OCT-angiography detects longitudinal microvascular changes in glaucoma: a systematic review

To evaluate optic nerve head (ONH) vessel density (VD) changes after cataract surgery using optical coherence tomography angiography (OCTA). This was a prospective observational study. Thirty-four eyes with mild/moderate cataracts were included. ONH scans were obtained before and 3mo after cataract surgery using OCTA. Radial peripapillary capillary (RPC) density, all VD, large VD and retinal nerve fiber layer thickness (RNFLT) in total disc, inside disc, and different peripapillary sectors were assessed and analyzed. Image quality score (QS), fundus photography grading and best-corrected visual acuity (BCVA) were also collected, and correlation analyses were performed between VD change and these parameters. Compared with baseline, both RPC and all VD increased in inside disc area 3mo postoperatively (from 47.5%±5.3% to 50.2%±3.7%, and from 57.87%±4.30% to 60.47%±3.10%, all P<0.001), but no differences were observed in peripapillary area. However, large VD increased from 5.63%±0.77% to 6.47%±0.72% in peripapillary ONH region (P<0.001). RPC decreased in inferior and superior peripapillary ONH parts (P=0.019, <0.001 respectively). There were obvious negative correlations between RPC change and large VD change in inside disc, superior-hemi, and inferior-hemi (r=-0.419, -0.370, and -0.439, P=0.017, 0.044, and 0.015, respectively). No correlations were found between VD change and other parameters including QS change, fundus photography grading, postoperative BCVA, and postoperative peripapillary RNFLT. RPC density and all VD in the inside disc ONH region increase 3mo after surgery in patients with mild to moderate cataract. No obvious VD changes are found in peripapillary area postoperatively.

Introduction: The aim of the study was to quantitatively characterize the longitudinal changes in macular vessel density (VD) in eyes with high myopia using swept source-optical coherence tomography angiography (SS-OCTA). Methods: A total of 108 high myopic subjects (axial length [AL] ≥26.0 mm) and 180 age-matched normal subjects were recruited and followed up for at least 1 year. Here, 6 × 6 mm SS-OCTA scans centered at the fovea were used to obtain measurements of macular VD in both the superficial capillary plexus (SCP) and deep capillary plexus (DCP). Linear regression analyses were performed to determine the independent factors associated with the change rates of parafoveal VD over time. Results: High myopia group presented a great loss of VD in both SCP and DCP, whereas control group only showed a significant reduction of VD in the SCP (all p < 0.05). The decrease of VD in the parafoveal region of high myopia group was faster than that of control group (SCP, −2.81%/year vs. −1.05%/year, p = 0.002; DCP, −1.06%/year vs. −0.01%/year, p = 0.004), as well as in the inner and outer ring (all p < 0.05). Longer baseline AL was demonstrated to be significantly associated with faster reduction of parafoveal VD in both SCP (estimate, −0.49; 95% CI: −0.79 to −0.18; p = 0.002) and DCP (estimate, −0.22; 95% CI: −0.42 to −0.03; p = 0.025) in high myopia group. Conclusions: High myopes exhibited a faster reduction of VD in parafoveal region and in the inner and outer ring in comparison with healthy controls. Longer baseline AL was associated with greater loss of parafoveal VD in patients with high myopia.

Signal Strength Reduction Effects in OCT Angiography

The objective of this study was to determine the correlation between topographic vessel density (VD) and retinal thickness (RT) reductions induced by vascular endothelial growth factor inhibitors (anti-VEGF) in patients with diabetic macular edema (DME) using optical coherence tomography angiography (OCTA). This was a prospective, interventional case series. VD and RT measurements were separately taken in four parafoveal subfields at baseline and after six months of treatment. This correlation was statistically assessed using Spearman's rho correlation coefficient after adjustment for multiple comparisons. The study included a total of 48 eyes in the final analysis. Mean VD decreased from baseline to month 6 (from 45.2 (±3.5) to 44.6% (±3.2) in the superficial capillary plexus and from 50 (±3.3) to 49% (±3.9) in the deep capillary plexus). Statistically significant reductions in RT were observed in all ETDRS sectors (p < 0.0001). No significant association was found between RT and VD, even when analyzing responders and non-responders separately. After six months of anti-VEGF treatment, no significant correlation was observed between the topographic VD and RT values. These findings suggest that reductions in VD values may not solely result from a reduction in microaneurysms, also being affected by the repositioning of displaced vessels due to edema and a reduction in their caliber. Therefore, VD changes may not be a suitable indirect OCTA biomarker of microaneurysm turnover and treatment response.

This study investigates vessel density (VD) changes in the lamina cribrosa (LC) and peripapillary sclera (PPS) after glaucoma surgery and their association with visual field (VF) progression. Primary open-angle glaucoma patients undergoing surgery for uncontrolled intraocular pressure (IOP) at Seoul St. Mary’s Hospital were included. Optical coherence tomography angiography (OCT-A) assessed VD changes in the LC and PPS one month post-surgery. VF progression was evaluated using mean deviation (MD) values from serial VF tests over six months. Of 80 enrolled eyes, 74 were analyzed. Laminar VD recovery occurred in 12 eyes (16.2%), with a 21.92% ± 7.37% increase, linked to shorter axial length (P = 0.005), thinner corneal thickness (P = 0.016), and less PPS VD change (P < 0.001). PPS VD recovery occurred in 14 eyes (18.9%), with an 18.50% ± 7.28% increase, associated with younger age (P = 0.043), longer axial length (P = 0.010), and lower preoperative PPS VD (P < 0.001). Multivariate analysis showed that both laminar and PPS VD recovery significantly reduced VF progression risk (P < 0.001). VD recovery, particularly in the LC, predicts better glaucoma outcomes. The distinct responses of LC and PPS to IOP reduction highlight the need to consider individual anatomical factors in glaucoma management.

Background: Myopia is a leading cause of correctable visual impairment worldwide, with its prevalence rapidly increasing, particularly in Asia. High myopia (spherical equivalent > -6.00 D) is associated with structural ocular complications that can result in permanent visual loss. Optical coherence tomography angiography (OCTA) allows non-invasive, high-resolution evaluation of retinal and peripapillary vascular changes in myopic eyes. This study aimed to evaluate macular and peripapillary vessel density changes among myopic adults using OCTA and identify associated factors. Methods: A prospective cross-sectional study was conducted from December 2023 to April 2024 involving 60 eyes of myopic adults (18-42 years) at an eye clinic center. Participants were grouped by myopia severity: mild, moderate, and high. OCTA was used to measure vessel density in five macular and peripapillary regions. Statistical analysis included ANOVA and Pearson's correlation. Results: Significant reductions in macular and peripapillary vessel densities were observed in high myopia, particularly in nasal and temporal areas (p<0.0001). Vessel density correlated positively with spherical equivalent and negatively with axial length. Conclusion: Vascular alterations increase with myopia severity. OCTA is a valuable tool in detecting early microvascular changes, emphasizing its role in the monitoring and management of myopic progression.

To study the precise structural aspects of a type 2 neovascular membrane in a patient with age-related macular degeneration (AMD) using optical coherence tomography (OCT) angiography and perform sequential quantitative analysis of the membrane after ranibizumab therapy. Split-spectrum amplitude-decorrelation (SSADA) OCT angiography macular cubes (3 × 3 mm) were acquired with a light source centered at 840 nm, a bandwidth of 45 nm, and an A-scan-rate of 70 000 scans per second. Visible pathologic vessels were outlined manually on average intensity projection en face images, and the area of the lesion and the vessel density were measured at baseline and follow-up. At baseline, the neovascular lesion measured 4.12 mm(2) and the vessel density was 19.83 mm(-1). Four weeks after the first, and 2 and 4 weeks after the second ranibizumab injection, OCT angiography revealed a progressively smaller vascular lesion (2.32, 1.77 and 1.64 mm(2)), and vessel density (10.24, 8.52 and 7.57 mm(-1)), although the large central trunks of the lesion were unchanged. In this study, an obvious reduction in size and vessel density of the neovascular lesion was noted after treatment with ranibizumab using SSADA OCT angiography technology. Microvascular components can be delineated with precision, suggesting that this technique may be useful for the management of patients with neovascular AMD in a clinical setting as well as for future clinical trials.

Optical coherence tomography (OCT) and OCT angiography (OCTA) are widely used in the diagnosis of ophthalmic diseases. This study aims to provide a comprehensive bibliometric analysis of ophthalmologic OCT and OCT angiography. We retrieved publications on ophthalmic OCT and OCTA from 2003 to 2022 from the Web of Science Core Collection and used bibliometric tools to analyze and visualize the distribution, trend, and hotspots. In total, 20,817 articles written by 48,160 authors from 106 countries were selected. The number of publications has significantly increased. In the last two decades, the USA was the most productive country and received the highest citations. The most productive journal was Investigative Ophthalmology and Visual Science and received the highest number of citations. Moorfields Eye Hospital was the most productive institution. Bandello F published the most papers, while Spaide RF was the highest cited author. SPAIDE RF, 2011, AM J Ophthalmology was the most cited document. "OCT", "glaucoma" and "OCTA" were three hotspots in the last two decades. "Vessel density" and "deep learning" would be research hotspots in the future. The bibliometric analysis of ophthalmic OCT and OCTA research over the past two decades on keywords, authors, citations, hotspots and trends will provide global researchers with valuable information for future research and cooperation.

ABSTRACTPurpose: To investigate changes in peripapillary retinal vessel density after acute intraocular pressure (IOP) elevation caused by laser peripheral iridotomy (LPI) in primary angle-closure suspects (PACS) by optical coherence tomography angiography (OCTA).Materials and Methods: Ninety-seven participants with PACS were included in this cross-sectional observational study. OCTA and IOP measurement were performed at baseline and 1 h after LPI. PACS eyes were further divided into three groups according to IOP increase 1 h after LPI (group 1 = IOP elevation <5 mmHg, 42eyes; group 2 = IOP elevation ≥5 mmHg and <10 mmHg, 34 eyes; group 3 = IOP elevation ≥10 mmHg, 21eyes). The changes of vessel density in radial peripapillary capillary (RPC) and entire retina were compared among groups.Results: When all eyes were included, the vessel density of RPC and entire retina 1 h after LPI were significantly decreased compared to the baseline (RPC: 64.5 ± 7.9 vs.67.8 ± 6.8, P < .001; retina: 86.3 ± 4.6 vs.88.3 ± 3.8, P < .001). There were significant differences among the three groups in the RPC and retinal vessel density at 1 h after LPI (RPC: 67.4 ± 7.3 vs. 63.2 ± 7.6 vs. 60.9 ± 7.5, P = .003; retinal: 87.7 ± 4.0 vs. 85.8 ± 4.5 vs. 84.3 ± 5.2, P = .015). In group 2 with an increased IOP from 5 mmHg to 10 mmHg, the reduction of vessel density in the RPC was more significant than that of the entire retina (RPC vs. retina: 7.1 ± 10.0% vs. 3.0 ± 4.4%, P = .006).Conclusions: LPI-induced IOP spikes resulted in a decrease in retina vessel density with PACS eyes by OCTA. The reduction of RPC vessel density was more significant than that of the entire retina in the subgroup of IOP increase from 5 to 10 mmHg. This suggests that vessel density in RPC was more sensitive to IOP increase than that of the entire retina in the peripapillary area.

Optical coherence tomography (OCT) and OCT Angiography in Stages 3 and 4 proliferative sickle cell retinopathy

Background Glaucoma is a prevalent cause of visual impairment, and early detection is critical to prevent progressive vision loss. Optical coherence tomography angiography (OCT-A) enables visualization of retinal and optic nerve microvasculature and holds promise for early glaucoma detection. Aims This study aims to assess microvasculature density alterations in glaucoma using OCT-A. Methods An observational cross-sectional case–control study was conducted at Benghazi Eye Hospital in Libya from December 2022 to August 2023. It included 160 eyes of 126 patients diagnosed with primary open-angle glaucoma and 120 eyes of 96 control subjects. OCT-A was performed using the Swept-Source OCT DRI Triton. Vessel density measurements were obtained from OCT-A images using new built-in software within the device. The data presented as mean ± standard deviation and percentages were analyzed using SPSS. The statistical significance of the differences between different groups was determined using independent t-tests, and the level of significance was set at p-value less than 0.05. Results OCT-A demonstrated significantly reduced microvasculature density in glaucoma eyes across all optic nerve sectors including the inferior (29.0%), superior (25.2%), central (23.5%), nasal (9.9%), and temporal sectors (9.3%; p &lt; 0.02). Moreover, glaucoma patients exhibited a significant reduction in vessel density in the superior macula (17% reduction), the temporal (15.7%,), nasal (12.9%), and inferior sectors (12.6%) (p &lt; 0.002). No statistical difference was seen with vessel density of the central sector (0.49%, p &gt;0.05). Conclusion OCT-A demonstrated significant reductions in microvasculature density in glaucoma patients compared with healthy controls. These findings support the association between glaucoma and vascular changes. Additionally, the TOPCON Swept-Source OCT DRI Triton new software shows promise as a valuable tool for early detection and monitoring of glaucoma-related vascular changes.

AimTo newly describe a spectral-domain (SD) optical coherence tomography angiography (OCTA) for the cornea and directly compare two OCTA system scans of the same eyes with corneal vascularisation.MethodsCross-sectional, observational, comparative...

To compare choroidal neovascularization (CNV) area and vessel density (VD) measurements between two different swept-source optical coherence tomography angiography (SS-OCTA) devices. En face optical coherence tomography angiography (OCTA) images of patients affected by neovascular age-related macular degeneration were collected prospectively from two devices: Zeiss PLEX Elite 9000 (Carl Zeiss Meditec, Dublin, CA) and Topcon DRI OCT Triton SS-OCTA (Topcon, Tokyo, Japan). Choroidal neovascularization area and VD of images were measured and analyzed with ImageJ software by two readers to evaluate the agreement between two devices, with respect to different image size (3 × 3 and 6 × 6 mm) and different image segmentation (automatic vs. manual), and a Topcon equivalent Zeiss segmentation as control (i.e., the equivalent anatomical slab given by Topcon device on the Zeiss device). A total of 30 eyes (30 patients) were analyzed. There was an excellent agreement between the two readers in CNV area measurements intraclass correlation coefficient >0.9 in all analyses. We found excellent agreement in CNV area measurements (manual and automatic segmentations) when comparing 3 × 3-mm or 6 × 6-mm images both for each single device and between the two devices (overall intraclass correlation coefficient > 0.9). Vessel density measurements between manual to automatic segmentation within the same device and same image size had a high intraclass correlation coefficient value, but there was a poor agreement in VD between different image sizes (3 × 3 mm vs. 6 × 6 mm) in the same device and also comparing the two devices (3 × 3 Topcon vs. 3 × 3 Zeiss; 6 × 6 Topcon vs. 6 × 6 Zeiss). There was a poor agreement between the Topcon equivalent Zeiss segmentation and all other segmentations. There was an excellent agreement in CNV area measurements for both swept-source optical coherence tomography angiography devices in automatic and manual segmentations. However, the Topcon equivalent Zeiss segmentation was not comparable with any of the preset segmentations of Topcon and Zeiss devices. There was a poor agreement in CNV VD between different image size and different devices. For these reasons, it seems that, for accurate longitudinal analysis of VD, it is better to use the same device for each individual, even if both devices can be used interchangeably for CNV area measurements using automatic or manual segmentations.

To evaluate the diagnostic efficacy of optical coherence tomography (OCT) angiography, in patients with pre-perimetric open-angle glaucoma. Thirty-eight consecutive eyes of 26 patients with pre-perimetric open-angle glaucoma and 48 normal eyes of 32 controls were included in this prospective study. We evaluated OCT angiography, spectral-domain OCT and visual fields parameters. Differences between controls and patients and between OCT angiography parameters and traditional glaucoma measurements were evaluated. Receiver operating characteristic curves for OCT angiography parameters were assessed. The flow index (p=0.021) and vessel density (p=0.001) were significantly lower in pre-perimetric glaucoma eyes versus normal eyes. Ganglion cell complex parameters were significantly correlated to OCT angiography parameters (p<0.05). Neither retinal nerve fiber layer (RNFL) nor visual field parameters correlated with OCT angiography parameters. OCT angiography can be considered a reliable, easy-to-perform method with which to evaluate microvascular changes of optic nerve head for the early diagnosis and follow-up of glaucoma.

To evaluate the structural, microvascular, and functional progression of normal tension glaucoma (NTG) with or without high myopia by examining longitudinal changes in optical coherence tomography angiography (OCTA) and visual field (VF) parameters. We evaluated 61 NTG eyes and classified 25 of the eyes with axial lengths (ALs) of ≥26 mm as highly myopic. We assessed the rate of change in OCTA parameters, namely radial peripapillary capillary (RPC) vessel density (VD), parafovea VD, deep parafovea VD, retinal nerve fibre layer (RNFL) thickness, and ganglion cell complex thickness. We evaluated the correlation of the rate of change in OCTA parameters with VF loss and AL. Among the 61 NTG eyes, rates of loss of RPC VD, parafovea VD, deep parafovea VD, and RNFL thickness were significantly different from zero despite the nonsignificant rate of change in VF mean deviation (MD). Changes in these OCTA parameters did not differ significantly in highly myopic NTG eyes. The rate of change in VF MD was significantly correlated with the rate of change in parafovea VD in highly myopic and non-highly myopic NTG eyes. In highly myopic NTG eyes, AL was negatively correlated with the rates of loss of RNFL thickness, VF MD, and VF PSD. NTG eyes with a relatively stable VF exhibited loss of VD and RNFL thickness. VF progression in NTG was correlated with decreasing parafovea VD, indicating a structure-function correlation. Greater AL may indicate faster VF loss and RNFL thinning in highly myopic NTG eyes.