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.

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.

Optical Microangiography and Progressive Retinal Nerve Fiber Layer Loss in Primary Open Angle Glaucoma.

PURPOSE: To evaluate the association between optical microangiography (OMAG) measurements and progressive retinal nerve fiber layer (RNFL) loss in primary open angle glaucoma (POAG). DESIGN: Prospective case series. METHODS: Sixty-four eyes of 40 patients with POAG (108 quadrants) with mild to moderate functional damage were longitudinally studied for at least 2 years and with a minimum of 3 optical coherence tomography examinations. OMAG imaging was performed at the baseline visit. Effect of clinical parameters (age, sex, presence of systemic diseases, central corneal thickness, presence of disc hemorrhage, and mean and fluctuation of intraocular pressure during follow-up), baseline hemifield mean deviation, baseline quadrant optical coherence tomography RNFL and ganglion cell inner plexiform layer thickness), and OMAG (peripapillary and macular perfusion density [PD] and vessel density [VD]) on the rate of RNFL change was evaluated using linear mixed models. RESULTS: Average (±SD) mean deviation, RNFL, and ganglion cell inner plexiform layer thickness of the analyzed quadrants at baseline were -5.5 ± 2.9 dB, 96.5 ± 17.9 µm, and 73.8 ± 8.6 µm, respectively. Peripapillary PD and VD in the quadrant were 44.6% ± 5.9% and 17.5 ± 2.2 mm/mm2, respectively. Rate of quadrant RNFL change was -1.8 ± 0.6 µm/y. Multivariate mixed models showed that lower peripapillary PD (coefficient = 0.08, P = .01) and lower VD (coefficient = 0.21, P = .02) were significantly associated with a faster rate of RNFL loss. CONCLUSIONS: Lower baseline peripapillary PD and VD measured using OMAG were significantly associated with a faster rate of RNFL loss in POAG. OMAG imaging provides useful information about the risk of glaucoma progression and the rate of disease worsening.

Optical Microangiography and Progressive Ganglion Cell-Inner Plexiform Layer Loss in Primary Open-Angle Glaucoma.

PURPOSE: To evaluate the association between optical microangiography (OMAG) measurements and progressive ganglion cell-inner plexiform layer (GCIPL) loss in patients with primary open-angle glaucoma (POAG). DESIGN: Prospective case series. METHODS: Sixty-three eyes of 38 patients with POAG were studied for ≥2 years and with ≥ 3 optical coherence tomography examinations. Only those hemifields with mild to moderate functional damage at baseline (106 hemifields) were included in the analysis. OMAG imaging was performed at the baseline visit. The effects of clinical parameters (age, gender, central corneal thickness, presence of disc hemorrhage, and mean and fluctuation of intraocular pressure), baseline mean deviation, retinal nerve fiber layer, and GCIPL thickness and baseline OMAG measurements (peripapillary and macular perfusion density [PD] and vessel density [VD]) on the rate of change of GCIPL thickness were evaluated using linear mixed models. RESULTS: Average (± standard deviation) mean deviation, quadrant retinal nerve fiber layer, and sector GCIPL thickness of the analyzed hemifields respectively at baseline were -5.2 ± 2.8 dB, 94.5 ± 20.0 µm, and 72.4 ± 8.7 µm, respectively. Peripapillary PD and VD in the quadrant were 43.1% ± 7.0% and 17.0 ± 2.6 mm/mm2, respectively. Macular PD and VD in the quadrant were 37.2% ± 6.9% and 15.1 ± 2.6 mm/mm2, respectively. Rate of sector GCIPL change was -0.97 ± 0.15 µm per year. Multivariate mixed models showed that lower peripapillary PD (coefficient 0.04, P = .01) and VD (coefficient 0.09, P = .05) were significantly associated with a faster rate of GCIPL loss. CONCLUSIONS: Lower baseline peripapillary OMAG measurements were significantly associated with a faster rate of GCIPL loss in patients with mild to moderate POAG.

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.

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.

Diagnostic Abilities of the Optical Microangiography Parameters of the 3×3 mm and 6×6 mm Macular Scans in Glaucoma.

PURPOSE: To evaluate the diagnostic abilities of macular vessel length and perfusion densities measured with optical microangiography (OMAG) over a 3×3 mm and a 6×6 mm region, and to compare these with macular ganglion cell-inner plexiform layer (GCIPL) thickness in eyes with primary open-angle glaucoma (POAG). METHODS: In a cross-sectional study, 96 eyes of 57 control subjects and 88 eyes of 57 POAG patients underwent macular imaging with optical coherence tomography. Area under receiver operating characteristic curves (AUC) and sensitivities at 90% specificity of OMAG and GCIPL parameters were evaluated. RESULTS: Most OMAG parameters of the 3×3 mm macular scan and all inner sector parameters of the 6×6 mm scan were similar (P>0.05) in the POAG and control eyes. All outer sector OMAG parameters of the 6×6 mm scan were significantly less (P<0.05) in the POAG eyes. AUC and sensitivity at 90% specificity of the best parameter of the 3×3 mm OMAG scan (inner temporal vessel length density; 0.65% and 26%, respectively) were statistically similar (P>0.05) to that of the 6×6 mm scan (outer inferior vessel length density; 0.72% and 30%, respectively). AUC and sensitivity of the best GCIPL thickness parameter (inferotemporal GCIPL thickness, 0.84% and 67%) were significantly better (P<0.05) than that of the vessel length densities. CONCLUSIONS: The outer sector measurements of the 6×6 mm macular OMAG scans seem to be better than the inner sector measurements in diagnosing glaucoma. The GCIPL thickness measurements were significantly better than all macular OMAG parameters in diagnosing glaucoma.

Relationship of Macular Thickness and Function to Optical Microangiography Measurements in Glaucoma.

PURPOSE: The purpose of this article was to evaluate the relationship between macular optical microangiography (OMAG), ganglion cell-inner plexiform layer (GCIPL) thickness, and visual sensitivity measurements of different macular sectors in primary open-angle glaucoma. METHODS: In a cross-sectional study, 39 eyes of 26 primary open-angle glaucoma patients underwent optical coherence tomography imaging and 10-2 visual field examination of the macula in the same session. Linear regression models were used to evaluate the relationships between OMAG, GCIPL thickness, and visual sensitivity measurements in different macular sectors. Strength of relationship was reported as coefficient of determination (R). RESULTS: R values for the associations between OMAG and GCIPL thickness measurements ranged from 0.37 in the temporal sector to 0.56 in the inferior macular sector. R values for the association between OMAG and visual sensitivity measurements ranged from 0.23 in the superior to 0.53 in the inferior macular sector. R values for the association between GCIPL thickness and visual sensitivity measurements ranged from 0.15 in the superior to 0.62 in the temporal sector. CONCLUSIONS: The strongest associations between OMAG, GCIPL thickness, and visual sensitivity measurements were found in the inferior macular sector. The association of OMAG with GCIPL thickness measurements was as strong as the association between OMAG and visual sensitivity measurements in the inferior macular sector.

Diagnostic Ability and Structure-function Relationship of Peripapillary Optical Microangiography Measurements in Glaucoma.

PURPOSE: The aim of this study was to evaluate the diagnostic abilities of peripapillary optical microangiography (OMAG) measurements in eyes with primary open-angle glaucoma (POAG) and to evaluate the relationship of these measurements with retinal nerve fiber layer (RNFL) thickness and visual sensitivities in different peripapillary sectors. METHODS: In a cross-sectional study, 97 eyes of 57 control subjects and 101 eyes of 66 POAG patients underwent OMAG and RNFL imaging with optical coherence tomography. POAG was diagnosed on the basis of the masked evaluation of optic disc stereo photographs. Area under receiver operating characteristic curves and sensitivities at 90% specificity of the OMAG and RNFL thickness measurements in different peripapillary sectors were evaluated. Association between OMAG, RNFL thickness, and visual sensitivity measurements were evaluated using fractional polynomial regression models. RESULTS: All OMAG and RNFL measurements were significantly less in the POAG compared with the control eyes. Diagnostic abilities of the best OMAG measurement (inferior sector vessel length density, area under receiver operating characteristic curves: 0.84, sensitivity at 90%, specificity: 65%) were significantly less (P<0.05) than that of the best RNFL measurement (inferior sector RNFL thickness, 0.94 and 81%). Inferior sector vessel length density showed the strongest association with inferior sector RNFL thickness (R=0.66, P<0.001) and the superior sector visual sensitivity loss (R=0.21, P=0.006). CONCLUSIONS: The inferior sector OMAG measurements had the best diagnostic ability in glaucoma and the strongest association with RNFL and the visual sensitivity measurements. Diagnostic ability of OMAG measurements, however, were significantly less than the RNFL thickness measurements.

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.

Vessel Density and Structural Measurements of Optical Coherence Tomography in Primary Angle Closure and Primary Angle Closure Glaucoma.

PURPOSE: To evaluate the vessel density measurements of the optic nerve head (ONH), peripapillary, and macular regions on optical coherence tomography (OCT) angiography in eyes with primary angle closure (PAC) and primary angle closure glaucoma (PACG), and to compare their diagnostic abilities with the ONH rim area, peripapillary retinal nerve fiber layer (RNFL) thickness, and the macular ganglion cell complex (GCC) thickness measurements on OCT in PACG. DESIGN: Cross-sectional study. METHODS: Seventy-seven eyes of 50 control subjects, 65 eyes of 45 patients with PACG, and 31 eyes of 22 PAC patients with a history of high intraocular pressure underwent imaging with OCT. Area under receiver operating characteristic curves (AUC) and sensitivities at fixed specificities of vessel densities were compared with structural measurements. RESULTS: All the vessel density and structural measurements were significantly lower (P < .05) in the PACG compared with the control group. Vessel densities in the PAC were similar (P > .05) to that of the controls; the superotemporal RNFL, however, was significantly thinner in the PAC group (127 µm vs 135 µm, P = .01). The AUC and sensitivity at 95% specificity of vessel densities within the ONH (0.76 and 42%) and macular region (0.69 and 18%) in PACG were significantly lower P < .001) than ONH rim area (0.90 and 77%) and GCC thickness (0.91 and 55%), respectively. AUC and sensitivity of peripapillary vessel density (0.85 and 53%) were similar (P = 0.25) to RNFL thickness (0.91 and 65%). CONCLUSIONS: These results suggest that structural changes in PACG occur earlier than the reduction in retinal vessel densities.

Determinants of Peripapillary and Macular Vessel Densities Measured by Optical Coherence Tomography Angiography in Normal Eyes.

PURPOSE: The aim of this study was to evaluate the effect of subject-related (age, sex, and systemic hypertension and diabetes), eye-related (refractive error, optic disc size), and technology-related (signal strength index, SSI of the scans) determinants on the peripapillary and macular vessel densities measured with optical coherence tomography angiography (OCTA) in normal eyes. METHODS: In a cross-sectional study, 181 normal eyes of 107 subjects (45 men, 62 women, median age: 50 y, range: 18 to 77 y) underwent OCTA imaging. Linear mixed models were used to analyze the effect of the determinants on the peripapillary and macular vessel densities measured with OCTA. RESULTS: It was found that age and optic disc size did not affect the vessel densities of any of the regions (P>0.05 for all associations). En face optic disc (coefficient: 1.67, P<0.001) and most of the peripapillary vessel densities were higher in female individuals. En face disc (coefficient=-1.88, P=0.02) and most of the peripapillary vessel densities were lower, whereas the parafoveal vessel density was higher (coefficient=2.32, P=0.01), in subjects with hypertension. Most of the vessel densities were lower in subjects with diabetes. SSI showed a statistically significant association with the vessel densities of all regions (coefficients: 0.14 to 0.27 for peripapillary and 0.20 to 0.27 for macular sectors). CONCLUSIONS: Most of the peripapillary vessel densities were higher in female subjects. Hypertension and diabetes also affected the vessel densities. Vessel densities in all the regions were significantly higher in scans with higher SSI. These results should be considered when interpreting the vessel densities in retinal diseases and glaucoma.

A comparison of the diagnostic ability of vessel density and structural measurements of optical coherence tomography in primary open angle glaucoma.

PURPOSE: To compare the diagnostic abilities of vessel density measurements of the optic nerve head (ONH), peripapillary and macular regions on optical coherence tomography (OCT) angiography in eyes with primary open angle glaucoma (POAG) with that of the ONH rim area, peripapillary retinal nerve fiber layer (RNFL) thickness and the macular ganglion cell complex (GCC) thickness measurements. METHODS: In a cross sectional study, 78 eyes of 50 control subjects and 117 eyes of 67 POAG patients underwent vessel density and structural measurements with spectral domain OCT. POAG was diagnosed based on the masked evaluation of optic disc stereo photographs. Area under receiver operating characteristic curves (AUC) and sensitivities at fixed specificities of vessel densities in ONH, peripapillary and macular regions were compared with rim area, RNFL and GCC thickness. RESULTS: The AUC (sensitivity at 95% specificity) of average vessel densities within the ONH, peripapillary and macular region were 0.77 (31%), 0.85 (56%) and 0.70 (18%) respectively. The same of ONH rim area, average RNFL and GCC thickness were 0.94 (83%), 0.95 (72%) and 0.93 (62%) respectively. AUCs of vessel densities were significantly lower (p<0.05) than that of the corresponding structural measurements. Pre-treatment IOP (coefficient: 0.08) affected (p<0.05) the AUC of ONH vessel density but not of any other vessel density or structural measurements. CONCLUSIONS: Diagnostic abilities of ONH, peripapillary and the macular vessel densities in POAG were significantly lower than ONH rim area, peripapillary RNFL and macular GCC measurements respectively. At fixed levels of glaucoma severity, the diagnostic ability of the ONH vessel density was significantly greater in eyes with higher pre-treatment IOP.

Predicting the Magnitude of Functional and Structural Damage in Glaucoma From Monocular Pupillary Light Responses Using Automated Pupillography.

PURPOSE: To predict the magnitude of functional damage [mean deviation (MD) on visual field examination] and structural damage [retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness on spectral domain optical coherence tomography] in glaucoma from monocular pupillary light response measurements using automated pupillography. METHODS: In total, 59 subjects (118 eyes) with either a confirmed or suspected diagnosis of glaucoma underwent automated pupillography, along with visual fields and spectral domain optical coherence tomography examinations. Association between pupillary light response measurements of each eye [amplitude of constriction, latency of onset of constriction (Loc), latency of maximal constriction (Lmaxc), velocity of constriction and velocity of redilation] and corresponding MD, average RNFL, and average GCC measurements were evaluated using univariate and multivariate regression analysis after accounting for the multicollinearity. Goodness of fit of the multivariate models was evaluated using coefficient of determination (R). RESULTS: Multivariate regression models that contained Loc and Lmaxc showed the best association with MD (R of 0.30), average RNFL thickness (R=0.18) and average GCC thickness (R=0.26). The formula that best predicts the MD could be described as: MD=-14.06-0.15×Loc+0.06×Lmaxc. The formula that best predicts the average RNFL thickness could be described as: Average RNFL thickness=67.18-0.22×Loc+0.09×Lmaxc. CONCLUSIONS: Glaucomatous damage as estimated by MD, RNFL, and GCC thickness measurements were best predicted by the latency parameters (Loc and Lmaxc) of pupillography. Worsening of glaucomatous damage resulted in a delayed onset of pupillary constriction and a decreased Lmaxc.