Quantitative Analysis of the Choriocapillaris in Uveitis Using En Face Swept-Source Optical Coherence Tomography Angiography

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.

Choroidal and retinal vascular changes in HLA-B27-associated anterior uveitis

PURPOSE

To quantitatively analyze choroidal and retinal vascular changes in HLA-B27-associated anterior uveitis.

STUDY DESIGN

A retrospective study.

METHODS

Medical records of 51 eyes with unilateral HLA-B27-associated anterior uveitis, their fellow eyes and 47 sex and age-matched healthy eyes were retrospectively reviewed. Their choroidal and retinal vasculature were analyzed using swept-source (SS) optical coherence tomography (OCT) and OCT angiography (OCTA) scans.

RESULTS

Deep capillary plexus (DCP) vessel density (VD) (p < 0.001), choroidal vascularity index (CVI) (p = 0.012), and choriocapillary flow deficit (CCFD) (p < 0.001) of uveitic and fellow eye group were significantly higher than those of control group. On the contrary, superficial capillary plexus (SCP) VD (p < 0.001) of uveitic and fellow eye group were significantly lower than of control group. The vascular parameters of uveitis and fellow eye group showed no significant difference between uveitic and resolution period.

CONCLUSION

Certain choroidal and retinal vascular parameters were significantly changed in both HLA-B27-associated anterior uveitis without posterior segment involvement and the quiet fellow eyes, suggesting their possible effects as a systemic inflammatory disorder.

Assessment of choriocapillaris and choroidal vascular changes in posterior uveitis using swept-source wide-field optical coherence tomography angiography

PURPOSE

To evaluate choriocapillaris (CC) and choroidal vascular changes in patients with posterior uveitis using swept-source (SS) wide-field optical coherence tomography angiography (OCTA).

METHOD

Consecutive patients with posterior uveitis were evaluated using 3×3 mm and 12×12 mm OCTA scan patterns and montage images of 5×12×12 mm or 2×15×9 mm, covering approximately 70°-90° of the retina. The images were quantitatively and qualitatively analysed and compared with healthy controls.

RESULTS

Eighty-six eyes of 56 patients with posterior uveitis (mean age 45.2±19.9 years; 58.9% female), and 38 eyes of 19 age-matched healthy controls (57.9% female) were included. The mean perfusion density (PD) in 3×3 mm and 12×12 mm CC scans was significantly lower in eyes with posterior uveitis compared with those of healthy controls. However, no significant difference in the mean PD of choroidal scans was found comparing eyes with posterior uveitis and healthy controls. The mean PD in eyes with active disease was significantly higher compared with the inactive eyes on 12×12 mm choroidal scans (55.61% vs 51.25%, p=0.02), while no difference was found in the CC slabs.

CONCLUSION

CC and choroidal assessment using OCTA provides useful information in patients with posterior uveitis. SS-OCTA metrics of the CC and choroidal slabs are promising tools in uveitis patients in the future.

TRIAL REGISTRATION NUMBER

NCT02811536.

Quantitative Analysis of the Choroidal Vascularity in Eyes with Uveitis Using Optical Coherence Tomography Angiography: A Systematic Review

PURPOSE

The purpose of this systematic review is to identify techniques used for quantification of choriocapillaris (CC) flow in eyes with uveitis using optical coherence tomography angiography (OCTA), report reliability and level of correlation with techniques such as indocyanine green angiography (ICGA).

METHODS

A systematic search of several databases was done. The studies were analyzed for techniques of measurement, reliability, and correlation with other modalities. Risk of bias assessment was performed.

RESULTS

Thirteen studies were included. CC vessel density (7 studies) and flow deficit area (4 studies) were the most used indices. There was significant heterogeneity in the studies due to differences in the scan protocol, thresholding strategy, and analysis. Comparison with ICGA was performed by only one study, and reliability indices were reported by only two studies.

CONCLUSION

OCTA is a useful tool to measure the CC vascularity in eyes with uveitis. However, standardized acquisition and analysis protocols are needed.

Rate of Retinal Nerve Fiber Layer Thinning in Glaucomatous Eyes With Optic Disc and Parapapillary Deep-Layer Microvasculature Loss

PRCIS

Microvasculature dropout in the parapapillary choroidal layer was a more important biomarker of glaucomatous nerve fiber layer thinning when it presented with deep-layer microvasculature of the optic disc rather than when it presents by itself.

PURPOSE

To characterize open angle glaucoma eyes with optic nerve head deep-layer microvasculature dropout (MvD-D) and parapapillary choroidal layer microvasculature dropout (MvD-P) and compare their retinal nerve fiber layer (RNFL) thinning rate.

MATERIAL AND METHODS

This study included 122 open angle glaucoma eyes that underwent ≥5 serial spectral-domain optical coherence tomography scans during a mean follow-up of 5.4 years. Swept-source optical coherence tomography angiography was used to evaluate MvD-P and MvD-D. Subjects were classified into 3 groups according to the presence of MvD-P and MvD-D: (1) no dropout (n=37); (2) solely MvD-P (n=40), and (3) both MvD-P and MvD-D (n=45). The RNFL thinning rate was compared among the 3 groups, and the associated factors were assessed by Cox proportional hazard analysis.

RESULTS

RNFL thinning rates were highest in the group with both MvD-P and MvD-D, followed by the group with solely MvD-P and finally by the no dropout group (-0.24 vs. -0.65 vs. -1.20 μm/y, P <0.001). Thinner central corneal thickness [hazard ratio (HR)0.990, P =0.003], presence of disc hemorrhage (HR=1.802, P =0.035), and coexistence of MvD-P and MvD-D (HR=2.941, P <0.001) were the factors associated with RNFL thinning.

CONCLUSIONS

The coexistence of MvD-P and MvD-D was associated with faster RNFL thinning than MvD-P alone or no dropout, which suggested that observing the optic disc deep microvasculature along with parapapillary choroidal layer using Swept-source optical coherence tomography angiography may be clinically relevant in monitoring glaucoma progression.

Temporal Optic Disc Microvasculature Dropout in Glaucoma

PURPOSE

To assess the clinical characteristics of focal temporal optic disc microvasculature dropout (MvD-D) in primary open-angle glaucoma (POAG) patients.

METHODS

One hundred and eighty-seven eyes of 187 POAG patients having MvD-D on Swept-Source optical coherence tomography angiography (SS-OCTA) were enrolled. Three groups were categorized according to the presence of temporal MvD-D within the upper and lower 45° of the fovea-Bruch's membrane (BM) opening axis: focal temporal MvD-D (Group 1, isolated focal temporal MvD-D; 44 eyes), supero/inferotemporal MvD-D (Group 2, MvD-D only in superotemporal or inferotemporal sector; 78 eyes), and diffuse temporal MvD-D (Group 3, MvD-D spanning ≥ 2 consecutive sectors, at least one of which being temporal sector; 65 eyes).

RESULTS

Group 1 had a significantly longer axial length and β-zone parapapillary atrophy without BM. There also was a larger horizontal tilt angle and ovality index than the other two groups (P < 0.001). Group 1 had a significantly thinner retinal nerve fiber layer (RNFL) in the temporal sector than did Group 2 (P < 0.001), despite similar thicknesses in all other areas (P > 0.05). Group 3 had significantly worse visual field mean deviation and thinner RNFL than the other two groups in all areas other than the nasal, temporal, and superotemporal sectors (P < 0.05).

CONCLUSIONS

Focal temporal MvD-D detected by SS-OCTA was associated with a longer axial length and related subsequent morphological changes of the optic disc and parapapillary area. This suggests that stretching of the optic disc consequent on axial elongation may lead to absence of temporal optic disc microvasculature.

Diagnosis, Classification, and Assessment of the Underlying Etiology of Uveitis by Artificial Intelligence: A Systematic Review

Recent years have seen the emergence and application of artificial intelligence (AI) in diagnostic decision support systems. There are approximately 80 etiologies that can underly uveitis, some very rare, and AI may lend itself to their detection. This synthesis of the literature selected articles that focused on the use of AI in determining the diagnosis, classification, and underlying etiology of uveitis. The AI-based systems demonstrated relatively good performance, with a classification accuracy of 93-99% and a sensitivity of at least 80% for identifying the two most probable etiologies underlying uveitis. However, there were limitations to the evidence. Firstly, most data were collected retrospectively with missing data. Secondly, ophthalmic, demographic, clinical, and ancillary tests were not reliably integrated into the algorithms' dataset. Thirdly, patient numbers were small, which is problematic when aiming to discriminate rare and complex diagnoses. In conclusion, the data indicate that AI has potential as a diagnostic decision support system, but clinical applicability is not yet established. Future studies and technologies need to incorporate more comprehensive clinical data and larger patient populations. In time, these should improve AI-based diagnostic tools and help clinicians diagnose, classify, and manage patients with uveitis.

OCT Angiography in Noninfectious Uveitis: A Description of Five Cases and Clinical Applications

BACKGROUND

Optical coherence tomography angiography (OCTA) is a noninvasive imaging modality used to analyze the retinochoroidal vasculature and detect vascular flow. The resulting images can be segmented to view each vascular plexus individually. While fluorescein angiography is still the gold standard for the diagnosis of posterior uveitis, it has limitations, and can be replaced by OCTA in some cases.

METHODS

This case series describes five patients with posterior noninfectious uveitis and their description by OCTA.

RESULTS

Cases included lupus retinopathy (n = 1) for which OCTA showed ischemic maculopathy as areas of flow deficit at the superficial and deep capillary plexus; choroidal granulomas (n = 1) with a non-detectable flow signal in the choroid; active punctate inner choroiditis and multifocal choroiditis (n = 1) with OCTA that showed active inflammatory chorioretinal lesions as non-detectable flow signals in choriocapillaris and choroid; dense type 2 inflammatory secondary neovascularization (n = 1) associated with active choroiditis; and acute posterior multifocal placoid pigment epitheliopathy (APMPPE) (n = 1) without flow abnormalities at the superficial and deep retinal plexuses but non-detectable flow at the levels of the choriocapillaris and choroid.

CONCLUSIONS

Ophthalmologists can use OCTA to identify inflammatory changes in retinal and choroidal vasculature, aiding in the diagnosis, management, and monitoring of posterior uveitis.

Features of hemodynamic and immunological parameters in patients with recurrent uveitis complicated by hypertension, Fuchs heterochromic uveitis and Posner-Schlossman syndrome

Introduction: Uveitis is a disease that manifests with increased vascular permeability and occlusion, with some ischemia and inflammatory mediators. It is characterized by a wide range of pathological processes, including inflammation, increased vascular permeability and occlusion, local ischemia and cell alteration by inflammatory mediators, and is characterized by the presence of complications. Aim: To study the state of ocular hemodynamics by rheoophthalmography, as well as the immune status in patients with idiopathic recurrent anterior uveitis complicated by intraocular hypertension, Fuchs heterochromic uveitis, Posner-Schlossman syndrome, during the relapse period. Materials and methods: 93 patients with idiopathic recurrent anterior uveitis were included in this study, 8 patients with Fuchs' uveitis, and 6 patients with Posner-Schlossman syndrome. According to clinical signs, relapse and remission were considered. The control group (healthy volunteers of the same age) consisted of 27 people. In this regard, 5 groups of subjects were formed. The mean age of the patients was (M ± SD) 39.2 ± 14.6 years. According to the Median (range), the duration of the disease in patients was 2033 (350-3285) days, intraocular hypertension being recorded at P0 > 20 mm Hg. Statistical analysis was carried out in spreadsheets using STATISTICA 8.0 (StatSoft.Inc) program. Quantitative indicators were evaluated according to the correspondence to the normal distribution and to the Kolmogorov-Smirnov criterion. With a normal distribution, arithmetic means (M) and standard deviations (SD), limits of the 95% confidence interval (95% CI) and Student's t-test were calculated. Results: The volumetric blood filling of the eye according to the rheoophthalmographic indicator RQ during the period of remission of uncomplicated and complicated by hypertension anterior uveitis was reduced by 32.4%-40.5%, respectively, compared with the norm. During the period of relapse, RQ was significantly higher by 28% (p<0.05) than in remission, in the group of uncomplicated uveitis, and in the group of uveitis with increased IOP, no significant differences between the periods of remission and relapse were observed, which reflected the ischemic process in the relapse period. Volumetric blood filling in Fuchs and Posner-Schlossman syndromes in the acute period did not differ from the norm. Cellular immunity in the groups of uncomplicated and complicated by intraocular hypertension idiopathic uveitis, as well as with Fuchs and Posner-Schlossman syndromes, had a higher level of CD4 helper lymphocytes and a lower level of CD8 suppressor lymphocytes, which reflected higher values of the immunoregulatory index. The increase in the immunoregulatory index is most pronounced in Fuchs and Posner-Schlossman syndromes. Discussion: In the presented study, the incidence of idiopathic recurrent anterior uveitis complicated by intraocular hypertension was 9,9% among all cases of idiopathic recurrent anterior uveitis in one-time period. According to literature, this complicated form of uveitis occurs in 11,5%-46,1% of cases. Most often (up to 92% of cases), the anterior chamber angle was open. Conclusions: Different activity of the mechanisms regulating the balance of cellular and humoral immunity, sensitivity of T-cells to eye antigens in idiopathic anterior uveitis, Fuchs and Posner-Schlossman syndromes was assumed. Peculiarities of eye hemodynamics in these forms of uveitis were also revealed. Abbreviations: IOP = intraocular pressure, IOHS = inflammatory ocular hypertension syndrome, HSV = herpes simplex virus, CMV = cytomegalovirus, OCT = optical coherence tomography, OD = right eye, OS = left eye.

Clinical and multimodal imaging characteristics of eyes with Vogt–Koyanagi–Harada disease: An Egyptian experience

BACKGROUND

Vogt-Koyanagi-Harada (VKH) disease is a vision-threatening inflammatory disorder that is challenging in diagnosis and management.

METHODS

Retrospective, record-based analysis of 54 eyes belonging to 27 adult patients that fulfilled the revised diagnostic criteria for VKH between January 2018 and January 2021. Demographic, clinical, and imaging data on presentation and during follow-up visits were collected for each patient. Available imaging studies included B-scan ultrasonography (B-scan US), spectral domain optical coherence tomography (OCT), fundus fluorescein angiography (FFA), and OCT angiography (OCT-A).

RESULTS

The female-to-male ratio was 2.38:1. Nineteen patients (70.37%) presented during an initial attack, while eight patients (29.63%) presented during recurrence. The most commonly presenting sign in the posterior segment was exudative retinal detachment (44 eyes, 81.48%). B-scan US was utilized in 4 eyes (7.41%), OCT was utilized in 48 eyes (88.89%) with the most common finding being subretinal fluid (43 eyes, 89.58%), FFA was performed in 39 eyes (72.22%) with the most common finding being punctate hyperfluorescence and late dye pooling (33 eyes, 84.62%), and OCT-A was performed in 30 eyes (55.56%), in which choriocapillaris flow deficit that correlated with disease activity was detectable in 25 eyes (83.33%). Improved visual acuity was noted in 85% of the eyes that were followed up.

CONCLUSION

Early diagnosis and treatment of VKH result in favorable visual outcome. Multimodal imaging, with the recent addition of OCT-A, provides complementary data that could serve in diagnosis and monitoring.

Interpreting posterior uveitis by integrating indocyanine green angiography, optical coherence tomography, and optical coherence tomography angiography data: A narrative review

Posterior uveitis is sight-threatening disease entity that can be caused by infectious and non-infectious entities. Vision loss in posterior uveitis can be following complications such as cystoid macular edema, epiretinal membrane, artery and vein occlusions, vasculitis, papillitis, choroidal neovascular membrane, retinal neovascularization, tractional retinal detachment, vitreous hemorrhage, glaucoma, cataract, among others. Diagnosis of posterior uveitic entities have been revolutionized following introduction of choroidal imaging with techniques such as indocyanine green angiography (ICGA), optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). Med Line search and PubMed search was performed pertaining to causes of posterior uveitis, ICGA in posterior uveitis, OCT in posterior uveitis, OCTA in posterior uveitis, retinal and choroidal vascular changes in posterior uveitis, quantification of choriocapillaris lesion area in posterior uveitis, subfoveal choroidal thickness in posterior uveitis, quantification of choriocapillaris in posterior uveitis, vascular indices for quantification of choriocapillaris. This review article highlights various changes in the choroid and the quantification of choroid using various parameters in ICGA, OCT and OCTA.

Comparison of Indocyanine Green Angiography and Swept-Source Wide-Field Optical Coherence Tomography Angiography in Posterior Uveitis

Purpose

To compare indocyanine green angiography (ICGA) and swept-source wide-field optical coherence tomography angiography (SS-OCTA) for the assessment of patients with posterior uveitis.

Method

SS-OCTA montage images of 5 x 12 x 12 mm or 2 x 15 x 9 mm, covering ~70-90 degree of the retina of consecutive patients with posterior uveitis were acquired. The choriocapillaries and choroidal slabs were compared to findings on ICGA.

Results

Sixty-eight eyes of 41 patients were included (mean age 47.2 ± 20.4 years; 58.5% female). In 23 (34%) lesions were visible on OCTA, but not discernable on ICGA. In turn, out of the 45 eyes with clearly discernable lesions on ICGA, 22 (49%) and 21 (47%) eyes showed no corresponding areas of flow deficit on OCTA in the CC and choroidal slab, respectively. Lesion size strongly correlated among ICGA and OCTA choriocapillaries- (CC) (r = 0.99, p ≤ 0.0001) and choroidal slabs (r = 0.99, p ≤ 0.0001), respectively. The mean lesion size on the late frames of ICGA (8.45 ± 5.47 mm2) was larger compared to the lesion size on OCTA CC scan (7.98 ± 5.47 mm2, p ≤ 0.0001) and choroidal scan (7.69 ± 5.10 mm2, p = 0.002), respectively. The lesion size on OCTA CC scan was significantly larger than on the OCTA choroidal scan (p ≤ 0.0001).

Conclusion

SS-wide field OCTA may be a promising tool to assess posterior uveitis patients and may replace ICGA to a certain extent in the future.

Artificial Intelligence and Imaging Processing in Optical Coherence Tomography and Digital Images in Uveitis

INTRODUCTION

Computer vision, understood as the area of science that trains computers to interpret digital images through both artificial intelligence (AI) and classical algorithms, has significantly advanced the analysis and interpretation of optical coherence tomography (OCT) in retina research. The aim of this review is to summarise the recent advances of computer vision in imaging processing in uveitis, with a particular focus in optical coherence tomography images.

MATERIAL AND METHODS

Literature review.

RESULTS

The development of computer vision to assist uveitis diagnosis and prognosis is still undergoing, but important efforts have been made in the field.

CONCLUSION

The automatising of image processing in uveitis could be fundamental to establish objective and standardised outcomes for future clinical trials. In addition, it could help to better understand the disease and its progression.

Optic Disc Microvasculature Dropout in Glaucoma Detected by Swept-Source Optical Coherence Tomography Angiography

PURPOSE

To assess the clinical utility of swept-source optical coherence tomography angiography (SS-OCTA) in detecting optic disc microvasculature dropout (MvD-D) in primary open-angle glaucoma (POAG) eyes.

DESIGN

Cross-sectional study.

METHODS

The study enrolled 197 eyes of 197 patients with POAG with acceptable-quality SS-OCTA (PLEX Elite 9000; Carl Zeiss Meditec) images. A whole-signal-mode 6.0- × 6.0-mm optic disc cube was obtained with projection artifact removal. Three groups were categorized: no MvD-D (group 1), MvD-D (group 2, complete loss of microvasculature within the optic disc), and indiscernible MvD-D (group 3, poor visualization of the anterior lamina cribrosa [LC]).

RESULTS

There were 82 (42.1%) and 81 (41.5%) eyes categorized as no MvD-D (group 1) and MvD-D (group 2), respectively. The remaining 32 eyes (16.4%), categorized as indiscernible MvD-D (group 3), had a significantly smaller anterior scleral canal opening (ASCO) area (P < .05). Group 2 had significantly worse visual field (VF) mean deviation (MD), thinner average retinal nerve fiber layer (RNFL), higher prevalence of focal LC defect, and parapapillary deep-layer microvasculature dropout (MvD-P) than the other 2 groups (P < .05). In the multivariable logistic regression analysis, higher prevalence of focal LC defect (odds ratio, 46.91; P < .001) and MvD-P (odds ratio, 48.94; P < .001) remained as factors associated with MvD-D.

CONCLUSIONS

The presence of MvD-D could be well determined by SS-OCTA in eyes with POAG. MvD-P and focal LC defects were strongly associated with MvD-D. This suggests that SS-OCTA can serve as a useful tool in detecting optic disc microvasculature damage.

Retino-choroidal evaluation of the macular region in eyes with tubercular serpiginous-like choroiditis using swept-source optical coherence tomography angiography

AIM

To analyse the alterations in retino-choroidal angioarchitecture in eyes with active tubercular serpiginous-like choroiditis (TB-SLC) using swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

This prospective cross-sectional study enrolled 34 eyes diagnosed with TB-SLC and 34 age-matched healthy controls. Data acquisition with SS-OCTA using the PLEX Elite 9000 (Carl Zeiss Meditec Inc., Dublin, CA, USA) with a 6 × 6 mm pattern centered on the foveal center was done. Automated retinal vessel length density (VLD) and perfusion density (PD) and foveal avascular zone architecture were obtained from the ARI hub. Choroidal vascularity index (CVI) and choriocapillaris flow deficits (CCFD) were obtained using Image J.

RESULTS

Eyes with TB-SLC showed significantly reduced vessel indices in all retinal layers (P < 0.05), decreased CVI (P = 0.001) and increased CCFD (P = 0.001) as compared to healthy eyes. CCFD was increased significantly in the involved quadrants in eyes with TB-SLC when compared with the uninvolved quadrants and corresponding healthy quadrants in control subjects. CCFD showed a significant negative correlation with visual acuity (r = - 0.46, P = 0.006).

CONCLUSION

Eyes with TB-SLC manifest reduced VLD and PD, decreased CVI and increased CCFD. The CCFD alterations are non-uniform in these eyes, mainly located under the regions with disease activity.

The use of optical coherence tomography angiography in comparing choriocapillaris recovery between two treatment strategies for multifocal choroiditis: a pilot clinical trial

PURPOSE

To compare differences in choriocapillaris flow deficit (CC FD) in multifocal choroiditis (MFC) between two treatment arms using optical coherence tomography angiography (OCTA).

METHODS

In this prospective randomized clinical trial, patients were randomized to either Group 1 which received standard tapering dose of oral corticosteroids, or Group 2 which received additional dexamethasone implant (or intravitreal methotrexate). The patients were followed-up until 12 weeks using OCTA and other imaging tools. CC FD and visual acuity between the two groups were compared at each visit.

RESULTS

Twenty-five subjects (17 males; 25 eyes) were studied (11 eyes in Group 1). There were no differences between the visual acuity or CC FD (1.12 versus 1.08 mm²; p = 0.86) at baseline between the groups. However, patients in Group 2 achieved better visual acuity (0.32 ± 0.23 versus 0.15 ± 0.11; p = 0.025) and CC FD (0.54 versus 0.15 mm²; p = 0.008) at 12 weeks.

CONCLUSIONS

OCTA is a useful tool in monitoring the CC FD recovery after treatment in MFC. Patients receiving intravitreal corticosteroid/methotrexate in addition to systemic corticosteroid showed greater resolution of CC FD on OCTA compared to those receiving only oral corticosteroids.

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.

Choriocapillaris perfusion assessed using swept source optical coherence tomographic angiography and the severity of diabetic retinopathy

AIMS

To investigate the relationship between choriocapillaris (CC) blood perfusion and the severity of diabetic retinopathy (DR) using swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

Type 2 diabetes mellitus in the Guangzhou was recruited. DR was graded according to the standardised seven-field colour retinal images adhering to the ETDRS scale. CC perfusion was quantified by evaluating the flow deficit (FD) density, FD number and FD size using SS-OCTA. Multivariable linear regressions were used to evaluate the correlation between CC FD metrics and DR severity.

RESULTS

A total of 1692 patients (eyes) were included in the final analysis. Participants with DR had a significantly higher FD density than the NDR group, with the differences of 1.61% (95% CI 1.04 to 2.18; p<0.001) among mild non-proliferative DR (NPDR) patients, 2.23% (95% CI 1.76 to 2.70; p<0.001) among moderate NPDR patients and 3.31% (95% CI 2.27 to 4.36; p<0.001) among severe DR than NDR patients after adjusting for confounding factors. Similarly, the higher FD number and size were also correlated with severer degree of DR (all p<0.05). Furthermore, the addition of FD density to conventional risk factors significantly improved the performance for discriminating DR from NDR patients (AUC 0. 829, 95% CI 0. 804 to 0. 855; p<0.001).

CONCLUSION

Quantitative FD density, number and size assessed by using SS-OCTA were independently correlated with the severity of DR. The assessment of the CC perfusion metrics in the macula may be a sensitive biomarker of DR changes.

Microvasculature Features of Vogt-Koyanagi-Harada Disease Revealed by Widefield Swept-Source Optical Coherence Tomography Angiography

Background: Vogt-Koyanagi-Harada (VKH) disease is a multisystem autoimmune disorder which could induce bilateral panuveitis involving the posterior pole and peripheral fundus. Optical coherence tomography angiography (OCTA) provides several advantages over traditional fluorescence angiography for revealing pathological abnormalities of the retinal vasculature. Until recently, however, the OCTA field of view (FOV) was limited to 6 × 6 mm² scans.

Purpose: This study examined retinal vasculature and choriocapillaris abnormalities across multiple regions of the retina (15 × 9 mm² wide field, macular, peripapillary regions) among acute and convalescent VKH patients using a novel widefield swept-source OCTA (WSS-OCTA) device and assessed correlations between imaging features and best-corrected visual acuity (BCVA).

Methods: Twenty eyes of 13 VHK disease patients in the acute phase, 30 eyes of 17 patients in the convalescent phase, and 30 eyes of 15 healthy controls (HCs) were included in this study. Vascular length density (VLD) in superficial and deep vascular plexuses (SVP, DVP), vascular perfusion density (VPD) in SVP, DVP, and choriocapillaris (CC), and flow voids (FV) in CC were measured across multiple retinal regions via WSS-OCTA (PLEX Elite 9000, Carl Zeiss Meditec Inc., USA) using the 15 × 9 mm² scan pattern centered on the fovea and quantified by ImageJ.

Results: Compared to HCs, acute phase VKH patients exhibited significantly reduced SVP-VLD, SVP-VPD, and CC-VPD across multiple retinal regions (all p < 0.01). Notably, the FV area was more extensive in VKH patients, especially those in the acute phase (p < 0.01). These changes were reversed in the convalescent phase. Stepwise multiple linear regression analysis demonstrated that macular DVP-VLD and macular CC-VPD were the best predictive factors for BCVA in the acute and convalescent VKH groups.

Conclusion: The wider field of SS-OCAT provides more comprehensive and detailed images of the microvasculature abnormalities characterizing VKH disease. The quantifiable and layer-specific information from OCTA allows for the identification of sensitive and specific imaging markers for prognosis and treatment guidance, highlighting WSS-OCTA as a promising modality for the clinical management of VKH disease.

Automated Quantification of Choriocapillaris Lesion Area in Patients With Posterior Uveitis

PURPOSE

To validate a custom algorithm for automated identification and quantification of clinically relevant inflammatory choriocapillaris (CC) lesions from en face swept-source optical coherence tomography (SS-OCTA) images.

DESIGN

Observational case series.

METHODS

Twenty eyes of 14 patients with posterior uveitis were imaged. The machine-generated en face OCTA CC slabs were exported to a computing platform, where a custom algorithm performed unsupervised lesion boundary delineation and area quantification. Lesions identified by the algorithm (AG) were compared to those identified by 2 masked human graders (HG1 and HG2), using the Sørensen-Dice coefficient (DSC) and intraclass correlation coefficient (ICC). Intragrader and intravisit reliability were determined by coefficient of variation (CV) and DSC.

RESULTS

The AG demonstrated excellent agreement with both HGs in determination of lesion area (HG1 vs AG ICC 0.92, 95% CI 0.81-0.97, HG2 vs AG ICC 0.91, 95% CI 0.78-0.97). The AG demonstrated good spatial overlap (DSC ≥0.70) with both HGs in 14 of 20 (70%) eyes and at least 1 HG in 16 of 20 (80%) eyes. Poor spatial overlap (DSC between 0.31 and 0.69) was associated with the presence of a choroidal neovascular membrane and low-contrast lesion boundaries. Intravisit repeatability for the AG was superior to both HGs (CV 2.6% vs >5%).

CONCLUSION

This custom algorithm demonstrated a high degree of agreement with HGs in identification of inflammatory CC lesions and outperformed HGs in reproducibility. Automated CC lesion delineation will support the development of objective and quantitative biomarker of disease activity in patients with posterior uveitis.

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.

Recent advances in wide field and ultrawide field optical coherence tomography angiography in retinochoroidal pathologies

Introduction: With the advent of wide field (WF) and ultra-wide field (UWF) imaging in color fundus photography and fluorescein angiography (FA), the importance of an expanded field-of-view (FOV) has been illustrated for early detection of several chorioretinal disorders. The need to bring similar utility to optical coherence tomography angiography (OCTA) is imperative.Areas covered: For this review, we explored all research items with WF or UWF on Pubmed Central and Google Scholar. Software-based methods included algorithms for motion correction, artifact reduction, image pre-processing, post-processing and montage protocols while hardware methods included swept-source OCTA, faster scanning sources, hardware-based motion tracking and image registration, scanning sources with faster speeds and lower resolution. For various disorders such as diabetic retinopathy, uveitis, vascular disorders, among others, the increased FOV showed demonstrably increased detection rates and diagnostic yield.Expert opinion: Increased FOV in OCTA imaging is a meaningful and impactful step in ophthalmic imaging. Overcoming the hardware-based limitations can potentially yield higher FOV without loss of important details. In addition to improvements in the hardware and available equipment, better software tools and image processing algorithms may greatly enhance the utility of UWF OCTA in care of patients with various retinochoroidal diseases.