Factors affecting corneal deformation amplitude measured by Corvis ST in eyes with open-angle glaucoma.

PURPOSE: To evaluate the factors affecting corneal deformation amplitude (DA) measured using Corvis ST in eyes with open-angle glaucoma. METHODS: This prospective, longitudinal study included 48 eyes with open-angle glaucoma who required additional intraocular pressure (IOP)-lowering drops. All eyes underwent a complete eye examination at baseline, including a Corvis ST, which was repeated 4-8 weeks after the change in therapy. Factors affecting the corneal biomechanics, namely the DA, were determined using mixed effect models. RESULTS: The mean age of the cohort was 65.0 ± 7.9 years. The mean IOP reduced from 23.4 ± 5.4 mmHg to 17.9 ± 5 mmHg after the change in glaucoma treatment ( P < 0.001). The DA increased from 0.89 ± 0.16 mm to 1.00 ± 0.13 mm after IOP reduction ( P < 0.001). On mixed effect model analysis, IOP (-0.02 ± 0.001, P < 0.001) and corneal pachymetry (-0.0003 ± 0.0001, P = 0.02) affected the change in the DA. CONCLUSION: IOP and corneal pachymetry affect the DA and must be accounted for when using Corvis ST to evaluate corneal biomechanics in glaucoma.

Progressive Vessel Density Reduction on OCT Angiography in Glaucoma Eyes with Disc Hemorrhages.

PURPOSE: To identify longitudinal changes in peripapillary and parafoveal vessel density (VD) measured by OCT angiography (OCTA) in primary open-angle glaucoma (POAG) eyes with disc hemorrhages (DHs). DESIGN: Prospective cohort study conducted from August 2016 through August 2020 PARTICIPANTS: Eighteen Asian-Indian participants with POAG (18 eyes) who sought treatment at the clinic with a single DH in the peripapillary region were recruited consecutively. METHODS: The study was conducted at a tertiary eye care center. All participants who were recruited underwent a baseline OCT and OCTA, which were repeated every 4 to 6 months. MAIN OUTCOME MEASURES: Peripapillary VD and retinal nerve fiber layer (RNFL) thickness, parafoveal VD and ganglion cell-inner plexiform layer (GCIPL) thickness in the DH sector, and the corresponding mirror-image sector across the horizontal meridian (control) were evaluated over time using linear mixed-effects models. RESULTS: The baseline average RNFL thickness was 79 ± 9 µm. Mean duration of follow-up was 2.6 ± 0.7 years. In the DH sector, all VD and structural parameters showed a significant negative slope (P < 0.01). In the control sector, the slopes of the structural parameters (RNFL and GCIPL thickness) were not significant (P > 0.05), but the rate of change of the peripapillary and parafoveal VDs were significant (P < 0.01). The rate of change of peripapillary VD was greater in the DH sector compared with the non-DH sector (-2.86 ± 0.6%/year vs. -1.71 ± 0.7%/year; P < 0.01). However, the parafoveal VD slopes did not differ significantly between DH and control sectors (-2.9 ± 0.17%/year vs. -2.8 ± 0.8%/year; P = 0.51). CONCLUSIONS: Eyes with POAG harboring a DH showed not only progressive RNFL and GCIPL loss in the DH sector, but also progressive peripapillary and parafoveal VD reduction in the DH and non-DH regions as documented on OCTA.

Prevalence of primary angle-closure disease in retinitis pigmentosa.

Purpose: To determine the prevalence of primary angle-closure disease (PACD) in patients with retinitis pigmentosa (RP). Methods: This was a retrospective review of the electronic medical records of all RP patients over the age of 10 years attending the Genetics Eye Clinic of a tertiary-care hospital during a 7-year period. Information regarding age, gender, vision, refraction, lens, intraocular pressure (IOP), type of RP, and inheritance pattern using pedigree charts for all patients were obtained. Patients with a shallow anterior chamber, high IOP, or glaucomatous optic discs were referred to the glaucoma department where they underwent additional IOP measurements, a gonioscopy, and disc evaluation by a glaucoma specialist. The prevalence of PACD was determined. Results: A total of 618 RP patients were examined during the study period, of which 95.1% had typical RP. The prevalence of primary angle-closure suspects was 2.9%, primary angle closure was 0.65%, and primary angle-closure glaucoma (PACG) was 2.27%. In contrast, the prevalence of primary open-angle glaucoma was 1.29%. The prevalence of PACG in those older than 40 years was 3.8% (95% confidence interval: 1.6-6.0). Conclusion: The prevalence of PACG in RP patients over 40 years was higher than that found in the general population of a similar age (3.8% vs. 0.8%). In our cohort of RP patients, 5.9% had PACD. Hence, gonioscopy is warranted in all RP patients to identify this condition and treat it appropriately.

The Importance of Signal Strength Index in Optical Coherence Tomography Angiography: A Study of Eyes with Pseudoexfoliation Syndrome.

Purpose: To evaluate the effect of the signal strength index (SSI) on a comparison of the vascular and structural OCT measurements between eyes with pseudoexfoliation syndrome (PXF) and healthy controls of Asian-Indian origin. Methods: In this cross-sectional study, 33 eyes of 33 PXF patients and 40 healthy eyes of 40 controls underwent OCT and OCT angiography (OCTA). Eyes with intraocular pressure (IOP) >21mmHg, glaucomatous disc changes, or any other ocular pathology were excluded. Peripapillary vessel density (VD) and retinal nerve fiber layer (RNFL) thickness were determined from the optic disc scans. Parafoveal VD and ganglion cell complex (GCC) thickness were measured from the macular scans. These parameters were compared between the groups using mixed effect models after adjusting for clinical confounders such as IOP, as well as SSI of the scans. Results: The 2 groups were demographically similar. Average RNFL (94µm vs 100µm, p = 0.01) and GCC (91µm vs 95µm, p = 0.03) were thinner in the PXF group compared to controls. The average peripapillary VD appeared lower in the PXF groups compared to controls (58.2% vs 58.8%, p = 0.04), but after adjusting for IOP and SSI, no difference was noted (p = 0.39). After accounting for confounders, parafoveal VD in the PXF group was significantly lower compared to controls (44.3% vs 46.8%, p = 0.008). Conclusion: Peripapillary RNFL thickness, parafoveal GCC thickness and parafoveal VD were decreased in eyes with PXF when compared to controls. VD measurements are associated with the SSI and, therefore, clinicians and researchers evaluating OCTA scans quantitatively must consider the SSI value during analysis and interpretation.

Comparison of the Performance of a Novel, Smartphone-based, Head-mounted Perimeter (GearVision) With the Humphrey Field Analyzer.

PRECIS: The agreement between a head-mounted perimeter [GearVision (GV)] and Humphrey field analyzer (HFA) for total threshold sensitivity was a mean difference of -1.9 dB (95% limits of agreement -5 to 1). GV was the preferred perimeter in 68.2% of participants. PURPOSE: The purpose of this study was to compare reliability indices and threshold sensitivities obtained using a novel, smartphone-based, head-mounted perimeter (GV) with the HFA in normal, glaucoma suspect and glaucoma patients. A secondary objective was to evaluate the subjective experience participants had with both perimeters using a questionnaire. METHODS: In a prospective, cross-sectional study; 107 eyes (34 glaucoma, 18 glaucoma suspect, and 55 normal) of 54 participants underwent HFA and GV in random order. The main outcome measure was the agreement of threshold sensitivities using Bland and Altman analysis. Participants also completed a questionnaire about their experience with the devices. RESULTS: Median false-positive response rate for GV was 7% (4% to 12%), while for HFA it was 0% (0% to 6%, P<0.001). Median false-negative response rate was similar for both tests. In all, 84 eyes with reliable HFA and GV results were included in the final analysis. Median threshold sensitivity of all 52 points on HFA was 29.1 dB (26.5 to 30.7 dB) and for GV was 30.6 dB (29.1 to 32.6 dB; P<0.001). Mean difference (95% limits of agreement) in total threshold sensitivity between HFA and GV was -1.9 dB (-5 to 1 dB). The 95% limits of agreement were fairly narrow (-8 to 2 dB) across the 6 Garway-Heath sectors. Most participants preferred to perform GV (68.2%) if required to repeat perimetry compared with HFA (20.6%, P<0.001). CONCLUSIONS: There was fairly good agreement between the threshold sensitivities of GV and HFA. GV was also preferred by most patients and could potentially supplement HFA as a portable or home perimeter.

Optical Coherence Tomography Angiography and Visual Field Progression in Primary Angle Closure Glaucoma.

PRECIS: Lower whole enface disc (coefficient: 0.02, P=0.03) and macular vessel densities (coefficient: 0.04, P=0.02) on optical coherence tomography angiography (OCTA) were significantly associated with faster rate of mean deviation (MD) decline. PURPOSE: To evaluate the association between OCTA features and prior visual field (VF) progression in primary angle closure glaucoma (PACG). METHODS: In a cross-sectional study, 46 eyes of 31 PACG patients with 5 reliable VF examinations performed over ≥3 years of follow-up underwent OCTA imaging. Effect of clinical (age, sex, number of antiglaucoma medications, mean, and SD of intraocular pressure during follow-up), optical coherence tomography (average retinal nerve fiber layer and ganglion cell complex thickness) and OCTA (whole enface vessel density of disc and macular scan, deep-layer microvascular dropout) parameters on the rate of MD change was evaluated using linear mixed models. RESULTS: Average (±SD) MD of the baseline VF was -7.4±7.3 dB, and rate of MD change was -0.32±0.29 dB/y. Whole enface vessel density of disc and macular scans was 39.5%±8.1% and 38.7%±4.4%, respectively. Microvascular dropout was noted in 33.3% of the eyes. Multivariate mixed models showed that lower whole enface disc (coefficient: 0.02, P=0.03) and macular vessel densities (coefficient: 0.04, P=0.02) were significantly associated with faster rate of MD decline. Other factors significantly associated with faster progression in multivariate models were older age (coefficient: -0.02, P<0.05) and the presence of systemic hypertension (coefficient: -0.37, P=0.01) and diabetes (coefficient: -0.28, P=0.05). CONCLUSIONS: Lower superficial vessel density measured using OCTA was significantly associated with faster VF progression in PACG. In these eyes, OCTA parameters can serve as biomarker suggestive of past VF progression.

Functional involvement of cone photoreceptors in advanced glaucoma: a multifocal electroretinogram study.

The purpose of the study is (1) to demonstrate the anatomical variation of cone photoreceptor density across normal retina as a sectoral amplitude asymmetry of photopic multifocal electroretinogram (mfERG) and (2) to study the potential presence of sequential or differential, functional cone photoreceptor damage in glaucoma using this amplitude asymmetry. A 37-Block scaled mfERG was recorded from 22 controls and 27 glaucoma subjects. The N1 and P1 amplitudes of averaged responses from corresponding zones nasal and temporal to fovea were analyzed for asymmetry in controls and glaucoma subjects. Amplitude asymmetry was demonstrable for both N1 (p < 0.001) and P1 (p < 0.001) parameters in control subjects. Although this amplitude asymmetry was preserved in glaucoma subjects with moderate field defects, it was not demonstrable in patients with advanced field defects. The anatomical variation in cone photoreceptor distribution across normal retina is demonstrated as an amplitude asymmetry in first order kernel responses of mfERG. The cone photoreceptors in the region nasal to fovea appear to be affected only in advanced glaucoma possibly suggesting that photoreceptors could follow a sequential damage like the overlying neuroretinal rim in glaucoma.

A comparison of the corneal biomechanics in pseudoexfoliation glaucoma, primary open-angle glaucoma and healthy controls using Corvis ST.

PURPOSE: To compare the corneal biomechanical parameters between pseudoexfoliation glaucoma (PXG), primary open-angle glaucoma (POAG) and healthy controls using Corvis ST. METHODS: A prospective, cross-sectional study was conducted which included 132 treatment-naïve eyes which underwent Corvis ST. The study cohort comprised of 44 eyes with PXG, 42 eyes with POAG and 46 healthy controls. Corneal biomechanical parameters, which included corneal velocities, length of corneal applanated surface, deformation amplitude (DA), peak distance and radius of curvature, were compared between the groups using analysis of variance models. RESULTS: The 3 groups were demographically similar. The mean IOP was 15.7 ±3 mmHg in the control group, 21.3 ±5 mmHg in the POAG group and 25.8 ±7 mmHg in the PXG group (p<0.0001). Corneal pachymetry was similar across the 3 groups. Mean DA was significantly lower (p<0.0001) in the PXG group (0.86 ±0.18 mm) compared to the POAG group (0.97 ±0.14mm) and the control group (1.10 ±0.15mm). Corneal velocities were also found to be statistically significantly different between the groups. However, after adjusting for IOP, there was no difference in any of the biomechanical parameters between the 3 groups. CONCLUSION: Corneal biomechanical parameters measured on Corvis ST are not different between eyes with PXG, POAG and healthy controls after adjusting for IOP.

A comparison of the corneal biomechanics in pseudoexfoliation syndrome, pseudoexfoliation glaucoma, and healthy controls using Corvis® Scheimpflug Technology.

Purpose: To compare the corneal biomechanical parameters among pseudoexfoliation syndrome (PXF), pseudoexfoliation glaucoma (PXG), and healthy controls using Corvis Scheimpflug Technology (ST). Methods: A prospective, cross-sectional study of 141 treatment-naïve eyes that underwent Corvis ST was conducted. These included 42 eyes with PXF, 17 eyes of PXF with ocular hypertension (PXF + OHT) defined as intraocular pressure (IOP)> 21 mmHg without disc/field changes, 37 eyes with PXG, and 45 healthy controls. Corneal biomechanical parameters, which included corneal velocities, length of corneal applanated surface, deformation amplitude (DA), peak distance, and radius of curvature, were compared among the groups using analysis of variance models. Results: The four groups were demographically similar. The mean IOP was lower in the controls (15.6 ± 3 mmHg) and PXF group (16.0 ± 3 mmHg) compared to the other two groups (>24 mmHg). Corneal pachymetry was similar across the four groups. Mean DA was significantly lower (P < 0.0001) in the PXG group (0.91 ± 0.18 mm) and the PXF + OHT group (0.94 ± 0.13 mm) when compared to the PXF (1.10 ± 0.11 mm) and control groups (1.12 ± 0.14 mm). Corneal velocities were also found to be statistically significantly lower in PXG and PXF + OHT compared to the PXF and control groups. However, after adjusting for age and IOP, there was no difference in any of the biomechanical parameters among the four groups. Conclusion: Corneal biomechanical parameters measured on Corvis ST are not different between healthy controls and eyes with PXF and PXG. Since PXG is a high-pressure glaucoma, corneal biomechanics may not play an important role in its diagnosis and pathogenesis.

A Comparison of the Visual Field Parameters of SITA Faster and SITA Standard Strategies in Glaucoma.

PURPOSE: To compare the visual field (VF) parameters of the new Swedish Interactive Thresholding Algorithm (SITA), SITA Faster (SFR) with that of SITA Standard (SS) on the Humphrey Field Analyzer. METHODS: Ninety-seven eyes of 97 subjects (63 glaucoma, 26 glaucoma suspects, and 8 normal eyes) underwent VF examination with SFR and SS strategies on the same day in random order. Agreement in VF parameters between SFR and SS strategies was assessed by Bland and Altman plots. In addition, some subjects underwent a second VF examination with SFR strategy to evaluate its test-retest variability. RESULTS: The median test duration of SS strategy was 6 minutes 14 seconds, whereas SFR was 2 minutes 49 seconds (55% shorter, P<0.001). Median mean deviation (-7.3 vs. -7.6 dB, P=0.73) and VF index (88 vs. 88%, P=0.32) were similar between the 2 strategies, whereas pattern standard deviation was significantly higher (4.8 vs. 4.7 dB, P=0.01) with SS strategy. Overall average threshold sensitivity and Garway-Heath sector-wise threshold sensitivities were similar between the 2 strategies except for the nasal sector where SFR strategy had higher sensitivity (26 vs. 25 dB, P=0.02). Bland-Altman plots showed the mean difference in all VF parameters between the SS and SFR strategies were small (ranging from -1.0 dB for the nasal sector to -0.01 dB for superotemporal sector sensitivity). The test-retest variability of VF parameters with SFR strategy was low. CONCLUSIONS: VF parameters with SFR showed good agreement with that of SS strategy. This, combined with low test-retest variability, suggests that SFR can be considered for diagnosis and monitoring of glaucoma.

Choroidal Microvascular Dropout in Pseudoexfoliation Glaucoma.

Purpose: To compare the prevalence of choroidal microvasculature dropout (CMvD) in pseudoexfoliation glaucoma (PXG) and disease severity-matched primary open-angle glaucoma (POAG) eyes. Methods: In a cross-sectional study, 39 eyes with PXG (33 patients) and 39 glaucoma severity-matched POAG eyes (34 patients) underwent visual fields, optical coherence tomography and optical coherence tomography angiography examination. Peripapillary vessel density (VD) was evaluated from the radial peripapillary capillary slab, parafoveal VD was measured on the superficial vascular plexus slab of the macula, and CMvD was evaluated on the choroidal slabs of the optic disc scan. Results: The PXG and POAG groups were similar with respect to average mean deviation on visual fields (-12.1 vs. -12.0 decibel, P = 0.96) and average peripapillary retinal nerve fiber layer thickness on optical coherence tomography (71 vs. 74 µ, P = 0.29). Average peripapillary superficial VD (49.7% vs. 51.3%, P = 0.35) and parafoveal VD (44.8% vs. 45.8%, P = 0.33) were similar between the PXG and POAG groups. CMvD was seen in 18 PXG and 31 POAG eyes (46.2% vs. 79.5%, P = 0.002). On multivariate analysis that accounted for the severity of glaucoma, the odds of CMvD was significantly lower in the PXG group when compared with the POAG group (odds ratio: 0.18-0.21, P < 0.01). Conclusions: The prevalence of CMvD was significantly lower in the PXG eyes when compared with the POAG eyes.

Choroidal Microvascular Dropout in Primary Open-angle Glaucoma Eyes With Disc Hemorrhage.

PURPOSE: The main purpose of this study was to compare the prevalence of choroidal microvascular dropout (CMvD) in primary open-angle glaucoma (POAG) eyes with and without disc hemorrhage (DH). METHODS: In a cross-sectional study, 44 eyes of 44 control subjects, 32 eyes of 32 POAG patients with DH, and 41 eyes of 41 POAG patients without DH underwent visual fields (VFs), optical coherence tomography (OCT) and OCT angiography (OCTA). Presence of CMvD was evaluated on the choroidal OCTA slab. VF defect in the glaucoma eyes were classified into initial nasal defect, initial parafoveal scotoma, and combined nasal and parafoveal defect. RESULTS: CMvD was detected in 17 POAG eyes with DH (53.1%) and 13 POAG eyes without DH (31.7%; P=0.06). On univariate analysis, CMvD in POAG eyes was associated with DH [odds ratio (OR): 2.44, P=0.06] and measures of glaucoma severity: VF mean deviation (OR: 0.85, P=0.02), retinal nerve fiber layer thickness (OR: 0.95, P=0.03), and peripapillary vessel density (OR: 0.94, P=0.09). On multivariate models that accounted for the measures of glaucoma severity, CMvD in POAG eyes was statistically significantly associated with DH (OR≥3, P<0.05). CMvD was more frequently seen in eyes with initial parafoveal scotoma than initial nasal defect both in POAG eyes with DH (P=0.06) and POAG eyes without DH (P<0.001). CONCLUSIONS: Prevalence of CMvD was significantly greater in POAG eyes with DH compared with POAG eyes without DH. CMvD in POAG eyes was also significantly associated with central VF defects and greater severity of glaucomatous damage.

Choroidal Microvascular Dropout in Primary Angle Closure Glaucoma.

PURPOSE: To determine the prevalence and factors associated with the presence of choroidal microvascular dropout (CMvD) in primary angle-closure glaucoma (PACG) eyes compared to primary open-angle glaucoma (POAG) eyes. DESIGN: Cross-sectional study. METHODS: Thirty-six POAG eyes (36 patients) and 28 PACG eyes (28 patients) underwent optical coherence tomography angiography (OCTA). Presence of CMvD was evaluated on choroidal OCTA slabs. Visual field (VF) defects in the glaucoma eyes were classified into initial nasal defect (IND), initial parafoveal scotoma (IPFS), and combined nasal and parafoveal defect, and the association between type of VF defect and CMvD was evaluated. RESULTS: CMvD was detected in 21 POAG (58.3%) and 10 PACG (35.7%) eyes (P = .07). CMvD in POAG eyes was associated with pretreatment intraocular pressure (odds ratio [OR] = 0.91/mm Hg higher intraocular pressure, P = .06), VF mean deviation (MD, OR = 0.75/dB higher MD, P = .007), retinal nerve fiber layer thickness (OR = 0.92/µm increase in thickness, P = .02), and peripapillary vessel density (OR = 0.80/unit increase in density, P = .01). CMvD in PACG eyes was associated only with VF MD (OR = 0.90/dB higher MD, P = .05). When analyzed in the entire cohort of glaucoma patients (64 eyes), CMvD was significantly associated with POAG (OR > 3.5, P < .05) after accounting for glaucoma severity. CMvD was seen in 6 of 7 eyes with IPFS and 1 of 13 with IND in the POAG group (P < .05) and 1 of 2 eyes with IPFS and 0 of 10 with IND in the PACG group (P < .05). CONCLUSIONS: Prevalence of CMvD was significantly lower in PACG compared to POAG. As in POAG, CMvD in PACG was associated with advanced VF damage and with IPFS on VF.

Repeatability and comparability of peripapillary vessel density measurements of high-density and non-high-density optical coherence tomography angiography scans in normal and glaucoma eyes.

AIMS: To compare the peripapillary vessel density (VD) measurements of high-density (HD) and non-HD optical coherence tomography angiography (OCTA) scans in normal and glaucoma eyes, and to evaluate the intrasession repeatability of VD measurements of HD scans. METHODS: In a cross-sectional study, 46 normal (33 subjects) and 89 glaucoma (64 patients) eyes underwent 3 HD and 1 non-HD optic nerve head OCTA scans in the same session. Agreement in VD measurements between HD and non-HD scans was assessed using Bland and Altman analysis. Repeatability of the VD measurements of HD scans was assessed using within-subject coefficient of repeatability (CRw) and variation (CVw). RESULTS: The mean difference in the VDs ranged between 0.7% (temporal sector VD) and 2.0% (inferonasal sector VD), with HD scans showing significantly greater VD values than non-HD scans. The 95% limits of agreement (LoA) in glaucoma eyes ranged between -2.0% and 5.0% for whole enface VD and between -4.8% and 9.6% for superotemporal VD. CRw (%) and CVw (%) of VD measurements of HD scans ranged from 3.0 to 4.9 and from 2.0 to 3.1 in normal eyes. The same ranged from 3.2 to 6.7 and from 2.6 to 4.8, respectively, in glaucoma eyes. CONCLUSIONS: VD of HD scans was higher than that of non-HD scans. The wide 95% LoA indicates that the VD measurements of HD and non-HD scans cannot be used interchangeably. Test-retest repeatability of VDs on HD scans was as high as 6%. These results should be considered while using OCTA for longitudinal evaluation of glaucoma.

Does the Presence of a Disc Hemorrhage Affect OCT-Measured Vessel Density and Retinal Nerve Fiber Layer Thickness?

PURPOSE: To determine if the presence of disc hemorrhage (DH) causes any artifactual change in peripapillary vessel density (VD) and retinal nerve fiber layer (RNFL) thickness as measured by OCT. DESIGN: Cohort study. PARTICIPANTS: Glaucoma patients having a single peripapillary DH. METHODS: Fifteen glaucoma patients having a single peripapillary DH underwent OCT and OCT angiography. Patients were reviewed every 2 months and scans were repeated on disappearance of the DH. Peripapillary VD and RNFL thickness were evaluated at these 2 time points in the DH sector to determine whether the presence of a DH affects these measurements. The mirror-image sector (e.g., superotemporal sector if DH is inferotemporal) was used as a control. Statistical analysis was carried out using the paired t test. Additionally, the analysis of covariance test was used to determine if there was any difference in the measurements between the visits after controlling for signal strength index (SSI). MAIN OUTCOME MEASURES: Peripapillary VD and RNFL thickness were measured in the presence of a DH, and then after DH resolution. RESULTS: The mean ± standard deviation (SD) interval between scans was 4.0±0.4 months. The inferotemporal sector was the most common site of DH (66.6%). The mean ± SD intraocular pressure was reduced medically from 16.1±4.7 mmHg at the time of DH to 13.4±4.2 mmHg at the time of DH resolution (P = 0.001). The mean ± SD VD in the DH sector was 52.5±9.7% at the time of DH and 51.1±8.7% on DH resolution (P = 0.30). The mean ± SD RNFL thickness in the DH quadrant was 91±20 µm in the presence of DH and 92±21 µm after DH resolution (P = 0.26). There was no significant difference between the mean VD or the mean RNFL thickness in the DH and control quadrants at these 2 time points after controlling for change in SSI (P > 0.05). CONCLUSIONS: The presence of a DH does not artifactually alter the VD or RNFL thickness measurements. Therefore, OCT scans obtained in the presence of a DH may be included in series used for studying progression.

A Sectoral Analysis of Vessel Density Measurements in Perimetrically Intact Regions of Glaucomatous Eyes: An Optical Coherence Tomography Angiography Study.

PURPOSE: To study sectoral vessel density (VD) and structural alterations in the peripapillary and parafoveal hemiretina corresponding to perimetrically intact regions of glaucomatous eyes with hemifield defects and to compare these with healthy eyes using optical coherence tomography. METHODS: This cross-sectional study included 37 eyes with open-angle glaucoma having visual fields defects restricted to 1 hemifield and 45 age-matched controls. Peripapillary VD and retinal nerve fiber layer (RNFL) thickness were measured in 8 sectors. Parafoveal VD and ganglion cell complex thickness were measured in the superior and inferior hemispheres of the macula. These parameters were compared between the intact hemiretinae of glaucomatous eyes and corresponding sectors of healthy eyes using the t test. RESULTS: Within the perimetrically intact regions of glaucomatous eyes, the mean VD and RNFL thickness were significantly reduced in inferotemporal, superonasal, and nasal upper peripapillary sectors as compared with healthy eyes (P<0.008). The temporal upper sector had reduced mean VD (60.3% vs. 62.9%, P=0.04) despite similar mean RNFL thickness (P=0.18). The superotemporal sector had decreased mean RNFL thickness (121 vs. 138 µm, P=0.0001) despite similar VD (P=0.06). At the macula, ganglion cell complex thickness was reduced in the superior and inferior hemispheres, but mean VD was reduced in the superior parafoveal region only. CONCLUSIONS: Peripapillary and parafoveal vascular changes precede functional decline. The extent of VD reduction and RNFL thinning varies in different peripapillary sectors and longitudinal studies are required to better understand the temporal relationship of vascular and RNFL loss.

Repeatability of vessel density measurements of optical coherence tomography angiography in normal and glaucoma eyes.

AIMS: To compare the intrasession repeatability of peripapillary and macular vessel density measurements of optical coherence tomography angiography (OCTA) in normal and glaucoma eyes, and to evaluate the effect of signal strength of OCTA scans on the repeatability. METHODS: In a cross-sectional study, three optic nerve head scans each of 65 eyes (30 normal, 35 glaucoma eyes) and three macular scans each of 69 eyes (35 normal, 34 glaucoma eyes) acquired in the same session with OCTA were analysed. Repeatability was assessed using within-subject coefficient of repeatability (CRw) and variation (CVw). Effect of signal strength index (SSI) on repeatability was evaluated with repeated-measures mixed-effects models. RESULTS: CRw (%) and CVw (%) of peripapillary measurements in normal eyes ranged between 3.3 and 7.0, and 2.5 and 4.4 respectively, and that in glaucoma eyes between 3.5 and 7.1, and 2.6 and 6.6. For the macular, these measurements ranged between 4.1 and 6.0, and 3.3 and 4.7 in normal eyes and 4.3 and 6.9, and 3.7 and 5.6 in glaucoma eyes. Repeatability estimates of most measurements were similar in normal and glaucoma eyes. Vessel densities of both peripapillary and macular regions significantly increased with increase in SSI of repeat scans (coefficients ranging from 0.15 to 0.38, p<0.01 for all associations). CONCLUSIONS: Repeatability estimates of OCTA measured peripapillary and macular vessel densities were similar in normal eyes and eyes with glaucoma. SSI values of the scans had a significant effect on the repeatability of OCTA with the vessel density values increasing in scans with higher SSI values.

Comparing the Performance of Compass Perimetry With Humphrey Field Analyzer in Eyes With Glaucoma.

PURPOSE: To evaluate the reliability indices [fixation losses, false negative response rates (FN) and false positive response rates] and threshold sensitivities obtained from glaucoma patients with a Compass perimeter and to compare the same with the Humphrey field analyzer (HFA). METHODS: In a cross-sectional study, 97 eyes of 58 subjects (64 glaucoma and 33 glaucoma suspect eyes) underwent visual field examination with Compass and HFA. Any test with a fixation losses, FN or FP of >20% was considered unreliable. Reliability indices and threshold sensitivities between the 2 instruments were compared and the agreement evaluated using Bland and Altman analysis. RESULTS: In total, 37 tests (38%) with Compass and 17 (18%) with HFA were unreliable. The number of unreliable tests due to high FN (>20%) was significantly more (P=0.005) with Compass (n=27) than HFA (n=3). The mean difference [95% limits of agreement (LoA)] in mean sensitivity between Compass and HFA in the 51 eyes with reliable Compass and HFA results was -0.7 dB (-5.6, 4.3 dB). The point-wise threshold sensitivities with Compass were lower than that with HFA in central and temporal but higher in the nasal field. The 95% LoA ranged from -8 to +5 dB at one of the central points to -20 to +20 dB at one of the peripheral points. CONCLUSIONS: The numbers of unreliable tests were higher with Compass compared with HFA. The LoA between Compass and HFA for point-wise threshold sensitivities as well as the global indices were wide, implying that the instruments cannot be used interchangeably.

Optical Coherence Tomography Angiography Vessel Density Measurements in Eyes With Primary Open-Angle Glaucoma and Disc Hemorrhage.

PURPOSE: To compare the vessel density measurements of optic nerve head, peripapillary and macular regions in severity-matched primary open-angle glaucoma (POAG) eyes with and without disc hemorrhage (DH) using optical coherence tomography (OCT) angiography, and to compare their diagnostic abilities with that of the rim area, retinal nerve fiber layer and the ganglion cell complex thickness measurements on OCT. METHODS: In a cross-sectional study, 66 eyes of 46 control subjects, 34 eyes of 33 POAG patients with DH (median mean deviation=-3.7 dB) and 63 eyes of 43 POAG patients without DH (median mean deviation=-3.8 dB) underwent imaging with spectral domain OCT. Area under receiver operating characteristic curves (AUC) and 5sensitivities at 90% specificity of vessel density and structural measurements in POAG eyes with DH were compared with those in POAG eyes without DH. RESULTS: Most of the vessel density and structural measurements were similar (P>0.05) in POAG eyes with and without DH. Whole enface vessel density of the disc scan and inferotemporal peripapillary vessel density showed the best AUC and sensitivity at 90% specificity both in POAG eyes with DH (0.82, 56% and 0.75, 59%) and without DH (0.91, 73% and 0.83, 67%). AUCs and sensitivities of vessel density and structural measurements of POAG eyes with and without DH were statistically similar (P>0.05). CONCLUSIONS: OCT angiography measured vessel densities and their diagnostic abilities in POAG eyes with and without DH were similar. This suggests that the cause of DH in POAG is unlikely to be vascular abnormality.

Relationship of Optic Nerve Structure and Function to Peripapillary Vessel Density Measurements of Optical Coherence Tomography Angiography in Glaucoma.

PURPOSE: To evaluate the sectoral and global structure-structure (vessel density-retinal nerve fiber layer thickness) and structure-function (vessel density-visual sensitivity loss) relationships of peripapillary vessel density measurements on optical coherence tomography angiography in primary open-angle glaucoma and to determine if fractional polynomial (FP) models characterize the relationships better than linear models. MATERIALS AND METHODS: In a cross-sectional study, structure-structure and structure-function relationships of peripapillary vessel densities were determined in 227 eyes of 143 subjects (63 control and 164 primary open-angle glaucoma eyes) who had undergone standard automated perimetry and optical coherence tomography testing within 6 months of each other, using linear and FP models. FP model evaluates the relationship between the dependent and the best-fitting fractional powers of the independent variable. Strength of relationship was reported as coefficient of determination (R). RESULTS: R values for structure-structure associations using linear models (0.53 for superotemporal sector, 0.61 for inferotemporal, and 0.53 for average measurements) were significantly less (P<0.05) than that determined using FP models (0.57, 0.65, and 0.55, respectively). R values for structure-function associations using linear models (0.35 for superotemporal vessel density-inferotemporal visual sensitivity loss, 0.49 for inferotemporal vessel density-superotemporal visual sensitivity loss, and 0.39 for average vessel density-average visual sensitivity loss) were significantly less than that determined using FP models (0.43, 0.58, and 0.47, respectively). CONCLUSIONS: The inferotemporal peripapillary vessel density showed the strongest association with the corresponding retinal nerve fiber layer thickness and visual sensitivity loss in the global and sectoral regions studied. The FP models were significantly better than linear models in describing these relationships.