Color Doppler imaging in ocular hypertension and open-angle glaucoma

Purpose. To quantify the retrobulbar hemodynamics of patients with ocular hypertension and open-angle glaucoma and to compare it with that of normal subjects. Methods. Nineteen eyes of 19 ocular hypertensive patients, 19 eyes of 19 open-angle glaucoma patients and 19 eyes of 19 normal subjects were recruited from our clinic and underwent color Doppler imaging evaluation of the ophthalmic, posterior ciliary, and central retinal arteries. The peak systolic and end-diastolic blood flow velocities and resistivity indices of all retrobulbar vessels were measured. Results. The retrobulbar blood flow velocities were lower and resistivity indices were higher in all retrobulbar vessels in ocular hypertensive patients than in normal subjects. The differences, however, did not reach statistical significance (P>0.05). Glaucoma patients had lower end-diastolic velocities and higher resistivity indices than did normal subjects in the ophthalmic (P=0.003 and P=0.003, respectively), posterior ciliary (P=0.001 and P<0.001, respectively), and central retinal arteries (P=0.03 and P=0.04, respectively). Glaucoma patients had significantly lower end-diastolic velocity and higher resistivity index than did patients with ocular hypertension in the posterior ciliary artery (P=0.04 and P=0.001, respectively). Conclusions. This study suggests that ocular hypertensive patients have more normal blood flow than do glaucoma patients, because all retrobulbar homodynamic measurements in ocular hypertension range between glaucoma and normal subjects. On the other hand, glaucoma is associated with blood-flow velocity reduction and resistivity index elevation in all retrobulbar arteries.