The Relationship Between Interocular Asymmetry of Visual Field Defects and Optic Nerve Head Blood Flow in Patients With Glaucoma

Purpose: To investigate the association between asymmetry of visual field (VF) defects and optic nerve head (ONH) blood flow in patients with glaucoma using laser speckle flowgraphy. Methods: In total, 170 eyes of 85 patients with primary open-angle glaucoma were included. Intraocular pressure, VF (Humphrey 24-2, SITA program), mean blur rate in the tissue area (MBR-T) of the ONH measured by laser speckle flowgraphy, axial length, circumpapillary retinal nerve fiber layer thickness (cpRNFLT), disc area, cup/disc area ratio, and parapapillary atrophy (PPA) area was measured in each eye. The paired eyes were divided into better and worse eyes according to the mean deviation (MD) of VF, and intereye differences of various parameters (better MD eye minus worse MD eye) were examined. Factors associated with MD difference, MBR-T difference, or cpRNFLT difference were investigated. Results: MD of the VF in better and worse eyes were -10.2 +/- 7.3 dB and -16.8 +/- 7.4 dB, respectively. In stepwise multiple regression analysis, MBR-T differences, cpRNFLT differences and sex (male) were significantly correlated with MD differences (beta, 0.26, 0.21, 0.20; P=0.01, 0.04, 0.047, respectively). MD differences were significantly associated with MBR-T differences (beta, 0.28; P=0.01). For cpRNFLT differences, differences in beta-PPA area and MD differences were identified as significant factors (beta, -0.26, 0.22; P=0.02, 0.04, respectively). Conclusions: Asymmetry of ONH blood flow is significantly associated with asymmetry of visual field defects in patients with glaucoma independently of cpRNFLT.