/- 1.8, EDV was 3.3 +/- 0.9, and RI was 0.71 +/- 0.05. In the short LPCA, PSV was 11.2 +/- 1.7, EDV was 3.7 +/- 1.0, and RI was 0.68 +/- 0.06. In the short MPCA, PSV was 11.2 +/- 11.7, EDV was 3.6 +/- 0.9, and RI was 0.68 +/- 0.05. In the CRV, mean maximal velocity was 4.5 +/- 0.9, and mean minimal velocity was 3.3 +/- 0.7. Age, gender, systolic blood pressure, diastolic blood pressure, and heart rate had no consistent statistically significant influence on the measured and calculated variables.
Conclusion: Normal values for blood-flow velocities in the extraocular vessels serve as a basis in deciding whether a measured value of a patient is normal or abnormal.