Effect of systemic blood pressure on optical coherence tomography angiography in glaucoma patients

Background The association between retinal microvascular structure and glaucoma has been revealed in multiple studies using optical tomography angiography (OCTA), but limited information on the macular vessel density (mVD) in patients with glaucoma is available. In this study, we tried to identity the factors that affected macular VD (mVD) in glaucomatous eyes. Methods This retrospective cross-sectional study evaluated OCT and OCTA images from 92 eyes from 58 healthy subjects and 179 eyes from 103 glaucoma patients using the SD-OCT database from July 2017 to July 2018. Glaucomatous eyes were further divided into two groups according to history of disc haemorrhage (DH). Association between mVD and demographic characteristics, ganglion cell-inner plexiform layer (GCIPL) thickness, visual field mean deviation (MD) and systemic blood pressure was analysed in each group. Results In both healthy and glaucomatous eyes, mVD was inversely associated with age (beta = -0.035,P = 0.025;beta= -0.039,P = 0.018). In the glaucomatous eyes, mVD was significantly decreased, as the MD value was worse (beta= 0.109,P = 0.002). In glaucomatous eyes with DH, mVD decreased as blood pressure increased (beta = -0.111,P = 0.003) Conclusions Reduced mVD is more common in older individuals in both healthy and glaucomatous eyes, and correlates with functional deterioration than structural damage in glaucomatous eyes. In glaucomatous eyes with DH, high systemic BP is associated with a reduction in mVD. This may indicate that glaucoma patients with DH are more susceptible to vascular damage secondary to hypertension