Ocular Pulse Amplitude is associated with ocular blood flow velocities in healthy subjects and patients with primary open angle glaucoma, but not normal tension glaucoma

Abstract Purpose Purpose: to determine the correlation between ocular blood flow changes throughout the cardiac cycle on ocular pulse amplitude (OPA) in glaucoma patients and healthy subjects. Methods Method: A prospective, case‐control study was designed with dynamic contour tonometry and color Doppler Imaging performed in healthy controls and glaucoma patients. An offline waveform analysis of the Doppler signal was performed by a masked observer for each of the retrobulbar arteries. Linear regression models using intraocular pressure (IOP), age and Doppler waveform variables [(resistance index (RI) and systolic/diastolic velocity ratio (Sm/Dm)] were designed to identify independent variables associated with OPA. Results Results: 192 patients were included [healthy controls: 55; normal tension glaucoma (NTG): 63, primary open‐angle glaucoma (POAG): 74]. OPA showed a significant associated with the constructed model in healthy individuals and in POAG patients (r=0.54, p<0.001; r=0.43, p<0.001, respectively). Short ciliary arteries flow variables were the only vascular‐related parameters independently associated with OPA in these groups (p<0.05). IOP was independently associated with OPA in the POAG group (p<0.001), but not the healthy group (p=0.48). OPA in the NTG group did not correlate with the constructed model (r=0.24, p=0.21). Conclusion Conclusions: OPA seems to reflect blood flow changes in the short ciliary arteries in healthy individuals and POAG patients, but not in NTG patients. In the latter, the ocular pulse may relate to other variables than blood flow velocities.