Color Doppler imaging is the recent development in ultrasonography that allows simultaneous two-dimensional structural imaging in Doppler evaluation of blood flow. With this technique, it is possible for the first time to indirectly display the fine orbital vessels such as the ophthalmic artery and its branches, the central retinal artery, the posterior ciliary artery, and the lacrimal artery. Also, the display of venous structures such as the superior ophthalmic vein, the vortex vein, and the central retinal vein is possible. In addition to the qualitative display of those vessels, the hemodynamics in those vessels can be quantitatively assessed by looking at the Doppler spectrum and determining flow velocities during various periods of the cardiac cycle. This technique is now being used in ophthalmology to evaluate orbital tumors and vascular lesions, intraocular tumors, carotid-cavernous-sinus-fistulas, and hemodynamic changes in patients with retinal vascular disease such as central retinal artery occlusion, central retinal vein occlusion, and diabetic retinopathy.