Abstract
Purpose :
To examine the relationship between blood pressure (BP) and ocular perfusion pressure (OPP) and changes in retrobulbar blood flow in open-angle glaucoma (OAG) patients with and without diabetes mellitus (DM)
Methods :
73 patients with OAG (13 DM, 60 without DM) were assessed for BP, OPP, and nasal posterior ciliary artery (NPCA) resistivity index (RI) by color Doppler imaging every six months for a four-year period. Systolic and diastolic blood pressure (SBP, DBP), mean arterial pressure (MAP), systolic and diastolic perfusion pressure (SPP, DPP), and mean perfusion pressure (MPP) were recorded at each visit. Additionally, 78 patients with OAG (12 DM, 66 without DM) were assessed for SBP, DBP, MAP, and ophthalmic artery (OA) peak systolic velocity (PSV) every six months over a four-year period. Pearson correlations were used to test for associations between measurements, with p<0.05 considered statistically significant.
Results :
In the group of 73 OAG patients (13 DM, 60 without DM), baseline SBP (r=-0.68, p=0.010), DBP (r=-0.66, p=0.012), MAP (r=-0.76, p=0.002), SPP (r=-0.72, p=0.004), DPP (r=-0.71, p=0.005), OPP (r=-0.82, p<0.001), and MPP (r=-0.81, p<0.001) negatively correlated with changes in NPCA RI in DM patients. In patients without DM, these correlations were weak and non-significant (r=0.06-0.19, all p>0.05); leading to a significant difference between groups (SBP: p=0.008; DBP: p=0.013, MAP: p=0.002; SPP: p=0.002; DPP: p=0.002; OPP: p<0.001; MPP: p<0.001). In DM OAG patients: SBP had a mean change of 2.9 (95% CI: -8.3, 14.1; p=0.604), DBP had a mean change of -1.6 (-8.3, 5.2; p=0.648), and MAP had a mean change of 0.0 (-7.7, 7.7; p=0.995). Changes in SBP (r=0.80, p=0.001), DBP (r=0.71, p=0.008), and MAP (r=0.77, p=0.002) strongly and positively correlated with changes in OA PSV. In OAG patients without DM, changes in SBP, DBP, and MAP weakly correlated with changes in OA PSV (r=0.0 to 0.06, all p>0.05); leading to a significant difference between groups (SBP: p=0.002; DBP: p=0.020; MAP: p=0.006).
Conclusions :
In OAG patients with DM, BP and OPP correlated with larger increases in retrobulbar vascular resistance and changes in retrobulbar blood flow after four years, compared to non-DM patients. This data suggests that mechanisms influencing the systemic vasculature may also affect localized ocular blood vessels more strongly in OAG patients with DM.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.