Quantitative analysis of retinal and choriocapillary vascular density of multiple evanescent white dot syndrome by optical coherence tomography angiography

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.

An Open-source Image Analysis Toolbox for Quantitative Retinal Optical Coherence Tomography Angiography

Background

Qualitative and quantitative assessment of retinal perfusion using optical coherence tomography angiography (OCTA) has shown to be effective in the treatment and management of various retinal and optic nerve diseases. However, manual analyses of OCTA images to calculate metrics related to Foveal Avascular Zone (FAZ) morphology, and retinal vascular density and morphology are costly, time-consuming, subject to human error, and are exposed to both inter and intra operator variability.

Objective

This study aimed to develop an open-source software framework for quantitative OCTA (QOCTA). Particularly, for analyzing OCTA images and measuring several indices describing microvascular morphology, vessel morphology, and FAZ morphology.

Material and Methods

In this analytical study, we developed a toolbox or QOCTA using image processing algorithms provided in MATLAB. The software automatically determines FAZ and measures several parameters related to both size and shape of FAZ including area, perimeter, Feret's diameter circularity, axial ratio, roundness, and solidity. The microvascular structure is derived from the processed image to estimate the vessel density (VD). To assess the reliability of the software, three independent operators measured the mentioned parameters for the eyes of 21 subjects. The consistency of the values was assessed using the intraclass correlation coefficient (ICC) index.

Results

Excellent consistency was observed between the measurements completed for the superficial layer, ICC >0.9. For the deep layer, good reliability in the measurements was achieved, ICC >0.7.

Conclusion

The developed software is reliable; hence, it can facilitate quantitative OCTA, further statistical comparison in cohort OCTA studies, and can assist with obtaining deeper insights into retinal variations in various populations.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

A case of angioid streaks that produced choroidal neovascularization after the onset of unilateral acute retinopathy in pseudoxanthoma elasticum

Purpose

Observations

Conclusions and importance

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.

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.

Structural Endpoints and Outcome Measures in Uveitis

Most uveitis entities are rare diseases but, taken together, are responsible for 5-10% of worldwide visual impairment which largely affects persons of working age. As with many rare diseases, there is a lack of high-level evidence regarding its clinical management, partly due to a dearth of reliable and objective quantitative endpoints for clinical trials. This review provides an overview of available structural outcome measures for uveitis disease activity and damage in an anatomical order from the anterior to the posterior segment of the eye. While there is a multitude of available structural outcome measures, not all might qualify as endpoints for clinical uveitis trials, and thorough testing of applicability is warranted. Furthermore, a consensus on endpoint definition, standardization, and "core outcomes" is required. As stipulated by regulatory agencies, endpoints should be precisely defined, clinically important, internally consistent, reliable, responsive to treatment, and relevant for the respective subtype of uveitis. Out of all modalities used for assessment of the reviewed structural outcome measures, optical coherence tomography, color fundus photography, fundus autofluorescence, and fluorescein/indocyanine green angiography represent current "core modalities" for reliable and objective quantification of uveitis outcome measures, based on their practical availability and the evidence provided so far.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

Translational Relevance

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

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.