Our purpose was to study the hemodynamic changes in the ophthalmic, central retinal and posterior ciliary arteries during the normal menstrual cycle and to relate the vascular changes to menstrual cycle. A total of 23 healthy women underwent serial color Doppler ultrasonography at least six times during a normal menstrual cycle, twice each in follicular, ovulatory and luteal phases. Pulsatility and resistance index and peak systolic velocity of the each arteries were assessed with color Doppler imaging. There was no statistical difference in any of the parameters during the menstrual cycle. This was supposed to be because generalized hormonal effects on heart rate, blood pressure, blood volume, cardiac output and on the diameter of the vessel cancel each other and this effect maintains the same ocular blood flow and perfusion during the menstrual cycle. (E-mail: firstname.lastname@example.org) (C) 2002 World Federation for Ultrasound in Medicine Biology.