Choroidal imaging biomarkers

RECURRENT ANTERIOR UVEITIS ASSOCIATED WITH MAJOR FLUCTUATIONS IN CHOROIDAL THICKNESS IN A PATIENT WITH PACHYCHOROID DISORDER

PURPOSE

To describe remarkable choroidal thickness fluctuations corresponding to episodes of recurrent anterior uveitis with subretinal fluid development when exceeding a choroidal thickness threshold.

METHODS

A patient with pachychoroid pigment epitheliopathy and unilateral acute anterior uveitis of the left eye was evaluated over a period of 3 years with multimodal retinal imaging including optical coherence tomography. Longitudinal changes in subfoveal choroidal thickness (CT) were measured and correlated with episodes of recurrent inflammation.

RESULTS

Over the course of five recurrent episodes of inflammation in the left eye treated with oral antiviral and topical steroid therapy, subfoveal CT increased as much as 200 μm or more. By contrast, subfoveal CT in the fellow quiescent right eye was within normal limits and minimally changed throughout the follow-up. Increased CT occurred with each episode of anterior uveitis and decreased by 200 µ m or more during periods of quiescence in the affected left eye. Subretinal fluid and macular edema developed with a maximum CT of 486 μm and spontaneously resolved when CT decreased after treatment.

CONCLUSION

In eyes with pachychoroid disease, anterior segment inflammation may lead to marked increases in subfoveal CT and the development of subretinal fluid at a threshold thickness value.

The effect of intravitreal anti-VEGF injections on choroidal vascular index in patients with diabetic macular edema

PURPOSE

This study aims to examine and compare the effects of intravitreal bevacizumab injection (IVB) at subfoveal 1500 micron (μm) and submacular 6000 μm in patients with diabetic macular edema (DME).

METHODS

Fifty eyes of 45 patients with DME who completed six doses of IVB were included in the study group, and 50 eyes of 42 patients who had diabetic retinopathy (DR) but did not receive any treatment were included in the control group. Central macular thickness (CMT), central choroidal thickness (CCT), subfoveal and total choroidal area (TCA), and choroidal vascular index (CVI) were calculated and their changes at zero, three and six months were evaluated.

RESULTS

At baseline, CVI was significantly lower in both the subfoveal and total macular areas in the study group (p = 0.004, p = 0.003). In the study group, a significant decrease was observed in CVI between zero and six months in the subfoveal area (p = 0.001). In the submacular area, the decrease in CVI in the study group was significant between zero to three months and zero to six months. There was moderate correlation between measurements of CVI in the subfoveal and total macular areas (r = 0.66, p < 0.001).

CONCLUSION

These findings indicate that intravitreal bevacizumab injection reduces the CVI and the effects of intravitreal anti-VEGF on CVI emerge earlier and more prominently in the submacular 6000 µm area.

The effect of heart rate variability on the choroidal vascularity of the optical coherence tomography and angiography in central serous chorioretinopathy

PURPOSE

To investigate the correlation between the autonomic nervous system and choroidal vascularity in patients with central serous chorioretinopathy (CSC), using heart rate variability (HRV) analysis, optical coherence tomography (OCT) and OCT angiography (OCTA).

METHODS

We retrospectively analyzed data of 25 patients with unilateral CSC (50 eyes, including the unaffected fellow eyes) and 25 healthy controls. The assessment involved a 5-minute HRV analysis encompassing both frequency and time domains, especially low frequency (LF), high frequency (HF), and LF/HF ratio. In OCT (12 × 9 mm) and en-face OCTA (3 × 3 mm) scans, we measured parameters including choroidal vascularity index (CVI), choroidal vessel density in the middle and deep layers, and choriocapillaris flow void. Regression analysis was conducted to elucidate the associations between HRV parameters and OCT/OCTA measurements.

RESULTS

Normalized LF(LFnorm) and LF/HF ratios were higher in patients with CSC than in healthy controls. LFnorm and the log-transformed ratio of LF to HF [log(LF/HF)] demonstrated a significant and borderline correlation with CVI in the linear regression analysis (P = 0.040, R2 = 0.171, and P = 0.059, R2 = 0.147, respectively). Both CVI and deep choroid vessel density showed a more significant association with LFnorm and log (LF/HF) in the non-linear quadratic regression analysis than in the linear analysis (all, P < 0.04, R2 > 0.25).

CONCLUSION

The frequency-domain parameters of HRV, including LFnorm and log (LF/HF), demonstrated a significant association with indicators reflective of large choroidal vessel luminal area on macular OCT/OCTA scans. This observation implies complicated modulation of choroidal blood flow by the autonomic nervous system in CSC.

Retinal and choroidal thickness in fuchs uveitis syndrome: a contralateral eye study

BACKGROUND

To investigate the subfoveal retinal and choroidal thickness in patients with unilateral Fuchs Uveitis Syndrome (FUS).

METHODS

This comparative contralateral study was performed in affected eyes with FUS versus fellow eyes. For each eye parameters such as subfoveal choroidal thickness (SCT), subfoveal choriocapillary thickness (SCCT), central macular thickness (CMT), and central macular volume (CMV) were measured; then the measured values of affected and fellow unaffected eye were compared.

RESULTS

Thirty-seven patients (74 eyes) including 19 females (51.4%) with a mean age of 36.9 ± 7.6 years were enrolled. The mean SCT was lower in the affected eyes (344.51 ± 91.67) than in the fellow (375.59 ± 87.33) with adjusting for duration of disease and axial lengths (P < 0.001). The mean SCCT, CMT, and CMV were higher in eyes with FUS than in fellow eyes (P < 0.05).

CONCLUSIONS

The result of our study demonstrated that affected eyes in patients with FUS tend to have thinner SCT and thicker SCCT and CMT compared to uninvolved fellow eyes.

Macular choroidal thickness, volume, and vascularity index in patients with systemic sclerosis

PURPOSE

The aim of this study was to investigate choroidal parameters in patients with systemic sclerosis (SSc) using enhanced depth imaging spectral-domain optical coherence tomography (EDI-SD-OCT) and to determine their relationships with clinical variables and ocular features.

METHODS

Thirty-three patients with SSc and 40 controls were enrolled. The groups did not differ with regard to age, sex, and axial length. The mean choroidal thickness and volume were obtained in each conventional Early Treatment of Diabetic Retinopathy Study grid subfield. The choroidal vascularity index (CVI), which provides a quantitative analysis of vasculature by calculating the proportion of the luminal area (LA) to the total choroidal area (TCA), was determined.

RESULTS

Lower choroidal thickness and volume were observed in the SSc group. The CVI was significantly higher in SSc patients, whereas the TCA, LA, and stromal area were significantly lower in the SSc group; however, the significant difference of the stromal component was more pronounced than that of the luminal component. Regression analyses did not identify any clinical factors associated with the CVI (except Ca-blocker use), central macular thickness, or volume. No significant differences in choroidal parameters were found within the SSc subtypes (diffuse cutaneous systemic sclerosis (dcSSc) vs. limited cutaneous systemic sclerosis (lcSSc)), or between eyes stratified according to SSc pattern (early, active, or late) using nailfold capillaroscopy (p > 0.05 for all).

CONCLUSION

Our results, with notably higher CVI values, may shed new light on choroidal impairment in patients with SSc. Stromal involvement appeared to dominate the vascular component.

PGKD-Net: Prior-guided and Knowledge Diffusive Network for Choroid Segmentation

The thickness of the choroid is considered to be an important indicator of clinical diagnosis. Therefore, accurate choroid segmentation in retinal OCT images is crucial for monitoring various ophthalmic diseases. However, this is still challenging due to the blurry boundaries and interference from other lesions. To address these issues, we propose a novel prior-guided and knowledge diffusive network (PGKD-Net) to fully utilize retinal structural information to highlight choroidal region features and boost segmentation performance. Specifically, it is composed of two parts: a Prior-mask Guided Network (PG-Net) for coarse segmentation and a Knowledge Diffusive Network (KD-Net) for fine segmentation. In addition, we design two novel feature enhancement modules, Multi-Scale Context Aggregation (MSCA) and Multi-Level Feature Fusion (MLFF). The MSCA module captures the long-distance dependencies between features from different receptive fields and improves the model's ability to learn global context. The MLFF module integrates the cascaded context knowledge learned from PG-Net to benefit fine-level segmentation. Comprehensive experiments are conducted to evaluate the performance of the proposed PGKD-Net. Experimental results show that our proposed method achieves superior segmentation accuracy over other state-of-the-art methods. Our code is made up publicly available at: https://github.com/yzh-hdu/choroid-segmentation.

Effects of hydroxychloroquine therapy on choroidal volume and choroidal vascularity index

PURPOSE

To determine changes in choroidal volume (CV) and choroidal vascularity index (CVI) in patients on hydroxychloroquine (HCQ) therapy.

METHODS

Retrospective analysis of patients on HCQ therapy. CV and CVI were assessed below the central foveal region on spectral-domain optical coherence tomography using an automatic denoising and localization algorithm. CV and CVI were compared with age-matched controls. Regression analyses were performed to generate associations between CV and CVI with demographics and HCQ treatment parameters. Associations were assessed using a generalized estimating equation model adjusted for intra-subject inter-eye correlations.

RESULTS

A total of 137 adult patients (23 males and 114 females) were included. Mean age was 45.6 ± 13.7 years and most patients identified as Caucasian (79%). Total duration of HCQ therapy ranged from 3 months to 20 years. Daily HCQ intake varied from 150-600 mg (mean = 304 mg), while cumulative doses ranged from 18-2,800 g. At presentation, the median CV was 0.51 (IQR:0.356-0.747) mm, and median CVI was 0.559 (IQR:0.528-0.578). Increased cumulative HCQ dose was associated with decreased CV (p = 0.006). Compared to age-matched controls, CV, CVI, and luminal area were significantly lower in the study group (p = 0.0003, 0.0001, and 0.0002).

CONCLUSION

In this study, we present a novel analysis of key biomarkers which predate the occurrence of HCQ retinopathy. Choroidal volume and vascularity index are significantly reduced in patients on HCQ therapy, especially at higher cumulative doses. These findings suggest new tools to guide medical decision-making for patients receiving HCQ therapy for rheumatologic diseases.

Validation of reliability, repeatability and consistency of three-dimensional choroidal vascular index

This study aimed to investigate the reliability, repeatability and consistency of choroidal vascularity index (CVI) measurements provided by an artificial intelligence-based software in swept-source optical coherence tomography (SS-OCT) in normal subject, and to evaluate the influencing factors for 3D-CVI. Repeatability of 3D-CVI by SS-OCT was evaluated based on different scanning modes including Macular Cubes (3 mm × 3 mm, 6 mm × 6 mm, 9 mm × 9 mm) and Optic Nerve Head 6 mm × 6 mm. Intraclass Correlation Coefficient (ICC) was used to estimate the repeatability and reproducibility of five repeated measurement by SS-OCT. Consistency of CVI between SS-OCT and spectral-domain optical coherence tomography (SD-OCT) was measured and compared in a pilot study of ten eyes and agreement between SS-OCT and SD-OCT was evaluated by Bland-Altman analysis and Deming regression. The influencing factors for 3D-CVI including age, gender, axial length and spherical equivalent on CVI was further investigated in a prospective study of 125 eyes of 125 healthy subjects. ICC between different measurements by SS-OCT was 0.934 (95% CI 0.812-0.956) indicating good repeatability. Intraclass correlation coefficient between CVI measure by SS-OCT and SD-OCT was 0.887 (95% CI 0.796-0.938, P value < 0.001). The mean difference between 3D-CVI measured by SS-OCT and SD-OCT 0.133. CVI measured with SS-OCTA showed stronger correlations with axial length and age but not correlated with gender. There is good agreement between CVIs obtained from the built-in software that requires less timing in manual quantification. Studies investigating choroidal vascularity can be standardized by the AI-based CVI analyze software.

Interocular Symmetry of Choroidal Parameters in Patients with Diabetic Retinopathy with and without Diabetic Macular Edema

This study focuses on the interocular comparison of choroidal parameters in diabetic patients with diabetic retinopathy (DR) with and without diabetic macular edema (DME), as well as in patients with unilateral DME (present in only one eye). The aim of this study was to determine the symmetry in order to obtain better insights into the pathophysiology of diabetic choroidopathy. This retrospective single-center cross-sectional study included 170 eyes from 85 patients (61 with DR and 24 controls), divided into subgroups depending on the presence of DME. The patients underwent fluorescein angiography and spectral domain optical coherence tomography examination, and the analysis included various choroidal parameters: choroidal thickness, volume, and the choroidal vascularity index (CVI). In terms of the choroidal thickness, one eye of a patient with DR, regardless of the presence, absence, or unilaterality of DME, may be treated as representative for that patient. CVI proved symmetrical for controls and patients with DR without DME. However, there was some asymmetry of CVI in patients with bilateral or unilateral DME. There was no straightforward relationship between choroidopathy and DME. Other mechanisms were also involved in the pathogenesis.

Semi-supervised contrast learning-based segmentation of choroidal vessel in optical coherence tomography images

Objective.Choroidal vessels account for 85% of all blood vessels in the eye, and the accurate segmentation of choroidal vessels from optical coherence tomography (OCT) images provides important support for the quantitative analysis of choroid-related diseases and the development of treatment plans. Although deep learning-based methods have great potential for segmentation, these methods rely on large amounts of well-labeled data, and the data collection process is both time-consuming and laborious.Approach.In this paper, we propose a novel asymmetric semi-supervised segmentation framework called SSCR, based on a student-teacher model, to segment choroidal vessels in OCT images. The proposed framework enhances the segmentation results with uncertainty-aware self-integration and transformation consistency techniques. Meanwhile, we designed an asymmetric encoder-decoder network called Pyramid Pooling SegFormer (APP-SFR) for choroidal vascular segmentation. The network combines local attention and global attention information to improve the model's ability to learn complex vascular features. Additionally, we proposed a boundary repair module that enhances boundary confidence by utilizing a repair head to re-predict selected fuzzy points and further refines the segmentation boundary.Main results.We conducted extensive experiments on three different datasets: the ChorVessel dataset with 400 OCT images, the Meibomian Glands (MG) dataset with 400 images, and the U2OS Cell Nucleus Dataset with 200 images. The proposed method achieved an average Dice score of 74.23% on the ChorVessel dataset, which is 2.95% higher than the fully supervised network (U-Net) and outperformed other comparison methods. In both the MG dataset and the U2OS cell nucleus dataset, our proposed SSCR method achieved average Dice scores of 80.10% and 87.26%, respectively.Significance.The experimental results show that our proposed methods achieve better segmentation accuracy than other state-of-the-art methods. The method is designed to help clinicians make rapid diagnoses of ophthalmic diseases and has potential for clinical application.

Choroidal Vascularity Index Fluctuations in Epiretinal Membranes in Vitreoretinal Surgery: Comparison Between Idiopathic and Diabetic Ones

Purpose

The aim of the study was to analyze choroidal vascularity index (CVI) fluctuations in patients with epiretinal membrane after vitreoretinal surgery, comparing idiopathic and secondary diabetic ones.

Methods

Thirty eyes suffering from idiopathic ERMs (I-ERMS; n = 15) and diabetic ERMs (D-ERMS; n = 15) were analyzed in this observational prospective study. Anatomical (central macular thickness) and functional (best-corrected visual acuity) parameters were analyzed preoperatively and at 1 and 3 months after vitrectomy. Perfusion findings regarding CVI and luminal area were also calculated.

Results

At 1 month after surgery, the luminal area and CVI significantly decreased in the I-ERMS group, whereas they were increased in the D-ERMS group. At the 3-month follow-up, the CVI tended to return to baseline values in I-ERMS and to reduce in D-ERMS, but without any statistical differences.

Conclusions

The significant change in the CVI after surgery seems to imply that the choroidal layer is affected by vitreomacular disease and can become a novel potential biomarker of predictiveness in vitreoretinal surgery.

Translational Relevance

The aim of the study was to focus on the early choroidal changes to better understand initial predictive elements of long-term functional postoperative outcomes.

Choroidal structural changes in patients with early diabetic nephropathy

PURPOSE

To determine alterations of the choroidal thickness (CT) and the choroidal vascularity index (CVI) in patients with glomerular hyperfiltration, a marker of early diabetic nephropathy (DN).

METHODS

Twenty-two patients with type 2 diabetes (T2D) with glomerular hyperfiltration (early DN group) and 28 patients with T2D without DN (NDN group) were included in the study. Patients with diabetic retinopathy were excluded. Parameters including subfoveal CT, the subfoveal choroidal vascularity index (CVI), and total CVI were measured using spectral-domain enhanced depth imaging optical coherence tomography method.

RESULTS

The early DN group included 22 patients and the NDN group comprised 28 patients. The groups were similar in terms of age and sex (p>0.05). The CT values were statistically significantly lower in the early DN group than in the NDN group (p < 0.001). There was no significant difference between the early DN group and the NDN group in terms of total and subfoveal CVI (p>0.05).

CONCLUSION

The choroidal thickness decreased in patients with T2D with glomerular hyperfiltration, but there were no differences in CVI when they were compared with patients with T2D without DN.

Comparison of the morphological characteristics of the choroidal sublayer between idiopathic macular holes and epiretinal membranes with automatic analysis

PURPOSE

To compare the choroidal sublayer morphologic features between idiopathic macular hole (IMH) and idiopathic epiretinal membrane (iERM) on spectral-domain optical coherent tomography (SD-OCT) using an automatic segmentation model.

METHODS

Thirty-three patients with idiopathic IMHs and 44 with iERMs who underwent vitrectomies were involved. The enhanced depth imaging mode of SD-OCT was used to obtain the B-scan image after single line scanning of the macular fovea. The choroidal sublayer automatic analysis model divides the choroidal into the choroidal large vessel layer, the middle vessel layer and the small vessel layer (LVCL, MVCL and SVCL, respectively) and calculates the choroidal thickness (overall, LVCL, MVCL and SVCL) and vascular index (overall, LVCL, MVCL and SVCL). The morphological characteristics of the choroidal sublayer in the ERM eyes and the IMH eyes were compared.

RESULTS

The mean choroidal thickness in the macular centre of the IMH eyes was significantly thinner than that of the ERM eyes (206.35 ± 81.72 vs. 273.33 ± 82.31 μm; P < 0.001). The analysis of the choroidal sublayer showed that the MVCL and SVCL macular centres and 0.5-1.5 mm of the nasal and temporal macula were significantly thinner in the IMH eyes than in the ERM eyes (P < 0.05), and there was a difference in the macular centre of the LVCL between the two groups (P < 0.05). In contrast, the choroidal vascular index of the macular centre in the IMH eyes was significantly higher than that in iERM eyes (0.2480 ± 0.0536 vs. 0.2120 ± 0.0616; P < 0.05). There was no significant difference in the CVI of other parts of the macula, the LVCL or MVCL between the two groups.

CONCLUSION

The choroidal thickness of the IMH eyes was significantly thinner than that of the iERM eyes, which was mainly observed in 3 mm of the macular centre and the MVCL and SVCL layers of the choroid. The choroidal vascular index of the IMH eyes was higher than that of the iERM eyes. These findings suggest that the choroid may be involved in the pathogenesis of IMH and iERM.

Optical Coherence Tomography in Inflammatory and Neoplastic Lesions Deforming the Choroidal Profile

The choroid is the main part of the uvea, the vascular layer of the eye that lies between the retina and the sclera. The high vascular component of the choroid makes this structure susceptible to inflammation in multisystemic diseases, as well as the most common site of metastasis in the eye. Therefore, the choroid is involved in many pathological conditions, from uveitis to intraocular tumors. Differentiating between inflammatory and neoplastic lesions deforming the choroidal profile can sometimes be challenging. In addition, scleral disorders can also deform the choroidal profile. Choroidal imaging includes ophthalmic ultrasonography, indocyanine green angiography, and optical coherence tomography (OCT). Recent advances in choroidal imaging techniques, such as enhanced depth imaging optical coherence tomography (EDI-OCT) and swept-source optical coherence tomography (SS-OCT), have facilitated an in-depth analysis of the choroid. The purpose of this review article is to report on and highlight the most common OCT findings to help in the differential diagnosis between inflammatory and neoplastic lesions deforming the choroidal profile.

Changes in Subfoveal Choroidal Thickness Following Uncomplicated Cataract Surgery: A Scoping Review

This scoping review investigates the relationship between subfoveal choroidal thickness (SFCT) and cataract surgery. We synthesized existing research to clarify SFCT changes following surgery and identify contributing factors. Our aim was to enhance understanding of the ocular changes associated with cataract surgery. A comprehensive database search identified studies on SFCT changes after uncomplicated cataract surgery, categorized as "SFCT changes after cataract surgery," "Factors influencing SFCT," "Macular thickness changes," and "Long-term changes." Quantitative data and findings were extracted from a total of 13 research articles. Studies on SFCT changes after cataract surgery provided valuable insights for the subject under review. Factors influencing SFCT changes included age, axial length, and cataract surgery. Macular thickness increased at various time points. Long-term SFCT changes varied among studies. The present research provides valuable insights into SFCT changes after cataract surgery. Factors including age, axial length, and cataract surgery consistently influence SFCT. The clinical relevance of macular thickness changes remains uncertain, and the influence of age, ocular pathologies, and patient populations is highlighted. Long-term changes in SFCT vary, suggesting a need for further research. Standardized measurement techniques and larger cohort studies are recommended to enhance comparability and generalizability. This review enhances understanding of ocular changes associated with cataract surgery and informs future research.

Choroidal vascularity index (CVI)-Net-based automatic assessment of diabetic retinopathy severity using CVI in optical coherence tomography images

A deep learning model called choroidal vascularity index (CVI)-Net is proposed to automatically segment the choroid layer and its vessels in overall optical coherence tomography (OCT) scans. Clinical parameters are then automatically quantified to determine structural and vascular changes in the choroid with the progression of diabetic retinopathy (DR) severity. The study includes 65 eyes consisting of 34 with proliferative DR (PDR), 17 with nonproliferative DR (NPDR), and 14 healthy controls from two OCT systems. On a dataset of 396 OCT B-scan images with manually annotated ground truths, overall Dice coefficients of 96.6 ± 1.5 and 89.1 ± 3.1 are obtained by CVI-Net for the choroid layer and vessel segmentation, respectively. The mean CVI values among the normal, NPDR, and PDR groups are consistent with reported outcomes. Statistical results indicate that CVI shows a significant negative correlation with DR severity level, and this correlation is independent of changes in other physiological parameters.

Choroidal modifications assessed by means of choroidal vascularity index after oral eplerenone treatment in chronic central serous chorioretinopathy

BACKGROUND

To investigate choroidal vascularity index (CVI) changes after oral eplerenone treatment in chronic central serous chorioretinopathy (cCSC) using the Spectral-domain (SD)-Optical Coherence Tomography (OCT) with enhanced depth imaging (EDI) mode.

METHODS

Thirty-six eyes of 18 patients suffering from cCSC with monolateral foveal subretinal fluid (FSRF) successfully treated with oral eplerenone treatment and 18 age-matched healthy subjects were enroled in this retrospective study. EDI-OCT images obtained using Heidelberg Spectralis OCT device in patients with cCSC and FSRF (group 1); fellow eye (group 2) or healthy patients (healthy) were exported and then imported into image analysis ImageJ software for subsequent quantitative analysis. The main outcome measures were luminal area (LA) and CVI.

RESULTS

A higher value of CVI was detected in group 1 compared to healthy eyes (p = 0.006). LA and CVI significantly reduced during follow up in group 1 and group 2. LA at 120 days was significantly lower compared to all previous time points both in group 1 and group 2 (p < 0.001). Median and [1st -3rd quartile] CVI values were 0.8 [0.7; 1.1] at baseline, 0.8 [0.7; 0.9] at 30 days; 0.7 [0.6; 0.9] at 60 and 90 days and 0.6 [0.5; 0.8] at 120 days in group 1 (p = 0.007) and 0.7 [0.6; 0.9] at baseline, 0.7 [0.7; 0.8] at 30 days; 0.7 [0.6; 0.7] at 60 and 90 days and 0.6 [0.6; 0.7] at 120 days in group 2 (p = 0.018).

CONCLUSIONS

Choroidal vascularity index reduced in cCSC patients after oral eplerenone treatment during follow up both in eyes with SRF and fellow eyes thus demonstrating the effectiveness of mineral corticoid receptor antagonists in recovering choroidal morphology.

Choroidal and Retinal Vascular Findings in Patients with COVID-19 Complicated with Pneumonia: Widefield Imaging

Purpose: The purpose of this study was to analyze choroidal and retinal vascular alterations of both the macula and midperiphery areas in patients hospitalized for COVID-19 infection complicated with pneumonia within 30 days from discharge. Methods: A total of 46 eyes of 23 subjects with a history of symptomatic COVID-19 infection and recent hospitalization for pneumonia were enrolled in this observational study. Patients had not been previously vaccinated against COVID-19. A group of patients homogenous for age and sex was enrolled as controls. Microvascular retinal and choroidal features of the enrolled patients were studied with widefield optical coherence tomography angiography (OCT-A). Perfusion parameters in terms of the vessel density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) and the choroidal vascularity index (CVI) on enhanced depth imaging (EDI) mode OCT scans were analyzed. Results: Our cohort of patients showed a trend of reduction in VD, significantly in the SCP VD of the superior and inferior midperiphery sectors, whereas the CVI did not show significant differences between the cases and controls. Moreover, a positive correlation between CVI and vessel density in the deep capillary plexus in the macular area (VD-DCP-MAC) was found. Conclusion: The systemic disease due to COVID-19 can also involve the retina and choroid with multiple mechanisms: ischemic and inflammatory. Our study showed changes in perfusion occurring in the eyes of patients with a recent hospitalization for COVID-19 complicated with pneumonia and without any possible ocular effect due to the vaccines. There is still the need to better comprise how long COVID-19 actually affects vascular changes in the eye.

A Deep Learning-Based Fully Automated Program for Choroidal Structure Analysis Within the Region of Interest in Myopic Children

Purpose

To develop and validate a fully automated program for choroidal structure analysis within a 1500-µm-wide region of interest centered on the fovea (deep learning-based choroidal structure assessment program [DCAP]).

Methods

A total of 2162 fovea-centered radial swept-source optical coherence tomography (SS-OCT) B-scans from 162 myopic children with cycloplegic spherical equivalent refraction ranging from -1.00 to -5.00 diopters were collected to develop the DCAP. Medical Transformer network and Small Attention U-Net were used to automatically segment the choroid boundaries and the nulla (the deepest point within the fovea). Automatic denoising based on choroidal vessel luminance and binarization were applied to isolate choroidal luminal/stromal areas. To further compare the DCAP with the traditional handcrafted method, the luminal/stromal areas and choroidal vascularity index (CVI) values for 20 OCT images were measured by three graders and the DCAP separately. Intraclass correlation coefficients (ICCs) and limits of agreement were used for agreement analysis.

Results

The mean ± SD pixel-wise distances from the predicted choroidal inner, outer boundary, and nulla to the ground truth were 1.40 ± 1.23, 5.40 ± 2.24, and 1.92 ± 1.13 pixels, respectively. The mean times required for choroidal structure analysis were 1.00, 438.00 ± 75.88, 393.25 ± 78.77, and 410.10 ± 56.03 seconds per image for the DCAP and three graders, respectively. Agreement between the automatic and manual area measurements was excellent (ICCs > 0.900) but poor for the CVI (0.627; 95% confidence interval, 0.279-0.832). Additionally, the DCAP demonstrated better intersession repeatability.

Conclusions

The DCAP is faster than manual methods. Also, it was able to reduce the intra-/intergrader and intersession variations to a small extent.

Translational Relevance

The DCAP could aid in choroidal structure assessment.

Outcome Measures for Disease Monitoring in Intraocular Inflammatory and Infectious Diseases (OCTOMERIA): Understanding the Choroid in Uveitis with Optical Coherence Tomography (OCT)

PURPOSE

To compare imaging modalities for the choroid of the eye, and evaluate various choroidal changes in uveitides entities.

METHODS

A comprehensive systematic literature review was conducted looking at current imaging modalities available to assess choroid architecture and commonly used parameters available to qualify and quantify choroidal changes, before looking at specific uveitides entities with choroidal involvement which have been broadly separated into non-infectious and infectious in etiology.

RESULTS

We describe the various modalities currently available to evaluate the choroid of the eye such as Ultrasound B Scan, ICGA, and OCT. Choroidal changes in various ocular and systemic diseases such as Behcet's Disease, Sarcoidosis, Syphillis, Tuberculosis, and many more have been reported and published.

CONCLUSION

Multiple choroidal tomographic and angiotomographic findings have been demonstrated for evaluation in uveitis. These findings can manifest in multiple ocular and systemic diseases, and can be illustrated using the various imaging modalities at present. Future advancements in choroidal imaging would help to adapt these findings into parameters for clinical practice to properly evaluate these ocular and systemic diseases.

Choroidal layer segmentation in OCT images by a boundary enhancement network

Morphological changes of the choroid have been proved to be associated with the occurrence and pathological mechanism of many ophthalmic diseases. Optical Coherence Tomography (OCT) is a non-invasive technique for imaging of ocular biological tissues, that can reveal the structure of the retinal and choroidal layers in micron-scale resolution. However, unlike the retinal layer, the interface between the choroidal layer and the sclera is ambiguous in OCT, which makes it difficult for ophthalmologists to identify with certainty. In this paper, we propose a novel boundary-enhanced encoder-decoder architecture for choroid segmentation in retinal OCT images, in which a Boundary Enhancement Module (BEM) forms the backbone of each encoder-decoder layer. The BEM consists of three parallel branches: 1) a Feature Extraction Branch (FEB) to obtain feature maps with different receptive fields; 2) a Channel Enhancement Branch (CEB) to extract the boundary information of different channels; and 3) a Boundary Activation Branch (BAB) to enhance the boundary information via a novel activation function. In addition, in order to incorporate expert knowledge into the segmentation network, soft key point maps are generated on the choroidal boundary, and are combined with the predicted images to facilitate precise choroidal boundary segmentation. In order to validate the effectiveness and superiority of the proposed method, both qualitative and quantitative evaluations are employed on three retinal OCT datasets for choroid segmentation. The experimental results demonstrate that the proposed method yields better choroid segmentation performance than other deep learning approaches. Moreover, both 2D and 3D features are extracted for statistical analysis from normal and highly myopic subjects based on the choroid segmentation results, which is helpful in revealing the pathology of high myopia. Code is available at https://github.com/iMED-Lab/Choroid-segmentation.

Optical coherence tomography evaluation of choroidal structure changes in diabetic retinopathy patients: A systematic review and meta-analysis

Introduction

Diabetic retinopathy (DR) is one of the major causes of blindness among working-aged adults worldwide. This study aimed to evaluate the differences in the subfoveal choroidal thickness (SFCT) and choroidal vascularity index (CVI) using optical coherence tomography (OCT) of patients with diabetic eyes with no retinopathy (NDR) and with diabetic retinopathy (DR).

Methods

We performed a comprehensive literature search of the PubMed, Embase, and Cochrane Library databases up to October 2021. The weighted mean difference (WMD) with the 95% confidence interval (CI) was pooled for continuous outcomes.

Results

Twenty-three cross-sectional studies comprising 2,534 eyes including 1,070 NDR eyes, 1,464 DR eyes were included in the systematic review and meta-analysis. The pooled results showed SFCT was significantly thicker in DR than in NDR patients after adjusting for axial length (WMD = 27.90 μm; 95% CI: 11.51 to 44.28; P = 0.001), and the CVI was significantly lower in DR patients (WMD = −1.59; 95% CI: −2.67 to −0.52; P = 0.004).

Conclusion

We described changes in the SFCT and CVI in DR. Resultantly, the CVI and SFCT may be valuable parameters for monitoring the onset of DR and helpful for a better understanding of the role of the choroid in the pathological process of DR.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#myprospero, CRD42021228738.

Enhanced Apoptosis in Choroidal Tissues in Lens-Induced Myopia Guinea Pigs by Activating the RASA1 Signaling Pathway

Purpose

This study aimed to explore the role of the RAS p21 protein activator 1 (RASA1) signaling pathway in apoptosis in choroid tissues from guinea pigs with negative lens-induced myopia (LIM).

Methods

Biometric measurements were performed to examine refractive status, ocular parameters, and choroidal thickness (ChT) after myopia induction. The choroidal morphology was observed by hematoxylin and eosin (H&E) staining and TUNEL assay. The expression of the RASA1 signaling pathway at the mRNA and protein levels in choroidal tissues was measured by real-time quantitative PCR (qPCR) and western blot assays.

Results

Compared with the normal control (NC) group, the ocular length of the guinea pigs in LIM increased remarkably, as did the myopic refraction. ChT decreased after myopia induction. H&E staining showed that the thickness and laxity of the choroidal tissues in LIM were strikingly reduced. The number of apoptotic cells in the LIM eyes was increased. Moreover, qPCR and western blot assays showed that the expression levels of both RASA1 and BCL-2-associated agonist of cell death (BAD) were higher in the LIM group than in the NC group, whereas the expression level of B-cell lymphoma 2 (BCL-2) was decreased after 2 weeks of experimental myopia. However, the trend of RASA1, BAD, and BCL-2 expression was reversed after 4 weeks of experimental myopia compared with levels after 2 weeks of experimental myopia.

Conclusions

Results showed that the RASA1 signaling pathway is activated in choroid tissues in myopic guinea pigs. Activated RASA1 signaling induces high BAD expression and low BCL-2 expression, which in turn promotes apoptosis and ultimately causes ChT thinning in myopic guinea pigs.

Peripapillary and Macular Choroidal Vascularity Index in Eyes with Fuchs' Uveitis

BACKGROUND

To investigate the choroidal vascularity alterations of macula and peripapillary area in eyes with unilateral Fuchs uveitis (FU).

METHODS

This study included 18 eyes with unilateral FU and 18 healthy fellow eyes. The choroidal vascularity index (CVI) was analyzed, and the results were compared between eyes with FU and healthy fellow eyes (control group).

RESULTS

The mean subfoveal (s)CVI (%) value was significantly lower in the FU group as compared with the control group: 60.92 ± 2.63 vs. 64.01 ± 2.54, respectively (p = .001). The mean pCVI (%) values of superior and inferior quadrant were significantly lower in the Fuchs group as compared with the control group:58.87 ± 4.48 vs. 61.98 ± 3.32, respectively, in superior quadrant (p = .035); and 57.29 ± 6.65 vs. 61.44 ± 4.76, respectively, in inferior quadrant (p = .014).

CONCLUSION

The chronic continuous inflammation in FU causes inflammation-mediated thinning in the vascular area of the subfoveal and peripapillary choroid. The changes in the peripapillary region are remarkable in terms of the further glaucoma risk of these eyes.

The Essential Role of the Choriocapillaris in Vision: Novel Insights from Imaging and Molecular Biology

The choriocapillaris, a dense capillary network located at the posterior pole of the eye, is essential for supporting normal vision, supplying nutrients, and removing waste products from photoreceptor cells and the retinal pigment epithelium. The anatomical location, heterogeneity, and homeostatic interactions with surrounding cell types make the choroid complex to study both in vivo and in vitro. Recent advances in single-cell RNA sequencing, in vivo imaging, and in vitro cell modeling are vastly improving our knowledge of the choroid and its role in normal health and in age-related macular degeneration (AMD). Histologically, loss of endothelial cells (ECs) of the choriocapillaris occurs early in AMD concomitant with elevated formation of the membrane attack complex of complement. Advanced imaging has allowed us to visualize early choroidal blood flow changes in AMD in living patients, supporting histological findings of loss of choroidal ECs. Single-cell RNA sequencing is being used to characterize choroidal cell types transcriptionally and discover their altered patterns of gene expression in aging and disease. Advances in induced pluripotent stem cell protocols and 3D cultures will allow us to closely mimic the in vivo microenvironment of the choroid in vitro to better understand the mechanism leading to choriocapillaris loss in AMD.

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.

Evaluation of the choroidal vascularity index after subthreshold yellow laser treatment in the patients with chronic central serous chorioretinopathy

PURPOSE

To assess the choroidal vascularity index (CVI) after subthreshold laser treatment in patients with central serous chorioretinopathy (CSC).

METHOD

A total of 32 eyes with CSC were included in this study. In group 1, 14 eyes with persistent CSC were treated with the PASCAL (Endpoint Management Software) at 577-nm wavelength and in group 2, 18 eyes without treatment. The luminal area (LA), stromal area (SA), total area of choroid (TA), and CVI were measured by binarization (ImageJ) of optical coherence tomography images. Changes of choroidal structure parameters were evaluated over 3 months.

RESULT

A significant decrease was observed in LA, TA, and CVI at the third month after the laser treatment (p = 0.018, p = 0.024, p = 0.046). The best-corrected visual acuity (BCVA) and choriocapillaris plexus (CCP) flow area values were increased after treatment in group 1 (p < 0.001, p = 0.002). The final subfoveal fluid height, and CVI were lower in group 1 (p = 0.003, p = 0.011). The visual acuity and CCP flow area were higher in group 1 at the third month (p < 0.001, p = 0.003). A positive correlation between the final BCVA and CVI was observed (r = 0.539, p = 0.01).

DISCUSSION

Decreased CVI was observed in CSC eyes after subthreshold yellow laser treatment. The CVI may be a useful index to evaluate the response to treatment.

Imaging-based Assessment of Choriocapillaris: A Comprehensive Review

PURPOSE

Over the past two decades, advancements in imaging modalities have significantly evolved the diagnosis and management of retinal diseases. Through these novel platforms, we have developed a deeper understanding of the anatomy of the choroidal vasculature and the choriocapillaris. The recently developed tools such as optical coherence tomography (OCT) and OCT angiography (OCTA) have helped elucidate the pathological mechanisms of several posterior segment diseases. In this review, we have explained the anatomy of the choriocapillaris and its close relationship to the outer retina and retinal pigment epithelium.

METHODS

A comprehensive search of medical literature was performed through the Medline/PubMed database using search terms: choriocapillaris, choroid, quantification, biomarkers, diabetic retinopathy, age-related macular degeneration, choroidal blood flow, mean blur rate, flow deficit, optical coherence tomography, optical coherence tomography angiography, fluorescein angiography, indocyanine green angiography, OCTA, Doppler imaging, uveitis, choroiditis, white dot syndrome, tubercular serpiginous-like choroiditis, choroidal granuloma, pachychoroid, toxoplasmosis, central serous chorioretinopathy, multifocal choroiditis, choroidal neovascularization, choroidal thickness, choroidal vascularity index, choroidal vascular density, and choroidal blood supply. The search terms were used either independently or combined with choriocapillaris/choroid.

RESULTS

The imaging techniques which are used to qualitatively and quantitatively analyze choriocapillaris are described. The pathological alterations in the choriocapillaris in an array of conditions such as diabetes mellitus, age-related macular degeneration, pachychoroid spectrum of diseases, and inflammatory disorders have been comprehensively reviewed. The future directions in the study of choriocapillaris have also been discussed.

CONCLUSION

The development of imaging tools such as OCT and OCTA has dramatically improved the assessment of choriocapillaris in health and disease. The choriocapillaris can be delineated from the stromal choroid using the OCT and quantified by manual or automated methods. However, these techniques have inherent limitations due to the lack of an anatomical distinction between the choriocapillaris and the stromal choroid, which can be overcome with the use of predefined segmentation slabs on OCT and OCTA. These segmentation slabs help in standardizing the choriocapillaris imaging and obtain repeatable measurements in various conditions such as diabetic retinopathy, age-related macular degeneration, pachychoroid spectrum, and ocular inflammations. Additionally, Doppler imaging has also been effectively used to evaluate the choroidal blood flow and quantifying the choriocapillaris and establishing its role in the pathogenesis of various retinochoroidal diseases. As tremendous technological advancements such as wide-field and ultra-wide field imaging take place, there will be a significant improvement in the ease and accuracy of quantifying the choriocapillaris.

Correlation between Choroidal Vascularity Index and Outer Retina in Patients with Diabetic Retinopathy

The choroid supplies blood to the outer retina. We quantified outer retinal and choroidal parameters to understand better the pathogenesis of diabetic retinopathy (DR) and diabetic macular edema (DME). The retrospective cross-sectional single-center study included 210 eyes from 139 diabetic patients and 76 eyes from 52 healthy controls. Spectral-domain optical coherence tomography (OCT) was carried out with a Spectralis HRA + OCT imaging device. The outer retinal layer (ORL), outer nuclear layer (ONL), and choroidal thicknesses were assessed along with the choroidal vascularity index (CVI). The presence of DR, whether with DME or without, was associated with choroidal thinning (p < 0.001). Compared with the controls, patients with DR without DME presented with lower ORL and ONL thickness (p < 0.001), whereas those with DR and DME had higher values of both parameters (p < 0.001). Significant correlations between outer retinal and choroidal parameters were found only in patients with DR without DME (ORL with choroidal thickness: p = 0.003, rho = 0.34; ORL with CVI: p < 0.001, rho = 0.49, ONL with CVI: p < 0.027, rho = 0.25). No correlations between choroidal and outer retinal parameters were observed in the controls and patients with DR and concomitant DME. Aside from diabetic choroidopathy, other pathogenic mechanisms seem to predominate in the latter group.

The status of the choroid in patients with optic disc drusen

PURPOSE

To investigate the subfoveal and peripapillary choroidal thickness (CT) and the choroidal vascularity index (CVI) in patients with optic disc drusen (ODD).

METHODS

This cross-sectional study examined the eyes of 17 patients with ODD and 18 healthy control subjects. The CT values were calculated manually from the images captured by enhanced depth imaging-optical coherence tomography (EDI-OCT). The CVI was defined as the proportion of the vascular area to the total choroidal area at the subfoveal and peripapillary areas after binarization of the EDI-OCT images.

RESULTS

It was found that the mean subfoveal CVI value in the ODD group was significantly lower than that in the control group (p = 0.006). The mean peripapillary CVI values were significantly lower in all of the quadrants in the ODD group when compared with the control group (p = 0.008 for the temporal quadrant, p = 0.014 for the nasal quadrant, p = 0.024 for the superior quadrant, and p = 0.038 for the inferior quadrant). Regarding the CT, there were no significant differences in the subfoveal and peripapillary CT values between the ODD group and the control group (p >  0.05 for all values).

CONCLUSION

The findings of this study indicate ODD to be associated with decreased subfoveal and peripapillary CVI, even though the subfoveal and peripapillary CT values were within the normal range. This result may prove important in relation to identifying a choroidal vascular network that appears to be morphologically normal but microstructurally impaired due to ODD. Further studies are required to verify the significance of CVI in the pathogenesis and complications of ODD.

Retinal magnification factors at the fixation locus derived from schematic eyes with four individualized surfaces

Retinal magnification factors (RMFs) allow the conversion of angles to lengths in retinal images. In this work, we propose paraxial and non-paraxial RMF calculation methods that incorporate the individual topography and separation of the anterior and posterior surfaces of the cornea and crystalline lens, assuming homogeneous ocular media. Across 34 eyes, the two RMF methods differ by 0.1% on average, due to surface tilt, decenter, and lack of rotational symmetry in the non-paraxial modeling, which results in up to 2.2% RMF variation with retinal meridian. Differences with widely used individualized RMF calculation methods are smallest for eyes with ∼24 mm axial length, and as large as 7.5% in a 29.7 mm long eye (15D myope). To better model the capture of retinal images, we propose the tracing of chief rays, instead of the scaling of posterior nodal or principal distances often used in RMF definitions. We also report that RMF scale change is approximately proportional to both refractive error and axial separation between the ophthalmoscope's exit pupil and the eye's entrance pupil, resulting in RMF changes as large as 13% for a 1cm displacement in a 15D myopic eye. Our biometry data shows weak correlation and statistical significance between surface radii and refractive error, as well as axial length, whether considering all eyes in the study, or just the high myopes, defined as those with refractive error sphere equivalent ≤ -4D. In contrast, vitreous thicknesses show a strong correlation (r ≤ -0.92) and significance (p ≤ 10-13) with refractive error when considering all eyes or just high myopes (r ≤ -0.95; p ≤ 10-5). We also found that potential RMF change with depth of cycloplegia and/or residual accommodation is smaller than 0.2%. Finally, we propose the reporting of individual ocular biometry data and a detailed RMF calculation method description in scientific publications to facilitate the comparison of retinal imaging biomarker data across studies.

Volumetric quantification of choroid and Haller's sublayer using OCT scans: An accurate and unified approach based on stratified smoothing

BACKGROUND AND OBJECTIVE

The choroid, a dense vascular structure in the posterior segment of the eye, maintains the health of the retina by supplying oxygen and nutrients, and assumes clinical significance in screening ocular diseases including age-related macular degeneration (AMD) and central serous chorioretinopathy (CSCR). As a technological assist, algorithmic estimation of choroidal biomarkers has been suggested based on sectional (B-scan) optical coherence tomography (OCT) images. However, most such 2D estimation techniques are compute-intensive, yet enjoy limited accuracy and have only been validated on OCT image datasets of healthy eyes. Not surprisingly, fine-scale analyses, including those involving Haller's sublayer, remain relatively rare and unsophisticated. Against this backdrop, we propose an efficient algorithm to quantify desired biomarkers with improved accuracy based on volume OCT scans. Specifically, we attempted an accurate, computationally light volumetric segmentation method involving stratified smoothing to detect choroid and Haller's sublayer.

METHODS

For detecting the various boundaries of the choroid and the Haller's sublayer, we propose a common volumetric method that performs suitable exponential enhancement and maintains smooth spatial continuity across 2D B-scans. Further, we achieve suitable volumetric smoothing by primarily deploying light-duty linear regression, and sparingly using compute-intensive tensor voting, and hence significantly reduce overall complexity. The proposed methodology is tested on five health and five diseased OCT volumes considering various metrics including volumetric Dice coefficient and corresponding quotient measures to facilitate comparison vis-à-vis intra-observer repeatability.

RESULTS

On five healthy and five diseased OCT volumes, respectively, the proposed method for choroid segmentation recorded volumetric Dice coefficients of 93.53 % and 93.30 %, which closely approximate the respective reference observer repeatability values of 95.60 % and 95.49 %. In terms of related quotient measures, our method achieved more than 50 % improvement over a recently reported method. In detecting Haller's sublayer as well, our algorithm records statistical performance closely matching that of reference manual method.

CONCLUSION

Advancing the state-of-the-art, the proposed volumetric segmentation, tested on both healthy and diseased datasets, demonstrated close match with the manual reference. Our method assumes significance in accurate screening of chorioretinal diseases including AMD, CSCR and pachychoroid. Further, it enables generating accurate training data for developing deep learning models for improved detection of choroid and Haller's sublayer.

Optical Coherence Tomography Imaging: Advances in Ophthalmology

Since its advent in 1991, optical coherence tomography (OCT) has become the most commonly used imaging modality in vitreo-retina practice [...].

[Features of structural and microvascular changes of the choroid in angioretinopathy of various etiologies]

PURPOSE

To study structural and microvascular changes in the choroid in patients with chronic kidney disease (CKD), diabetic retinopathy (DR) and arterial hypertension (AH), and their relationship with the level of renal function, carbohydrate metabolism and blood pressure.

MATERIAL AND METHODS

The study involved 172 patients (325 eyes): 56 patients with CKD (109 eyes); 66 patients with DR (121 eyes); 50 patients with AH (95 eyes). All patients underwent comprehensive ophthalmological examination including visometry, biomicroscopy, ophthalmoscopy, optical coherence tomography (OCT) and OCT angiography.

RESULTS

In patients with DR and CKD, a decrease in the thickness of the ganglion cell complex and the inner plexiform layer (GCL+IPL) was noted: in proliferative DR (PDR) - 62.45±4.25 µm, in stage 4-5 CKD - 75.23±6.43 µm; a decrease in choroidal thickness (CT) of minimal values in stage 4-5 CKD (179.9±37.72 µm) and PDR (211.0±40.7 µm). The decrease in choroidal vascularity index (CVI) depended on the stage of CKD and PDR (in PDR - 63.47±1.37, in stage 4-5 CKD - 65.93±2.01). Maximum decrease in perfusion density and vascular density was found in patients with DR (37.22±9.00% and 15.11±3.39 mm, respectively). An increase in the area, perimeter of the foveolar avascular zone (FAZ), and a decrease in the circularity index were noted in all groups, with most pronounced changes in PDR and stage 4-5 CKD. Patients with CKD were found to have strong correlations of CT and CVI with creatinine, urea, proteinuria and glomerular filtration rate (GFR). Patients with diabetes mellitus and PDR were revealed to have strong relations of CT, CVI, GCL+IPL, the area and perimeter of FAZ with creatinine levels and the duration of diabetes mellitus.

CONCLUSION

Choroidal thickness and choroidal vascularity index are important diagnostic markers of disorders of chorioretinal microcirculation that allow stratifying individual assessment of risk factors for progression of both chronic kidney disease and diabetic retinopathy.

Choroidal involvement in systemic vasculitis: a systematic review

Systemic vasculitides are a large group of heterogeneous diseases characterized by inflammatory destruction of blood vessels targeting diverse organs and tissues including the eye. As the most vascularized layer of the eye, the choroid is expected to be affected in multiple systemic rheumatologic diseases with vascular involvement. While there are plenty of studies investigating retinal vascular involvement, choroidal vascular involvement in systemic vasculitides has not been investigated in isolation. However, choroidal manifestations including thickness changes, choroidal vasculitis and ischemia may be the earliest diagnostic features of systemic vasculitic diseases. Thus, multimodal imaging of the choroid may help early detection of choroidal involvement which may also have prognostic implications in these life-threatening diseases. This article aimed to review involvement of the choroid in systemic vasculitic diseases.

Mechanisms, Pathophysiology and Current Immunomodulatory/Immunosuppressive Therapy of Non-Infectious and/or Immune-Mediated Choroiditis

Non-infectious choroiditis comprises immune-mediated diseases resulting from diverse pathophysiological mechanisms. These conditions are sub-divided into two main groups, (1) diseases of the choriocapillaris and (2) diseases of the choroidal stroma. The purpose of this study is to expose the pathophysiology of the most common diseases of both these groups and recommend the optimal immunomodulatory/immunosuppressive therapy of each analyzed condition based on literature data and data from our own centers. Material and Methods: Narrative review. In the group of choriocapillaritis entities or primary inflammatory choriocapillaropathies (PICCPs) including multiple evanescent white dot syndrome (MEWDS), acute posterior multifocal placoid pigment epitheliopathy (APMPPE), idiopathic multifocal choroiditis (MFC) and serpiginous choroiditis (SC), as well as secondary choriocapillaritides including acute syphilitic posterior multifocal placoid chorioretinitis (ASPMPC) and tuberculosis-related SC (TB-SC), were analyzed. In the group of stromal choroidites, HLA-A29 birdshot retinochoroiditis (BRC) and Vogt-Koyanagi-Harada (VKH) disease were included. For each entity a literature search, in the PubMed database, on treatment was performed and analyzed and the therapeutic attitudes of our own centers were presented. Management of immune-mediated choroiditis implies vigorous immunosuppressive therapy given in a prompt and prolonged fashion in most of these entities.

Evaluation of choroidal melanin-containing tissue in healthy Japanese subjects by polarization-sensitive optical coherence tomography

In this study, the choroidal melanin content in healthy eyes was evaluated with polarization-sensitive optical coherence tomography (PS-OCT). We evaluated 105 healthy eyes of 105 Japanese subjects. The mean thickness of melanin-containing tissue in the choroid (thickness of MeCh) and the choroidal melanin occupancy rate within a 5-mm circular region from the foveal center were calculated using the degree of polarization uniformity obtained by PS-OCT and compared with the choroidal thickness, patient age, and axial length. To evaluate regional variations, the 5-mm circular region was divided into a center area and an outer ring area, and the outer ring area was further divided into four areas (nasal, temporal, superior, and inferior). The mean thickness of MeCh showed a significant positive correlation with the choroidal thickness. The mean choroidal melanin occupancy rate showed a significant positive correlation with age. The mean choroidal melanin occupancy rate of the center area was significantly larger than that of the outer ring area. The mean thickness of MeCh and choroidal melanin occupancy rate of the nasal area were significantly lower than those of other areas. The distribution of melanin-containing tissue in the choroid varies significantly with age and location.

Choroidal Vascularity Index Assessment: A Potential Noninvasive Technique for Diagnosing Diabetic Nephropathy

Aims

This study aimed to compare the accuracy of the choroidal vascularity index (CVI) and diabetic retinopathy (DR) in the diagnosis of diabetic nephropathy (DN).

Methods

We performed a cross-sectional study of 117 patients with proteinuria and diabetes mellitus (DM) in which 45 patients were diagnosed with DN by renal pathology. Demographic information, clinical features, and laboratory data were collected. A total of 234 eyes underwent evaluation of DR and the CVI using enhanced depth imaging-optical coherence tomography scans. We analyzed the association between the CVI and DN and compared the CVI and DR for diagnosing DN using area under receiver operating characteristic curves (AUROCs).

Results

The severe nonproliferative DR and proliferative DR groups showed a lower CVI than the no DR and mild/moderate nonproliferative DR groups (P < 0.01 or P < 0.001). There was a significantly lower CVI in patients with DN stage III (63.01% ± 1.47%) compared with those in DN stages IIa (62.1% ± 1.41%, P < 0.001) and IIb (59.85% ± 1.98%, P < 0.01). The sensitivity and specificity of the CVI for diagnosing DN were 84% (71%–94%) and 95% (88%–99%), respectively, which were preferable to those of DR. The AUROCs for the CVI and DR for diagnosing DN were 0.932 and 0.831, respectively. The CVI outperformed DR for diagnosing DN (P < 0.05). The cutoff value of the CVI was 63.13%.

Conclusion

The CVI might be a reliable noninvasive technique for predicting the pathological stage of DN and is superior to DR in diagnosing DN.

Factors Associated with Macular Staphyloma Area on Ultra-widefield Fundus Images

Purpose

To assess the feasibility of applying ultra-widefield fundus (UWF) images for macular staphyloma area (MSA) measurement and investigate the associated factors with MSA.

Methods

This is a retrospective study. MSA was measured by UWF imaging. Central foveal thickness, subfoveal choroidal thickness, subfoveal scleral thickness were measured on spectral domain optical coherence tomography. Intraclass correlation coefficients of MSA measurement would be evaluated. Multiple linear regression analysis was used to analyze the associated factors with MSA.

Results

In total, 135 eyes of 92 patients were enrolled. The mean age was 64.73 ± 10.84 years. Mean MSA on UWF image was 279.67 ± 71.70 mm². Intraclass correlation coefficients of MSA measurement was 0.965 (95% confidence interval [CI], 0.946 to 0.977; p < 0.001). In the multiple linear regression analysis, after adjusting for subfoveal choroidal thickness, best-corrected visual acuity, central foveal thickness, and subfoveal scleral thickness, the factors independently related to MSA were axial length (β = 8.352; 95% CI, 3.306 to 13.398; p = 0.001), sex (β = −26.673; 95% CI, −51.759 to −1.586; p = 0.037), age (β = 1.184; 95% CI, 0.020 to 2.348; p = 0.046).

Conclusions

It is feasible to measure MSA on UWF image. Female, longer axial length, and older age may indicate larger MSA.

Choroidal Morphologic and Vascular Features in Patients With Myopic Choroidal Neovascularization and Different Levels of Myopia Based on Image Binarization of Optical Coherence Tomography

Purpose: To characterize the choroidal morphologic and vascular features in different levels of myopes and patients with myopic choroidal neovascularization (mCNV). Methods: A total of 148 subjects were enrolled in this cross-sectional study, including 78 low-to-moderate myopes (LMM), 53 high myopes (HM), and 17 high myopic patients with mCNV. Ocular biometrics were measured using an optical low-coherence reflectometry device. Retinal and choroidal imaging was performed using enhanced depth imaging (EDI) spectral domain optical coherence tomography (OCT). Retinal parameters including retinal thickness and retinal volume were obtained from a built-in software. Binarization technique was adopted to investigate choroidal parameters including choroidal thickness (CT), vascular area, stromal area, and choroidal vascularity index (CVI). Choroidal parameters were measured at five locations to cover as much area of choroid as possible, and their patterns of distribution were further analyzed. Results: Patients with mCNV had an atrophic retina of comparable thickness to HM (273.65 ± 17.28 vs. 276.49 ± 13.29 μm, p = 0.47), but the choroid was thinner than that of HM (153.94 ± 15.12 vs. 236.09 ± 38.51 μm, p < 0.001). Subfoveal CVI was greatest in the mCNV eyes (0.651 ± 0.009), followed by HM (0.645 ± 0.012) and LMM eyes (0.636 ± 0.012). Similar to CT, CVI was also found significantly different among these three groups at all five locations (p for trend < 0.001 for all locations). Axial length (AL) was negatively correlated with retinal volume (r = -0.236, p = 0.009), which is the only significant finding in associations between ocular factors and retinal parameters. Strong, negative correlations were identified between AL and subfoveal choroidal thickness (SFCT, r = -0.820, p < 0.001). However, AL was positively correlated with subfoveal CVI (r = 0.668, p < 0.001). CVI was greater in myopic eyes with thinner choroid (r = -0.578, p < 0.001). BCVA exhibited no significant association with CVI (r = 0.139, p = 0.092), but was negatively correlated with SFCT (r = -0.386, p < 0.001) and positively correlated with AL (r = 0.351, p < 0.001). Conclusion: Choroid in patients with mCNV was thinner yet more vascularized than that in HM and LMM subjects. CVI increased with a longer AL which was associated with a smaller SFCT, choroidal vascular area (VA), and total choroidal area (TCA). Better BCVA was achieved in subjects with thicker SFCT and shorter AL.

Choroidal Thickness Profile in Chorioretinal Diseases: Beyond the Macula

Enhanced depth imaging optical coherence tomography (EDI-OCT) and swept-source OCT (SS-OCT) have emerged as essential diagnostic tools in the study and management of various chorioretinal diseases. Evidence from early clinical studies using EDI-OCT and SS-OCT indicates that choroidal dysfunction plays a major role in the pathogenesis of chorioretinal diseases. Measurement of choroidal thickness (CT) has already become a major research and clinical method, and CT is considered as an indicator of choroidal status in a variety of ophthalmic diseases. Recently, CT measurement has also been proposed as a non-invasive marker for the early detection and monitoring of various systemic diseases. Among the several possible CT measurement locations, subfoveal CT has rapidly become a reliable parameter for measuring CT in healthy and diseased eyes. Moreover, recent advancements in OCT technology have enabled faster and wider imaging of the posterior part of the eye, allowing the various changes in CT as measured outside the macula to be shown accordingly. In this review, we first provide an overview of the results of clinical studies that have analyzed the healthy macular choroid and that in various chorioretinal diseases, and then summarize the current understanding of the choroid outside the macula. We also examine the CT profile as an index that encompasses both within and outside of the macula. Furthermore, we describe the clinical applications of ultrawide OCT, which enables visualization of the far periphery, and discuss the prospects for the development of more reliable choroidal parameters that can better reflect the choroid's characteristics.

Choroidal vascularity index changes during the Valsalva manoeuvre in healthy volunteers

PURPOSE

To evaluate the effects of the Valsalva manoeuvre (VM) on the choroidal vascularity index (CVI) in healthy volunteers.

METHODS

This prospective, cross-sectional study included 60 eyes of 30 healthy volunteers. Enhanced depth imaging-optical coherence tomography scans of both eyes involving the fovea were taken, and a 1500 μm subfoveal choroidal area was selected for image binarization with open-access Fiji software. The binarized image was segmented into the stromal area (SA) and luminal area (LA), and CVI was calculated as the ratio (%) of LA to the total choroidal area (TCA). CVI, subfoveal choroidal thickness (SFCT), IOP, systolic and diastolic blood pressure were evaluated at rest and during the VM.

RESULTS

During the VM, a mean ± standard deviation increase in LA (0.02 ± 0.05 mm² , p < 0.001) and CVI (1.72 ± 2.83%, p < 0.001) was observed, whereas SA (-0.02 ± 0.05 mm² , p < 0.001) decreased. There was no significant change in TCA (0.00 ± 0.03 mm² , p = 0.55) or SFCT (1.05 ± 10.92 μm, p = 0.46). There was a moderate positive correlation between the spherical equivalent refractive error (SE) and SFCT both at rest and during VM (r₅₈  = 0.49, p < 0.0005 and r₅₈  = 0.49, p < 0.0005, respectively). However, there was no significant correlation between SE and CVI either at rest or during VM (p = 0.11 and 0.06, respectively). In a multiple linear regression analysis, CVI was only associated with SFCT; however, SFCT was also associated with SE, both at rest and during VM (p < 0.001).

CONCLUSION

Valsalva manoeuvre increases CVI by choroidal vascular dilation as demonstrated by an increase in LA and a decrease in SA. Researchers should be careful about unintentional VM during examinations.

Changes in Choroidal Vascularity Index (CVI) in Intermediate Uveitis

Purpose

To investigate the longitudinal changes in choroidal vascularity index (CVI) in eyes with active and quiescent intermediate uveitis using enhanced depth imaging optical coherence tomography (EDI-OCT).

Methods

EDI-OCT images of eyes with active and quiescent intermediate uveitis were retrospectively reviewed and binarized using ImageJ software. Choroidal parameters including CVI, total choroidal area (TCA), luminal area (LA), stromal area (SA), and subfoveal choroidal thickness (SCT) were measured and compared between baseline and follow-up visits among eyes with active and quiescent intermediate uveitis.

Results

Thirty-eight eyes from 21 patients with active intermediate uveitis and 30 eyes from 17 patients with quiescent intermediate uveitis were included. CVI in eyes with active intermediate uveitis significantly increased from baseline (66.50% ± 3.40%) with resolution of inflammation on follow-up (68.82% ± 3.90%; P < 0.001). In eyes with quiescent intermediate uveitis at baseline eyes, CVI did not significantly change after follow-up (66.34% ± 3.19% to 66.25% ± 3.13%; P = 0.850).

Conclusions

CVI significantly increased when active inflammation in intermediate uveitis resolved while CVI remained unchanged at follow-up in quiescent intermediate uveitis.

Translational Relevance

CVI may be a useful noninvasive tool to monitor treatment response in intermediate uveitis. Our findings also highlight the involvement of choroidal vasculature in uveitic eyes without any clinical evidence of choroiditis.

Comparison of choroidal structural changes between children born preterm without retinopathy of prematurity and age-matched children born at full term

AIM

To evaluate the effect of prematurity on choroidal structure in children born preterm with no history of retinopathy of prematurity (ROP) by comparing them with age-matched healthy children born at full term.

METHODS

Enhanced depth imaging optical coherence tomography (EDI-OCT) scans of children aged 5 to 9 years with a history of prematurity but no history of ROP, and age-matched full-term healthy children were evaluated, retrospectively. Choroidal thicknesses (CTs) were measured at subfoveal (SFCT), 1000 µm temporal and nasal from the fovea (T1, N1), and 2000 µm temporal and nasal (T2, N2) from the fovea. The EDI-OCT images were binarized to stromal (SA) and luminal areas (LA) using the ImageJ software. The choroidal vascularity index (CVI) was calculated by dividing LA by the total choroidal area (TCA).

RESULTS

Twenty-nine eyes of 15 preterm children and 41 eyes of 26 full-term children were included. Demographic characteristics including axial length (AL), eye side, age, and the sex of the children in the groups were similar (p>0.05). There was no statistically significant difference in the mean CVI, SFCT, N1, and T1 values between the groups (p>0.05); however, the mean T2 and N2 values were significantly higher in the full-term group than in the preterm group (p<0.05). There was a significant positive correlation between the birth week and the T1 (p<0.05) CONCLUSION: : Prematurity can affect CT even with no history of ROP. The decreases in CTs were significant at 2000 µm nasal and temporal from the fovea. The impairment of temporal choroidal region was more evident than nasal choroidal region. The mean CVI values were similar between the groups.

Automated Analysis of Choroidal Sublayer Morphologic Features in Myopic Children Using EDI-OCT by Deep Learning

Purpose

The purpose of this study was to analyze the choroidal sublayer morphologic features in emmetropic and myopic children using an automatic segmentation model, and to explore the relationship between choroidal sublayers and spherical equivalent refraction (SER).

Methods

We collected data on 92 healthy children (92 eyes) from the Ophthalmology Department of Peking University First Hospital. The data were allocated to three groups: emmetropia (+0.50 diopters [D] to -0.50 D), low myopia (-0.75 D to -3.00 D), and moderate myopia (-3.25 D to -5.75 D). We performed standardized optical coherence tomography (OCT) and developed a new segmentation technique to measure choroidal thickness (CT), large-vessel choroidal layer (LVCL), medium-vessel choroidal layer (MVCL), and small-vessel choroidal layer thickness (SVCL), and evaluated the choroidal vascular system (choroidal vascular volume [VV], choroidal vascular index [CVI], and choroidal vascular density [CVD]).

Results

All choroidal sublayers (LVCL, MVCL, and SVCL) were significantly thinner in myopic than in emmetropic eyes (P < 0.05), the thinnest choroidal region being the nasal outer subfield (P < 0.05). In all choroidal regions of SVCL, a positive correlation was found between SER and thickness ratio (P < 0.001). In most subfields of MVCL, a similar correlation was found (P < 0.050), the exceptions being the two nasal subfields (0.050 < P < 0.300). In contrast, the thickness ratio of LVCL decreased in all subfields (P < 0.050). VV correlated with SER negatively in LVCL in all subfields (all P < 0.001) and most subfields in MVCL except for two temporal subfields (0.050 < P < 0.200). However, no significant correlations were found between CVI and SER in LVCL (P > 0.050) and MVCL (with the exception being the temporal inner subfield, P = 0.011).

Conclusions

Thickness of choroidal sublayers was reduced with higher myopic SER, whereas changes in thickness ratio varied between sublayers. No significant correlations between CVI and SER suggested that both choroidal stromal and vascular volume decreases proportionately.

Translational Relevance

Automatic segmentation model will be helpful for future clinical trials to quantify choroidal sublayer morphologic features in myopia.

Swept-source optical coherence tomography objective composite activity score for uveitis

PURPOSE

To develop an objective intraocular inflammation composite score.

METHODS

Cross-sectional study. Non-invasive image acquisition and processing were conducted from April 2017 to April 2019. Inflammation-grade stratified eyes from patients with active, inactive uveitis and healthy controls were recruited. After clinical assessment, four anterior and posterior segment image acquisition protocols per eye, using swept-source optical coherence tomography (SS-OCT), were performed at inclusion. Eight imaging biomarkers in three domains: anterior, intermediate and posterior were studied. They were ranked and selected by discriminatory power and correlation with clinical scores. A final SS-OCT-derived composite uveitis activity score (SS-UAS) was developed through multiple linear regression.

RESULTS

We studied 224 eyes with uveitis (165 active and 59 inactive) from 165 patients (mean age 46.6 SD 15.5 years; 55.3% women) and 38 eyes from 19 healthy controls (mean age 43.6 SD 17.1; 47% women). The selected SS-OCT-derived biomarkers to build the final score were anterior chamber hyper-reflective dots (anterior), high-definition relative vitreous intensity (intermediate) and the averaged thickened retinal index (posterior). Swept-source (SS)-UAS was highly discriminant between active and inactive, and between active and healthy eyes (means 2.06 SD 1.86, 0.93 SD 0.44, and 0.96 SD 0.38, respectively, both p -, Mann-Whitney U). Construct validity (Cronbach's alpha = 0.7), internal consistency, criterion validity and reliability (concordance correlation coefficient intra-rater = 0.99, 95% CI: 0.98-0.99; inter-rater = 0.98, 95% CI: 0.96-0.99) were favourable.

CONCLUSIONS

Global intraocular inflammation can potentially be staged and scored objectively, continuously, consistently and in a valid manner through the combined processing of SS-OCT scans.

Choroidal thickness in relation to urinary albumin excretion rate in type 2 diabetes mellitus without retinopathy

Background

To evaluate choroidal thickness (CT) in diabetic patients without diabetic retinopathy (DR) in relation to the urinary albumin excretion rate (UAER).

Methods

This is a prospective case-control study that included a consecutive sample of 120 patients with type 2 diabetes without clinically evident DR and a group of 60 matched healthy controls. Diabetic patients were included in two groups according to their UAER (normoalbuminuria and microalbuminuria). Complete ophthalmological examination was performed followed by optical coherence tomography (SD-OCT) for retinal and choroidal assessment. Twenty-four-hour urine samples were collected for UAER and blood samples for HbA1c and serum creatinine were obtained.

Results

The study included 180 eyes from 180 subjects in three groups. Patients with higher levels of albuminuria had a thinner choroid than normal controls, with decremental thinning as albuminuria progressed. Diabetics with normoalbuminuria showed no significant differences from controls. Choroidal thickness showed a significant moderate negative correlation with UAER (r  =  − 0.58, p  <  0.001). Multiple regression analyses for diabetic patients with microalbuminuria demonstrated that UAER is the most important determinant of subfoveal choroidal thickness (SFCT) (p  <  0.001).

Conclusions

Decreased CT was significantly correlated with UAER in diabetic patients without retinopathy and otherwise normal kidney functions. This decrease in thickness might be a predictor of DR.

Comparison of the choroidal structural components and choroidal vascularity index between patients with obstructive sleep apnea syndrome and healthy controls

AIM

To compare the choroidal structural components and choroidal vascularity index (CVI) between patients with obstructive sleep apnea syndrome (OSAS) and healthy controls.

METHODS

The choroidal images of the eyes of patients with OSAS and healthy controls, which were obtained by using enhanced depth imaging optical coherence tomography (EDI-OCT), were binarized into luminal area (LA) and stromal area (SA) using the ImageJ software. CVI was calculated as the ratio of LA to the total choroid area (TCA). The CVI, LA, SA, and TCA measurements were compared between the groups.

RESULTS

Seventy-one eyes of 57 patients, 33 eyes of 27 patients with OSAS and 38 eyes of 30 healthy individuals, were included. The mean age of all patients was 46.77±9.75 (range, 30-67) years. There was no statistically significant difference for age, sex, axial length (AL) or the side of the eyes between the groups (p>0.05). The mean body mass index (BMI) of the patients was significantly higher in the OSAS group (p<0.05). The mean CVI value was 68.33±1.81% in the OSAS group and 69.21±1.27% in the control group (p<0.05). There was no statistically significant difference for the mean values of LA, SA, and TCA between the groups (p>0.05). No significant correlation was found between the polysomnography test results and the choroidal measurements (p>0.05).

CONCLUSION

In our study, CVI was found to be lower in patients with OSAS than in the healthy controls. Further studies with larger sample sizes are required to evaluate the role of CVI in OSAS.