COLOR DOPPLER IMAGING OF NORMAL ORBITAL VASCULATURE

Background: Color Doppler imaging has become a useful adjunctive tool in diagnosing ophthalmic vascular disease. However, a paucity of infor mation exists regarding normal values. This investigation was conducte d to generate a database of normal retrobulbar circulatory parameters. Methods: The authors prospectively studied the retrobulbar hemodynami c parameters of 53 normal eyes from 32 healthy individuals of various ages, all without risk factors for the development of systemic vascula r disease. Preliminary Doppler spectral analysis was used to demonstra te normal carotid arterial, carotid siphon, and ophthalmic vascular an atomy. Results: Mean hemodynamic values were recorded for each retrobu lbar vessel. Diastolic blood pressure significantly correlated with op hthalmic arterial end-diastolic velocity (P < 0.05) and pulsatility in dex (P < 0.05). Although end-diastolic velocity significantly decrease d (P < 0.05) and vascular resistance significantly increased (P < 0.05 ) as a function of age in the posterior ciliary and central retinal ar terial circulation, no such correlation was identified in the ophthalm ic artery which demonstrated significantly more hemodynamic variabilit y among individuals (P < 0.00001). No significant differences in blood flow or vascular resistance were noted between sexes, fellow orbits, or the nasal and temporal branches of the posterior ciliary artery wit hin individual orbits. Conclusion: Orbital hemodynamic parameters do n ot appear to be sex dependent or variable between fellow orbits. These data suggest that age and diastolic blood pressure may affect normal orbital blood flow and vascular resistance patterns. Significant inter individual variability is limited only to ophthalmic arterial blood Ro w,