EN FACE OPTICAL COHERENCE TOMOGRAPHY AND OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF MULTIPLE EVANESCENT WHITE DOT SYNDROME: New Insights Into Pathogenesis

Comprehensive insights into COVID-19 vaccine-associated multiple evanescent white dot syndrome (MEWDS): A systematic analysis of reported cases

Considering the widespread use of COVID-19 vaccines as a preventive measure against the spread of the virus, it's necessary to direct attention to the adverse effects associated with vaccines in a limited group of populations. Multiple evanescent white dot syndrome (MEWDS) following COVID-19 vaccination is a rare adverse reaction associated with COVID-19 vaccines. In this systematic review, we collected 19 articles with 27 patients up to November 1, 2023, summarizing the basic information, clinical manifestations, examinations, treatments, and recoveries of the 27 patients. The 27 enrolled patients (6 males, 21 females) had a median age of 34.1 years (15-71 years old) and were mainly from 5 regions: Asia (8), the Mediterranean region (8), North America (7), Oceania (3) and Brazil (1). Symptoms occurred post-first dose in 9 patients, post-second dose in 14 (1 with symptoms after both), post-third dose in 1, and both post-second and booster doses in 1, while details on 2 cases were not disclosed. Treatments included tapered oral steroids (6), topical steroids (3), tapered prednisone with antiviral drugs and vitamins (1), and valacyclovir and acetazolamide (1), while 16 received no treatment. All patients experienced symptom improvement, and nearly all patients ultimately recovered. Moreover, we summarized possible hypotheses concerning the mechanism of COVID-19 vaccine-associated MEWDS. The findings provide insights into the clinical aspects of COVID-19 vaccine-associated MEWDS. More attention should be given to patients with vaccine-associated MEWDS, and necessary treatment should be provided to patients experiencing a substantial decline in visual acuity to improve their quality of life.

Changes in Density of Peripapillary and Intrapapillary Capillaries on OCT Angiography in Acute Retinal Necrosis Treated by Pharmacotherapy Alone without Surgery

PURPOSE

To analyze radial peripapillary capillaris (RPC) and intra-papillary capillaris (IPC) using optical coherence tomography angiography (OCTA) in acute retinal necrosis (ARN) with good outcome.

METHODS

RPC and IPC were analyzed by OCTA in patients diagnosed with ARN and treated with pharmacotherapy alone without surgery at the Tokyo Medical University Hospital.

RESULTS

A total of 13 patients were studied. Ophthalmoscopic examination showed no abnormality in the optic disc in 12 of the 13 patients. However, OCTA findings of the affected eye compared with the unaffected fellow eye revealed morphological abnormalities in RPC in nine cases (69%) and decrease in capillary network in RPC or IPC in eight cases (62%).

CONCLUSION

In ARN, RPC and IPC were impaired even in eyes that were healed with medical treatment only without requiring surgical intervention and had no abnormal findings on ophthalmoscopic examination. This result suggests the presence of some degrees of optic neuropathy even in mild cases with good visual prognosis.

Active Ocular Toxoplasmosis Associated with Simultaneous Multiple Evanescent White Dot Syndrome

PURPOSE

We describe the association between active ocular toxoplasmosis and Multiple Evanescent White Dot Syndrome (MEWDS).

PATIENTS AND METHODS

Retrospective observational case report of a patient who presented with concomitant ocular toxoplasmosis and MEWDS (Erasmus University Hospital, Brussels, Belgium). Clinical record and multimodal imaging including fundus autofluorescence (FAF), fluorescein angiography (FA), indocyanine green angiography (ICGA), and spectral domain optical coherence tomography (SD-OCT) were analyzed.

RESULTS

Multimodal imaging of a 25-year-old-woman that presented with concomitant active ocular toxoplasmosis and MEWDS is described. Both clinical entities regressed completely after 8 weeks under steroidal anti-inflammatory drugs and antibiotics.

CONCLUSION

Active ocular toxoplasmosis can be associated with simultaneous multiple evanescent white dot syndrome. Further reports are needed to precise and characterize this clinical relationship and its management.Abbreviations: MEWDS: Multiple Evanescent White Dot Syndrome; Fundus Autofluorescence FAF; BCVA: Best-corrected Visual Acuity; FA: Fluorescein Angiography; ICGA: Indocyanine Green Angiography; SD-OCT: Spectral Domain Optical Coherence Tomography; IR: Infrared.

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.

A case of secondary multiple evanescent white dot syndrome in a patient with preexisting wet age-related macular degeneration

Purpose

To report a case of secondary Multiple Evanescent White Dot Syndrome in a patient with preexisting wet age-related macular degeneration.

Observation

A 75-year-old male on treat and extend regimen for wet age-related macular degeneration (AMD) presented with a sudden loss of vision and saw central dark shadow in the right eye (RE) for a duration of 1 week. There was no significant history preceding the visual loss. Examination showed a visual acuity (VA) of counting fingers at 1 meter in the right eye and 20/25 in the left eye. Anterior segment examination was unremarkable with dilated fundus examination showing a clear vitreous, tortuous blood vessel, a hyperemic disc and fibrosis at the macula. The left eye (LE) examination was unremarkable. Optical Coherence Tomography (OCT) showed fibrosis due to the previous wet AMD and hyperreflective excrescences projecting from the retinal pigment epithelium (RPE) outside of the old area of wet AMD. Fundus Fluorescein Angiogram (FFA) showed hyperfluorescent spots in a wreath-like pattern increasing in intensity in the early phase and showing late staining towards the late phase while Indocyanine green angiography (ICGA) did not clearly delineate the lesions. Fundus autofluorescence (FAF) revealed hyper Autofluorescence (AF) at the posterior pole. Optical Coherence Tomography Angiography (OCTA) revealed a flow reduction in the choriocapillaris of the affected area. Basic blood investigations with Venereal Disease Research Laboratory (VDRL), syphilitic IgM and IgG antibodies, Quantiferon TB gold test, complete renal function tests and liver function tests were performed. All the blood investigations were within normal limits and the workup for syphilis and tuberculosis was negative. The patient was started on 1mg/kg body weight of oral prednisolone (after the non-response to low dose of oral steroids) with the diagnosis of secondary multiple evanescent white dot syndrome (MEWDS) secondary to wet AMD. The patient was followed up every weekly and the last visit showed improvement in visual acuity to 20/50 with resolution of lesions on FAF and OCT macula.

Conclusion and importance

Secondary MEWDS is extremely rare and unique in terms of its presentation and its association with preexisting chorioretinal disease where there is damage to the choriocapillaris- Bruch's membrane-RPE complex. This case report highlights one such rare case scenario and how multimodal imaging helps in the diagnosis, management and follow-up of patients with secondary MEWDS.

Value and Significance of Hypofluorescent Lesions Seen on Late-Phase Indocyanine Green Angiography

Background and Purpose

The hypofluorescence of fundus lesions observed during the late phase of indocyanine green angiography (ICGA) in various diseases has often been overlooked or misinterpreted. This article explores the significance of fundus lesions that are initially isofluorescent during the early phase of ICGA but become hypofluorescent later in the examination.

Findings

Pathologies such as multiple evanescent white spot syndrome, acute posterior placoid syphilitic chorioretinitis, chronic central serous chorioretinopathy, choroidal hemangioma, and some fundus with drusen, present this phenomenon of late hypofluorescence.

Interpretation

The interpretation of ICGA images and the role of indocyanine green (ICG) uptake by the retinal pigment epithelium (RPE) in late fundus fluorescence is debated. Experimental evidence suggests that ICG accumulates progressively in the RPE after intravenous injection of the dye or after direct contact in vitro, making it a potential marker of RPE activity. Although the exact mechanisms of ICG diffusion through the choroid and its binding to the RPE require further investigation, the late hypofluorescence observed in certain ICGA diseases provides information on different modalities of RPE dysfunction.

Financial Disclosures

The author has no proprietary or commercial interest in any materials discussed in this article.

Wide Field Optical Coherence Tomography and Optical Coherence Tomography Angiography in Uveitis

BACKGROUND

We review the current literature on the use of wide-field optical coherence tomography (OCT) and wide-field optical coherence tomography angiography (OCTA) in different uveitic phenotypes as well as various sequelae of uveitis and discuss the limitations of this evolving technology.

MAIN BODY

Current consensus guidelines on nomenclature in wide-field OCT and OCTA are described. The specific utility of wide-field OCT and OCTA in assessment of the retina and choroid using different en-face and cross-sectional slabs in various inflammatory diseases is reviewed. Furthermore, we discuss widefield OCT and OCTA in assessment of retinal ischemia and its limitations in assessing retinal vascular leakage.

CONCLUSION

Wide-field OCT and OCTA deliver more sensitive measures of inflammation. With continued advancement in both hardware technology and software processing, these modalities will allow for more accurate assessment of uveitis, better understanding of disease mechanisms, and precise monitoring of treatment response.

Fundus autofluorescence in uveitis: from pathogenesis to imaging interpretation

PURPOSE

This review aims to summarize the current fundus autofluorescence (FAF) ailment for diagnosis and follow-up of uveitis.

METHODS

A thorough literature search was performed in the PubMed database.

RESULTS

FAF maps the retinal pigment epithelium's (RPE) health. Therefore, several posterior infectious and non. This fast, easy-to-perform, noninvasive technique can detect and manage infectious uveitis.

CONCLUSIONS

FAF serves to understand pathophysiologic mechanisms of uveitis and is a valuable prognostic indicator of themselves.

Latest advances in white spot syndromes: New findings and interpretations

White spot syndromes (WSS) pose challenges in the field of ophthalmology, particularly in terms of accurate diagnosis and effective management. However, recent advancements in multimodal imaging (MMI) have significantly contributed to our understanding of WSS, allowing for improved characterization of these inflammatory chorioretinopathies. By employing various imaging modalities, including fundus fluorescein angiography, indocyanine green angiography, fundus autofluorescence, optical coherence tomography (OCT), ultra-widefield imaging, and OCT angiography, researchers and clinicians have gained valuable insights into the underlying pathophysiological changes and clinical progression of WSS. Furthermore, MMI has unveiled novel and atypical variants within the spectrum of WSS, expanding our knowledge in this field. Notably, the identification of secondary forms of WSS occurring concurrently with unrelated chorioretinal disorders has suggested a potential autoimmune mechanism underlying these conditions. The introduction of MMI has also facilitated a more comprehensive evaluation of previously ill-defined entities, such as acute zonal occult outer retinopathy, leading to improved diagnostic criteria and enhanced recognition of distinct features. This review paper provides a comprehensive overview of the latest advances and interpretations in WSS. By integrating MMI into the diagnosis and management of these conditions, this review aims to enhance patient outcomes and provide valuable insights into the complexities surrounding WSS.

Presumed Müller Cell Activation in Multiple Evanescent White Dot Syndrome

Purpose

The purpose of this study was to investigate the foveal changes occurring in multiple evanescent white dot syndrome (MEWDS) using multimodal imaging techniques with a specific focus on hyper-reflective dots (HRDs).

Methods

This was a retro-prospective observational study including 35 eyes with active MEWDS. Structural and en face optical coherence tomography (OCT) was performed, with follow-up visits at 2 weeks, 6 weeks, and 2 months from baseline. HRD percentage area (HRD % area) was calculated in a 600 µm fovea centered circle on en face OCT, after background subtraction and image binarization. HRD % area was compared with 23 fellow control eyes. Longitudinal changes in the HRD % areas were assessed using repeated-measure statistics.

Results

HRDs were observed as scattered hyper-reflective spots on the vitreoretinal interface on en face OCT images, colocalizing with HRDs or vertical hyper-reflective lines on structural OCT images. The baseline evaluation showed a significantly higher HRD % area in MEWDS eyes compared to fellow eyes (0.10 ± 0.03 vs. 0.08 ± 0.04, P = 0.01). The HRD % area correlated positively with LogMAR visual acuity and inversely with the duration of symptoms. Longitudinal analysis revealed a significant reduction in the HRD % area over time. There was no significant interaction between the rate of HRD disappearance and clinical or demographic factors at baseline.

Conclusions

As HRD potentially represents the end-feet projections of activated Müller cells on the retinal surface, this study supports the involvement of Müller cells in the pathogenesis of the disease. The findings highlight the potential of en face OCT imaging for monitoring the progression of MEWDS.

A Long Term Recurrent Case of Acute Retinal Pigment Epithelitis

PURPOSE

To describe the case of a young adult who developed two episodes of Acute Retinal Pigment Epithelitis (ARPE) in the same eye 7 years apart, describing retinal morphologic changes using SD-OCT scan.

OBSERVATIONS

ARPE is an acute, self-limiting macular disorder characterized by a stippled dark macular lesion surrounded by a hypopigmented halo under fundus examination, corresponding to a foveal disruption of the outer retinal layers and an hyperreflective lesion under SD-OCT scan. Despite ARPE lesions usually appearing to be situated within the macula, a diffuse involvement of the RPE has been suggested1. SD-OCT scan in our patient showed multiple focal lesions involving the whole posterior pole of the affected eye.

CONCLUSIONS AND IMPORTANCE

We report the first case where a diffuse involvement of the RPE in the disease is supported by an OCT finding and the case with the longest period between two recurrent self-limited episodes described so far.

Topographic patterns of retinal lesions in multiple evanescent white dot syndrome

PURPOSE

To demonstrate different topographic distributions of multiple-evanescent white dot syndrome (MEWDS) and secondary MEWDS disease and to describe possible associations.

METHODS

Clinical evaluation and multimodal retinal imaging in 27 subjects with MEWDS (29 discrete episodes of MEWDS). Ophthalmic assessment included best-corrected visual acuity testing and multimodal retinal imaging with OCT, blue-light autofluorescence, fluorescein and indocyanine green angiography, fundus photography, and widefield pseudocolor and autofluorescence fundus imaging.

RESULTS

The topographic distribution of MEWDS lesions was centered on or around the optic disc (n = 17, 59%), centered on the macula (n = 7, 24%), sectoral (n = 2, 7%), or was indeterminate (n = 3, 10%). The MEWDS episodes either occurred in the absence ('primary MEWDS'; n = 14, 48%) or presence of concurrent chorioretinal pathology ('secondary MEWDS'; n = 15, 52%). In patients with the latter, MEWDS lesions were often centered around a coexisting chorioretinal lesion. The majority of patients in both groups experienced resolution of their symptoms and retinal changes on multimodal imaging by 3 months.

CONCLUSIONS

Distinct distributions of MEWDS lesions were identified. MEWDS may occur in tandem with other chorioretinal pathology, which may impact the topography of MEWDS lesions.

PRIMARY MULTIPLE EVANESCENT WHITE DOT SYNDROME AND MULTIPLE EVANESCENT WHITE DOT SYNDROME SECONDARY TO MULTIFOCAL CHOROIDITIS/PUNCTATE INNER CHOROIDOPATHY: A Comparative Study

PURPOSE

To present and compare the clinical features and multimodal imaging (MMI) findings of the primary form of multiple evanescent white dot syndrome (MEWDS) and MEWDS secondary to multifocal choroiditis/punctate inner choroidopathy (MFC/PIC).

METHODS

A prospective case series. Thirty eyes of 30 MEWDS patients were included and divided into the primary MEWDS group and MEWDS secondary to MFC/PIC group. Demographic, epidemiologic, and clinical characteristics and MEWDS-related MMI findings of the two groups were compared.

RESULTS

Seventeen eyes from 17 patients with primary MEWDS and 13 eyes from 13 patients with MEWDS secondary to MFC/PIC were evaluated. Patients with MEWDS secondary to MFC/PIC tended to have a higher degree of myopia than those with primary MEWDS. No other significant differences in demographic, epidemiologic, and clinical characteristics and MMI findings were found between the two groups.

CONCLUSION

"MEWDS-like reaction" hypothesis seems to be correct for MEWDS secondary to MFC/PIC, and the authors highlight the importance of MMI examinations in MEWDS. Further research is needed to confirm whether the hypothesis is applicable to other forms of secondary MEWDS.

HIGH-RESOLUTION SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY OF MULTIPLE EVANESCENT WHITE DOT SYNDROME

PURPOSE

To evaluate a patient with multiple evanescent white dot syndrome with multimodal imaging including high-resolution spectral-domain optical coherence tomography.

METHODS

The patient was evaluated with wide-field color and autofluorescence imaging, microperimetry, and near-infrared imaging. Spectral-domain optical coherence tomography was performed using an instrument capable of 3- μ m axial resolution, the high-resolution Heidelberg Spectralis.

RESULTS

A 28-year-old woman developed photopsias and a scotoma in the field of vision of her left eye. She had multiple whitish spots with granularity in her fovea, consistent with the diagnosis of multiple evanescent white dot syndrome. She had supportive fluorescein angiographic and autofluorescence findings. Because of the high resolution and good layer contrast, it was possible to create en face slab images of the external limiting membrane, ellipsoid zone, interdigitation zone, and retinal pigment epithelium. The external limiting membrane showed no abnormalities. There were multiple regions of decreased reflectance in the ellipsoid zone slab but even more prominent changes in the interdigitation zone. The retinal pigment epithelium showed nearly no variation in layer reflectivity. With resolution of symptoms, the color and autofluorescence images returned to normal, the defects in the ellipsoid zone almost completely resolved, and the interdigitation zone continued to show abnormalities.

CONCLUSION

Although past studies concluded that the ellipsoid zone was the main region of involvement in multiple evanescent white dot syndrome, high-resolution spectral-domain optical coherence tomography suggests the interdigitation zone was more prominently affected in this case.

Presence of Choroidal Caverns in Patients with Posterior and Panuveitis

Choroidal caverns (CCs) have been described in association with age-related macular degeneration and pachychoroid disease. However, it is unknown if caverns are found in patients with chronic non-infectious uveitis (NIU). Herein, we evaluated patients with NIU who had optical coherence tomography and indocyanine green angiography for CCs. Clinical and demographic characteristics were extracted from the chart review. Univariate and multivariate mixed-effects logistical models were used to assess the association between clinical and demographic factors and the presence of CCs. One hundred thirty-five patients (251 eyes) met the inclusion criteria: 1 eye had anterior uveitis, 5 had intermediate uveitis, 194 had posterior uveitis, and 51 had panuveitis. The prevalence of CCs was 10%. CCs were only observed in patients with posterior and panuveitis, with a prevalence of 10.8% and 7.8%, respectively. Multifocal choroiditis (MFC) was the type of uveitis where CCs were most frequently observed, with 40% of eyes with MFC having CCs. In addition, male sex (p = 0.024) was associated with CCs. There was no significant difference in the degree of intraocular inflammation or mean subfoveal choroidal thickness between CC+ and CC- eyes. This is the first study to describe CCs in uveitis. Overall, these findings suggest that caverns may be a sequela of structural and/or vascular perturbations in the choroid from 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.

Stepwise approach for fundus imaging in the diagnosis and management of posterior uveitis

An array of retinochoroid imaging modalities aid in comprehensive evaluation of the immunopathological changes in the retina and choroid, forming the core component for the diagnosis and management of inflammatory disorders such as uveitis. The recent technological breakthroughs have led to the development of imaging platforms that can evaluate the layers of retina and choroid and the structural and functional alteration in these tissues. Ophthalmologists heavily rely on imaging modalities such as dye-based angiographies (fluorescein angiography and indocyanine green angiography), optical coherence tomography, fundus autofluorescence, as well as dye-less angiography such as optical coherence tomography angiograph,y for establishing a precise diagnosis and understanding the pathophysiology of the diseases. Furthermore, these tools are now being deployed with a 'multimodal' approach for swift and accurate diagnosis. In this comprehensive review, we outline the imaging platforms used for evaluation of posterior uveitis and discuss the organized, algorithmic approach for the assessment of the disorders. Additionally, we provide an insight into disease-specific characteristic pathological changes and the established strategies to rule out disorders with overlapping features on imaging.

En Face OCT in Diagnosis of Persistent Subretinal Fluid and Outer Retinal Folds after Rhegmatogenous Retinal Detachment Repair

PURPOSE

To evaluate the role of en face OCT as a diagnostic tool for the detection of persistent subretinal fluid (PSRF) and outer retinal folds (ORFs) after successful rhegmatogenous retinal detachment (RRD) repair.

DESIGN

Observational post hoc analysis of 2 prospective surgical trials.

PARTICIPANTS

All patients with gradable (signal strength ≥ 5 and no segmentation error) 6 × 6-mm² macular cube scans obtained using spectral-domain OCT (Carl Zeiss Meditec) between 1 and 2 months after surgery were included in this study.

METHODS

The scans were assessed for the presence or absence of PSRF or ORFs using en face OCT and cross-sectional B scans by 2 masked graders, with any disagreements adjudicated by a third senior masked grader.

MAIN OUTCOME MEASURES

The sensitivity, specificity, and predictive accuracy (using area under the curve [AUC]) of en face OCT were compared with those of cross-sectional OCT, which is considered the gold standard.

RESULTS

Two hundred twenty-three patients were included in this study. The Cohen kappa between the graders in the diagnosis of PSRF and ORFs using en face OCT was 0.84 and 0.86, respectively. The sensitivity of en face OCT was 100% (95% confidence interval [CI], 100%-100%) in the diagnosis of PSRF and 98.8% (95% CI, 96.5%-101.1%) in the diagnosis of ORFs. Similarly, the specificity of en face OCT was 98.7% (95% CI, 96.8%-100.5%) and 84.2% (95% CI, 78.1%-90.2%) in the diagnosis of PSRF and ORFs, respectively. The AUC was 0.99 for PSRF and 0.91 for ORFs.

CONCLUSIONS

En face OCT has good sensitivity, specificity, and predictive accuracy (using AUC) in the diagnosis of PSRF and ORFs. En face OCT is an efficient screening tool for postoperative anatomic abnormalities, such as PSRF and ORFs, after RRD repair.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Use of optical coherence tomography angiography in the uveitis clinic

As optical coherence tomography angiography is revolutionizing the ophthalmology world, the uveitis community is learning to understand where and how this new powerful imaging tool fits into the management of the panorama of ocular inflammations and infections. A non-invasive method of studying the retinal and choroidal vasculature, OCTA allows for the assessment of vessel density changes during active and inactive uveitis making it the natural imaging application of choice in uveitis clinical trials. However, these data and results are of limited utility to the ophthalmologists who are looking to apply OCTA in their everyday uveitis clinic. If employed strategically, OCTA can be a powerful tool for the uveitis specialist to evaluate iris involvement in viral uveitis; to assess the integrity of the vascular layers in the settings of white dot syndromes; to distinguish inflammatory choroidal neovascularization from outer retinal avascular inflammatory material; and to diagnose and follow infectious choroidal granulomas and satellite foci of chorioretinal inflammation without the need to administer dyes. The present review will analyze all the recent publications that apply OCTA in uveitis to offer the reader a guide on how to maximize the utility of this imaging modality in a clinical practice.

Benefits and Limitations of OCT-A in the Diagnosis and Follow-Up of Posterior Intraocular Inflammation in Current Clinical Practice: A Valuable Tool or a Deceiver?

Purpose: Optical coherence tomography angiography (OCT-A) has been applied to uveitis and intraocular inflammation since its availability after 2014. The imaging of retinal and choroidal vascularization without the use of dyes was a major development and represented a potentially valuable tool in ocular research. In addition to such use, OCT-A is often put forward as being able to potentially replace invasive methods needing dye injection, such as fluorescein angiography (FA) and indocyanine green angiography (ICGA). The aim of this review was to establish whether OCT-A was sufficiently useful in everyday routine clinical practice to monitor disease evolution and to perform treatment adjustments to the extent that it could reliably replace the standard dye methods. Methods: Selective literature review and analysis of own data and experience. Results: OCT-A is a technologically high-grade imaging modality allowing to analyze retinal circulation in inflammatory diseases of the posterior pole with a high sensitivity useful for research purposes. However, there is no evidence that it reaches equal effectiveness in the routine management of posterior uveitis involving the retina. OCT-A is unable to show leakage. In choriocapillaritis involving pre-capillary vessels, it shows capillary drop-out but does not seem to have an advantage over ICGA except that it can be repeated easily, not being invasive, and so allows a closer follow-up. It is, however, less useful in end-choriocapillary non-perfusion, such as in MEWDS. For choroidal stromal inflammation, OCT-A is ill-suited as it only shows inconsistent secondary circulatory changes produced by choroidal foci. OCT-A seems to be useful in the diagnosis and follow-up of inflammatory chorioneovascularisation (iCNV), although dye exams are more precise in showing the activity of the iCNV. Conclusion: In summary, OCT-A is a very sensitive modality for the retinal circulation in uveitis for research purposes; it is sometimes useful for close follow of choriocapillary drop-out but not in end-capillary non-perfusion. Its use for monitoring purposes in stromal choroiditis, however, is questionable. Its claim to possibly replace classical angiographic work-up for the practical management of posterior uveitis is largely overrated.

Diagnosis, Mechanisms, and Differentiation of Inflammatory Diseases of the Outer Retina: Photoreceptoritis versus Choriocapillaritis; A Multimodal Imaging Perspective

Background and aim: Inflammatory diseases that affect the outer retina do so by different mechanisms. Some of them result from the direct, primary involvement of the outer retina (primary photoreceptoritis) such as acute zonal outer occult retinopathy (AZOOR). Others affect the photoreceptors secondarily due to the inflammatory involvement of the choriocapillaris. This results in choriocapillaris non-perfusion that damages the photoreceptors due to the ensuing ischaemia, a mechanism characterising primary inflammatory choriocapillaropathies (PICCPs) such as multiple evanescent white dot syndrome (MEWDS), idiopathic multifocal choroiditis (MFC), and others. Thanks to multimodal imaging (MMI), it is now possible to differentiate between these two mechanisms of outer retinal damage. The aim of this study is to determine the MMI characteristics that allow us to differentiate primary photoreceptoritis, including AZOOR, from PICCPs such as MEWDS and MFC. Methods: A series of eight PICCPs cases (five typical MEWDS and three typical active MFC cases) and four typical primary photoreceptoritis/AZOOR cases (five eyes) that had undergone complete MMI investigation, including fundus photography (FP), blue light fundus autofluorescence (BL-FAF), spectral domain optical coherence tomography (SD-OCT), OCT angiography (OCT-A, when available), fluorescein angiography (FA), and indocyanine green angiography (ICGA) were analysed, pointing out the differences that allow us to distinguish primary photoreceptoritis from PICCPs. Results: All primary photoreceptoritis/AZOOR cases showed (1) faint fundus pallor around the fovea, (2) BL-FAF hyperautofluorescence, (3) loss of photoreceptor outer segments (PROS) on SD-OCT, (4) absence of choriocapillary drop-out on OCT-A, (5) normal FA or faint FA hyperfluorescence, and (6) conserved ICGA fluorescence/no hypofluorescent areas; (1), (2), (3), and (5) indicated loss of photoreceptor outer segments, and (4) and (6) indicated conserved choriocapillaris circulation. For PICCPs, (a) fundus showed discreet white dots or none (in MEWDS) and punched-out scars in MFC, (b) BL-FAF hyperautofluorescence, (c) loss of PROS on SD-OCT, (d) FA faint hyperfluorescence in MEWDS, also minimal in active MFC lesions (e) in all cases ICGA hypofluorescent areas; (b) and (c) indicating loss of PROS, and (e) indicating choriocapillaris non-perfusion in all cases. The OCT-A did not show consistent findings with faint or no capillary drop-out in MEWDS and MFC. Conclusions: MMI combining the SD-OCT and BL-FAF clearly showed loss of PROS in both groups, while the ICGA determined whether this was due to choriocapillaris non-perfusion in PICCPs or whether the choriocapillaris was intact in case of primary photoreceptoritis. The FA and OCT-A were found to be less useful and/or less sensitive for the appraisal of both these entities.

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.

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.

Coarsening of choriocapillaris on optical coherence tomography angiography as a sign of acute idiopathic blind spot enlargement

Purpose

Acute idiopathic blind spot enlargement is a rare syndrome that is classified within a spectrum of primary inflammatory choriocapillaropathies with circumscribed outer retinal dysfunction.

Observations

We observed coarsening of the choriocapillaris on en-face optical coherence tomography angiography when compared to the fellow eye in a patient with suspected acute idiopathic blind spot enlargement.

Conclusions and Importance

Increased granularity of the choriocapillaris as imaged by optical coherence tomography angiography may assist in the diagnosis of acute idiopathic blind spot enlargement, particularly during a global pandemic when access to electrodiagnostics is limited. This finding supports the current evidence of choriocapillaris hypoperfusion in the pathogenesis of acute idiopathic blind spot enlargement.

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Acute idiopathic blind spot enlargement is a rare syndrome.

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It is classified within a spectrum of primary inflammatory choriocapillaropathies.

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Optical coherence tomography angiography is useful in diagnosing acute idiopathic blind spot enlargement.

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Coarsening of the choriocapillaris as imaged by optical coherence tomography angiography is seen in this disease.

AUTOFLUORESCENT TIMELINE OF SPOTS AND DOTS IN MULTIPLE EVANESCENT WHITE DOT SYNDROME

PURPOSE

To describe the recovery timeline of spots and dots in multiple evanescent white dot syndrome.

METHODS

Sequential multimodal retinal imaging including fundus autofluorescence and cross-sectional and en face optical coherence tomography was performed to track the development and resolution of spots and dots in a case of multiple evanescent white dot syndrome.

RESULTS

En face optical coherence tomography showed that the spots are the result of ellipsoid zone loss and are hyperautofluorescent due to unmasking of the underlying retinal pigment epithelium autofluorescence. Conversely, the dots are hyperreflective with cross-sectional and en face optical coherence tomography and hyperautofluorescent, which we propose may be due to accumulation of degenerated photoreceptor material including fluorophores with autofluorescent capability such as precursors of A2E. The earlier resolution of the hyperautofluorescent spots allowed for later detection of the hyperautofluorescent dots.

CONCLUSION

This case report illustrates the different recovery timelines of spots and dots in multiple evanescent white dot syndrome. Although both lesion types are hyperautofluorescent, the mechanism of autofluorescence is distinctive and may be explained by their contrasting pathoanatomy.

Navigating the White Dot Syndromes with Optical Coherence Tomography (OCT) and OCT Angiography (OCT-A)

INTRODUCTION

White dot syndromes are a heterogeneous group of diseases that affect different layers in the retina and choroid. Multimodal imaging is fundamental in the diagnosis, but also can be crucial in unveiling the pathogenesis of these entities.

MATERIAL AND METHODS

Literature review.

RESULTS

Optical coherence tomography (OCT) provides depth-resolved, histological grade images of the vitreous, retina, and choroid. This technology is very useful to localize the primary nature and level of pathology of the various white dot syndromes. En face OCT can provide additional information regarding the interrelationship of lesion types. Vascular involvement at the level of the retina, choriocapillaris or choroid can be assessed by en face OCT angiography (OCT-A) and is not limited by masking, leakage or staining as can occur with conventional angiography (fluorescein or indocyanine green angiography) which requires dye injection.

CONCLUSION

OCT and OCTA are fundamental in the diagnosis and follow-up of white dots syndromes.

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.

Consensus-based recommendations for optical coherence tomography angiography reporting in uveitis

BACKGROUND/AIMS

To establish a consensus in the nomenclature for reporting optical coherence tomography angiography (OCTA findings in uveitis.

METHODS

The modified Delphi process consisted of two rounds of electronic questionnaires, followed by a face-to-face meeting conducted virtually. Twenty-one items were included for discussion. The three main areas of discussion were: wide field OCTA (WF-OCTA), nomenclature of OCTA findings and OCTA signal attenuation assessment and measurement. Seventeen specialists in uveitis and retinal imaging were selected by the executive committee to constitute the OCTA nomenclature in Uveitis Delphi Study Group. The study endpoint was defined by the degree of consensus for each question: 'strong consensus' was defined as >90% agreement, 'consensus' as 85%-90% and 'near consensus' as >80% but <85%.

RESULTS

There was a strong consensus to apply the term 'wide field' to OCTA images measuring over 70° of field of view, to use the terms 'flow void' and 'non-detectable flow signal' to describe abnormal OCTA flow signal secondary to vessels displacement and slow flow respectively, to use the terms 'loose' and 'dense' to describe the appearance of inflammatory choroidal neovascularisation, and to use the percentage of flow signal decrease to measure OCTA ischaemia with a threshold greater than or equal to 30% as a 'large area'.

CONCLUSIONS

This study sets up consensus recommendations for reporting OCTA findings in uveitis by an expert panel, which may prove suitable for use in routine clinical care and clinical trials.

ARE THERE TWO FORMS OF MULTIPLE EVANESCENT WHITE DOT SYNDROME?

PURPOSE

To analyze the nature of multiple evanescent white dot syndrome (MEWDS) and differentiate an idiopathic or primary form of MEWDS from a secondary form that is seen in association with other clinical conditions affecting the posterior segment of the eye.

METHODS

Clinical and multimodal imaging findings including color fundus photography, fundus autofluorescence, fluorescein angiography, indocyanine green angiography, spectral-domain optical coherence tomography, and optical coherence tomography angiography of patients with secondary MEWDS are presented.

RESULTS

Twenty consecutive patients with secondary MEWDS were evaluated. Fifteen patients were female. Most were young adults aged between 20 to 40 years with myopia (less than -6 diopters). Pathologic conditions associated with the secondary MEWDS reaction were high myopia (greater than -6 diopters) in two eyes, previous vitreoretinal surgery for rhegmatogenous retinal detachment in 2 eyes, and manifestations of multifocal choroiditis in 18 eyes. In all eyes, the MEWDS lesions followed a course of progression and resolution independent from the underlying condition.

CONCLUSION

Secondary MEWDS seems to be an epiphenomenon ("EpiMEWDS") that may be seen in association with clinical manifestations disruptive to the choriocapillaris-Bruch membrane-retinal pigment epithelium complex.

Novel Findings of Retinal and Choroidal Features Utilizing Optical Coherence Tomography Angiography Analysis in Patients With Autoimmune Posterior Uveitis

Purpose: To analyze the quantitative parameters acquired by optical coherence tomography angiography (OCTA) in patients with autoimmune posterior uveitis. Methods: OCTA images of 65 eyes affected with uveitis and 65 normal control (NC) eyes were obtained. The central macular thickness (CMT), retinal thicknesses, foveal avascular zone (FAZ) area, foveal density 300 μm (FD300), and vascular density (VD) were compared among acute uveitic eyes, chronic uveitic eyes, and NC eyes. VDs were evaluated in the choriocapillaris, outer retina, optic disk, whole and parafovea superficial capillary plexus (SCP), and whole and parafovea deep capillary plexus (DCP). Correlation analysis was used to analyze the relationship between LogMAR best-corrected visual acuity (BCVA) and quantitative parameters from OCTA. Results: Compared with NC eyes, the CMT and retinal thicknesses were increased significantly in eyes with uveitis (p < 0.05, respectively). No significant difference was observed in the FAZ area. FD300, VDs in the optic disk, SCP, and DCP both in whole image and parafovea, choriocapillaris were significantly decreased in uveitis eyes (p < 0.05, respectively) compared with NC eyes, only the acute group had decreased VD of the outer retina and choriocapillaris compared with the NC group (p < 0.05). Moreover, quantitative parameters of OCTA showed a significant correlation with LogMAR BCVA in the patients with uveitis. Whole VD DCP was the best predictive factor for BCVA in the patients with uveitis. Conclusion: Quantitative measurement by OCTA is a promising strategy for objective assessment of autoimmune posterior uveitis.

Diagnosis and Treatment of Primary Inflammatory Choriocapillaropathies (PICCPs): A Comprehensive Overview

Purpose: Primary inflammatory choriocapillaropathies (PICCPs) belong to a group of intraocular inflammatory diseases with the common characteristic of inflammatory choriocapillaris hypo- or non-perfusion as the main clinicopathological mechanism. The purpose of our article is to describe clinical characteristics and multimodal imaging, that can help the diagnosis and treatment of PICCPs. Methods: Narrative review with multimodal imaging analysis. Results: Choriocapillaris non-perfusion can affect the end-choriocappilaries, at the benign end of the PICCP spectrum (MEWDS), to larger choriocapillaris vessels or precapillary vessels at the origin of more severe forms such as acute posterior multifocal placoid pigment epitheliopathy (APMPPE), idiopathic multifocal choroiditis (MFC) and Serpiginous Choroiditis (SC). Diagnosis is mostly based on multimodal imaging and especially on indocyanine green angiography (ICGA), fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (SD-OCT)/OCT-angiography (OCT-A). ICGA shows the typical pattern of patchy lobular hypofluorescence reflecting hypo- or non-perfusion of the choriocapillaris that can also take the aspect of geographic areas in the more severe forms. Treatment depends on the severity of the disease and goes from observation in MEWDS and some mild cases of APMPPE, to oral corticosteroid and/or immunomodulator agents in the more severe conditions of APMPPE and MFC and SC cases. Close multimodal monitoring is crucial in order to introduce or adjust treatment. Conclusion: PICCPs are resulting from one common clinicopathological mechanism, inflammatory choriocapillaris hypo- or non-perfusion. ICGA findings are essential for the diagnosis and follow-up of PICCPs, but non-invasive methods such as FAF and SD-OCT/OCT-A also have their role especially in follow-up of the diseases. Treatment should be individualized according to the pathology and the evolution of lesions.

Choroidal Imaging in uveitis: an update

An important goal of advancements in ocular imaging algorithms and devices has been to improve the image acquisition and resolution of deeper ocular tissues, namely the choroid and its vasculature that are otherwise inaccessible to direct clinical examination. These advancements have contributed to the understanding of the pathophysiology of a number of ocular inflammatory conditions. We focuse on the imaging characteristics of clinical conditions where imaging the choroid has improved or radically changed the understanding of the disease, has helped in differentiation of phenotypically similar but distinct lesions, and where imaging features have proven vital formonitoring disease activity. The last two decades have seen some major developments in ocular imaging relevant to uveitis. The current review addresses both the imaging characteristics and their interpretation on conventional modalities such as fundus photography, fluorescein angiography, indocyanine green angiography and fundus autofluorescence and the recent additions in the armamentarium including optical coherence tomography (OCT) with enhanced depth imaging, swept-source OCT, and OCT angiography.

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.

Clinicopathology of non-infectious choroiditis: evolution of its appraisal during the last 2-3 decades from "white dot syndromes" to precise classification

Choroidal imaging investigation techniques were very limited until 2–3 decades ago.

Fluorescein angiography (FA) was not suited for the analysis of the choroidal compartment and B-scan ultrasonography did not provide enough accuracy. It was on this background that a purely phenomenological approach was attempted to classify these choroiditis diseases by regrouping them under the vague potpourri term of “white dot syndromes”. With the availability of precise investigational modalities of choroidal inflammation or choroiditis-induced lesions, such as indocyanine green angiography (ICGA), spectral domain optical coherence tomography (SD-OCT) and enhanced depth imaging optical coherence tomography (EDI-OCT) it became possible to better classify these diseases based on clinico-pathological mechanisms rather than on purely phenomenological observation.

Recently OCT-angiography has implemented the armamentarium of diagnostic techniques possibly also contributing to the classification of choroidal inflammatory diseases.

Based on pioneering pragmatism, the aim of this article was to give a clear classification of non-infectious choroiditis. Thanks to new imaging investigations of the choroid, it is now possible to classify and understand the diverse clinicopathological mechanisms in the group of non-infectious choroiditis entities.

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.

Multimodal imaging supporting the pathophysiology of white dot syndromes

White dot syndromes (WDS) represent a heterogeneous group of inflammatory diseases, primarily affecting the outer retina, choriocapillaris and choroid. Recent advances in the field of ocular imaging and development of new technologies, including optical coherence tomography angiography (OCT-A), have allowed a better characterization of the morphology of these conditions. This review will analyse the WDS from an imaging-based perspective, providing a better understanding of the pathophysiology underlying these disorders.

HYPERAUTOFLUORESCENT SPOTS IN ACUTE OCULAR TOXOPLASMOSIS: A New Indicator of Outer Retinal Inflammation

PURPOSE

The aim of this study was to describe the fundus autofluorescence patterns in acute ocular toxoplasmosis (OT) and to correlate these findings with other imaging.

METHODS

A retrospective multicenter case series of 27 eyes from 27 patients with acute onset of posterior OT was conducted. Multimodal imaging including fundus autofluorescence was performed at diagnosis and during follow-up.

RESULTS

All OT lesions were hypoautofluorescent on fundus autofluorescence imaging. Fourteen patients (51.8%) also had hyperautofluorescent spots around the active foci that disappeared after retinal photobleaching. Although these spots were not seen on early phase of indocyanine green angiography, they become hypofluorescent in the late phase without choriocapillaris flow impairment on optical coherence tomography angiography. On B-scan spectral domain optical coherence tomography, spots corresponded to outer retinal alterations in all cases. All hyperautofluorescent spots disappeared during follow-up as acute OT resolved. Younger patients and those with more posterior inflammatory symptoms (vasculitis and/or papillitis) were more frequent with the presence of hyperautofluorescent spots.

CONCLUSION

Ocular toxoplasmosis may trigger a transient outer retinal disruption in eyes with marked inflammatory symptoms of the younger patients.

An uncommon cold of the retina

A 39-year-old woman with progressive loss of vision left eye was referred for evaluation. Notably, she had been diagnosed with COVID-19 two weeks beforehand. Examination and ancillary testing confirmed atypical multifocal evanescent white dot syndrome. Possible other masquerades were excluded. A few weeks later, visual acuity improved in the left eye and symptoms resolved together with normalization of ancillary testing, including visual fields.

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.

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.

Classification of Non-Infectious and/or Immune Mediated Choroiditis: A Brief Overview of the Essentials

The choroid was poorly accessible to imaging investigation until the last decade of the last century. With the availability of more precise imaging methods such as indocyanine green angiography (ICGA) and, later, optical coherence tomography (OCT), enhanced depth OCT (EDI-OCT), and OCT angiography (OCTA), appraisal of choroidal inflammation has substantially gained in accuracy. This allowed to precisely determine which structures were touched in the different non-infectious choroiditis entities and made it possible to classify this group of diseases, ICGA signs, mainly hypofluorescent lesions, were identified and described. Previous publications have divided angiographic findings into two main sets of signs: (1) irregular “geographic” hypofluorescent areas corresponding to choriocapillaris non-perfusion and (2) round more regular, hypofluorescent dark dots more evenly distributed in the fundus corresponding to more deep choroidal stromal foci. These distinct findings allowed to subdivide and classify choroiditis into choriocapillaritis and stromal choroiditis. Additional signs were identified from EDI-OCT and OCTA examination supporting the classification of choroiditis into choriocapillaritis and stromal choroiditis. Results: Diseases involving principally the choriocapillaris included Multiple Evanescent White Dot Syndrome (MEWDS), Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE), Idiopathic Multifocal Choroiditis (MFC), and Serpiginous Choroiditis (SC) as well as mixed forms. Diseases primarily involving the choroidal stroma included HLA-A29 Birdshot Retinochoroiditis (BRC), Vogt-Koyanagi-Harada disease (VKH), Sympathetic Ophthalmia (SO), and Sarcoidosis chorioretinitis (SARC). Thanks to new imaging investigations of the choroid, it is now possible to classify and understand the diverse clinicopathological mechanisms in the group of non-infectious choroiditis entities.

Review of the Current Literature and Our Experience on the Value of OCT-angiography in White Dot Syndromes

PURPOSE

To describe the application of OCT-A in various posterior uveitis disorders in our experience and to compare it with the available literature.

METHODS

Eighteen eyes with the diagnoses of multifocal choroiditis (MFC), multifocal placoid pigment epitheliopathy (APMPPE), multiple evanescent white dot syndrome (MEWDS), tuberculous serpiginous-like choroiditis (SLC), serpiginous choroiditis (SC), and birdshot chorioretinopathy (BSCR) were studied.

RESULTS

We found flow void of the choriocapillaris in patients with APMPPE, SC, MFC, BSCR, and in SLC. In contrast, perfusion of the choriocapillaris seemed normal in patients with MEWDS.

CONCLUSIONS

We confirmed that OCT-A contributes new information on the physiopathology of white dot syndromes and inflammatory chorioretinopathies, notably on whether or not the choriocapillaris is involved. Comparing the OCT-A features allowed us to suggest that both APMPPE and SLC might be part of the same spectrum of inflammatory disease with primary involvement at the level of the choriocapillaris and secondary RPE damage.

AN ELDERLY PATIENT WITH ACUTE TRANSIENT OUTER RETINAL DISRUPTION RESEMBLING BILATERAL MULTIPLE EVANESCENT WHITE DOT SYNDROME

PURPOSE

To report an unusual case of an elderly patient with transient outer retinal disruption resembling bilateral multiple evanescent white dot syndrome.

METHODS

Observational case report. Fundus photographs, fluorescein angiography, standard and ultra-widefield fundus autofluorescence, and cross-sectional and en face optical coherence tomography were used to characterize and describe the clinical findings.

RESULTS

A 67-year-old woman presented with decreased vision and floaters in her left eye. Best-corrected visual acuity was 20/20-3 in the right eye and 20/80-2 in the left eye. Funduscopic examination showed small deep white dots and foveal granularity of the left eye corresponding to hyperautofluorescent spots on fundus autofluorescence and ellipsoid zone disruption on spectral domain optical coherence tomography. The asymptomatic right eye had evidence of subretinal deposits on spectral domain optical coherence tomography but was otherwise unremarkable. At 4-week follow-up, the patient noted resolution of her symptoms in the left eye but had developed floaters and blurry vision in her right eye. The left eye showed resolving white spots and ellipsoid zone disruption. However, the right eye had new evidence of white spots corresponding to hyperautofluorescent spots on fundus autofluorescence. Spectral domain optical coherence tomography demonstrated subretinal deposits overlying areas of ellipsoid zone disruption. At 8-week follow-up, the patient was asymptomatic in both eyes with best-corrected visual acuity of 20/20 in both eyes. The hyperautofluorescent spots on ultra-widefield fundus autofluorescence had faded with restoration of ellipsoid zone disruption in both eyes and disappearance of subretinal deposits.

CONCLUSION

Our case demonstrates multimodal retinal imaging findings resembling multiple evanescent white dot syndrome in an elderly patient. The bilateral presentation, presence of subretinal deposits before symptom onset, and older age of the patient were atypical features for this entity.