Waveform changes of laser speckle flowgraphy in the temporal optic nerve head and peripapillary atrophy after trabeculectomy in open-angle glaucoma.

A prospective study was conducted on 33 eyes of 33 patients with open-angle glaucoma who underwent trabeculectomy to investigate hemodynamic changes in the temporal optic nerve head (ONH) and peripapillary atrophy (PPA) after trabeculectomy. Laser speckle flowgraphy of ONH and PPA was performed at baseline and at 1, 3, and 6 months postoperatively. The waveforms of the mean blur rate in the tissue area (MT) in the temporal ONH, ßPPA (with Bruch's membrane), and γPPA (without Bruch's membrane) were evaluated. Mean intra-ocular pressure (IOP) decreased from 19.1 ± 0.8 to 8.5-9.6 ± 0.7 mmHg at postoperative visits. The average MT in the ßPPA region increased significantly at all postoperative time points, whereas those in the ONH and γPPA regions remained unchanged. The blowout score (BOS) increased significantly, and the resistivity index decreased significantly at all time points in all regions, which was associated with decreased IOP. The current study showed two novel findings: MT increased after trabeculectomy only in ßPPA, where the choroid was present. IOP decrease-associated BOS increase occurred postoperatively in all regions, which indicates that IOP reduction may decrease vascular transmural pressure and contribute to stable blood flow uniformly, despite structural differences between the regions.

Relationship Between Changes in the Choroidal Structure and Blood Flow of the Macula After Trabeculectomy.

Purpose: To elucidate the relationship between changes in the choroidal structure and blood flow of the macula after trabeculectomy. Methods: A prospective study of 30 eyes of 30 patients with glaucoma who underwent trabeculectomy. Enhanced depth imaging optical coherence tomography with choroidal image binarization and laser speckle flowgraphy of the macula were performed at baseline and 1, 3, and 6 months postoperatively. Mixed-effects models with adjustment for confounders were used to analyze longitudinal changes in the mean choroidal thickness (mCT), mean choroidal vascular thickness (mCVT), mean choroidal interstitial thickness (mCIT), and mean blur rate (MBR). Results: The decrease in the intraocular pressure (IOP; 45%-51%) and axial length (0.5%-0.8%) and the increase in ocular perfusion pressure (OPP; 34%-38%), mCT (16%-19%), mCVT (16%-20%), mCIT (17%-20%), and MBR (22%-25%) were significant at each postoperative time point (all P < 0.001). In the multivariate analysis, the mCVT changes were positively correlated with the OPP and MBR changes (P = 0.04 and P < 0.001, respectively), whereas the mCIT changes were negatively correlated with IOP changes (P = 0.005). The MBR changes correlated significantly with changes in mCVT but not mCIT (P < 0.001 and P = 0.39, respectively). Conclusions: Thickness changes in the intraluminal and extraluminal parts of the choroid were closely associated with changes in blood flow and IOP, respectively, although both parts thickened comparably after IOP reduction by trabeculectomy. Translational Relevance: The choroid reacts to IOP reduction differently between the intraluminal and extraluminal areas, blood flow dependence in the vascular area, and IOP dependence in the stromal area.

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 (ß, 0.26, 0.21, 0.20; P=0.01, 0.04, 0.047, respectively). MD differences were significantly associated with MBR-T differences (ß, 0.28; P=0.01). For cpRNFLT differences, differences in ß-PPA area and MD differences were identified as significant factors (ß, -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.

Effects of Trabeculectomy on Waveform Changes of Laser Speckle Flowgraphy in Open Angle Glaucoma.

Purpose: To investigate the effect of trabeculectomy on the waveform changes of laser speckle flowgraphy (LSFG) in the optic nerve head (ONH) in patients with glaucoma. Methods: Forty-eight eyes of 48 patients with open angle glaucoma were included in this prospective study. LSFG was performed before and 1, 3, and 6 months after trabeculectomy. Longitudinal changes in average mean blur rate (MBR), blow out score (BOS), resistivity index (RI), falling rate, skew, acceleration time index, and blow out time in the tissue area of the ONH were analyzed by using mixed-effects models. Results: Intraocular pressure (IOP) decreased and ocular perfusion pressure increased significantly at each postoperative time point (P < 0.001, each). BOS increased (P < 0.001, each) and RI decreased (P < 0.001, each) significantly at each postoperative time point, although average MBR and other waveform parameters did not change significantly. Multivariate analyses revealed that younger age (coefficients = -0.13 and 0.0014, P = 0.006 and 0.03 for BOS change and RI change, respectively), worse baseline mean deviation of visual fields (coefficients = -0.18 and 0.0026, P = 0.009 and 0.005), larger IOP reduction (coefficients = -0.29 and 0.0037, P < 0.001, each), and larger pulse rate increase (coefficients = 0.17 and -0.0024, P < 0.001, each) are significantly associated with postoperative BOS increase and RI decrease. Conclusions: Given that postoperative BOS increased and RI decreased with the average MBR remaining unchanged, IOP reduction by trabeculectomy may contribute to stable blood flow throughout the duration of the heartbeat in the tissue area of the ONH.