Relationship between optical coherence tomography sector peripapillary angioflow-density and Octopus visual field cluster mean defect values

Influence of Refractive Error on Circumpapillary Structure-Function Versus Vessel Density-Function Relationships in Open Angle Glaucoma

PRCIS

In Japanese open angle glaucoma (OAG) eyes correlation of 30-degree visual field mean deviation (MD) and visual field index (VFI) with circumpapillary vessel density is systematically stronger than that with circumpapillary retinal nerve fiber layer thickness (RNFLT), and is preserved in myopia and high myopia.

PURPOSE

The purpose of this study was to investigate the influence of refractive error on the relationship between circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and circumpapillary vessel density (cpVD), respectively, and global visual field parameters in Japanese open angle glaucoma (OAG) eyes.

MATERIAL AND METHODS

One eye of 81 Japanese OAG patients (spherical equivalent refractive error: +3.0 to -9.0 D) underwent 360-degree cpRNFLT and cpVD measurements with Cirrus HD 5000-AngioPlex optical coherence tomography and 30-2 Humphrey visual field testing for mean deviation (MD) and visual field index (VFI) within 1 month. Correlations were determined for the whole population and each refractive error subgroups, separately: emmetropia/hyperopia (n=24), mild (n=18), moderate (n=20), and high myopia (n=19).

RESULTS

For the total population, significant strong to very strong correlations were found between MD, VFI, and both cpRNFLT and cpVD, respectively, with consistently higher r -values for cpVD (highest r -values: 0.532 for cpRNFLT, P <0.001; 0.722 for cpVD, P <0.001). Of the refractive subgroups, statistically significant correlations between cpRNFLT and the visual field parameters were maintained only in the hyperopia/emmetropia and moderate myopia groups. In contrast, statistically significant, strong to very strong correlations between cpVD and both MD and VFI, always exceeding the corresponding r -values found for cpRNFLT were found in all refractive subgroups, with r -values ranging between 0.548 ( P =0.005) and 0.841 ( P <0.001).

CONCLUSIONS

Our results suggest that in Japanese OAG eyes the relationship of MD and VFI with cpVD is strong. It is systematically stronger than that with cpRNFLT and preserved in each conventional refractive error category including high myopia.

[Optical coherence tomography and optical coherence tomography angiography for detecting glaucoma progression. Part 2. Clinical and functional correlations, monitoring of advanced glaucoma and limitations of the method]

The purpose of this study is to analyze the literature on the role of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in the diagnosis of glaucoma. This review considers the structural and functional correlations observed during the progression of glaucomatous optic neuropathy, as well as the capabilities of the method in late glaucoma, describes the strengths and weaknesses of OCT and OCTA, and pays particular attention to the role of OCT in assessing the effectiveness of treatment. Optical coherence tomography is the main method for determining the progression of glaucoma, which plays a key role in the choice of treatment algorithm. However, the use of OCT in far advanced glaucoma has certain particularities and limitations. OCTA can be helpful in overcoming this problem.

Comparison of the Structure-Function Relationship in Glaucoma Using Optical Microangiography in the Peripapillary Retinal Nerve Fiber Layer

PRCIS

Optical microangiography measurements correlated with functional parameters in glaucoma patients. Optical coherence tomography angiography-derived vessel perfusion density (VPD) better reflected the structure-function relationship than flux index (FI) and retinal nerve fiber layer thickness.

PURPOSE

The purpose of this study was to compare the structure-function relationship between peripapillary optical microangiography (OMAG) measurements and standard automated perimetry (SAP) loss by comparison with peripapillary retinal nerve fiber layer (pRNFL) thickness in primary open-angle glaucoma.

MATERIALS AND METHODS

One eye from each of 128 patients with early-to-severe glaucoma (including preperimetric glaucoma) and 23 normal participants underwent optic nerve head scanning of the radial peripapillary capillaries and pRNFL scans with OMAG centered on the optic disc and SAP (mean age: 67.8±12.0 y; SAP mean deviation: -5.84±6.6 dB). Regional relationships between VPD, FI, pRNFL thickness, and corresponding SAP sensitivity were compared using linear and fractional polynomial (FP) models.

RESULTS

Structure was significantly related to function for all but the nasal pRNFL thickness region. For VPD, the coefficient of determination (R2) using the FP model was significantly stronger than that of the linear model (FP: 0.25 to 0.67, linear: 0.19 to 0.61), while no difference was found for FI in any region (FP: 0.19 to 0.44, linear: 0.15 to 0.42). R2 for VPD was stronger than FI and pRNFL (FP: 0.11 to 0.52, linear: 0.01 to 0.44) in inferior and superior regions, while VPD and FI were not different in temporal and nasal regions.

CONCLUSIONS

VPD showed a stronger association with visual field loss than FI or retinal nerve fiber layer thickness except in the temporal region. The FI relationship was weak but more linear around the peripapillary region. The strength of the structure-function relationship may differ depending on the region of OMAG measurements.

Optical Coherence Tomography and Glaucoma

Early detection and monitoring are critical to the diagnosis and management of glaucoma, a progressive optic neuropathy that causes irreversible blindness. Optical coherence tomography (OCT) has become a commonly utilized imaging modality that aids in the detection and monitoring of structural glaucomatous damage. Since its inception in 1991, OCT has progressed through multiple iterations, from time-domain OCT, to spectral-domain OCT, to swept-source OCT, all of which have progressively improved the resolution and speed of scans. Even newer technological advancements and OCT applications, such as adaptive optics, visible-light OCT, and OCT-angiography, have enriched the use of OCT in the evaluation of glaucoma. This article reviews current commercial and state-of-the-art OCT technologies and analytic techniques in the context of their utility for glaucoma diagnosis and management, as well as promising future directions.

The agreement between optical coherence tomography angiography and non-mydriatic retinal camera in estimating the optic nerve head parameters and relations with the peripapillary vessel density in primary open-angle glaucoma

BACKGROUND/OBJECTIVES

To investigate the agreement between optical coherence tomography angiography (OCT-A) and non-mydriatic retinal camera (NMRC) in estimating the optic nerve head (ONH) parameters and evaluate the associations between peripapillary vessel density (VD) with ONH parameters assessed by both devices.

METHODS

The OCT-A and NMRC images of 262 participants (138 eyes were diagnosed with POAG, 63 were glaucoma suspect, and 61 were healthy subjects) were screened retrospectively. The vertical cup-to-disc ratio (VCDR), cup-to-disc area ratio (CDAR), rim area (RA), disc area (DA), and cup volume (CV) were recorded using both devices. Peripapillary VD data were also recorded using OCT-A. The intraclass correlation coefficient (ICC) and Bland-Altman plots were obtained to investigate the agreement between the devices. Age- and intraocular pressure (IOP)-corrected associations between the VD and ONH parameters measured by the two devices were analyzed using linear regression models.

RESULTS

ICC revealed excellent agreement for VCDR and CDAR, but poor agreement for RA, DA, and CV (ICC = 0.801, 0.793, 0.445, 0.298, and 0.527, respectively). The Bland-Altman plots showed poor agreement for VCDR and CDAR with a large span of limits of agreement (0.500 and 0.528, respectively) and significant proportional biases (P < 0.05). VD was found to be strongly associated with the VCDR and CDAR measurements of both devices (P < 0.001), but the associations were stronger for the measurements of NMRC.

CONCLUSIONS

The disagreement between the devices should be considered in clinical practice. The associations between the VD and ONH parameters proved once again the importance of the ONH parameters in terms of the management of glaucoma patients.

Optical coherence tomography angiography in glaucoma: analysis of the vessel density-visual field sensitivity relationship

Glaucoma, a well-defined group of progressive optic neuropathies is one of the leading causes of irreversible blindness worldwide. In order to stop or slow down the progression of glaucomatous vision deterioration, intraocular pressure reduction by medical, laser or surgical treatment is needed. To ensure that treatment is efficient and tailored to the actual needs both cross sectional evaluation of disease severity and measurement of rate of progression are essential. Currently staging and progression are investigated with visual field and retinal thickness measurements. Perimetry, however, is influenced by several biological factors which are not related to glaucoma, and the use of retinal thinning is limited by floor effect. Therefore, clinical application of optical retinal coherence tomography angiography, a new and rapidly developing non-invasive measurement of the capillary perfusion in the various retinal layers, respectively, is now in the focus of clinical glaucoma research. This comprehensive review summarizes the current knowledge on one of the most important research areas in optical coherence tomography angiography in glaucoma, the relationship between retinal capillary perfusion and the spatially corresponding visual field threshold sensitivity.

Optical coherence tomography angiography in glaucoma

Assessment of the vasculature within the optic nerve, peripapillary superficial retina, macula, and peripapillary choroid can be determined in glaucoma using optical coherence tomography angiography (OCTA). Decreased perfusion within the pre-laminar layer of the optic nerve has been correlated with glaucoma severity. The peripapillary superficial retinal vessel density allows diagnosis and detection of glaucoma progression in a manner similar to the peripapillary retinal nerve fiber layer (RNFL) thickness. Furthermore, decreased peripapillary vessel density of the intact hemiretina or unaffected eye of glaucomatous eyes suggests that vascular changes can occur prior to detectable visual field damage. The accuracy for glaucoma detection of the macular ganglion cell (MGC) thickness compared to macular vessel density has differed among studies. Several studies have reported reduction of macular vessel density as well as its ganglion cell thickness. Results of studies evaluating the parapapillary choroid have shown a greater prevalence of choroidal microvasculature dropout in glaucomatous eyes with a parapapillary gamma zone, which is associated with central visual field defects or glaucoma progression. It remains unclear whether the reduced vessel density in glaucoma is a primary event or secondary to glaucomatous damage. Further studies are warranted to elucidate this question.

Comparison of Thickness-Function and Vessel Density-Function Relationship in the Superior and Inferior Macula, and in the Superotemporal and Inferotemporal Peripapillary Sectors

PRéCIS:: In primary open-angle glaucoma (POAG), unlogged mean macular hemifield visual field sensitivity correlates significantly better with superficial capillary vessel density (VD) than with ganglion cell complex (GCC) thickness of the opposite macular hemifield.

PURPOSE

The aim of this study was to compare the relationship of the spatially corresponding superficial retinal capillary VD and retinal thickness parameters with the corresponding visual field sensitivity, for the superior and inferior macula, and the superotemporal and inferotemporal peripapillary sectors, respectively.

PATIENTS AND METHODS

One eye of 27 POAG, 14 ocular hypertensive, and 9 healthy participants were subjected to optical coherence tomography angiography imaging with the Angiovue optical coherence tomography and Octopus G2 perimetry on the same day. Superior and inferior unlogged hemifield average macular sensitivity was correlated with the opposite macular hemifield VD and GCC thickness, respectively. Correlation of visual field cluster unlogged average sensitivity with the spatially corresponding sector VD and sector retinal nerve fiber layer thickness were compared for the superotemporal and inferotemporal peripapillary sector, respectively.

RESULTS

For all participants and the glaucoma population, the correlations for macular hemifield GCC were strong or very strong (r: 0.554 to 0.737, P<0.01). In these groups, the correlations for macular hemifield VD were all very strong (r: 0.823 to 0.838, P<0.0001) and significantly higher than the corresponding correlations for hemifield GCC (P≤0.050). No significant difference between the corresponding correlations was found in the combined normal and ocular hypertensive group for the macular hemifields, or in either population for the peripapillary sectors.

CONCLUSION

Our results suggest that, in contrast to superotemporal and inferotemporal peripapillary sectors in which the thickness-function and VD-function relationships are similar, in POAG, for the macular hemifields, the VD-function relationship is stronger than the thickness-function relationship.

Assessments of vessel density and foveal avascular zone metrics in multiple sclerosis: an optical coherence tomography angiography study

BACKGROUND/OBJECTIVES

To investigate optical coherence tomography angiography (OCT-A) findings of foveal avascular zone (FAZ) metrics and macular & peripapillary vessel densities (VD) in subjects with multiple sclerosis (MS).

METHODS

The study design was prospective and cross-sectional. FAZ metrics and VDs of the superficial capillary plexus (SCP), deep capillary plexus (DCP), retinal peripapillary capillary plexus (RPCP) along with the structural OCT measurements were scanned by using the Nidek's RS-3000 Advance in MS patients and healthy controls. All subject also underwent an assessment of visual evoked potentials (VEPs). The relationships between the OCT-A parameters with other clinical findings were analysed.

RESULTS

Forty-seven MS patients (94 eyes) and 61 healthy volunteers (122 eyes) were included in this study. Thirty-five eyes of the MS patients had an ON history. The structural OCT measurements were significantly differed between the groups (P < 0.001). All FAZ metrics were inversely correlated with central foveal thickness (CFT) (P < 0.001). The FAZ area and perimeter were inversely correlated with the VD of both SCP and DCP (P < 0.05). The VDs of SCP and DCP were significantly differed between the study groups (P < 0.001). The VEP latency was inversely correlated with the retinal nerve fibre layer, macular and ganglion cell layer thicknesses, the VD of SCP, and the VD of the DCP (P < 0.001).

CONCLUSIONS

Based on OCT angiography, VDs of macular and peripapillary area may be useful in detecting damage from ON in patients with MS.

Comparison of Peripapillary OCT Angiography Vessel Density and Retinal Nerve Fiber Layer Thickness Measurements for Their Ability to Detect Progression in Glaucoma

PURPOSE

The aim of this study was to investigate the applicability of peripapillary optical coherence tomography angiography angioflow vessel density measurements in the retinal nerve fiber layer for the detection of glaucomatous progression and to compare its performance with that of retinal nerve fiber layer thickness (RNFLT) measurements.

METHODS

Prospective RNFLT and vessel density measurements with the same Angiovue/RTVue-XR instrument were made immediately one after another on 1 eye of 9 normal eyes, 20 under treatment ocular hypertension eyes, and 24 under treatment open angle glaucoma eyes at 6-month intervals for 2 years (5 visits for all eyes). High image quality (signal strength index 50 to 91) was obtained for all measurements. No surgery was performed on any study eye during the study period. The normal and OHT cases were combined for comparison with the glaucoma group.

RESULTS

A statistically significant negative RNFLT slope was found in 16 eyes, whereas no eye had a significant negative vessel density slope (P<0.0001). The relative RNFLT and vessel density slopes were significantly different in the combined normal and OHT group, the glaucoma group, and the total population, respectively (P<0.0001). For the same groups, the relative residual SD was significantly higher for vessel density than for RNFLT measurements (P≤0.0019). The relative residual SD of RNFLT measurements was higher in the glaucoma group than in the combined normal and OHT group (P=0.0056), whereas the relative residual SD of vessel density measurements did not differ between the groups (P=0.3032).

CONCLUSION

In this 2-year prospective study, peripapillary vessel density measurement did not support the detection of glaucomatous progression.

Optical coherence tomography angiography in glaucoma

PURPOSE OF REVIEW

Optical coherence tomography angiography (OCTA) studies have demonstrated reduced microcirculation in the superficial optic nerve, peripapillary retina, and the macula of glaucoma patients. The scope of this review is to outline recent studies using OCTA in glaucoma and highlight how OCTA may help improve diagnosis and follow-up in glaucoma patients.

RECENT FINDINGS

OCTA studies have provided evidence of vascular changes in the optic nerve head, peripapillary, and macula region in glaucoma in comparison to glaucoma suspects and normal eyes. Additionally, OCTA can detect longitudinal reduction of peripapillary and macula vessel density in glaucoma patients. It remains unclear whether the reduced microcirculation in glaucoma patients induces the neuronal damage or arises through reduced circulation requirements in damaged tissue.

SUMMARY

OCTA is a novel imaging modality that has great potential to enhance our understanding of glaucoma and to improve our ability to detect and treat it.

Optical Coherence Tomography Angiography in Glaucoma

Optical coherence tomography angiography (OCTA) comprises different OCT-based technologies developed for non-invasive assessment and measurement of optic nerve head and retinal perfusion. Currently the most clinically established approach is based on the split spectrum amplitude decorrelation algorithm, which detects moving red blood cells and eliminates all other information. The two main clinical fields in which OCTA offers clinically useful information are investigation of the macular retina (e.g. in macular degeneration and diabetic macular disease) and glaucoma. For glaucoma, the optic nerve head and the peripapillary retinal perfusion in the retinal nerve fiber layer, and the superficial perifoveal macular vasculature are the areas of interest. This review provides a comprehensive summary of the most important current and potential future applications of OCTA in glaucoma, but it does not address the nonglaucomatous optic nerve head or peripapillary and macular diseases.

Impact of Natural Blind Spot Location on Perimetry

We study the spatial distribution of natural blind spot location (NBSL) and its impact on perimetry. Pattern deviation (PD) values of 11,449 reliable visual fields (VFs) that are defined as clinically unaffected based on summary indices were extracted from 11,449 glaucoma patients. We modeled NBSL distribution using a two-dimensional non-linear regression approach and correlated NBSL with spherical equivalent (SE). Additionally, we compared PD values of groups with longer and shorter distances than median, and larger and smaller angles than median between NBSL and fixation. Mean and standard deviation of horizontal and vertical NBSL were 14.33° ± 1.37° and −2.06° ± 1.27°, respectively. SE decreased with increasing NBSL (correlation: r = −0.14, p < 0.001). For NBSL distances longer than median distance (14.32°), average PD values decreased in the upper central (average difference for significant points (ADSP): −0.18 dB) and increased in the lower nasal VF region (ADSP: 0.14 dB). For angles in the direction of upper hemifield relative to the median angle (−8.13°), PD values decreased in lower nasal (ADSP: −0.11 dB) and increased in upper temporal VF areas (ADSP: 0.19 dB). In conclusion, we demonstrate that NBSL has a systematic effect on the spatial distribution of VF sensitivity.