Reproducibility of color Doppler imaging for orbital arteries in Japanese patients with normal-tension glaucoma.

The reproducibility of measurements by color Doppler imaging (CDI) were evaluated in Japanese patients with normal-tension glaucoma. Measurements were taken in the central retinal artery, the ophthalmic artery, and the short posterior ciliary arteries. Reproducibility was evaluated by calculating the coefficients of reproducibility for the peak systolic and end diastolic velocities and for the resistance index. The coefficient of reproducibility was calculated as magnitude of V1 - V2/¿(V1 + V2)/2¿ where V1 is the value of the first measurement and V2 is the value of the measurement taken 48 hours later. In calculating the resistance index of the orbital arteries, the central retinal artery and the short posterior ciliary artery temporal to the optic nerve both had coefficients of reproducibility of 0.04 +/- 0.04 (mean +/- standard deviation); the ophthalmic artery and the short posterior ciliary artery nasal to the optic nerve both had coefficients of reproducibility of 0.04 +/- 0.05. The high reproducibility of the CDI technique supports the validity of using CDI in a clinical setting to measure the hemodynamic parameters of small retrobulbar blood vessels.