Quantitative assessment of the retinal microvasculature and choriocapillaris in myopic patients using swept-source optical coherence tomography angiography

Changes in retinal and choroidal optical coherence tomography angiography indices among young adults and children over 1 year

CLINICAL RELEVANCE

Optical coherence tomography angiography (OCT-A) indices are likely to change across time and optometrists should be aware of the variability expected during childhood development and in healthy adults.

BACKGROUND

Cross-sectional studies have shown that OCT-A indices are associated with age in adults and children. The aim of this study is to investigate longitudinal changes in retinal and choroidal OCT-A indices over 1 year among healthy children and young adults.

METHODS

This prospective longitudinal study captured macular OCT-A and OCT scans, and biometry measures at baseline and 1-year follow-up for 22 adults (18-30 years; -6.87 to +0.37 D) and 21 children (6-15 years; -5.75 to +0.25 D). Superficial and deep retinal layer, choriocapillaris and deep choroidal en face OCT-A images were analysed to extract magnification-corrected vascular indices in foveal, parafoveal and perifoveal regions. The retinal indices included foveal avascular zone metrics, perfusion, and vessel density. Flow deficit number, size, and density were extracted from choriocapillaris and perfusion density from deep choroid. Associations between annual changes in the OCT-A indices and axial length and baseline refraction were also studied.

RESULTS

Among children, significant reductions were noted only in parafoveal superficial retinal and foveal and perifoveal deep retinal layer indices over 1 year (p < 0.05). Choroidal OCT-A indices in children and both retinal and choroidal OCT-A indices in adults did not show significant changes. Myopia was associated with a larger reduction in the perifoveal retinal OCT-A indices in children, and with increases in sub-foveal and sub-parafoveal choroidal indices in adults. There were associations between OCT-A indices and axial length changes but differently in adults and children.

CONCLUSIONS

Significant changes were noted in retinal OCT-A indices over 1 year among children but not adults. In comparison, choroidal OCT-A indices in adults and children showed a stable morphology over this period of time.

Morphological characteristics of the foveal avascular zone in pathological myopia and its relationship with macular structure and microcirculation

PURPOSE

To explore the characteristics of macular structure, microcirculation, and foveal avascular zone (FAZ) morphology in pathological myopia and to research the associations between these factors and pathological myopia.

METHODS

This is a cross-sectional study. The study included 103 eyes with non-high myopia and 206 eyes with high myopia (139 with simple high myopia and 67 with pathological myopia). Macular structural and microcirculation parameters were determined using optical coherence tomography angiography (OCTA). The FAZ morphological parameters were measured manually using Image J software. Correlations between pathological myopia and various factors were analyzed.

RESULTS

Patients with pathological myopia had a thinner retinal thickness (RT) and choroidal thickness (CT) and a lower retinal superficial vascular density (SVD), retinal deep vascular complex density (DVD), choriocapillaris perfusion area (CCPA), and choroidal vascularity index (CVI) (all P < 0.05). Patients with pathological myopia had a larger FAZ area, perimeter, major axis, minor axis, acircularity index (AI), and lower circularity index (CI) (all P < 0.01). The axial length (AL), the major axis of the superficial FAZ, CI, and AI were significantly correlated with myopia severity (all P < 0.05).

CONCLUSIONS

Patients with pathological myopia exhibited worse macular microcirculation and thinner macular retina and choroid. The FAZ in pathological myopia was larger and more irregular. The AL, CI, and AI were significantly associated with myopia severity. Thus, CI and AI might serve as new indicators for monitoring the progression of myopia. Further investigations should be performed.

TRIAL REGISTRATION

Clinical Trials.gov Identifier: ChiCTR2100046590.

Comparative quantitative analysis of optical coherence tomography angiography in varied morphologies of macular neovascularization following intravitreal conbercept and ranibizumab treatments for neovascular age‑related macular degeneration

The present study aimed to examine the optical coherence tomography angiography (OCTA) parameters associated with macular neovascularization (MNV) in patients diagnosed with neovascular age-related macular degeneration (nAMD) and treated with either intravitreal conbercept (IVC) or ranibizumab (IVR). It enrolled 39 nAMD patients presenting with MNV, including 23 in the IVC group and 16 in the IVR group. All participants were treatment-naïve with intravitreal therapy and they underwent treatment following a '3+PRN' regimen. The MNV patterns identified through OCTA were categorized as Medusa, tangled, seafan and other variations. Key outcome measures encompassed best-corrected visual acuity (BCVA), MNV vascular area (MNV-VA), MNV vascular density (MNV-VD) ratio and central macular thickness (CMT). In the present study, 44 eyes were included, with 28 eyes undergoing treatment with IVC and 18 eyes with IVR. On day 90, there was a statistically significant improvement in mean BCVA from baseline among all patients treated with IVC (P=0.002). Notably, improved outcomes were observed in those with the 'tangled' pattern compared with the other three patterns (P=0.007). CMT exhibited a significant decrease from baseline (P=0.007), with consistent improvement observed across all four patterns (P=0.052) on day 90. The mean MNV-VA decreased in all patients, reaching statistical significance for the Medusa pattern (P=0.008), although the improvement in visual acuity was deemed unsatisfactory. Patients with the seafan pattern treated with IVR improved significantly in BCVA (P=0.042). The mean CMT significantly improved from baseline (P=0.001), consistent across the four patterns (P=0.114). Significant improvements were noted in the mean MNV-VA for the seafan pattern and in the mean MNV-VD ratio for the other patterns. The two regimens had no significant differences regarding BCVA, CMT, and MNV parameters. Conbercept emerged as a viable treatment option for patients presenting with tangled MNV patterns. On the other hand, ranibizumab might be considered an effective intervention for individuals with seafan MNV patterns. Notably, the Medusa MNV pattern was associated with a morphologic configuration indicative of a poor prognosis.

Choriocapillaris flow features in children with myopic anisometropia

AIMS

To examine differences between the eyes in choriocapillaris perfusion and choroidal thickness in children with myopic anisometropia.

METHODS

In this observational and prospective study, 46 children with myopic anisometropia were enrolled. Choriocapillaris perfusion parameters, including the percentage of flow voids, the total number of flow voids and the average flow void area were obtained by optical coherence tomography angiography (OCTA). The OCTA image was divided into a 1 mm-diameter central circle (C1) and a 2.5 mm-diameter annulus (without the inner central 1 mm circle, C1-2.5). Both C1 and C1-2.5 are centred on the foveola. The C1-2.5 was divided into nasal (N1-2.5), temporal (T1-2.5), inferior (I1-2.5) and superior (S1-2.5) areas. Differences in these parameters in different regions between eyes were analysed.

RESULTS

There were no significant differences in the percentage of flow voids and the average flow void area between the fellow eyes. The total number of signal voids was significantly higher in the less myopic eyes in C1-2.5 (p=0.032), S1-2.5 (p=0.008) and N1-2.5 (p=0.019). Changes in spherical equivalent refraction and axial length were both correlated with the changes in the total number of flow voids in N1-2.5 (R=-0.431, p=0.03; R=-0.297, p=0.047).

CONCLUSIONS

The choroid in the macular region becomes thinner and the total number of flow voids in the nasal macular region decreased with the amplitude of myopia. This suggests that a decrease in total number of flow voids may indicate an early change in myopia.

Reduced contrast sensitivity function is correlated with changes to cone photoreceptors in simple high myopia

Purpose

To investigate the contrast sensitivity function (CSF) changes in simple high myopia (SHM) and evaluate the correlations between these changes with the early changes in the retinal microstructure.

Methods

This prospective study comprised 81 subjects, 20 with emmetropia (EM), 26 with low myopia and moderate myopia (LM/MM), and 35 with SHM. The area under the log CSF curve (AULCSF) and the cut-off spatial frequency (Cut-off SF) were employed as measures of CSF. Adaptive optics (AO) was employed to quantify the cone density, spacing, and regularity. The thickness and blood flow of the retinal sublayers were determined from vertical and horizontal optical coherence tomography angiography (OCTA) A-scans. Swept-source optical coherence tomography (SS-OCT) was employed to analyze the choroidal thickness (CT) and choroidal vascularity using a custom algorithm. Differences in the retinal and choroidal parameters, cone distribution, AULCSF, and Cut-off SF were compared among the three groups. Multivariate linear mixed models were used to elucidate the associations between photoreceptor morphological alterations, retinal and choroidal parameters, and AULCSF.

Results

The AULCSF and Cut-off SF were significantly lower in the SHM group compared to the EM and LM groups (p < 0.05). The SHM group had less cone density, larger cone spacing, and lower cone regularity than the EM and LM/MM groups (p < 0.05). Moreover, the thickness of the inner segment of photoreceptors (IS), retinal pigment epithelium (RPE) layer and choroid were reduced, and the outer segment of photoreceptors (OS) was thicker in the SHM group compared to the EM and LM/MM groups (all p < 0.05). A longer axial length (AL) was correlated with decreased AULCSF, cone density, and cone spacing (r = -0.800 to 0.752, all p < 0.050). Additionally, decreased CSF was correlated with lower cone density (r = 0.338, p = 0.035).

Conclusion

Decreased contrast sensitivity was observed in patients with SHM and cone density was significantly correlated with reduced AUCSF.

Optic neuropathy in high myopia: Glaucoma or high myopia or both?

Due to the increasing prevalence of high myopia around the world, structural and functional damages to the optic nerve in high myopia has recently attracted much attention. Evidence has shown that high myopia is related to the development of glaucomatous or glaucoma-like optic neuropathy, and that both have many common features. These similarities often pose a diagnostic challenge that will affect the future management of glaucoma suspects in high myopia. In this review, we summarize similarities and differences in optic neuropathy arising from non-pathologic high myopia and glaucoma by considering their respective structural and functional characteristics on fundus photography, optical coherence tomography scanning, and visual field tests. These features may also help to distinguish the underlying mechanisms of the optic neuropathies and to determine management strategies for patients with high myopia and glaucoma.

Association Between Choroidal Thickness and Myopic Maculopathy in a Japanese Population: The Hisayama Study

Purpose

To examine the association between choroidal thickness and myopic maculopathy in a general Japanese population.

Design

Population-based cross-sectional study.

Participants

A total of 2841 residents of a Japanese community aged ≥ 40 years, who consented to participate and had available data of choroidal thickness and fundus photographs, were enrolled in this study.

Methods

The choroidal thickness was measured by swept-source OCT. Participants were divided into quartiles of choroidal thickness. Myopic maculopathy was defined according to the classification system of the Meta-analysis of Pathologic Myopia Study Group. Main outcome measures were odds ratios (ORs) of choroidal thickness for prevalent myopic maculopathy. The ORs and 95% confidence intervals (CIs) were estimated using a logistic regression model.

Main Outcome Measures

Prevalent myopic maculopathy.

Results

Eighty-one participants had myopic maculopathy (45 diffuse chorioretinal atrophy, 31 patchy chorioretinal atrophy, and 5 macular atrophy). Individuals in the lowest quartile of choroidal thickness had a significantly greater OR for the presence of myopic maculopathy than those in the highest quartile of choroidal thickness (OR: 4.78 [95% CI: 1.78-16.72]) after adjusting for confounders, including axial length. The sensitivity analysis among the 1176 myopic individuals with axial length of ≥ 24.0 mm also showed that thinner choroidal thickness was significantly associated with prevalent myopic maculopathy.

Conclusions

The present study demonstrated the significant inverse association between choroidal thickness and the likelihood of myopic maculopathy, suggesting that the measurement of choroidal thickness in addition to axial length would be useful for assessing the risk of myopic maculopathy and elucidating its pathogenesis.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Association between choriocapillaris perfusion and axial elongation in children using defocus incorporated multiple segments (DIMS) spectacle lenses

PURPOSE

To investigate choroidal and ocular biological variables that influence axial length (AL) elongation in children wearing defocused incorporated multiple segments (DIMS) spectacle lenses.

METHODS

This cohort study included 106 myopic children aged 7-14 years with a 1-year follow-up. Participants were divided into two groups according to the increase in AL in one year: rapid (>0.2 mm) and slow (≤0.2 mm) axial elongation groups. Cycloplegic autorefraction and AL were measured at baseline and after 6 and 12 months. The area of choriocapillaris flow voids (FVs) and choroidal thickness (ChT) at baseline were measured.

RESULTS

Univariate linear regression analysis showed that AL elongation were significantly associated with the FVs area (standardised β = 0.198, P < 0.05) and age (standardised β = -0.201, P < 0.05). Multiple linear regression showed that the FVs area, age, and average K reading were associated with AL elongation. Multiple logistic regression analyses showed that greater degrees of myopia and larger FVs areas were risk factors for rapid axial elongation, while older age, large pupil diameter and steeper cornea were protective factors. In estimating axial elongation, the FVs area alone demonstrated an area under the curve (AUC) of 0.672 (95% CI, 0.569-0.775, P < 0.01), and that of FVs area and other ocular variables was 0.788 (95% CI, 0.697-0.878, P < 0.001).

CONCLUSION

Larger choriocapillaris FVs area at baseline may help to predict axial elongation in myopic eyes. The association between FVs area and axial elongation should be taken into consideration in further myopic cohort studies.

Application of ImageJ in Optical Coherence Tomography Angiography (OCT-A): A Literature Review

Background

This study aimed to review the literature on the application of ImageJ in optical coherence tomography angiography (OCT-A) images.

Methods

A general search was performed in PubMed, Google Scholar, and Scopus databases. The authors evaluated each of the selected articles in order to assess the implementation of ImageJ in OCT-A images.

Results

ImageJ can aid in reducing artifacts, enhancing image quality to increase the accuracy of the process and analysis, processing and analyzing images, generating comparable parameters such as the parameters that assess perfusion of the layers (vessel density (VD), skeletonized density (SD), and vessel length density (VLD)) and the parameters that evaluate the structure of the layers (fractal dimension (FD), vessel density index (VDI), and lacunarity (LAC)), and the foveal avascular zone (FAZ) that are used widely in the retinal and choroidal studies), and establishing diagnostic criteria. It can help to save time when the dataset is huge with numerous plugins and options for image processing and analysis with reliable results. Diverse studies implemented distinct binarization and thresholding techniques, resulting in disparate outcomes and incomparable parameters. Uniformity in methodology is required to acquire comparable data from studies employing diverse processing and analysis techniques that yield varied outcomes.

Conclusion

Researchers and professionals might benefit from using ImageJ because of how quickly and correctly it processes and analyzes images. It is highly adaptable and potent software, allowing users to evaluate images in a variety of ways. There exists a diverse range of methodologies for analyzing OCTA images through the utilization of ImageJ. However, it is imperative to establish a standardized strategy to ensure the reliability and consistency of the method for research purposes.

Choriocapillary Flow Correlation with Axial Length in High Myopia - An Angiography Study with Optical Coherence Tomography

PURPOSE

To investigate parameters of retinal and choroidal microcirculation quantitatively with optical coherence tomography angiography (OCTA) in high myopic children, and to explore potential correlations with age, axial length (AL), spherical equivalent (SE), and central retinal thickness (CRT).

METHODS

En face angiograms were generated with an OCTA device and evaluated with automated density and flow analyzer algorithms. Perfusion parameters were correlated with age, AL, SE, and CRT using Spearman's rank correlation analysis. Repeatability and reproducibility of perfusion parameter measurements were calculated in a high myopic cohort.

RESULTS

Repeatability and reproducibility of OCTA measurements were good, ranging from 3.6 - 6.5%. Strong positive correlation was identified between age and CRT (rho = 0.673, p = 0.00) as well as between AL and SE (rho = 0.844, p = 0.00). There was a strong negative correlation between AL and choriocapillary flow density (CCFD) (rho = - 0.612, p = 0.00), and a moderate negative correlation between age and superficial parafoveal retinal vessel density (SPRVD) as well as CCFD (rho = - 0.497, p = 0.013 and rho = - 0.483, p = 0.023, respectively).

CONCLUSION

OCTA appears to be a reliable tool for the quantitative investigation of retinal and choroidal microcirculation in a high myopic pediatric cohort. CCFD reduction was associated with increasing AL in this cohort.

Biomarker Signature in Aqueous Humor Mirrors Lens Epithelial Cell Activation: New Biomolecular Aspects from Cataractogenic Myopia

Inflammatory, vasculogenic, and profibrogenic factors have been previously reported in vitreous (VH) and aqueous (AH) humors in myopic patients who underwent cataract surgery. In light of this, we selected some mediators for AH and anterior-capsule-bearing lens epithelial cell (AC/LEC) analysis, and AH expression was correlated with LEC activation (epithelial-mesenchymal transition and EMT differentiation) and axial length (AL) elongation. In this study, AH (97; 41M/56F) and AC/LEC samples (78; 35M/43F) were collected from 102 patients who underwent surgery, and biosamples were grouped according to AL elongation. Biomolecular analyses were carried out for AH and LECs, while microscopical analyses were restricted to whole flattened AC/LECs. The results showed increased levels of interleukin (IL)-6, IL-8, and angiopoietin-2 (ANG)-2 and decreased levels of vascular endothelium growth factor (VEGF)-A were detected in AH depending on AL elongation. LECs showed EMT differentiation as confirmed by the expression of smooth muscle actin (α-SMA) and transforming growth factor (TGF)-βR1/TGFβ isoforms. A differential expression of IL-6R/IL-6, IL-8R/IL-8, and VEGF-R1/VEGF was observed in the LECs, and this expression correlated with AL elongation. The higher VEGF-A and lower VEGF-D transcript expressions were detected in highly myopic LECs, while no significant changes were monitored for VEGF-R transcripts. In conclusion, these findings provide a strong link between the AH protein signature and the EMT phenotype. Furthermore, the low VEGF-A/ANG-2 and the high VEGF-A/VEGF-D ratios in myopic AH might suggest a specific inflammatory and profibrogenic pattern in high myopia. The highly myopic AH profile might be a potential candidate for rating anterior chamber inflammation and predicting retinal distress at the time of cataract surgery.

Influencing factors associated with high myopia in Chinese college students

Background

High myopia (HM) may elicit irreversible pathological changes in the fundus and severely impair visual quality, thereby becoming a major public health issue in China. However, the influencing factors associated with HM remain unknown in Chinese college students, whose visual quality is crucial to country development.

Methods

This is a cross-sectional observational study. Two thousand three hundred and fifteen undergraduate and graduate students were initially recruited from various majors in 3 universities in Tianjin, China. Under the principle of voluntary participation and informed consent, simple random sampling was conducted in the recruited subjects while maintaining balanced number of subjects from each major. After screening with inclusion and exclusion criteria, 96 undergraduate and graduate students (186 eyes) were finally included and divided into non-HM and HM groups. The eyes of subjects were examined by optical coherence tomography angiography (OCTA) for vessel density and structure thickness at the macula and optic disc, and the subjects were surveyed by an itemized questionnaire on lifestyles and study habits.

Results

The OCTA and questionnaire results revealed 10 factors, including hemodynamic and anatomic parameters and lifestyle metrics, with statistical significance between the non-HM and HM groups. Receiver operating characteristic curve analysis showed that vessel density of the inner retina at the macula, vessel density of the radial peripapillary capillary at the optic disc, smartphone usage time, continuous near work time, and sleeping after midnight had superior values of area under the curve (AUC > 0.700). Therefore, these 5 factors were selected for univariant and multivariant logistic regression analyses. A prediction model comprising the 5 influencing factors had an AUC of 0.940 and 95% CI of 0.908-0.972.

Conclusion

This study for the first time identified the vessel density of the inner retina at the macula, the vessel density of the radial peripapillary capillary at the optic disc, smartphone usage time, continuous near work time, and sleeping after midnight as influencing factors associated with HM in Chinese college students. A prediction model comprising the 5 influencing factors was proposed for calculating likelihood of a Chinese college student developing HM, based on which lifestyle improvement and medical intervention might be recommended.

Evidence of vascular involvement in myopia: a review

The benign public perception of myopia (nearsightedness) as a visual inconvenience masks the severity of its sight-threatening consequences. Myopia is a significant risk factor for posterior pole conditions such as maculopathy, choroidal neovascularization and glaucoma, all of which have a vascular component. These associations strongly suggest that myopic eyes might experience vascular alterations prior to the development of complications. Myopic eyes are out of focus because they are larger in size, which in turn affects their overall structure and function, including those of the vascular beds. By reviewing the vascular changes that characterize myopia, this review aims to provide an understanding of the gross, cellular and molecular alterations identified at the structural and functional levels with the goal to provide an understanding of the latest evidence in the field of experimental and clinical myopia vascular research. From the evidence presented, we hypothesize that the interaction between excessive myopic eye growth and vascular alterations are tipping-points for the development of sight-threatening changes.

Choroidal Vascular Density Quantification in High Myopia with or without Choroidal Neovascularization Using Optical Coherence Tomography Angiography

Purpose

The aim of this study was to analyze choroidal vascular density alteration in high myopia with or without choroidal neovascularization by using optical coherence tomography angiography (OCTA).

Methods

This was a cross-sectional, observational study that included 60 high-myopia eyes. All the participants had comprehensive ophthalmic assessments with visual acuity, intraocular pressure, slit lamp-assisted biomicroscopy, color fundus photography, axial length, optometry, and OCTA. Age, sex, and comorbidities were collected from their medical charts. Univariate and multiple analyses were made to compare the age, spherical equivalent, choroidal vascular density, gender, and choroidal thickness between normal and patients with choroidal neovascularization.

Results

60 eyes with high myopia were included in our study, including 30 eyes with choroidal neovascularization and 30 eyes without choroidal neovascularization or other fundus pathology. The mean age of high myopic patients was older in the choroidal neovascularization group than in the normal group (48.43 ± 19.06 years vs. 28.83 ± 9.92 years, p < 0.01). The mean choroidal thickness of high myopic patients was thinner in the neovascularization group than in the normal group (68.81 ± 48.81 μm vs. 137.80 ± 66.33 μm, p < 0.01). The mean choroidal vascular density in the normal group was greater than in the choroidal neovascularization group (82.43 ± 8.73 vs. 67.54 ± 12.56, p < 0.01). There was no significant difference in spherical equivalent between the choroidal neovascularization group and the normal group (-10.56 ± 2.97D vs. -11.93 ± 3.38D, p = 0.11). Multivariate analysis showed that after adjusting for covariates, less choroidal vascular density and older age were independent factors associated with choroidal neovascularization in the high myopic eye.

Conclusion

Decreased choroidal vascular density and older age played an important role in the development of choroidal neovascularization in high myopic eyes. OCTA may help us to identify the highly myopic patients that need to intervene.

Wide-field swept-source optical coherence tomography angiography in the assessment of retinal microvasculature and choroidal thickness in patients with myopia

BACKGROUND/AIMS

Pathological myopia (PM) is a leading cause of blindness worldwide. We aimed to evaluate microvascular and chorioretinal changes in different stages of myopia with wide-field (WF) swept-source (SS) optical coherence tomography angiography (OCTA).

METHODS

This prospective cross-sectional observational study included 186 eyes of 122 patients who had undergone imaging between November 2018 and October 2020. Vessel density (VD) and vessel skeletonised density (VSD) of superficial capillary plexus, deep capillary plexus and whole retina, as well as foveal avascular zone parameters, retinal thickness (RT) and choroidal thickness (CT), were calculated.

RESULTS

This study evaluated 75 eyes of 48 patients with high myopia (HM), 43 eyes of 31 patients with mild to moderate myopia and 68 eyes of 53 age-matched controls. Controlling for age and the presence of systemic hypertension, we found that HM was associated with decrease in VD and VSD in all layers on 12×12 mm² scans. Furthermore, HM was associated with a VD and VSD decrease in every Early Treatment Diabetic Retinopathy Study grid, with a larger decrease temporally (βVD=-0.39, βVSD=-10.25, p<0.01). HM was associated with decreased RT and CT. Reduction in RT was outside the macular region, while reduction in CT was in the macular region.

CONCLUSION

Using WF SS-OCTA, we identified reduction in microvasculature and structural changes associated with myopia. Decrease in VD and VSD was greater in the temporal quadrant, and reductions in RT and CT were uneven across the retina. Further work may help identify risk factors for the progression of PM and associated vision-threatening complications.

Ultra-Widefield Swept-Source Optical Coherence Tomography Angiography in the Assessment of Choroidal Changes in Young Adults With Myopia

Purpose

To evaluate choroidal changes in young adults with myopia using ultra-widefield swept-source optical coherence tomography angiography (SS-OCTA).

Methods

This study enrolled 105 eyes of 105 participants who underwent SS-OCTA imaging (24 mm × 20 mm) centered on the fovea. Eyes were categorized as low myopia, moderate myopia, or high myopia. Choroidal thickness, choroidal capillary plexus (CCP) vessel density, and choroidal Sattler's and Haller's layer (CSHL) vessel density were analyzed in nine grids using built-in angiography analysis software.

Results

A significant decrease in choroidal thickness was found in most grids (P < 0.01) in high myopia. The CSHL vessel density also showed a significant decrease in most grids (P < 0.05) in high myopia. Choroidal thickness was negatively correlated with axial length in most grids (P < 0.05). Choroidal thinning was most evident in the macular grid (β = -22.55, P < 0.001). CSHL vessel density was negatively correlated with axial length in most grids (P < 0.05).

Conclusions

Choroidal changes could be quantified using ultra-widefield SS-OCTA. Choroidal thinning with increasing axial length indicated regional differences in eyes with myopia, which were most evident in the macular area. Decreased CSHL vessel density with increasing axial length also indicated regional differences in eyes with myopia.

Translational Relevance

This study explored choroidal changes with a wider field of view than has been currently available.

Pentosan Polysulfate Sodium-Associated Maculopathy: Early Detection Using OCT Angiography and Choriocapillaris Flow Deficit Analysis

PURPOSE

To compare choriocapillaris flow deficit (CC-FD) analysis using optical coherence tomography angiography (OCTA) in eyes of patients treated with high cumulative dosages of pentosan polysulfate sodium (PPS) but no signs of retinal toxicity versus healthy age-matched controls.

DESIGN

Retrospective clinical cohort study.

METHODS

Patients treated with PPS for interstitial cystitis with a cumulative dose of > 1000 g underwent multimodal imaging screening to exclude evidence of PPS maculopathy or other retinal findings. All study patients and age-matched healthy controls completed a 3 × 3 mm macular volume scan OCTA using the SOLIX full-range OCT. En face OCTA images at the level of the CC were exported and CC-FDs were computed and compared between groups.

RESULTS

Fifteen patients treated with PPS and 15 age-matched controls were included. The mean PPS cumulative dose was 1974 ± 666 g over a mean of 17.6 ± 6.8 treatment years. All patients registered a visual acuity of 20/25 or better and normal fundus autofluorescence (FAF), OCT, multicolor, near-infrared reflectance (NIR), and ultra-widefield fundus color and autofluorescence images. The CC-FD was 32.7 ± 3.6% in the PPS group compared with 28.6 ± 4.3% in the control group (P = .023).

CONCLUSIONS

Patients treated with PPS long enough to accumulate dosages > 1000 g showed significant CC flow impairment before the development of macular toxicity signs with OCT, NIR, and FAF compared with age-matched normal controls. Thus, the choroid may be the earliest manifestation of ocular toxicity, predating the development of clinically evident retinal pigment epithelium (RPE) injury. The subsequent RPE disruption may be the result of choriocapillaris impairment or primary PPS toxicity. Assessment of the CC on OCTA may be a useful tool for early detection of toxicity, although further longitudinal studies are required.

Axial Length and Choriocapillaris Flow Deficits in Non-pathological High Myopia

PURPOSE

To examine the relationship between axial length (AL) and choriocapillaris (CC) flow deficits percentage (FD%) in non-pathological highly myopic eyes.

DESIGN

Prospective cross-sectional study.

METHODS

This study included Chinese patients with non-pathological high myopia, which was defined by an AL of > 26 mm and a META-PM classification grade of <2. Swept-source optical coherence tomography angiography was used to obtain 6 × 6 mm images of the macular CC. The CC FD% was measured in the fovea, parafovea, and perifovea subfields.

RESULTS

A total of 1017 individuals (1017 eyes) with a mean age of 35.95 ± 14.11 years were included. After adjusting for age, sex, intraocular pressure, body mass index, systolic blood pressure, and image quality score, the overall CC FD% increased by 0.27% (95% CI 0.02, 0.52; P = .034) for each mm increase in AL. Among subfields, longer AL was associated with a higher CC FD% in the perifovea (β = 0.53, 95% CI 0.30, 0.77; P < .001), and was not associated with a higher CC FD% in the parafovea (β = 0.08, 95% CI -0.26, 0.42; P = .652) and fovea (β = 0.001, 95% CI -0.50, 0.50; P = .999).

CONCLUSIONS

The CC FD% increased with a longer AL in high myopia in the perifovea region but not in the fovea and parafovea fields. These findings may be of interest in elucidating the etiology of myopic axial elongation.

Choriocapillaris Flow Deficit in Tubercular Serpiginous-Like Choroiditis with and without Paradoxical Worsening

PURPOSE

The aim is to analyze automated quantification of choriocapillaris flow deficit (CCFD) on swept-source (SS)-optical coherence tomography angiography (OCTA) in tubercular serpiginous-like choroiditis (TBSLC).

METHODS

In this prospective study, automated CCFD calculations were performed on SS-OCTA and compared with CCFD areas on indocyanine green angiography (ICGA). Patients were divided into two groups based on the occurrence of paradoxical worsening (PW).

RESULTS

Twenty-nine eyes (29 subjects; 18 males; mean age: 33±12 years) were included. The mean CCFD at baseline was 34.9 ± 4.3% on OCTA in eyes without PW and 35.4 ± 5.0% on SS-OCTA with PW (p = .77). At 4 and 12 weeks, CCFD on SS-OCTA improved to 30.6 ± 3.9% and 28.0 ± 4.2% (p < .001) without PW, respectively, and increased to 42.9 ± 4.4% and 48.8 ± 4.1% (p < .001) with PW, respectively. The SS-OCTA CCFD correlated well with ICGA (r = 0.48; p < .001).

CONCLUSIONS

Automated quantitative serial assessment of CCFD on SS-OCTA can serve as a useful biomarker of disease activity in eyes with TBSLC.

Short-term effect of orthokeratology lens wear on choroidal blood flow in children with low and moderate myopia

We investigated changes in choroidal vascularity and choriocapillaris blood perfusion during orthokeratology (Ortho-K) lens wear. Sixty-two children with low to moderate myopia were enrolled. The Ortho-K group (n = 42) continuously wore Ortho-K lenses for 3 months, and the controls (n = 20) wore single-vision distance spectacles. All of the patients were instructed to return for follow-up visits after 1 day, 1 week and 1 month and 3 months of treatment. The subfoveal choroidal thickness (SFChT), choroidal vascularity [including the total choroidal area, luminal area, stromal area, and choroidal vascularity index (CVI)] and percentage of choriocapillaris flow voids (FV%) were determined with a Cirrus HD-OCT instrument. Additionally, ocular parameters were measured. In the Ortho-K group, the SFChT significantly increased by 12.61 ± 5.90 μm, the CVI was significantly increased by 2.99 ± 2.07% and 3.01 ± 2.32% on the horizontal and vertical scans respectively, and the FV% was significantly decreased by 0.89 ± 0.34% from baseline at the 1-week visit (all p < 0.001). The choroidal parameters remained unchanged at the 1-month and 3-month follow-ups with respect to the 1-week follow-up. In the control group, the choroidal parameters did not change significantly at 1 month (all p > 0.05). At the 3-month visit, the changes in the axial length (AL) and vitreous chamber depth (VCD) were significantly greater in the control group than in the Ortho-K group (0.14 ± 0.23 and 0.03 ± 0.05 mm in AL, 0.15 ± 0.23 and 0.06 ± 0.03 mm in VCD respectively). Our longitudinal study showed several choroidal parameter changes in the early stage in Ortho-K lens wearers with low to moderate myopia, and these changes persisted over 3 months. We speculate that Ortho-K lenses regulate choroidal thickness and blood perfusion, affecting myopia development.

Compartmental analysis of three-dimensional choroidal vascularity and thickness of myopic eyes in young adults using SS-OCTA

Purpose: We aimed to investigate the change of three-dimensional (3D) choroidal thickness (ChT), choroidal vessel volume (CVV), and choroidal vessel index (CVI) in young myopic adults using swept-source optical coherence tomography angiography (SS-OCTA) and compare the difference of these indicators in different quadrants of the macula and optic disc.

Methods: A total of 248 eye samples from 135 participants were used in this cross-sectional study. Each participant underwent detailed history taking and ocular examinations. Based on axial length (AL), patients were divided into the emmetropia (EM) group, mild-myopia (MIM) group, moderate-myopia (MOM) group, and high-myopia (HM) group. 6 mm × 6 mm (1,024 × 1024 B-scans) SS-OCTA scans were performed centered on the fovea and optic disc. 3D ChT, CVV, and CVI were measured based on a built-in deep learning algorithm. Differences in ChT, CVV, and CVI were analyzed in different regions and different myopic groups.

Results: Significant reduction in the global CVV were found in the HM group (1.930 ± 0.865) in comparison with the EM (3.486 ± 0.992), MIM (3.238 ± 1.033), and MOM (2.589 ± 1.083) groups (p < 0.001). The global CVI was also lower in the HM group (0.258 ± 0.061) than in the EM (0.320 ± 0.055), MIM (0.320 ± 0.051), and MOM (0.286 ± 0.066) groups (p < 0.001). The ChT was thinner in eyes with HM (242.753 ± 65.641) than in eyes with EM (377.532 ± 80.593), MIM (348.367 ± 78.191), or MOM (300.197 ± 87.175) (p < 0.001). Compartmental analysis revealed that ChT, CVV, and CVI in the nasal quadrant of the macula and temporal and inferior quadrants of the optic disc were much lower than those in other quadrants (p < 0.05). Correlation analyses found that ChT, CVV, and CVI were negatively correlated with AL and spherical equivalence.

Conclusion: 3D ChT, CVV, and CVI gradually decreased as the degree of myopia increased. The changes were more dramatic on the nasal side of the macula and the temporal and inferior sides of the optic disc. These findings demonstrated the 3D choroidal change and highlighted the papillo-macular bundle as a sensitive region in myopic development.

Quantitative assessment of retinal vessel density and thickness changes in internal carotid artery stenosis patients using optical coherence tomography angiography

OBJECTIVE

To quantitatively assess the retinal features of patients with different degrees of internal carotid artery stenosis (ICAS), particularly mild ICAS patients, utilizing optical coherence tomography angiography (OCTA).

METHODS

Thirty-two mild ICAS patients (mild ICAS group), 34 moderate to severe ICAS patients (nonmild ICAS group), and 40 controls were enrolled in this study. Retinal vessel density was quantitatively measured by OCTA, including radial peripapillary capillary vessel density (RPC-VD), superficial and deep capillary plexus vessel density (SCP/DCP-VD). Structural parameters were collected from optical coherence tomography (OCT), including retinal thickness and subfoveal choroidal thickness (SFCT). Furthermore, LASSO-penalized logistic regression was used to construct the diagnostic model based on retinal parameters. ROC curves and nomogram plots were used to assess the diagnostic ability of this model for ICAS.

RESULTS

The macular SCP-VD of mild ICAS patients was significantly lower than that of controls and lower than that of nonmild ICAS patients (all p < 0.05). However, there was no difference among the three groups in terms of DCP-VD (p > 0.05). RPC-VD could effectively discriminate between the mild ICAS group and the nonmild ICAS group (p = 0.005). For structural OCT, only the SFCT decreased as the ICAS degree increased (p < 0.05). Diagnostic scores based on retinal parameters showed a strong diagnostic capability for mild ICAS (AUC = 0.8656).

CONCLUSION

Mild ICAS patients exhibited distinct retinal features compared to nonmild ICAS patients and control subjects. OCTA potentially represents a promising method for the early detection of ICAS patients and the noninvasive surveillance of haemodynamic changes in those patients.

Advances in OCT Imaging in Myopia and Pathologic Myopia

Advances in imaging with optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) technology, including the development of swept source OCT/OCTA, widefield or ultra-widefield systems, have greatly improved the understanding, diagnosis, and treatment of myopia and myopia-related complications. Anterior segment OCT is useful for imaging the anterior segment of myopes, providing the basis for implantable collamer lens optimization, or detecting intraocular lens decentration in high myopic patients. OCT has enhanced imaging of vitreous properties, and measurement of choroidal thickness in myopic eyes. Widefield OCT systems have greatly improved the visualization of peripheral retinal lesions and have enabled the evaluation of wide staphyloma and ocular curvature. Based on OCT imaging, a new classification system and guidelines for the management of myopic traction maculopathy have been proposed; different dome-shaped macula morphologies have been described; and myopia-related abnormalities in the optic nerve and peripapillary region have been demonstrated. OCTA can quantitatively evaluate the retinal microvasculature and choriocapillaris, which is useful for the early detection of myopic choroidal neovascularization and the evaluation of anti-vascular endothelial growth factor therapy in these patients. In addition, the application of artificial intelligence in OCT/OCTA imaging in myopia has achieved promising results.

Macular Retinal Microvasculature of Hyperopia, Emmetropia, and Myopia in Children

Purpose

To compare macular retinal microcirculation in myopia, emmetropia, and hyperopia groups and investigate the relationship between macular retinal microcirculation and axial length (AL) in children.

Methods

Forty myopic, 29 emmetropic, and 34 hyperopic eyes were included. All the recruited eyes underwent optical coherence tomography angiography (OCTA) examinations. After adjusting the image size by the Littmann method and Bennett formula, the vessel density (VD) of the deep capillary plexus (DCP) and superficial vascular plexus (SVP) were assessed.

Results

The VD of the DCP was significantly lower in the myopia group than in the hyperopia group, whereas no significant differences in the VD of the SVP were observed among the myopia, emmetropia, and hyperopia groups. The VD of the DCP was significantly associated with AL, spherical equivalent (SE), and foveal retinal thickness (FRT), whereas the VD of the SVP was only significantly associated with FRT but not with AL or SE.

Conclusions

The myopic VD of the DCP was significantly lower than the hyperopic one, and the VD of the DCP was significantly associated with AL, indicating that myopia has a lower VD of the DCP, and AL could have a negative effect on the VD of the DCP. Thus, early myopic axial stretching might decrease retinal blood perfusion of the DCP in children.

Hemodynamic and morphological changes of the central retinal artery in myopic eyes

Due to excessive elongation of the eyeball, myopia-related vascular abnormalities are frequently observed in the central retinal artery (CRA) and its intraretinal branches. In addition to inconsistency in previously reported findings, hemodynamic (reduced flow velocity, increased vascular resistance) and morphological changes (narrower vessel diameter) were usually studied separately. This cross-sectional study evaluated the hemodynamic and morphological characteristics concurrently in a large sample of healthy myopes, by using the color Doppler ultrasound and adaptive optics retinal camera. Results showed that the retrobulbar segment of CRA had a tendency of slightly reduced flow velocity in eyeballs with longer axial length, but the correlation was not significant after adjusting for the multiple correlations. Vascular resistance was not affected by the axial elongation. With respect to the intraretinal branches, no significant changes in longer eyes of total diameter or lumen diameter were observed, while both the wall thickness and the wall cross-sectional area were significantly increased, but only a marginally increase in the wall to lumen ratio was found with increasing axial length. This implies some potential small artery remodeling in the intraretinal CRA branches. Overall, blood supply of the inner retina in healthy young myopes is likely to be maintained. Additionally, morphological parameters of vascular microstructure could be potential biomarkers to monitor myopia progression and understand myopia-related vascular abnormalities in future studies.

Corneal morphology correlates with choriocapillaris perfusion in myopic children

AIMS

The present study investigated the difference in choriocapillaris (CC) perfusion between different AL/K ratio groups with similar spherical equivalent refraction (SER) and analyzed factors affecting CC perfusion.

METHODS

This cross-sectional study included 129 children with low-to-moderate myopia. Axial length (AL), average K-reading (Ave-K), and SER were measured. Choroidal vascularity, including the total choroidal area (TA), choroidal luminal area (LA), stromal area (SA), choroidal vascularity index (CVI), CC flow voids (FVs), and FVs%, was obtained using optical coherence tomography angiography.

RESULTS

Participants with similar SER were divided into two groups (high AL/K ratio, n = 57; low AL/K ratio, n = 72). The high AL/K group had lower LA, TA, and CVI (P < 0.01) and lower FVs (inner ring and fovea, P < 0.05) and FVs% (outer ring, inner ring, and fovea, P < 0.05). The AL/K ratio and FVs% were negatively correlated in the outer ring (r =  - 0.174, P < 0.05) and inner ring (r =  - 0.174, P < 0.05). The Ave-K and inner FVs (r = 0.178, P < 0.05), outer FVs% (r = 0.175, P < 0.05), and inner FVs% (r = 0.196, P < 0.05) were positively correlated. In stepwise multiple regression for the outer ring, the horizontal CVI was related to FVs (β = 0.175, P < 0.05), and the vertical CVI was related to FVs% (β = 0.232, P < 0.01). Independent risk factors associated with inner FVs area were vertical CVI (β = 0.329; P < 0.001) and SER (β =  - 0.196, P < 0.05); FVs% was also associated with vertical CVI (β = 0.360, P < 0.01) and SER (β =  - 0.196, P < 0.05).

CONCLUSION

With a similar SER, myopic eyes with a higher AL/K ratio maintained more CC perfusion and lower CVI, which may indicate rapid myopic progression. Low K-reading eyes had more CC perfusion and less CVI, which may explain the relatively poor myopia control efficacy in the clinic.

Quantitative evaluation of retinal and choroidal vascularity and retrobulbar blood flow in patients with myopic anisometropia by CDI and OCTA

AIMS

To investigate the association between the myopic severity and retinal microvascular density, choroidal vascularity and retrobulbar blood flow in adult anisomyopes.

METHODS

This study comprised 90 eyes of 45 myopic anisomyopes who were recruited for Colour Doppler imaging (CDI) and optical coherence tomography angiography (OCTA). The superficial vessel density (SVD), deep vessel density (DVD), choroidal thickness (ChT) and choroidal vascularity, including total choroidal area (TCA), luminal area (LA), stromal area (SA) and Choroidal Vascularity Index (CVI), were measured using OCTA. Moreover, the Pulsatile Index, peak systolic velocity (PSV) and end diastolic velocity (EDV) of posterior ciliary artery (PCA), central retinal artery (CRA) and ophthalmic artery (OA) were quantified by CDI, and all parameters were compared between two eyes and the correlations among parameters were analysed.

RESULTS

The mean difference of spherical equivalent (SE) and axial lengths (AL) between eyes were -6.00±2.94 D and 2.48±1.31 mm, respectively. The SVD, DVD, ChT, TCA, LA, SA and CVI were significantly lower in more myopic eyes compared with the contralateral eyes. In more myopic eyes, CDI parameters of CRA and PSV and EDV of PCA were also significantly lower. After adjusting for age and sex, the binocular asymmetry in LA and ChT was independent risk factor affecting interocular difference in both AL and SE.

CONCLUSION

Retinal microvascular density, choroidal vascularity and retrobulbar blood flow were simultaneously lower in adult myopic anisomyopes with more myopic eyes and disturbed choroid circulation was related to the severity of myopia. Further longitudinal study was helped to identify the effect of choroidal parameters for myopic progression.

Impact of signal strength on quantitative retinal and choriocapillaris flow measurement from optical coherence tomography angiography

We evaluated the impact of signal strength (SS) on quantitative measurements from optical coherence tomography (OCTA). Twenty healthy-volunteers were included. A neutral density filter (NDF) was attached to spectral-domain OCTA (SD-OCTA) and swept-source OCTA (SS-OCTA). All subjects were imaged with both devices three times using three different conditions: no filter, NDF0.3, and NDF0.6. For SD-OCTA, SS decreased from 10.0 to 8.2 and 4.0 with the NDF0.3 and 0.6, respectively. The vessel density (VD) and vessel length density (VLD) of the superficial capillary plexus (SCP) decreased when SS decreased from 10 to 8.2, but no further decrease when SS changed from 8.2 to 4.0. The flow metrics of the deep capillary plexus (DCP) did not change. For SS-OCTA, SS decreased from 10 to 9.5 and 7.2. The VD and VLD of the SCP and DCP decreased when SS decreased, except for the VD of the DCP when SS changed from 10 to 9.5. The choriocapillaris flow deficits significantly increased along with the decrease in SS. Quantitative flow parameters were significantly affected by a small change in SS and were most conspicuous in the SCP and choriocapillaris. These finding highlight the importance of high and consistent SS in quantitative OCTA studies.

Assessment of Choroidal Vascularity and Choriocapillaris Blood Perfusion After Accommodation in Myopia, Emmetropia, and Hyperopia Groups Among Children

Purpose

To investigate choroidal vascularity (CV) and choriocapillaris blood perfusion before and after accommodation in myopia, emmetropia, and hyperopia groups among children.

Methods

This study included 39 myopic eyes from 22 subjects, 17 emmetropic eyes from 11 subjects, and 18 hyperopic eyes from 10 subjects. All subjects were children. Choroidal thickness (CT) and CV, including total choroidal area (TCA), luminal area (LA), and stromal area (SA) were measured using swept-source optical coherence tomography (SS-OCT). Choriocapillaris luminal area (CLA) was measured using SS-OCT-angiography before and after accommodation (near reading with an additional −3 diopter lens).

Results

For baseline results, except horizontal CV (showing no significant differences between myopia and emmetropia groups), both horizontal and vertical CT and CV were significantly smaller in the myopia group than in the emmetropia or hyperopia groups. In terms of CLA, no significant differences were observed among the myopia, emmetropia, and hyperopia groups. In addition, only myopic eyes showed significant decreases in CT and CV, whereas most CT and CV of emmetropic and hyperopic eyes showed non-significant decreases after accommodation. Furthermore, accommodation induced no significant changes in CLA in the myopia, emmetropia, or hyperopia groups.

Conclusion

Myopia had thinner baseline choroid and lower baseline choroidal blood perfusion. Furthermore, myopic eyes were more prone to choroidal thinning and blood perfusion decreases after accommodation.

Characteristic Assessment of Angiographies at Different Depths with AS-OCTA: Implication for Functions of Post-Trabeculectomy Filtering Bleb

This study aimed to analyze the quantitative vascular biomarkers of filtering bleb function at different depths using anterior segment optical coherence tomography angiography (AS-OCTA). This cross-sectional study is registered on Clinicaltrails.gov (NCT 04515017). Forty-six eyes with primary open-angle glaucoma that had undergone trabeculectomy with mitomycin-C for more than six months were included. Vessel density (VD) and vessel diameter index (VDI) in the superficial layer (SL), Tenon’s layer (TL), and deep layer (DL) of the bleb were obtained. The VD and VDI were higher in the failure group (both p = 0.000). Significant correlations were found between the SL, TL, DL’s VDI, and IOP in the success group (p = 0.013, 0.016, 0.031, respectively). The VD of the TL and DL were related to IOP in the failure group (p = 0.012, 0.009). Tenon’s VD (TVD) and Tenon’s VDI (TVDI) correlated with IOP adjusting for TVD, TVDI, and the Indiana Bleb Appearance Grading Scale (IBAGS) (p = 0.009, 0.043) or Kenfeld grading system (KGS) (p = 0.011, 0.016). The area under curve (AUC) of the TVD, TVDI, IBAGS, and KGS to predict surgery failure were 0.960, 0.925, 0.770, and 0.850. AS-OCTA realized the quantitative evaluation of vessels, especially the invisible vascularity beneath the conjunctiva. TVD and TVDI as detected by AS-OCTA better reflected bleb function than conventional grading systems.

Changes in Retinal Optical Coherence Tomography Angiography Indexes Over 24 Hours

Purpose

To evaluate changes in the retinal microvasculature of young adults over 24 hours using optical coherence tomography angiography (OCT-A).

Methods

Participants (n = 44, mean age 23.2 ± 4.1 years, 24 myopes and 20 nonmyopes) with normal ophthalmological findings were recruited. Two macular OCT-A and OCT scans, systemic blood pressure, intraocular pressure (IOP), and biometry measurements were taken every four hours over 24 hours. Superficial and deep retinal layer en face images were analyzed to extract magnification-corrected vascular indexes using image analysis including foveal avascular zone metrics, vessel density, and perfusion density for the foveal, parafoveal, and perifoveal zones.

Results

Significant diurnal variations (P < 0.001) were observed in the vessel and perfusion density in the three superficial retinal layer regions, with acrophase between 4:30 PM and 8:30 PM. Only foveal and parafoveal regions of the deep retinal layer exhibited significant diurnal variations with acrophase between 9 AM and 3 PM. Myopes and nonmyopes had different acrophases but not amplitudes in the parafoveal perfusion density of superficial retinal layer (P = 0.039). Significant correlations were observed between diurnal amplitudes or acrophases of superficial retinal layer indexes and systemic pulse pressure, IOP, axial length and retinal thickness.

Conclusions

This study shows, for the first time, that significant diurnal variation exists in OCT-A indexes of macular superficial and deep retinal layer over 24 hours and were related to variations in various ocular and systemic measurements. Myopes and nonmyopes showed differences in the timing but not in amplitude of the superficial retinal layer parafoveal perfusion density variations but not in deep retinal layer.

Choriocapillaris Flow Deficits in Normal Chinese Imaged by Swept-Source Optical Coherence Tomographic Angiography

PURPOSE

To evaluate the ocular and systemic determinants of the choriocapillaris flow deficits percentage (CC FD%) in normal eyes.

DESIGN

Observational cross-sectional study.

METHODS

Healthy Chinese participants without ocular or systemic diseases underwent detailed ophthalmic evaluations, including swept-source optical coherence tomography angiography (SS-OCTA) with 6- × 6-mm macular choriocapillaris images. The CC FD% was assessed in circular regions with diameters of 1.0 and 5.0 mm, rings with 1.0- to 2.5-mm diameters, and rings with 2.5- to 5.0-mm diameters.

RESULTS

The study included 830 individuals (mean ± SD age 58.66 ± 8.75 years). CC FD% (mean ± SD 22.05% ± 1.13%) was the lowest in the 2.5- to 5.0-mm ring, followed by the 1.0- to 2.5-mm ring, and highest in the 1.0-mm circle. In multivariable analysis, a higher CC FD% was associated with older age (β = 0.16 [95% confidence interval {CI}] 0.08-0.24, P < .001), higher intraocular pressure (β = 0.34 [95% CI 0.25-0.42], P < .001), higher serum concentrations of high-density lipoprotein cholesterol (β = 0.24 [95% CI 0.17-0.32], P < .001), and lower image quality score (β = -0.22 [95% CI -0.30 to -0.14], P < .001). CC FD% was also independent of axial length.

CONCLUSIONS

In healthy adult Chinese individuals, a higher CC FD% was associated with older age, higher intraocular pressure, and higher high-density lipoprotein cholesterol serum concentration. These factors may influence clinical assessments of the choriocapillaris. The lack of an association between CC FD% and axial length is consistent with similar findings for Bruch membrane thickness, macular retinal thickness, and macular retinal pigment epithelium cell density.

Association Between Perforating Scleral Vessel and Myopic Maculopathy: A Cross-Sectional Study of a Chinese Cohort

Purpose: To investigate the association between perforating scleral vessel (PSV) and different types of myopic maculopathy (MM) in a highly myopic population.

Methods: In total, 188 highly myopic eyes (117 participants) were enrolled. Each participant underwent detailed history taking and ocular examinations. Based on fundus photographs and optical coherence tomography, patients were subdivided into the non-MM group and MM group. Based on a new classification system (ATN), MM cases were classified as myopic atrophy maculopathy (MAM), myopic tractional maculopathy (MTM), and myopic neovascular maculopathy (MNM). The number of PSV and the macular choroidal thickness (mChT) were measured.

Results: Compared with non-MM group, MM group was characterized by relatively larger age (48.40 vs. 32.34; p < 0.001), longer axial length (AL, 29.72 vs. 27.75, p < 0.001), thinner mChT (52.90 vs. 122.52; p < 0.001), and lower PSV counts (6.73 vs. 9.47, p ≤ 0.001). The non-MM group had higher PSV counts in total area (0–9 mm, 9.47 vs. 6.73, p < 0.001) and perifovea area (3–9 mm, 7.25 vs. 4.71, p < 0.001) compared to the MM group. Univariate and multivariate analyses showed that PSV count had no association with MAM (p = 0.2419) and MTM (p = 0.5678). Total PSV count [odds ratio (OR) 0.78, 95% CI 0.64–0.95, p = 0.0149] and perifovea PSV count (OR 0.80, 95% CI 0.65–0.98, p = 0.0299) were both protective factors for MNM. The stratified analysis revealed that in groups with AL <28 mm, or mChT <50 μm, or mChT ≥100 μm, or eyes with cilioretinal artery, PSV count had no significant association with MNM.

Conclusion: Higher PSV counts in perifovea area (3–9 mm centered fovea) and total area (0–9 mm centered fovea) were protective factors for MNM, whereas PSV count had no association with MAM and MTM. These findings may provide novel insights into the mechanisms of pathologic myopia.

Evaluation of peripapillary - macular microvascularity and choroidal vascularity index after refractive surgery

BACKGROUND

To evaluate the microvascularity and choroidal vascularity index (CVI) using optical coherence tomography angiography (OCTA) and OCT following femtosecond laser-assisted in-situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) procedures.

METHODS

Patients with myopia (<-6.0D sphere) or myopic astigmatism (<-4.0D astigmatism) were enroled. The percentage of vessel density and foveal avascular zone (FAZ) size, optic disc flux index and perfusion were noted and the CVI was calculated before and after surgery.

RESULTS

Twenty-nine eyes of 16 patients in the FS-LASIK group and 30 eyes of 16 patients in the SMILE group were enroled. Macular vessel density, FAZ size, and optic disc flux index were significantly higher on postoperative 1st day compared to preoperative day (p = 0.001, p = 0.007, and p < 0.001, respectively). There was no significant difference in terms of macular and peripapillary CVI between postoperative 1st day and preoperative day (p > 0.05). All microvascular parameters were similar on postoperative 7th day and preoperative day (p > 0.05).

CONCLUSIONS

It was detected that there is a transient alteration in macular and peripapillary microvascularity after FS-LASIK/SMILE, whereas choroidal circularity is not significantly affected by these refractive surgeries.

Development of a Novel Retina-Based Diagnostic Score for Early Detection of Major Depressive Disorder: An Interdisciplinary View

BACKGROUND

Clinically effective markers for the diagnosis of major depressive disorder (MDD) are lacking. Alterations in retinal features are closely related to the pathophysiological progression of MDD. However, the reliable retina-related diagnostic model for MDD remains to be developed. Thus, our study aimed to quantitatively evaluate retinal vascular and structural changes in MDD patients and to develop a reliable diagnostic model of MDD based on retinal parameters.

METHODS

Seventy-eight patients with MDD and 47 healthy controls (HCs) underwent retinal vessel density and structure examination using optical coherence tomography angiography and visual field examination using perimetry. Independent-sample t test was used to assess the differences in retinal parameters between the groups. Meanwhile, we constructed the corresponding retina-based diagnostic model by LASSO logistic regression. Finally, the diagnostic ability of the model was evaluated by area under the curve (AUC) of receiver operating characteristic curves and calibration plot of nomogram.

RESULTS

MDD patients showed lower retinal vessel density (including radial peripapillary capillary vessel density, superficial and deep capillary plexus vessel density), thinner subfoveal choroidal thickness, and poorer visual fields compared to HCs (all p < 0.05). Furthermore, a retina-based diagnostic model was constructed and shows a strong diagnostic capability for MDD (AUC = 0.9015, p < 0.001).

CONCLUSION

Patients with MDD showed distinct retinal features compared to HCs. The retina-based diagnostic model is expected to be a necessary complement to the diagnosis of MDD.

Macular and submacular choroidal microvasculature in patients with primary open-angle glaucoma and high myopia

AIMS

To characterise the influence of primary open-angle glaucoma (POAG) and high myopia (HM) on the macular and choroidal capillary density (CD).

METHODS

Two hundred and seven eyes were enrolled, including 80 POAG without HM, 50 POAG with HM, 31 HM without POAG and 46 normal controls. A fovea-centred 6×6 mm optical coherence tomography angiography scan was performed to obtain the CD of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris. Macular and choroidal CDs were compared among the groups and the association of CDs with visual field mean deviation (MD) was determined using linear regression models.

RESULTS

Compared with normal eyes, SCP CD was decreased in the POAG without HM group (p<0.05), while DCP CD was significantly decreased in the HM without POAG group (p<0.05). Both SCP and DCP CDs were significantly decreased in the POAG with HM group (p<0.05). CD reduction occurred mainly in the outer rather than inner ring of the 6×6 mm scan size. In multivariate regression analysis, worse MD was associated with lower CD in the outer ring of the SCP in all the HM eyes (p<0.05).

CONCLUSIONS

POAG and HM reduced macular CD in different layers of the retinal capillary plexus and both particularly in the outer ring of the 6×6 mm scans. Furthermore, assessment of the CD in the outer ring of the SCP may facilitate the diagnosis of glaucoma in eyes with HM.

Choroidal thickness and choriocapillaris vascular density in myopic anisometropia

BACKGROUND

This study aims to examine interocular differences in the choroidal thickness and vascular density of the choriocapillaris in anisometropic myopes and to further explore the relationship between choroidal blood flow and myopia.

METHODS

The sample comprised 44 participants with anisometropic myopia, aged 9 to 18 years, with normal best-corrected visual acuity. All participants underwent a series of examinations, including spherical equivalent refraction (SER) and axial length (AL), measured by a Lenstar optical biometer and optical coherence tomography angiography (OCTA) scanner. OCT measured the choroidal thickness, vascular density, and flow voids of the choriocapillaris, and a customized algorithm was implemented in MATLAB R2017a with the post-correction of AL. The choroidal thickness was measured at the fovea and 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mm nasally, temporally, inferiorly, and superiorly to the fovea. The vascular density and the flow voids of the choriocapillaris were measured at a 0.6-mm-diameter central circle, and the 0.6-2.5 mm diameter circle in the nasal, temporal, inferior, and superior regions. Repeated-measured ANOVAs were used to analyze the interocular differences. Partial correlations with the K value and age adjustments were used to study the relationships between the choroidal thickness, the choriocapillaris vascular density and flow voids, the SER and AL.

RESULTS

The choroidal thickness of the more myopic eyes was significantly thinner than less myopic eyes (P ≤ 0.001), and the flow voids in the more myopic eyes were more than less myopic eyes (P = 0.002). There was no significant difference in the vascular density of the choriocapillaris between the more and less myopic eyes (P = 0.525). However, when anisometropia was more than 1.50 D, the vascular density of choriocapillaris in the more myopic eyes was significantly less than the less myopic eyes (P = 0.026). The interocular difference of the choroidal thickness was significantly correlated with the interocular difference in SER and AL in the center, superior, and inferior regions but not in the nasal or temporal regions. The interocular differences of the vascular density and the flow voids of the choriocapillaris were not correlated with the interocular difference of SER and AL.

CONCLUSIONS

The choroidal thickness is thinner in the more myopic eyes. The flow void is increased, and the vascular density of the choriocapillaris is reduced in the more myopic eyes of children with anisometropia exceeding 1.50 D.

Longitudinal Macular Retinal and Choroidal Microvasculature Changes in High Myopia

Purpose

The purpose of this study was to determine the longitudinal changes in macular retinal and choroidal microvasculature in normal healthy and highly myopic eyes.

Methods

Seventy-one eyes, including 32 eyes with high myopia and 39 healthy control eyes, followed for at least 12 months and examined using optical coherence tomography angiography imaging in at least 3 visits, were included in this study. Fovea-centered 6 × 6 mm scans were performed to measure capillary density (CD) of the superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC). The rates of CD changes in both groups were estimated using a linear mixed model.

Results

Over a mean 14-month follow-up period, highly myopic eyes exhibited a faster rate of whole image CD (wiCD) loss (−1.44%/year vs. −0.11%/year, P = 0.001) and CD loss in the outer ring of the DCP (−1.67%/year vs. –0.14%/year, P < 0.001) than healthy eyes. In multivariate regression analysis, baseline axial length (AL) was negatively correlated with the rate of wiCD loss (estimate = −0.27, 95% confidence interval [CI] = −0.48 to −0.06, P = 0.012) and CD loss in the outer ring (estimate = −0.33, 95% CI = −0.56 to −0.11, P = 0.005), of the DCP. The CD reduction rates in the SCP and CC were comparable in both groups (all P values > 0.05).

Conclusions

The rate of CD loss in the DCP is significantly faster in highly myopic eyes than in healthy eyes and is related to baseline AL. The CD in the outer ring reduces faster in eyes with longer baseline AL.

Quantitative Assessment of Three-Dimensional Choroidal Vascularity and Choriocapillaris Flow Signal Voids in Myopic Patients Using SS-OCTA

Purpose: To compare the choroidal vascularity of large- and middle-sized choroidal vessels and choriocapillaris (CC) perfusion in patients with different degrees of myopia using swept-source optical coherence tomography angiography (SS-OCTA). Methods: One hundred and thirteen people with myopia were enrolled. SS-OCTA was performed to analyze the choroidal vascularity and CC perfusion. Three-dimensional (3D) choroidal vascularity index (CVI) and choroidal luminal volumes (LV) were obtained by artificial intelligence segmentation of the choroidal lumen in Volume OCT images. CC perfusion was assessed by flow signal voids (FSVs). Results: In the macular, multiple linear regression model showed that choroidal thickness (CT), total choroidal volume, LV, and choroidal stromal volume were negatively correlated with axis length (AL), respectively (all p < 0.001). Three dimensional CVI was negatively associated with AL (p < 0.05). FSV% was positively correlated with age only (p < 0.001). Additionally, after adjustment for age and AL, FSV% had a significant negative correlation with CT (p < 0.05). Conclusion: Choroidal vascularity decreases gradually with increasing severity of myopia. The decrease of CC blood perfusion was related to a higher severity of myopia and the thinning of choroid.

Visualising the choriocapillaris: Histology, imaging modalities and clinical research - A review

The choriocapillaris plays a considerable role in the normal physiology of the eye as well as in various diseases. Assessing the changes in the choriocapillaris can therefore provide important information about normal ageing and pathogenesis of visual impairment, and even some systemic diseases. In vivo imaging of the choriocapillaris has evolved from non-depth resolved, dye-based angiography to advanced, high-resolution optical coherence tomography angiography (OCTA). However, the intricate microvascular networks within the choriocapillaris are still beyond the resolving limits of most OCTA instruments. Knowledge of histology, meticulous image acquisition methods, recognition of artefact and post-acquisition processing techniques are necessary for optimising OCTA choriocapillaris images. Qualitative and quantitative analyses of the choriocapillaris provide clinical information in age-related macular degeneration (AMD), diabetic retinopathy (DR), pathologic myopia and central serous chorioretinopathy (CSC). Furthermore, studies have revealed choriocapillaris changes in posterior uveitis that are correlated with treatment outcome and have important prognostic significance. In addition to retinal diseases, choriocapillaris changes have been observed in systemic vascular diseases and complications associated with pregnancy.

Structural and haemodynamic properties of ocular vasculature in axial myopia

The high prevalence of myopia has become a global concern, especially in East and Southeast Asia. Alarmingly, the prevalence of high myopia is increasing. Mechanical stretching caused by excessive eyeball elongation leads to various anatomical changes in the fundus. This stretching force may also lead to the development of vascular abnormalities, which tend to be subtle and easily overlooked. A healthy ocular vasculature is a prerequisite of adequate oxygen supply for normal retinal functions. This review summarises previous findings on structural and haemodynamic aspects of myopia-related vascular changes.

Relative Postpartum Retinal Vasoconstriction Detected With Optical Coherence Tomography Angiography

Purpose

To characterize changes in retinal perfusion during pregnancy and the postpartum period using optical coherence tomography angiography (OCTA).

Methods

A nonmydriatic OCTA camera was used to image healthy women who were pregnant or in the postpartum period along with nonpregnant controls. Perfusion density (PD) and vessel length density (VLD) in the superficial capillary plexus (SCP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP) were evaluated.

Results

A total of 16, 15, and 13 eyes from nonpregnant, pregnant, and healthy postpartum subjects, respectively, were evaluated. When compared to controls, there were significant increases in ICP PD during the second and third trimester of pregnancy, along with significant decreases in both PD and VLD in SCP, ICP, and DCP up to 14 weeks postpartum.

Conclusions

During pregnancy, vascular changes consistent with retinal vasodilation were noted in the ICP. During the postpartum period, changes in retinal vasculature suggest relative vasoconstriction involving all three layers when compared to both the pregnant and nonpregnant states.

Translational Relevance

Detecting postpartum changes in retinal vasculature could offer important insights into postpartum physiology throughout the body.

Assessment of Choroidal Vascularity and Choriocapillaris Blood Perfusion in Anisomyopic Adults by SS-OCT/OCTA

Purpose

To explore the association of choroidal vascularity and choriocapillaris blood perfusion with myopic severity in anisomyopes.

Methods

Refractive error, axial length (AL), and other biometric parameters were measured in 34 anisomyopic young adults. Macular choroidal thickness (ChT) and choroidal vascularity, including total choroidal area (TCA), luminal area (LA), stromal area (SA), and choroidal vascularity index (CVI), were determined from swept-source optical coherence tomography (SS-OCT) vertical and horizontal B-scans. The percentage of choriocapillaris flow voids (FV%) was obtained from en face SS-OCT-angiography.

Results

The spherical equivalent refraction (SER) was –3.35 ± 1.25 diopters in the more myopic eyes and –1.25 ± 1.17 diopters in the less myopic eyes (P < 0.001). The interocular difference in SER was highly correlated with that in AL (P < 0.001). The macular ChT, TCA, LA, and SA were smaller in the more myopic eyes than in the less myopic eyes in both vertical and horizontal scans (all P < 0.001). Importantly, the CVIs in vertical and horizontal scans were smaller and the FV% was greater in the more myopic eyes (P < 0.05). In vertical scans, the interocular difference in CVIs was correlated with that in the SER, AL, and ChT (all P < 0.05). The interocular difference in FV% was correlated with that in SER, AL, and vertical and horizontal ChTs (all P < 0.05).

Conclusions

Choroidal vascularity and choriocapillaris blood perfusion were lower in the more myopic eyes of anisomyopic adults. These changes were correlated with the severity of myopia and choroidal thinning, indicating that choroidal blood flow is disturbed in human myopia.

Associations between optic disc characteristics and macular choroidal microvasculature in young patients with high myopia

BACKGROUND

This study aimed to examine changes to optic disc characteristics and macular choroidal microvasculature, and their relationships in young patients with high myopia (HM).

METHODS

A total of 90 patients were enrolled in this cross-sectional study. Based on their refractive power, the patients were divided into three groups: 27 in the control group, 34 in the HM group and 29 in the extremely high myopia group. Images of each patient's macula and optic disc were taken by ocular coherence tomography angiography. The macular choroidal and retinal thickness, capillary vessel density and capillary flow area were measured using Matlab software. Parapapillary atrophy (PPA) and the ovality index (OI) obtained from the scanning laser ophthalmoscopy images and the degree of optic disc tilt obtained from the optic nerve head ocular coherence tomography B-scans were analysed by Image J and Matlab software.

RESULTS

The PPA area, OI and degree of optic disc tilt were significantly different among the three groups (all p ≤ 0.001). The macular choroidal thickness and microvasculature were significantly different among the three groups (all p < 0.05). Macular choroidal thickness was significantly correlated with PPA area and the degree of optic disc tilt (r = -0.331, p = 0.003; r = -0.394, p = 0.001, respectively). Macular choroidal capillary vessel density and choriocapillaris flow area were associated with PPA area (r = -0.251, p = 0.047; r = -0.326, p = 0.009, respectively).

CONCLUSIONS

PPA area, OI and the degree of optic disc tilt were increased in patients with HM, and these changes were correlated with macular choroidal thickness and choroidal microvasculature.

Retinal microvasculature and optic disc alterations in non-pathological high myopia with optical coherence tomography angiography

PURPOSE

This study aims to investigate the early characteristics of retinochoroidal and peripapillary perfusion in non-pathological high myopia (HM) without retinopathy and compare them to the age- and sex-matched healthy subjects using optical coherence tomography angiography (OCTA).

METHODS

This prospective, cross-sectional study included 35 eyes of 35 patients in the non-pathological HM group (axial length (AL) ≥ 26 mm) and 35 eyes of 35 subjects in the control group. OCT and OCTA were used for the assessment of vessel density, foveal avascular zone, subfoveal choroidal thickness, choriocapillaris flow area, retinal nerve fiber layer thickness, and optic nerve head measurements.

RESULTS

The VDs of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were significantly reduced in the HM group (47.9 ± 3.8%; 47.3 ± 6.6%) compared to the control group (50.8 ± 2.6%; 54.1 ± 4.8%) (p < 0.001). The whole vessel density (wpVD) (53.7 ± 2.7% vs. 56.2 ± 2.2%) and peripapillary VD (ppVD) (56.4% (range, 45.8-60.4%) vs. 58.4% (range, 52.6-62.3%)) values were significantly lower in the HM group (p < 0.005). The inside disc vessel density (iVD) was similar in both groups (62 ± 3.3% vs. 61.4 ± 2.7%) (p = 0.511).

CONCLUSION

The vessel densities (VDs) of SCP and DCP, wpVD, and ppVD were lower in the non-pathological HM group, but the iVD value was similar in both groups. This suggests that the main cause of VD reduction is more likely related to globe elongation rather than reduced oxygen and nutrients due to the thinning of the posterior pole (retina, sclera, and choroid). CLINICALTRIALS.

GOV REGISTRATION ID

NCT04631991, 11/11/2020.

Optical Coherence Tomography Angiography of the Choriocapillaris in Age-Related Macular Degeneration

The advent of optical coherence tomography angiography (OCTA) has allowed for remarkable advancements in our understanding of the role of the choriocapillaris in age-related macular degeneration (AMD). As a relatively new imaging modality, techniques to analyze and quantify choriocapillaris images are still evolving. Quantification of the choriocapillaris requires careful consideration of many factors, including the type of OCTA device, segmentation of the choriocapillaris slab, image processing techniques, and thresholding method. OCTA imaging shows that the choriocapillaris is impaired in intermediate non-neovascular AMD, and the severity of impairment may predict the advancement of disease. In advanced atrophic AMD, the choriocapillaris is severely impaired underneath the area of geographic atrophy, and the level of impairment surrounding the lesion predicts the rate of atrophy enlargement. Macular neovascularization can be readily identified and classified using OCTA, but it is still unclear if neovascularization features with OCTA can predict the lesion’s level of activity. The choriocapillaris surrounding macular neovascularization is impaired while the more peripheral choriocapillaris is spared, implying that choriocapillaris disruption may drive neovascularization growth. With continued innovation in OCTA image acquisition and analysis methods, advancement in clinical applications and pathophysiologic discoveries in AMD are set to follow.

Wide-Field Swept-Source Optical Coherence Tomography Angiography Analysis of the Periarterial Capillary-Free Zone in Branch Retinal Vein Occlusion

Purpose

To investigate the characteristics of the retinal periarterial capillary-free zone (paCFZ) with wide-field swept-source optical coherence tomography angiography (SS-OCTA) in eyes with branch retinal vein occlusion (BRVO).

Methods

Seventy treatment-naïve eyes with BRVO and 35 healthy eyes were included. The paCFZ areas, artery calibers, and areas of the major arteries in the unaffected quadrants of BRVO eyes were measured in 12 × 12-mm SS-OCTA images and compared with those of the contralateral eyes and healthy eyes. Other multimodal imaging data were collected.

Results

There were no significant differences in the unaffected artery caliber or area among the three groups (all P > 0.05). The unaffected paCFZ areas and the ratios of the unaffected paCFZ area to the counterpart artery area (paCFZ/artery area) of the major arteries were significantly larger than those in the contralateral or healthy eyes (all P < 0.05). Subgroup analysis revealed that the paCFZ/artery area value differed significantly between ischemic and nonischemic BRVO eyes (P < 0.01). The paCFZ/artery area value was positively correlated with logMAR best-corrected visual acuity, symptom duration, central macular thickness, and retinal nonperfusion area in BRVO.

Conclusions

Quantitative SS-OCTA measurements confirmed enlarged paCFZs along the unaffected major retinal arteries in BRVO eyes. The paCFZ parameters were correlated with symptom duration, retinal ischemia, and visual function.

Translational Relevance

Retinal periarterial capillary-free zones in BRVO can be non-invasively measured by SS-OCTA, assisting in clinically identifying retinal ischemia and evaluating visual function.