Swept Source Optical Coherence Tomography Angiography Findings in Birdshot Chorioretinitis: A Cross Sectional Study of 21 Patients

PURPOSE

Birdshot chorioretinitis (BSCR) is a form of posterior uveitis that is classically characterized by hypopigmented choroidal lesions outside of the major arcades. However, little is known about the extent of choroidal involvement in the macula. We aim to describe the vascular abnormalities observed at the level of the choriocapillaris (CC) in the maculae of BSCR patients, using swept source optical coherence tomography angiography (SS-OCTA).

METHODS

A cross-sectional, observational study was conducted. Eligible patients underwent clinical examination and SS-OCTA imaging. The main outcome measures were the frequency of vascular abnormalities observed at the level of the CC on SS-OCTA and foveal choriocapillaris vascular density (CVD).

RESULTS

Twenty-one patients were included, with a median age of 61.5 years. All patients had bilateral disease with a median disease duration of 6 years. All but one patient received systemic immunosuppressive drug therapy, and 19 patients had suppressed inflammation on treatment at the time of the SS-OCTA assessment. Of the 42 affected eyes, 39 (92.9%) had gradable SS-OCTA images, with a mean LogMAR visual acuity of 0.18 (Snellen equivalent 20/30). In total, 34 of 39 (87.2%) eyes had some degree of pathologic flow loss, and after controlling for patient age and disease activity, both worse VA and longer disease duration remained statistically significantly associated with reduced foveal CVD.

CONCLUSIONS

Our findings suggest that pathologic CC flow loss in the macula is frequently encountered and may contribute to visual function decline in patients with BSCR. Further studies with longitudinal follow-up are needed to characterize the evolution of these areas of pathologic CC flow loss over time.

EOG and the En-Face Inner Segment/Outer Segment-Ellipsoid Complex Image in Multiple Evanescent White Dot Syndrome

Introduction

This study presents a rare case of multiple evanescent white dot syndrome (MEWDS) with atypical electrooculogram (EOG) findings, as well as abnormal en-face images of minimum intensity projection (Min-IP) and the en-face inner segment/outer segment-ellipsoid complex.

Methods

A 25-year-old female patient presented with painless visual impairment and photopsia in her right eye for a duration of two days. Multimodal imaging was employed including color fundus photography (CFP), fundus autofluorescence (FAF), spectral-domain optical coherence tomography (SD-OCT), and optical coherence tomography angiography (OCTA), and en-face images of Min-IP and the en-face inner segment/outer segment-ellipsoid complex were performed.

Results

In the right eye, multifocal small white spots were observed surrounding the posterior pole and optic disc of retina with the granular appearance of the fovea. FAF displayed of hyperfluorescence. SD-OCT appearance of MEWDS demonstrated primarily disrupted ellipsoid zone (EZ), photoreceptor outer segments, and interdigitation zone (IZ) complex within the fovea. The en-face images of the inner segment/outer segment-ellipsoid complex and Min-IP exhibited hyperreflective spots in the right eye. In the left eye, interestingly, hyperreflective spots were also observed on the en-face image of the inner segment/outer segment-ellipsoid complex. EOG revealed an Arden ratio of 2.5 for the right eye, while the left eye exhibited an Arden ratio of 1.7.

Conclusion

The en-face image of the inner segment/outer segment-ellipsoid complex in MEWDS exhibits aberrant features and it is noteworthy that a similar alteration may occur in the fellow eye. Further investigation is required to explore the relationship between MEWDS and EOG. The en-face images of the inner segment/outer segment-ellipsoid complex and Min-IP may help to elucidate the pathogenesis of MEWDS.

MULTI-MODAL IMAGING IN DIFFUSE SUBRETINAL FIBROSIS WITH UVEITIS SYNDROME

PURPOSE

To describe clinical features including multimodal imaging in a case of diffuse subretinal fibrosis and uveitis syndrome.

METHODS

A young patient presented with counting fingers in both eyes due to posterior uveitis and unresponsive to systemic corticosteroids. Ultra-wide field pseudo-color and autofluorescence imaging, optical coherence tomography angiography (OCT-A), en-face OCT-A, and spectral-domain optical coherence were performed.

RESULTS

Clinical examination revealed a bilateral fibrosis plaque in both fovea and macular multifocal choroidal lesions associated, with no vitritis. Ultra-wide field-autofluorescence allowed us to determine activity showing a hyperfluorescent pattern. En-face OCT-A at the level of the ellipsoid layer showed multiple hyperreflective lesions surrounding a hyperreflective fibrosis plaque in both eyes, which improved and stabilized during the follow-up. Optical coherence tomography angiography at the level of retina pigmentary epithelium-choriocapillaris revealed neocapillary network changes along the chronification of the disease. The patient required the addition of intravitreal dexamethasone implants (Ozurdex) to control the acute rebounds and anti-TNFα to control the underlying inflammatory process.

CONCLUSION

This is the first diffuse subretinal fibrosis with uveitis syndrome reported with a complete En-face OCT-A and OCT-A examination. This multi-modal imaging will improve the monitoring of the disease's activity and the chronicity changes.

Case Report: Acute Posterior Multifocal Placoid Pigment Epitheliopathy after SARS-CoV-2 Vaccination

SIGNIFICANCE

Acute posterior multifocal placoid pigment epitheliopathy is an uncommon inflammatory chorioretinopathy that has been reported after vaccination. This is the first reported case, to our knowledge, after vaccination for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a healthy adolescent boy.

PURPOSE

This report aimed to inform the eye care community about a possible ocular sequela of SARS-CoV-2 vaccination.

CASE REPORT

A 17-year-old boy presented to a clinic for a second opinion after sudden-onset blind spots in his right eye. His medical history was remarkable for receiving the first dose of the Pfizer-BioNTech SARS-CoV-2 vaccine 2 weeks before symptom onset. He had no history of ocular inflammation, autoimmune disease, or systemic infection. A diagnosis of unilateral acute posterior multifocal placoid pigment epitheliopathy was made based on the presence of typical fundus lesions and noninvasive imaging with fundus autofluorescence, retinal optical coherence tomography, and optical coherence tomography angiography. The diagnosis was further confirmed with fluorescein angiography. The patient developed an anterior vitritis in the right eye 42 days after initial symptom onset. His unilateral intraocular inflammation resolved after a 5-week course of prednisone.

CONCLUSIONS

Acute posterior multifocal placoid pigment epitheliopathy is a self-limited inflammatory condition of the outer retina that usually affects young adults and often does not require treatment. It has been reported to occur after vaccination for influenza, polio, hepatitis B, meningococcus C, and varicella zoster virus. This is the first known case to occur after SARS-CoV-2 vaccination in a healthy adolescent boy.

The Role of Optical Coherence Tomography and Optical Coherence Tomography Angiography in the Differential Diagnosis of Posterior Uveitis

PURPOSE

Modalities such as optical coherence tomography (OCT) and OCT angiography (OCTA) have improved the diagnostic utility of fundus imaging in management of uveitis. The purpose of this study is to review role of OCT and OCTA in differential diagnosis of certain posterior uveitic entities.

METHODS

Narrative review.

RESULTS

In this review, we have comprehensively summarized the utility of OCT and OCTA in helping the clinician diagnose common but challenging inflammatory conditions including ocular toxoplasmosis, viral retinitis, and vitreoretinal lymphoma, among others. OCT and OCTA can also be used to assess the choriocapillaris involvement in conditions such as multiple evanescent white dot syndrome, and choroidal granulomas in tubercular and sarcoid uveitis.

CONCLUSIONS

Fundus imaging with OCT and OCTA has assumed a significant role in establishing the diagnosis in uveitis apart from microbiological and other laboratory analysis. Advantages such as rapidity and non-invasiveness make these imaging modalities very useful and convenient.

Multiple evanescent white dot syndrome (MEWDS): update on practical appraisal, diagnosis and clinicopathology; a review and an alternative comprehensive perspective

BACKGROUND

Multiple evanescent white dot syndrome (MEWDS) is a rare inflammatory eye condition affecting the outer retina as a consequence of choriocapillaris non perfusion. The pathophysiology of MEWDS will be discussed based clinical appraisal and on multimodal imaging appraisal.

METHODS

Narrative review and perspective opinion.

RESULTS

Literature review results helped us to put forward (1) the specific symptomatology (decreased/blurred vision, photopsia, subjective scotomas), (2) the ill-asserted character of clinical findings (foveal granularity, white dots in fundoscopy), (3) and the crucial importance of multimodal imaging with the diagnostic triad of ICGA hypofluorescent areas, BL-FAF hyperautofluorescent areas and loss/damage of IS/OS-ellipsoid zone on SD-OCT that characterise the disease and can practically help the clinician to diagnose MEWDS. A comprehensive alternative perspective of the disease was formulated.

CONCLUSIONS

The bulk of evidence that we are presenting in this review, thanks to new performing non-invasive and invasive imaging modalities, is sufficiently compelling to consider MEWDS as a primary choriocapillaritis/inflammatory choriocapillaropathy. Multimodal imaging allows the clinician to diagnose MEWDS with a high level of certainty and ensures a precise follow-up.

Multimodal imaging in multiple evanescent white dot syndrome and new insights in pathogenesis

PURPOSE

To report the multimodal imaging in multiple evanescent white dot syndrome (MEWDS) during the acute and convalescent stages in order to better understand the focus of the inflammatory process.

METHODS

Retrospective cohort study of 4 patients with MEWDS. Each patient underwent: enhanced depth imaging-optical coherence tomography (EDI-OCT), fundus autofluorescence (FAF), fluorescein angiography (FA), indocyanine green angiography (ICGA) and en-face OCT and OCT angiography (OCT-A). Choroidal subfoveal thickness (CST) was measured manually. All patients were studied in the acute stage and convalescent stage after disappearance of OCT abnormalities and resolution of visual symptoms.

RESULTS

Four MEWDS patients with a mean age of 23.5years were studied (range: 16-33years). Two patients were women. Initial mean visual acuity (VA) was 80.25 ETDRS. Final mean VA was 84.25 ETDRS. OCT imaging showed disruption of the ellipsoid zone and a slightly elevated RPE layer with overlying hyperreflective material, all of which corresponded to hyperautofluorescent FAF lesions. FA revealed multiple hyperautofluorescent lesions, correlated with hypocyanescent spots on the late ICGA. OCT-A showed normal superficial and deep retinal capillary plexus as well as choriocapillaris. The disease was self-limited in all the cases, with a mean time of 9weeks to resolution (range: 4-16).

CONCLUSION

The pathophysiology of MEWDS is still debated. We believe that there is still not enough evidence to implicate the outer retina as the primary cause. For now, we suggest that this transient disease is the consequence of choriocapillaris hypoperfusion, but further studies are required to elucidate this hypothesis.

Choriocapillaris: Fundamentals and advancements

The choriocapillaris is the innermost structure of the choroid that directly nourishes the retinal pigment epithelium and photoreceptors. This article provides an overview of its hemovasculogenesis development to achieve its final architecture as a lobular vasculature, and also summarizes the current histological and molecular knowledge about choriocapillaris and its dysfunction. After describing the existing state-of-the-art tools to image the choriocapillaris, we report the findings in the choriocapillaris encountered in the most frequent retinochoroidal diseases including vascular diseases, inflammatory diseases, myopia, pachychoroid disease spectrum disorders, and glaucoma. The final section focuses on the development of imaging technology to optimize visualization of the choriocapillaris as well as current treatments of retinochoroidal disorders that specifically target the choriocapillaris. We conclude the article with pertinent unanswered questions and future directions in research for the choriocapillaris.

Vascular abnormalities in uveitis

Inflammation can involve several ocular structures, including the sclera, retina, and uvea, and cause vascular changes in these tissues. Although retinal vasculitis is the most common finding associated with uveitis involving the posterior segment, other vascular abnormalities may be seen in the retina. These include capillary nonperfusion and ischemia, vascular occlusions, preretinal neovascularization, microaneurysms and macroaneurysms, and telangiectasia. Moreover, vasoproliferative tumors and subsequent coat-like response can develop secondary to uveitis. Fluorescein angiography is ideal for the investigation of retinal vascular leakage and neovascularization, while optical coherence tomography angiography can provide depth resolved images from the superficial and deep capillary plexus and can demonstrate vascular remodeling. Choroidal vascular abnormalities primarily develop in the choriocapillaris or in the choroidal stroma and can appear as flow void in optical coherence tomography angiography and filling defect and vascular leakage in indocyanine green angiography. Extensive choriocapillaris nonperfusion in the presence of choroidal inflammation can increase the risk of choroidal neovascular membrane development. Iris vascular changes may manifest as dilation of vessels in stroma due to inflammation or rubeosis that is usually from ischemia in retinal periphery secondary to chronic inflammation. More severe forms of scleral inflammation, such as necrotizing scleritis, are associated with vascular occlusion in the deep episcleral plexus, which can lead to necrosis of sclera layer and uveal exposure.

Multiple evanescent white dot syndrome and panuveitis: a case report

Aim

To report a patient with multiple evanescent white dot syndrome (MEWDS) complicated by iridocyclitis and vitritis.

Case description

A 70-year-old woman developed multiple subretinal white dots, iritis, and diffuse vitreous opacity. Angiographic and macular morphological features were consistent with those of MEWDS. Inflammatory findings including the white dots improved following only topical dexamethasone within 1 month after the initial visit. Best-corrected visual acuity recovered to 1.0 with restored photoreceptor structure.

Conclusion

The presence of iridocyclitis and vitritis, atypical to MEWDS, indicates the concurrent development of panuveitis associated with MEWDS. These results suggest that MEWDS is a clinical entity of uveitis.

Optimizing the Repeatability of Choriocapillaris Flow Deficit Measurement From Optical Coherence Tomography Angiography

PURPOSE

To evaluate the impact of processing technique and slab selection on the repeatability of choriocapillaris (CC) flow deficit (FD) measurements as assessed using optical coherence tomography angiography (OCTA) DESIGN: Prospective, cross-sectional study.

METHODS

Healthy subjects were imaged with 4 consecutive 3 × 3-mm OCTA using a swept-source OCT (PLEX elite 9000; Carl Zeiss Meditec). OCTA images were generated using the Max projection, and three 10-μm-thick slabs starting 11, 21, and 31 μm posterior to the automatically segmented retinal pigment epithelial band. The resultant images were binarized using the Phansalkar method with a 43.94-μm radius and then the CCFD% was computed. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) were computed for the 4 acquisitions to assess the repeatability of the CCFD%. This entire analysis was repeated after separately modulating several parameters: (1) Sum instead of the Max projection, (2) retinal pigment epithelial fit instead of the retinal pigment epithelial band as the offset reference, (3) 14.65 and 87.88 μm radius values instead of 43.94 μm.

RESULTS

Twenty-four healthy eyes (mean age; 36.4 years) were enrolled. The CCFD% in the 11-21-, 21-31-, and 31-41-μm slabs generated by the Max algorithm and the retinal pigment epithelial band showed high repeatability values (ICCs = 0.963, 0.975, and 911; CVs = 0.05, 0.05, and 0.05, respectively). As most of the cases were confounded with the hypointense region when the 11-21-μm slab was used, however, this slab could not be included in the subsequent analyses. Those values in the 21-31- and 31-41-μm slabs were higher than those of the corresponding slabs by the Sum algorithm (ICC = 0.916 and 0.776; CV = 0.15 and 0.19, respectively) or by the retinal pigment epithelial fit (ICC = 0.907 and 0.802; CV = 0.06 and 0.06, respectively). The Phansalkar radius of 43.94 μm had the highest ICC numerically, but this was not statistically significantly greater than for a radius of 14.65 μm (ICC = 0.960 and 0.911, respectively) or a radius of 87.88 μm (ICC = 0.958 and 0.897, respectively). Regardless of which parameter was modulated, the 21-31-μm slab was the most repeatable.

CONCLUSIONS

In normal eyes, en face CC OCTA images generated using the Max projection and a 10-μm-thick slab offset of 21 μm below the instrument-generated retinal pigment epithelial band yielded the most repeatable CCFD%. These findings have implications for the design of standardized processing algorithms for quantitative CC assessment.

Choroidal nonperfusion on optical coherence tomography angiography in a case of unilateral posterior segment ocular sarcoidosis misdiagnosed as MEWDS

PURPOSE

To report a case of presumed ocular sarcoidosis initially presenting with features of multiple evanescent white dot syndrome (MEWDS) with atypical optical coherence tomography angiography (OCTA) findings.

OBSERVATIONS

A 23 year-old woman presented with a unilateral central scotoma, photophobia, and decreased visual acuity after a viral illness. Examination of the right eye revealed multiple round white macular spots and stippled granularity at the fovea. Multimodal imaging with fluorescein angiography (FA), indocyanine green angiography (ICG), fundus autofluorescence (FAF), and optical coherence tomography (OCT) was consistent with a diagnosis of MEWDS. However, OCTA demonstrated choriocapillaris (CC) flow deficits, which is not typical for MEWDS. The clinical course was initially consistent with MEWDS, with spontaneous recovery of symptoms over ensuing months. The patient presented five months later with floaters and a central scotoma. Examination showed panuveitis, and systemic evaluation revealed an elevated angiotensin converting enzyme (ACE) and hilar lymphadenopathy on chest x-ray consistent with presumed sarcoidosis.

CONCLUSIONS AND IMPORTANCE

A case of MEWDS atypically demonstrated CC flow deficits on OCTA and subsequently presented as uveitis secondary to presumed sarcoidosis. Atypical features in MEWDS may be a sign of another disorder masquerading early on as MEWDS and ought to prompt further investigation.

Ophthalmic and Neuro-ophthalmic Manifestations of Coronavirus Disease 2019 (COVID-19)

PURPOSE

To describe a case of inflammatory chorioretinopathy and Adie's syndrome possibly associated with COVID-19.

METHODS

Observational case report.

RESULTS

A 51-year-old woman developed fever, cough, and headache followed by retro-ocular pain and reading impairment. She tested positive for SARS-COV-2 infection by qualitative real-time reverse-transcriptase-polymerase-chain-reaction. The slit-lamp and funduscopic exam revealed abnormal pupillary response and yellowish creamy deep chorioretinal lesions, which were not present in previous examinations. Instillation of pilocarpine demonstrated denervation supersensitivity, and it was suggestive of bilateral Adie tonic pupil. A comprehensive work-up ruled out other systemic, autoimmune, or infectious diseases.

CONCLUSIONS

This case illustrates the possible association between multifocal chorioretinitis and Adie's syndrome, and the SARS-COV-2 infection in humans. Further investigation of virus infectivity specifically within ocular tissues has to be conducted.

Retinal Microvasculature Changes After Repair of Macula-off Retinal Detachment Assessed with Optical Coherence Tomography Angiography

Objective

To characterize the microvascular retinal changes after repair of macula-off rhegmatogenous retinal detachment (RRD) using optical coherence tomography angiography (OCT-A).

Patients and Methods

A retrospective review of patients who underwent repair of macula-off RRD. Fellow unaffected eyes were used as controls. Post-operative OCT-A allowed comparison of vessel density (VD) and foveal avascular zone (FAZ) area in the superficial and deep retinal capillary plexus (DCP) as well as VD in the choriocapillaris layer.

Results

Seventeen eyes of 17 RRD patients were included in the final analysis. There was a reduction in VD of the deep retinal capillary plexus in affected eyes compared to fellow eyes (p = 0.046). RRD eyes with reduced VD in DCP compared with their fellow control eyes had worse visual acuity after repair compared to those without (p = 0.032). No significant microvasculature changes were detected in the FAZ area and VD in the superficial capillary plexus and choriocapillaris compared to fellow eyes.

Conclusion

In macula-off RRD eyes, significant microvascular changes were detected in the DCP using OCT-A even after successful anatomical repair. Decreased VD in the DCP compared to the fellow healthy eyes was correlated with worse visual acuity.

Inner choroidal ischaemia and CNV due to handheld laser-induced maculopathy: a case report and review

There has been a sharp rise of reported handheld laser-induced maculopathy (HLIM) cases over the past decade, a concerning trend that may continue due to unregulated online access to high power lasers. Though HLIM has distinct clinical features, not uncommonly it may masquerade as other retinal disorders. It is critical therefore to recognise the clinical and multimodal imaging characteristics of this important and potentially devastating condition. As HLIM patients are typically young, unique issues need to be considered, such as delayed presentation, difficult history, poor compliance and behavioural or psychiatric comorbidity. This article will review the clinical and diagnostic features of laser injury, with a special emphasis on the multimodal retinal findings. In addition, we present a unique case of HLIM, resembling the presentation of a placoid disease variant and illustrating choroidal ischaemia using advanced retinal imaging, that offers further insight into the mechanisms of laser injury and its complications. The issues addressed in this review aim to increase recognition of an increasingly important and trending condition with potentially profound visual complications.

[White dot syndromes : Principles, diagnostics, and treatment]

The white dot syndromes include a group of diseases which are characterized by multiple yellowish-white foci in the outer retina, retinal pigment epithelium, and choroid. For clinicians and researchers alike they present significant diagnostic and therapeutic challenges. White dot syndromes include primary inflammatory choriocapillaropathies, such as acute posterior multifocal placoid pigment epitheliopathy (APMPPE)/acute multifocal ischemic choriocapillaropathy (AMIC), multiple evanescent white dot syndrome (MEWDS)/acute idiopathic blind spot enlargement (AIBSE), multifocal choroiditis (MFC), punctate inner choroidopathy (PIC), serpiginous choroiditis (SC), acute zonal occult outer retinopathy (AZOOR), and acute macular neuroretinopathy (AMN). Among the primary stromal choroiditis is birdshot retinochoroidopathy (BSRC); however, the pathogenesis of these disorders is largely unknown. Immunological reactions to previous viral infections with a genetic disposition seem to be a common denominator.

Repeatability of Optical Coherence Tomography Angiography in Uveitic Eyes

Purpose

To investigate the intravisit repeatability of optical coherence tomography angiography (OCTA) in a cohort of uveitis patients.

Methods

One hundred ten patients were imaged twice per eye, per visit, using the Zeiss Cirrus HD-OCT Model 5000 device. To calculate choriocapillaris flow void area (CC FV) 6 × 6-mm images were used, and 3 × 3-mm images were used to calculate vessel density (VD) and the foveal avascular zone area (FAZ) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP). Repeatability was measured using Bland-Altman analyses and intraclass correlation coefficients (ICC) with associated coefficient of variation (CV).

Results

The level of intravisit repeatability differed across indices ranging from moderate to excellent. CC FV had the highest intravisit repeatability with an ICC of 0.980 (95%CI, 0.966–0.989), a CV of 15.9% and Bland-Altman limits of agreement from −0.398 to 0.411 mm². DCP FAZ had the lowest intravisit repeatability with an ICC of 0.677 (95%CI, 0.510–0.796), a CV of 17.4% and Bland-Altman limits of agreement from −0.395 to −0.355 mm². Intraoperator repeatability was excellent across all indices.

Conclusions

This study demonstrates that OCTA is a reliable tool to quantitatively assess specific indices of vascular structure in uveitis patients with good intravisit repeatability. However, the range of variability for each index should be taken into account when evaluating clinically meaningful changes.

Translational Relevance

The repeatability of the metrics we have described has implications in supporting the development of OCTA-derived quantitative assessments of the retinal and choroidal vasculature in uveitis patients as potential imaging biomarkers.

Involvement of Inner Choroidal Layer in Choroidal Thinning during Regression of Multiple Evanescent White Dot Syndrome

Purpose

To investigate relationships between total thickness and the thickness of inner and outer layers in the choroid during regression in patients with multiple evanescent white dot syndrome (MEWDS).

Methods

This retrospective observational case series included 15 unilaterally affected eyes and 13 unaffected fellow eyes from 15 MEWDS patients (4 men and 11 women; mean age, 37.6 ± 17.6 years). Using enhanced depth imaging optical coherence tomography, whole, inner, and outer choroidal layer thicknesses at the fovea and perifovea were manually measured at the initial visit and at 1 and 3 months after the initial visit. The mean thickness values of the layers were compared at each stage.

Results

With regression of MEWDS, the mean subfoveal whole and inner choroidal layer thicknesses significantly decreased at 1 and 3 months compared to baseline values in MEWDS eyes (P=0.01 and P < 0.0001, respectively), but not in fellow eyes. The outer layer in MEWDS eyes tended to thin. Changes in the inner and outer layers at the perifovea in MEWDS eyes also showed the same trends. Simple linear regression analysis revealed significant positive correlations in choroidal thickness changes between the whole and inner layers (R = 0.53, P=0.04) and between the whole and outer layers (R = 0.91, P < 0.0001) from baseline to 3 months. Multiple linear regression analysis revealed that choroidal thickness changes in the whole layer were significantly correlated with those in the inner (β = 0.51, P < 0.0001) and outer (β = 0.73, P < 0.0001) layers.

Conclusion

The inner choroidal layer significantly thinned with regression of MEWDS, correlating with the thinning of total choroidal thickness. These results suggest that MEWDS lesions in the choroid are likely to lie mainly in the inner layer.

Optical coherence tomography angiography (OCTA) as a new diagnostic tool in uveitis

Background

The broad spectrum of uveitis disorders requires a multimodal imaging approach in the daily practice of an ophthalmologist. As inflammatory conditions, they have in common an alteration in leukocyte migration. In this context, optical coherence tomography angiography (OCTA) might be of great value for diagnosing or following up patients with these disorders. To date, OCTA has rather been used as an additional tool besides the well-established diagnostic imaging tools, but its complementary diagnostic features become increasingly relevant, to follow disease activity and treatment response and for the understanding of pathomechanisms of various uveitis types.

This review summarizes the possible applications of OCTA and its advantages and disadvantages as opposed to dye-based angiographies in uveitic diseases.

Main body

Hitherto gold standards in the diagnostic workup of posterior or intermediate uveitis have been angiography on a dye-based method, which is fluorescein or indocyanine green. It gives information about the status of the blood-retinal barrier and the retinal and choroidal vasculature by visualizing diffuse leakage as a state of inflammation or complications as an ischemia or choroidal neovascularization. As noninvasive methods, fundus autofluorescence depicts the status of metabolic activity of the retinal pigment epithelium and OCT or enhanced depth imaging OCT, respectively, as a depth-resolving imaging method can supply additional information.

OCTA as a non-invasive, depth-resolution imaging tool of retinal and choroidal vessels adds detailed qualitative and quantitative information of the status of retinal and choroidal vessels and bridges the gap between the mentioned conventional diagnostic tools used in uveitis.

It is important, though, to be aware of its limitations, such as its susceptibility to motion artifacts, limited comparability among different devices, and restricted contribution of information regarding the grade of disease activity.

Conclusion

OCTA as a non-invasive, depth-resolution imaging tool can give qualitative and quantitative information about the status of retinal and choroidal vessels, but also has certain limitations. Employing OCTA as a complementary rather than exclusive tool, it can give important additional information about the macro- and microvasculature under inflammatory circumstances. Thereby, it also contributes to the understanding of the pathophysiology of various uveitis entities.

Optical Coherence Tomography Angiography: Review of Current Technical Aspects and Applications in Chorioretinal Disease

Optical coherence tomography angiography (OCT-A) has enabled fast, non-invasive, high-resolution visualization of vasculature within the eye. In the past few years, it has become increasingly utilized for a range of disorders including age-related macular degeneration, diabetic retinopathy, retinal vein occlusions, and uveitis among others. This article reviews technical aspects of OCT-A, its applications in chorioretinal disease, and known limitations of the technology.

Angiography and En Face Optical Coherence Tomography Findings in Acute Syphilitic Posterior Placoid Chorioretinopathy

Acute syphilitic posterior placoid chorioretinopathy (ASPPC) is one of the rarest ocular manifestations of syphilis. The pathophysiology of this entity is still unknown. We report the outer retinal findings on en face optical coherence tomography (OCT) and the alteration of choriocapillaris flow findings on OCT angiography in a patient with ASPPC at the time of presentation, after penicillin treatment completion and during follow-up.

Comparison of choroidal neovascularization secondary to white dot syndromes and age-related macular degeneration by using optical coherence tomography angiography

Purpose

To characterize and compare choroidal neovascularization (CNV) secondary to white dot syndromes (WDS) and age-related macular degeneration (AMD) using optical coherence tomography angiography (OCT-A).

Methods

This is a cross-sectional study in which we imaged patients with CNV secondary to WDS and AMD with either the Zeiss Angioplex OCT-A or Optovue AngioVue OCT-A. Relevant demographic and clinical characteristics were collected and analyzed. CNV area and vessel density (VD) were measured by three independent graders, and linear regression analysis was subsequently performed.

Results

Three patients with multifocal choroiditis and panuveitis, one patient each with birdshot chorioretinopathy, presumed ocular histoplasmosis syndrome, and persistent placoid maculopathy, and eleven patients with AMD with sufficient image quality were included. CNV associated with WDS was significantly smaller than that secondary to AMD (0.56±0.32 vs 2.79±1.80 mm², β=-2.22, P=0.01), while no difference in VD was detected (0.46±0.09 vs 0.44±0.09, β=0.02, P=0.71).

Conclusion

CNV networks secondary to WDS appear to be smaller than those secondary to AMD but have similar VD. OCT-A is a powerful tool to investigate properties of CNV from various etiologies. Larger studies are needed for further characterization and understanding of CNV pathogenesis in inflammatory conditions.

Imaging the Deep Choroidal Vasculature Using Spectral Domain and Swept Source Optical Coherence Tomography Angiography

Purpose

To evaluate the deeper choroidal vasculature in eyes with various ocular disorders using spectral domain (SD) optical coherence tomography angiography (OCTA) and swept source (SS) OCTA.

Methods

Patients underwent OCTA imaging with either SD-OCTA (Zeiss Cirrus Angioplex or Optovue AngioVue) or SS-OCTA (Topcon Triton). Retinal pigment epithelium (RPE) integrity, structural visualization of deep choroidal vessels on en face imaging, and OCTA of deep choroidal blood flow signal were analyzed. Choroidal blood flow was deemed present if deeper choroidal vessels appeared bright after appropriate segmentation.

Results

Structural visualization of choroidal vessels was feasible in all eyes by en face imaging. In both SD-OCTA and SS-OCTA, choroidal blood flow signal was present in all eyes with overlying RPE atrophy (100% of eyes with RPE atrophy, 28.6% of all imaged eyes, P < .001).

Conclusions

While choroidal vessels can be visualized anatomically in all eyes by en face imaging, choroidal blood flow detection in deep choroidal vessel is largely restricted to areas with overlying RPE atrophy. Intact RPE acts as a barrier for reliable detection of choroidal flow using current OCTA technology, inhibiting evaluation of flow in deeper choroidal vessels in most eyes.

Evolution of Choroidal Neovascularization due to Presumed Ocular Histoplasmosis Syndrome on Multimodal Imaging including Optical Coherence Tomography Angiography

A 37-year-old Caucasian woman presented with acute decrease in central vision in her right eye and was found to have subfoveal choroidal neovascularization (CNV) due to presumed ocular histoplasmosis syndrome (POHS). Her visual acuity improved from 20/70 to 20/20 at her 6-month follow-up, after 3 consecutive monthly intravitreal bevacizumab injections were initiated at her first visit. Although no CNV activity was seen on fluorescein angiography (FA) or spectral-domain optical coherence tomography (SD-OCT) at her 2-month, 4-month, and 6-month follow-up visits, persistent flow in the CNV lesion was detected on optical coherence tomography angiography (OCTA). OCTA shows persistent vascular flow as well as changes in vascular flow in CNV lesions associated with POHS, indicating the continued presence of patent vessels and changes in these CNV lesions, even when traditional imaging of the lesion with OCT and FA indicates stability of the lesion with no disease activity. Additional cases with longitudinal follow-up are needed to assess how OCTA should be incorporated into clinical practice.