Pulsatile Ocular Blood Flow Changes in Different Types of Glaucoma

Context: Color Doppler imaging (CDI) allows non invasive assessment of ocular blood flow allowing the assessment of vascular component of glaucoma etiopathogenesis. Aims: To evaluate changes in pulsatile ocular blood flow in different types of glaucoma. Settings and Design: Prospective case control study. Methods and Material: Color Doppler imaging was used to determine ocular blood flow parameters – peak systolic velocity ( Vmax), end diastolic velocity (Vd), time average mean of maximum velocity (TAmax), pulsatility index (PI), resistive index (RI) and systolic/diastolic ratio (S/D) in ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary artery (SPCA) in primary open angle glaucoma (POAG), primary angle closure glaucoma (PACG) and normal tension glaucoma (NTG). A comparison of the three groups was made with the normal subjects. Statistical analysis used: Unpaired Student’s t-test, p value ≤ 0.05 considered significant. Results: In the POAG group Vmax was decreased in the OA, CRA and SPCA when compared to normals but results were significant only in the CRA. Vd was significantly decreased in all the three vessels. PI and RI were signifantly increased in all three vessels except for the RI in OA which was increased insignificantly. S/D ratio was also significantly increased in CRA and SPCA as compared to normals. In the PACG group Vmax was decreased in all the three vessels as compared to normals but not significantly. Vd was significantly decreased in CRA and SPCA. PI and RI were significantly increased in CRA and SPCA. S/D ratio was significantly increased only in the SPCA. In the NTG group Vmax was decreased in all the three vessels when compared to normals but not significantly. Vd was significantly decreased in OA and CRA. The PI and RI were increased significantly in all the three vessels. S/D ratio was increased significantly in the OA and CRA. Conclusions: This study confirms that CDI provides an effective way of measuring part of the vascular component of glaucoma. We found decreased blood flow velocity and increased resistive indices in the ocular vasculature in the different types of primary glaucoma as compared to normal subjects