Junki Kwon

Quantitative optical coherence tomography angiography of macular vascular structure and foveal avascular zone in glaucoma

Objective The study aimed to evaluate the quantitative characteristics of the macular vessel density (VD) and foveal avascular zone (FAZ) in glaucoma using optical coherence tomography angiography (OCT-A). Design Cross-sectional, age- and sex-matched case–control study. Methods Fifty-two eyes of 52 patients with primary open angle glaucoma and 52 eyes from 52 healthy participants were recruited retrospectively. OCT-A was performed on a 3 x 3-mm macular region centered on the fovea. OCT-A scans were manually graded to define the FAZ. Parafoveal VD in superficial and deep retina were analyzed in the circular- and quadrant-segmented zone. The FAZ parameters included size, perimeter, and circularity index. The regression analysis among VD and FAZ-related parameters and ocular parameters was performed, and the diagnostic ability was calculated with refractive error adjusted. Results For both groups, the mean age and the sex ratio was not different between groups. With refractive error adjusted, the average macular VD was lower in glaucoma than in the control group for superficial (P = 0.013), deep (P<0.001), and the whole retina (P = 0.002). There were increased FAZ perimeter and decreased FAZ circularity index in glaucoma when compared with controls (P<0.001). In the multivariate regression models, FAZ circularity index were significantly associated with decreased peripapillary RNFL thickness (P = 0.007) and macular GCIPL thickness (P = 0.009) measured by OCT. The refractive-error adjusted area under receiver operating characteristics was highest for FAZ circularity index (0.905; 95% CI, 0.844–0.966), followed by temporal deep retinal VD (0.870; 95% CI, 0.803–0.937) and FAZ perimeter (0.858; 95% CI, 0.784–0.932). Conclusions Decreased macular VD, increased FAZ perimeter, and decreased FAZ circularity index were observed in eyes with glaucoma using OCT-A. With refractive error adjusted, these parameters showed considerable diagnostic value for glaucoma. FAZ circularity index may be a novel biomarker representing disruption of the parafoveal capillary network in glaucoma, as supported by its association with structural parameters.

Regional vascular density–visual field sensitivity relationship in glaucoma according to disease severity

Aims To study whether there are global and regional relationships between peripapillary vascular density (pVD) assessed by optical coherence tomography angiography (OCT-A) and visual field (VF) mean sensitivity at different glaucoma stages. Methods Microvascular images and peripapillary retinal nerve fibre layer (pRNFL) thicknesses were obtained using a Cirrus OCT-A device in 91 glaucoma subjects. The pVD was measured at various spatial locations according to the Garway-Heath map, using a MATLAB software (The MathWorks, Natick, Massachusetts). VF mean sensitivity (VFMS) was recorded in the 1/L scale. Global and regional vasculature–function (pVD vs VFMS) relationships were assessed in separate patient groups at mild and moderate-to-advanced stages of glaucoma. Results The pVDs at superotemporal and inferotemporal regions were significantly associated with corresponding VFMS in mild glaucoma (p<0.05). In moderate-to-advanced glaucoma, there were significant associations between pVD and VFMS, regardless of location. The association between global pVD and VFMS was significantly stronger than that between global pRNFL thickness and VFMS in moderate-to-advanced stage glaucoma (p <0.05). Conclusion Global and regional pVD measured by OCT-A was significantly associated with corresponding VFMS in moderate-to-advanced glaucoma. OCT-A may be useful in monitoring glaucoma at various stages.

Factors Associated With Visual Field Progression in Cirrus Optical Coherence Tomography-guided Progression Analysis: A Topographic Approach

Purpose: To identify factors associated with visual field (VF) progression in optical coherence tomography (OCT)-guided progression analysis (GPA) using a topographic approach. Methods: Topographic components of OCT-GPA maps (Cirrus HD-OCT; Carl Zeiss Meditec) were classified according to location (temporal, superotemporal, superonasal, nasal, inferornasal, and inferotemporal), size (small, medium, and large), shape (wedge and irregular types), and pattern of retinal nerve fiber layer (RNFL) progression (widening, deepening, and new development). All positive findings in OCT-GPA (RNFL thickness maps, profiles, and average RNFL thickness) were defined as strong RNFL progression. VF progression was determined by linear regression analysis of VF mean deviation over time. Univariate and multivariate logistic regression analyses were performed to evaluate the association of VF progression with OCT-GPA parameters. Results: In total, 276 primary open-angle glaucoma patients were followed up for 5.1 years. According to OCT-GPA, 89 eyes were found to have RNFL progression. Of these, VF progression was detected in 27 (30.3%) eyes. Eyes with progressed VF group showed topographically different characteristics, which were wedge-shaped (80.6%), large-sized (40.0%), and widening (69.5%) or deepening (11.1%) pattern of RNFL progression in the inferotemporal (44.4%) and superotemporal (30.6%) regions, compared with eyes with non-progressed VF group. In multivariate analysis, strong RNFL progression and widening or deepening pattern of RNFL progression were significantly associated with VF progression (P=0.012 and 0.016, respectively). Conclusions: Topographic analysis in OCT-GPA maps showed different characteristics between progressed VF and nonprogressed VF groups. Glaucoma patients with widening or deepening pattern of RNFL progression should be carefully monitored for greater risk of VF progression.

Glaucoma Diagnostic Capabilities of Foveal Avascular Zone Parameters Using Optical Coherence Tomography Angiography According to Visual Field Defect Location

Purpose: To assess the diagnostic ability of foveal avascular zone (FAZ) parameters to discriminate glaucomatous eyes with visual field defects (VFDs) in different locations (central vs. peripheral) from normal eyes. Patients and Methods: Totally, 125 participants were separated into 3 groups: normal (n=45), glaucoma with peripheral VFD (PVFD, n=45), and glaucoma with central VFD (CVFD, n=35). The FAZ area, perimeter, and circularity and parafoveal vessel density were calculated from optical coherence tomography angiography images. The diagnostic ability of the FAZ parameters and other structural parameters was determined according to glaucomatous VFD location. Associations between the FAZ parameters and central visual function were evaluated. Results: A larger FAZ area and longer FAZ perimeter were observed in the CVFD group than in the PVFD and normal groups. The FAZ area, perimeter, and circularity were better in differentiating glaucomatous eyes with CVFDs from normal eyes [areas under the receiver operating characteristic curves (AUC), 0.78 to 0.88] than in differentiating PVFDs from normal eyes (AUC, 0.51 to 0.64). The FAZ perimeter had a similar AUC value to the circumpapillary retinal nerve fiber layer and macular ganglion cell-inner plexiform layer thickness for differentiating eyes with CVFDs from normal eyes (all P>0.05, the DeLong test). The FAZ area was significantly correlated with central visual function (&bgr;=−112.7, P=0.035, multivariate linear regression). Conclusions: The FAZ perimeter had good diagnostic capability in differentiating glaucomatous eyes with CVFDs from normal eyes, and may be a potential diagnostic biomarker for detecting glaucomatous patients with CVFDs.

Myopic glaucomatous eyes with or without optic disc shape alteration: a longitudinal study

Aims To compare the clinical courses of patients with myopic primary open angle glaucoma (POAG) with and without optic disc shape alterations. Methods In this longitudinal retrospective study, 146 eyes from 146 patients with myopic (axial length(AXL), >24 mm) POAG were classified according to optic disc shape alterations defined by optic disc tilt and/or rotation. Glaucomatous progression was determined by either serial optic disc/retinal nerve fibre layer photographs or visual field (VF) exams. Rate of progression was calculated from serial VF mean deviation (MD) and visual field index values. Results Mean age, AXL and follow-up duration were 50.1±12.7 years, 26.1±1.6 mm and 4.6±1.3 years, respectively. The progression rate was faster in eyes with a non-tilted optic disc than with a tilted optic disc (−0.30(95% CI; −0.42 to −0.16) vs 0.05(−0.07 to 0.17) dB/year, −0.85(−1.20 to −0.49) vs −0.35(−0.68 to −0.03) %/year, all p<0.05). Twenty eyes (21.3%) in the non-tilted group but only one eye (1.9%) in the tilted group showed VF progression in both superior and inferior hemifields. By logistic regression analysis, worse initial VF MD and less optic disc tilt were significantly associated with both superior and inferior VF progression (OR=0.909 and 0.561 (for 0.1 tilt ratio); p=0.020 and 0.018, respectively). Conclusion Significant differences in glaucomatous progression were found between eyes with and without optic disc shape alterations, particularly disc tilt. More localised and stable courses of glaucoma progression were observed in eyes with tilted optic discs.

Circadian Patterns of Intraocular Pressure Fluctuation among Normal-Tension Glaucoma Optic Disc Phenotypes

Objective To characterize the 24-h habitual-position intraocular pressure (IOP) patterns of optic disc phenotypes (ODPs) in untreated normal-tension glaucoma (NTG) and the relationships between nocturnal IOP elevation and various clinical factors. Design Prospective, cross-sectional, observational study. Methods Eighty-two NTG patients with focal ischemic (FI) ODP and 82 age- and disease severity-matched NTG patients with myopic glaucomatous (MG) ODP were recruited prospectively over 3 years. The IOP was recorded 11 times over a 24-hour (h) period by a single ophthalmologist using a hand-held tonometer (TonoPen®XL). A cosinor model was used to describe the 24-h IOP rhythm. Associations between nocturnal IOP elevation and both ocular and demographic variables were evaluated using the generalized estimating equation (GEE). Results Mean habitual-position IOP was significantly higher during nighttime than daytime in the FI group (16.44 vs. 14.23 mmHg, P < 0.001), but not in the MG group (15.91 vs. 15.70 mmHg, P = 0.82). The FI group also exhibited a significantly higher peak IOP during sleeping hours (P = 0.01) and lower trough IOP during the 24-h period than the MG group (P < 0.01). The MG group showed a significantly higher peak IOP during waking hours than the FI group (P < 0.01). Therefore, 24-h IOP fluctuation range was significantly higher in the FI group than the MG group (P = 0.013). In the FI group, peak habitual-position IOP and the highest frequency of IOP peaks occurred during sleeping hours (12 AM–6 AM). By contrast, IOP peaks in the MG group occurred during morning hours (8 AM–12 PM). The FI group showed an overall nocturnal acrophase in habitual-position IOP, with 45 patients (54.9%) having a nocturnal acrophase; 10 (12.2%), a diurnal acrophase; and 27 (32.9%), no evident acrophase. By contrast, the MG group showed no evident peak in habitual-position IOP, with 9 patients (10.9%) having a nocturnal acrophase; 43 (52.4%), a diurnal acrophase; and 30 (36.6%), no evident acrophase. In multivariate modeling using the GEE, ODP (P < 0.001) and spherical equivalent (SE, P = 0.001) were independently associated with nocturnal IOP elevation. Conclusions Based on 24-h habitual-position IOP data, FI is associated with significant nocturnal IOP elevation, while no such nocturnal IOP elevation is observed in MG ODP. In untreated NTG, there are also significant differences in the 24-h IOP pattern between FI and MG ODPs.

Glaucoma Progression and its Relationship with Corrected and Uncorrected Intraocular Pressure in Eyes with History of Refractive Corneal Surgery

ABSTRACT Purpose: To investigate glaucoma progression and its relationship with corrected and uncorrected intraocular pressure (IOP) in patients with a history of refractive corneal surgery (RCS). Methods: Totally, 56 eyes of 56 primary open-angle glaucoma patients who had a history of RCS were included. Mean keratometry and central corneal thickness were measured at the time of glaucoma diagnosis. Three IOP measurements, i.e., uncorrected IOP (UCIOP) and corrected IOP calculated by applying the Kohlhaas (CKIOP) and Ehlers (CEIOP) formulas, were used. Participants were categorized into two groups (low-teen [<15 mmHg] and high-teen [≥15 mmHg] groups) according to the mean follow-up IOP, in each of the three IOP measurements. Glaucoma progression was determined based on either structurally or functionally by stereoscopic optic disc/retinal nerve fiber layer photographs or visual field tests. Kaplan–Meier survival curves were compared between the low-teens group and high-teens group for each IOP measurement. Risk factors for glaucoma progression, including uncorrected and corrected IOP measurements, were analyzed using a Cox proportional-hazards model. Results: Among total eyes, glaucoma progression was found in 19 (34%) eyes during 4.3 years of mean follow-up period. Individual values of uncorrected IOP and corrected IOP showed significant differences (p < 0.001). Incidence of glaucoma progression was higher in high-teens group than in low-teens group by corrected IOP values (both Kohlhaas and Ehlers, p = 0.006, 0.003), but not by uncorrected IOP values (p = 0.749). The cumulative probability of glaucoma progression was significantly greater in the high-teens group than in the low-teens group using the Elhers formula determined by Kaplan–Meier analysis (p = 0.030). Conclusions: For glaucoma eyes with history of RCS, high-teen group by corrected mean follow-up IOP showed more glaucoma progression than low-teen group. More intensive IOP-lowering treatment will be required for patient with high-teen follow-up corrected IOP to prevent glaucoma progression.

Relationship between vessel density and visual field sensitivity in glaucomatous eyes with high myopia

Aims To investigate the global and regional relationships between peripapillary vessel density (pVD) and visual field mean sensitivity (VFMS) in glaucomatous eyes with and without high myopia in comparison with those between peripapillary retinal nerve fibre layer thickness (pRNFLT) and VFMS. Methods A total of 130 eyes from 130 patients with glaucoma consisting of those with and without high myopia were included in a consecutive manner. High myopia was defined as a spherical equivalent <−6.0 dioptres or axial length >26.5 mm. The pVD and pRNFLT were evaluated using optical coherence tomography angiography (OCT-A) and spectral-domain optical coherence tomography. VFMS was assessed using a linear unlogged 1/L scale. The vasculature–function or structure–function relationships were analysed by comparing the pVD or pRNFLT to the corresponding VFMS, according to Garway-Heath map regionalisation. Results The global pVD-VFMS association was significantly stronger than the pRNFLT-VFMS association in glaucomatous eyes with high myopia (p=0.009). However, there were no significant differences between global pVD-VFMS and pRNFLT-VFMS associations in glaucomatous eyes without high myopia (p=0.343). Regionally, the pVD-VFMS association was significantly greater than the pRNFLT-VFMS association at the superonasal, nasal and temporal sectors (all p<0.05) in glaucomatous eyes with high myopia. Conclusions The pVD assessment by OCT-A shows a better global and regional correlation with VFMS than a pRNFLT assessment in glaucoma patients with high myopia. The pVD may be a useful parameter in monitoring disease progression of highly myopic glaucomatous eyes.

Progressive change in peripapillary atrophy in myopic glaucomatous eyes

Aim To evaluate the progressive change in peripapillary atrophy (PPA) according to its shape and to explore the relationship between PPA progression and glaucoma worsening in myopic eyes. Methods A total of 159 eyes of 159 patients with myopic (axial length (AXL) >24 mm) glaucoma (mean follow-up 4.4 years, 35 eyes with minimal PPA, 40 concentric-type PPA eyes (>270° around the optic disc) and 84 eccentric-type PPA eyes (<270°)) were included. Sequential stereoscopic colour optic disc photographs were evaluated to qualitatively determine PPA progression. Factors associated with PPA progression were explored by Cox proportional hazard modelling in each PPA group. Results Patients with concentric PPA were older than patients with eccentric PPA (54.1±11.7 vs 44.1±11.7 years; P<0.001), and AXL was longer in the eccentric group than in the other groups (25.54±1.68 vs 25.28±1.53 vs 26.41±1.29 mm; P<0.001). Twenty-six eyes (65%) in the concentric group and 36 eyes (42.9%) in the eccentric group showed PPA progression. Older age (hazard ratio (HR) 1.059, P=0.008), worse baseline visual field mean deviation (HR 0.857, P=0.009) and greater baseline PPA area (HR 1.000, P=0.012) were associated with PPA progression in the concentric type. Glaucoma progression (HR 3.690, P=0.002) and longer AXL (HR 1.521, P=0.002) were associated with PPA progression in the eccentric type. Conclusions Relationship between glaucoma worsening and PPA progression was strongest in myopic glaucomatous eyes with eccentric type PPA.

Effect of Preoperative Intravitreal Bevacizumab on the Surgical Outcome of Neovascular Glaucoma at Different Stages

Purpose To evaluate the effect of preoperative intravitreal bevacizumab (IVB) injection on the surgical outcome of Ahmed glaucoma valve (AGV) implantation according to the angle status in neovascular glaucoma (NVG) eyes. Materials and Methods This retrospective study included 70 NVG patients who underwent AGV implantation and were followed up for at least 12 months. An IVB injection before AGV implantation was administered to 45 eyes (IVB group), while it was not administered to 25 eyes (control group). Subgroup analyses were done at different stages in terms of the extent of peripheral anterior synechiae (PAS). Results Mean follow-up period after AGV implantation was 27 ± 15 months. The IVB group showed higher prevalence of the eyes with less than 50% of PAS than that of the control group (78% versus 44%). The overall success rate 1 year postoperatively was 80% and 64% for the IVB and control groups, respectively (P = 0.142). When PAS extent was less than 50%, preoperative IVB had a marginally positive effect on surgical outcome (HR = 0.39, P = 0.064, per 1-time IVB injection). Conclusions Preoperative IVB may enhance the success rate of AGV implantation in NVG eyes, before PAS has extensively formed. Further prospective randomized studies controlling the extent of PAS are warranted.