Color Doppler imaging in the study of retrobulbar hemodynamic changes of primary angle-closure glaucoma

To investigate the hemodynamic changes of ophthalmic and central retinal artery (OA, CRA) in Primary Angle-closure Glaucoma (PACG) and the effects of intraocular pressure (IOP) on the retrobulbar hemodynamics.

The hemodynamic changes of OA, CRA in PACG were explored with color Doppler imaging (CDI) technique. Peak systolic blood flow velocity (PSV), end-diastolic blood flow velocity (EDV), pulsatile and resistive indices (PI, RI) were recorded and compared with those of the normal subjects. There were 20 patients (40 eyes) with PACG who were divided into two groups according to their IOP levels: ocular hypertension (15 eyes) and normal tension (25 eyes).

Compared with the normal subjects, the hypertension group of PACG showed significant reduction in the EDV and increases in PI, RI of CRA; normal tension group of PACG also showed remarkable increase in RI of CRA. The ocular hypertension was significantly correlated with the RI and not with the EDV by the analysis of multiple linear regression (the partial correlation coefficient for IOP vs RI was 0.388, p = 0.0234, for IOP vs EDV was 0.053, p = 0.7688). Compared with the normal group, there might be a trend of reduction in the EDV of the OA in PACG group.

Intraocular pressure elevated is a major cause of the vascular resistance increased in PACG, which will make the end-diastolic blood flow of CRA decreased. There exists an abnormal vascular resistance in the normal tension eyes of PACG.