Optical coherence tomography angiography features of acute macular neuroretinopathy in dengue fever

Acute Macular Neuroretinopathy Associated with COVID-19 Pandemic: A Real-World Observation Study

PURPOSE

To evaluate the clinical and retinal imaging features of Chinese patients with acute macular neuroretinopathy (AMN) associated with COVID-19.

DESIGN

A prospective observational study.

METHODS

Retinal imaging, including color fundus photography, near-infrared imaging (NIR), swept-source optical coherence tomography (SS-OCT), optical coherence tomography angiography (OCTA), and Humphrey perimetry, were conducted for each case.

RESULTS

All cases were included within the first three months following the pandemic outbreak. A total of 12 male patients (36.36%) and 21 female patients (63.64%) were prospectively recruited, and 29 cases (87.88%) were bilaterally affected. The median interval between the onset of fever and the appearance of ocular symptoms was two days (range, 0.5-5.0 days). Apart from the outer retinal changes typical of AMN, changes in the inner retinal layers were observed, including intraretinal hemorrhage (8.06%), cotton wool spots (9.68%), and paracentral acute middle maculopathy (PAMM) (8.06%). Smaller retinal inner nuclear layer hyperreflective speckles (RIHS) (41.94%) were identified as a distinguishing feature from typical PAMM. Voids of vessel signals were found in the superficial (11.54%), intermediate (82.69%), and deep capillary plexus (98.08%), and in the choriocapillaris (19.23%) on OCTA. Humphrey perimetry illustrated central, paracentral, and peripheral scotomas. The occult lesions associated with AMN, PAMM, and some of the RIHS illustrated by OCT were visualized topographically and further confirmed by OCTA as perfusion defects.

CONCLUSION

An increase in AMN cases correlated with the SARS-CoV-2 outbreak. Additional features, including widespread inner retinal perfusion deficits, were observed and may serve as potential biomarkers for systemic microcirculation dysregulation in COVID-19.

Optical Coherence Tomography and Optical Coherence Tomography Angiography in Neglected Diseases

A group of self-limiting and frequently neglected diseases exist in the literature like Rickettsial disease, Malaria, Dengue fever, Chikungunya, West Nile virus infection, Rift Valley fever, Bartonellosis, or Lyme disease which are poorly understood due to lack of proper diagnostic testing. Currently, multimodal imaging has become a critical modality in the diagnosis and management of ocular diseases. Optical coherence tomography (OCT) is one such remarkable imaging modality in the field of ophthalmology providing high-resolution, cross-sectional images of the retina and choroid with the recent advances such as enhanced depth imaging and swept source OCT. Additionally, OCT angiography (OCTA) has further revolutionised dynamic imaging of retinal and choroidal vasculature non-invasively. This review article highlights the OCT and OCTA biomarkers in the diagnosis and prognosis of the aforementioned neglected diseases.

Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) - Report 6: Dengue Uveitis at a Tertiary Eye Institution in Singapore

OBJECTIVES

To identify the characteristics, treatment, and visual outcomes of dengue uveitis at a tertiary eye care centre in Singapore.

METHODS

Retrospective case record review of all consecutive dengue uveitis patients (2004 to 2015) from the Ocular Autoimmune Systemic Inflammatory and Infectious Study (OASIS) database.

RESULTS

Fifty-four patients were identified from the OASIS database. The most common ocular symptom was blurring of vision (n = 41, 75.9%), followed by floaters (n = 9, 17.0%), scotoma (n = 5, 9.3%), and metamorphopsia (n = 3, 5.7%). Scotoma based on history, Amsler grid, and perimetry accounted for 27 (50%) patients. Majority presented with either a posterior uveitis or retinal vasculitis (n = 51, 94.4%). Treatments ranged from close observation for spontaneous improvement, to the use of high-dose corticosteroids.

CONCLUSIONS

Dengue uveitis may present with a spectrum of disease manifestations including posterior uveitis, vasculitis, and macula edema. Scotoma is significant and may be found on history taking, Amsler charting, and perimetry.

Dengue Uveitis - A Major Review

Dengue fever is a significant global public health concern with increasing incidence over the past two decades. The symptoms range from mild to severe, including fever, headache, rash, and joint pain. Ocular complications are prevalent among hospitalized patients, estimated to be between 10% and 40.3%, with varying incidences based on the serotype and severity of dengue. These complications can be hemorrhagic or inflammatory and typically occur after the onset of fever. Modern diagnostic tools such as Optical Coherence Tomography (OCT) and Fundus Fluorescein Angiography (FFA) have enabled physicians to better understand the extent of ocular involvement and guide treatment. This article provides an updated overview of the various manifestations of dengue uveitis, including their diagnosis and treatment.

Visual Fields in Epidemic Retinitis

AIM

The aim of the study is to analyze visual fields defects (VFDs) in epidemic retinitis (ER).

METHODS

Patients with ER and Humphrey's visual field (HFA) 30-2 performed after resolution were studied. VFD severity grading was performed. Patients treated with oral doxycycline (Group-A) versus doxycycline-steroids (group-B) were compared.

RESULTS

Thirty-five eyes of 25 patients were studied. Nasal, inferior, temporal and central VFD were seen in 19 (54.2%), 13 (37.1%), 7 (20%) and 6 (17.1%) eyes, respectively. Grade 0, 1, 2 and 3 VFDs were seen in 4 (11.4%), 15 (42.8%), 12 (34.2%) and 4 (11.4%) eyes respectively. Seven eyes with ≥1 year of follow-up post-resolution also showed grade 0-3 scotomas. Mean severity of scotoma was grade 1.15 (Median: 1) and 1.42 (Median: 1.5) in groups A (n = 13) and B (n = 14), respectively (p = .637).

CONCLUSION

ER can cause VFD persisting long after resolution. Treatment with oral doxycycline without steroids was non-inferior to combined treatment with respect to VFD.

Comments on 'Presumed Post-COVID Infection Retinitis - Clinical and Tomographic Features of Retinitis as a Post-COVID Syndrome'

Characteristics and course of known seasonal diseases of pre-coronavirus disease (COVID-19) pandemic era may or may not change during the pandemic. Labelling COVID-19 as a novel etiology for those seasonal diseases or considering it as coinfection is debatable. Appropriate investigations are required to rule out previously known etiologies before correlating it with COVID-19. Epidemic retinitis (ER) or post fever retinitis is one such entity with seasonal variation. Multiple seropositivity for various organisms has been reported for ER during pre-pandemic era. This may significantly increase during the pandemic as the possibility of coinfection with COVID-19 is high. In the absence of gold-standard tests to exclude previously reported causes of ER, one should not undermine the possible coinfection before considering ER as post-COVID-19 syndrome. A study of incidence and pattern of seasonal variation of ER before and during the pandemic is needed before presumptively associating it with COVID-19.

Dengue fever ophthalmic manifestations: A review and update

Dengue fever, the most common arbovirus disease, affects an estimated 390 million people annually. Dengue virus (DENV) is an RNA virus of the Flaviviridae family with four different serotypes. Dengue haemorrhagic fever is the deadliest form of dengue infection and is characterised by thrombocytopaenia, hypotension, and the possibility of multi-system organ failure. The mechanism hypothesised for DENV viral replication is intrinsic antibody-dependent enhancement, which refers to Fcγ receptor-mediated viral amplification. This hypothesis suggests that the internalisation of DENV through the Fcγ receptor inhibits antiviral genes by suppressing type-1 interferon-mediated antiviral responses. DENV NS1 antibodies can promote the release of various inflammatory mediators in the nuclear transcription factor pathway (NF-κB-dependent), including monocyte chemoattractant protein (MCP)-1, interleukin (IL)-6, and IL-8. As a result, MCP-1 increases ICAM-1 expression and facilitates leukocyte transmigration. In addition, anti-DENV NS1 antibodies induce endothelial cell apoptosis via a nitric oxide-regulated pathway. A chain reaction involving pre-existing DENV heterotypic antibodies and innate immune cells causes dysfunction in complement system activity and contributes to the action of autoantibodies and anti-endothelial cells, resulting in endothelial cell dysfunction, blood-retinal barrier breakdown, haemorrhage, and plasma leakage. A spectrum of ocular diseases associated with DENV infection, ranging from haemorrhagic to inflammatory manifestations, has been reported in the literature. Although rare, ophthalmic manifestations can occur in both the anterior and posterior segments and are usually associated with thrombocytopenia. The most common ocular complication is haemorrhage. However, ophthalmic complications, such as anterior uveitis and vasculitis, suggest an immune-mediated pathogenesis.

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.

Acute macular neuroretinopathy in dengue virus serotype 1

Purpose

To report a case of acute macular neuroretinopathy (AMN) associated with dengue virus serotype 1 infection.

Observation

An 18-year-old Puerto Rican female was evaluated due to painless paracentral scotomas in each eye that developed after being hospitalized for dengue fever a week before. Clinical examination and multimodal imaging revealed bilateral hypopigmented macular lesions, hyperreflectivity at the outer nuclear and photoreceptor layer, and reduced flow signal in the deep capillary plexus. Additionally, hypoautofluorescent parafoveal lesions were found in the left eye. AMN was diagnosed. Two-month follow-up after the initial evaluation showed resolution of symptoms but persistence of some findings on optical coherence tomography.

Conclusions and importance

Patients with dengue virus serotype 1 may develop paracentral scotomas with classic AMN findings and obtain complete symptomatic recovery without treatment.

Optical coherence tomography angiography (OCTA) of retinal vasculature in patients with post fever retinitis: a qualitative and quantitative analysis

Post fever retinitis is a heterogenous entity that is seen 2-4 weeks after a systemic febrile illness in an immunocompetent individual. It may occur following bacterial, viruses, or protozoal infection. Optical coherence angiography (OCTA) is a newer non-invasive modality that is an alternative to fundus fluorescein angiography to image the retinal microvasculature. We hereby describe the vascular changes during the acute phase of post fever retinitis on OCTA. Imaging on OCTA was done for all patients with post fever retinitis at presentation with 3 × 3 mm and 8 × 8 mm scans centred on the macula and corresponding enface optical coherence tomography (OCT) scans obtained. A qualitative and quantitative analysis was done for all images. 46 eyes of 33 patients were included in the study. Salient features noted were changes in the superficial (SCP) and deep capillary plexus (DCP) with capillary rarefaction and irregularity of larger vessels in the SCP. The DCP had more capillary rarefaction when compared to the SCP. The foveal avascular zone (FAZ) was altered with an irregular perifoveal network. Our series of post fever retinitis describes the salient vascular features on OCTA. Although the presumed aetiology was different in all our patients, they developed similar changes on OCTA. While OCTA is not useful if there is gross macular oedema, the altered FAZ can be indicative of macular ischemia.

Acute Macular Neuroretinopathy in Purtscher Retinopathy

Purtscher retinopathy and acute macular neuroretinopathy are two rare clinical disorders that are both probably associated with ischemic pathogenesis. In this report, we describe for the first time the coexistence of Purtscher retinopathy and acute macular neuroretinopathy in a patient with visual complaints after chest trauma. Optical coherence tomography (OCT) scans demonstrated outer retinal defects, while OCT angiography illustrated areas of hypoperfusion in the superficial and deep capillary plexuses as well as the choriocapillaris. In this report, it is emphasized that acute macular neuroretinopathy is a clinical condition that should be kept in mind in patients presenting with post-traumatic vision loss. Although its clinical diagnosis is difficult, characteristic OCT and OCT angiography findings facilitate diagnosis.

Three-years follow-up swept source optical coherence tomography angiography findings in post-fever retinitis

Post fever retinitis (PFR), characterized by multiple cotton wool spot like lesions in the posterior pole, is commonly reported following viral and bacterial infections. Retinal perfusion defects have been documented with the help of optical coherence tomography angiography (OCTA) in cases of PFR. But long term changes in such cases have not been reported earlier. In the following report, we have described the swept-source OCTA findings of two PFR patients at initial presentation and three years follow-up. Initial OCTA scans may not provide accurate information regarding the perfusion status due to associated retinal edema and inflammation. However, persisting perfusion defects at the superficial and deep retinal capillary plexus were noted on long term follow-up in both the cases.

Dengue virus infects the mouse eye following systemic or intracranial infection and induces inflammatory responses

Dengue virus (DENV) infection is associated with clinical ocular presentations and here DENV infection of the eye was assessed in mice. In an AG129 mouse model of antibody-dependent enhancement of DENV infection, DENV RNA was detected in the eye and vascular changes were present in the retinae. Intraocular CD8 and IFN-γ mRNA were increased in mice born to DENV-naïve, but not DENV-immune mothers, while TNF-α mRNA was induced and significantly higher in mice born to DENV-immune than DENV-naïve mothers. DENV RNA was detected in the eye following intracranial DENV infection and CD8 mRNA but not IFN-γ nor TNF-α were induced. In all models, viperin was increased following DENV infection. Thus, DENV in the circulation or the brain can infect the eye and stimulate innate immune responses, with induction of viperin as one response that consistently occurs in multiple DENV eye-infection models in both an IFN-dependent and independent manner.

Bilateral Acute Macular Neuroretinopathy in a Young Patient: Imaging and Visual Field during Two-Year-Follow-Up

Acute macular neuroretinopathy (AMN) is a rare disorder. We report a case of bilateral AMN in a young female patient, without any risk factors. She referred a positive scotoma in both eyes after flu-like symptoms. Fundus examination revealed parafoveal dark-reddish oval lesions in both eyes. Therefore, we performed visual field, optical coherence tomography (OCT), fluorescein angiography (FA) and indocyanine green angiography (ICG) at baseline and several times during the two years of follow-up. The infrared (IR) imaging showed one rounded hyporeflective lesion in the left eye and two similar lesions in the right eye. The OCT demonstrated the characteristic alterations in the outer retina. The visual field also demonstrated scotomas corresponding with these lesions. The OCT and IR features disappeared at the end of the follow-up except for the left eye, which continued to have hyperreflective spots in the outer plexiform layer. The patient complained about a residual scotoma only in the left eye after two years. Our case shows a difference in disease progression in the two eyes of the same patient, suggesting that several mechanisms can be implicated in the pathology of AMN.

Monitoring Ischemic Changes in Retinal Vasculitis With Optical Coherence Tomography Angiography

Purpose:

This article illustrates the ability of optical coherence tomography angiography (OCTA) to aid in the diagnostic workup and management of occlusive retinal vasculitis over time.

Methods:

A case presentation is discussed.

Results:

In this case, OCTA helped define the extent and evolution of superficial and deep retinal capillary plexus occlusion and reperfusion over the treatment course.

Conclusions:

OCTA detects blood flow and maps retinal vasculature at the capillary level without the use of intravenous dye. Serial image acquisition can reveal patterns of ischemia and reperfusion in retinal vascular conditions as they evolve and respond to therapy, providing more granular information regarding the status of the retinal microvasculature that may guide treatment.

Acute Macular Neuroretinopathy Associated with Acute Influenza Virus Infection

Purpose: To describe a prospective case series of patients with acute macular neuroretinopathy (AMN) associated with acute influenza virus infectionMethods: Patients who presented with acute macular neuroretinopathy associated with confirmed influenza virus infection were subject to a detailed clinical history, HLA typing and longitudinal ophthalmological and imaging examinations.Results: Four female patients aged 18 to 32 years were studied. They reported the onset of ocular symptoms between 2 and 5 days after the development of flu like symptoms. Three patients had confirmed acute influenza B infection, while the fourth had influenza A. OCT angiography only demonstrated abnormal choriocapillaris perfusion in 1 patient and early oral Oseltamivir treatment appeared not to affect the ophthalmic outcome in one patient.Conclusion: This is the first report of AMN associated with virologically confirmed acute influenza virus infection. Variation in HLA alleles do not appear to predispose patients to influenza associated AMN.

Optical coherence tomography angiography features of retinitis post-rickettsial fever

The intraocular manifestations of rickettisial retinitis include retinal vasculitis, maculopathy, optic neuritis, and neurosensory detachment. Extensive leakage of dye on the fundus fluorescein angiography may obscure visualization in eyes with retinitis. We report the vascular changes in eyes with rickettsial retinitis and its response to treatment using optical coherence tomography angiography. The microvascular abnormalities we noted were, capillary drop out areas corresponding to retinitis patches, vascular loops, and pruning of vessels. The choriocapillary slabs showed signal void areas. Post-treatment there was vascular remodeling with decrease in non-perfused area, appearance of new vascular lateral branching, and appearance of collaterals.

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.

Infectious uveitis: an Asian perspective

Several intraocular infections can present with protean manifestations posing major diagnostic and management challenges. Infections such as tuberculosis, dengue and chikungunya fever have continued to remain major endemic diseases that are associated with uveitis in the Asia Pacific region. These entities often require a high index of clinical suspicion and laboratory analysis including assays of ocular fluids and/or tissues for confirmation of the diagnosis. Infectious uveitis caused by tuberculosis, dengue and chikungunya can present with characteristic clinical features and imaging findings on ancillary investigations; that may provide clue to the early diagnosis. Use of modern imaging modalities such as enhanced-depth imaging optical coherence tomography, optical coherence tomography angiography and ultra-wide field fundus photography greatly aid in the evaluation of these conditions. In the current review, we have discussed the epidemiology, clinical phenotypes, imaging characteristics, diagnosis and management of uveitis caused by tuberculosis, dengue and chikungunya.

Dengue-Induced Inflammatory, Ischemic Foveolitis and Outer Maculopathy: A Swept-Source Imaging Evaluation

PURPOSE

Dengue maculopathy can present with a unique constellation of features resulting in significant central visual morbidity. We aim to describe various findings of dengue-induced inflammatory, ischemic foveolitis, and outer maculopathy (DIII-FOM) and assess the serial changes in vitreous inflammation, retinal structure, and vascularity using swept-source OCT (SS-OCT) and OCT angiography (OCTA).

DESIGN

Retrospective case series.

PARTICIPANTS

A total of 32 eyes (16 patients; 7 male) with dengue fever (positive serology for NS1 antigen) were enrolled in the study.

METHODS

In this study, serial assessments of ocular findings and imaging using fundus photography, SS-OCT, and SS-OCTA were performed. All the patients received 0.5 to 1 mg/kg/day oral prednisolone that was tapered over 4 to 6 weeks.

MAIN OUTCOME MEASURES

Outcome measures included functional change, that is, improvement in best-corrected visual acuity (BCVA), structural changes in the vitreous and retinal layers on SS-OCT, and retinal perfusion on OCTA.

RESULTS

The mean age of the patients was 29.17±10.91 years. Swept-source OCT showed vitreous cells (32 eyes; 100%), disruption of outer retinal layers (foveolitis) (24 eyes; 75%), and conical foveal elevation (22 eyes; 68.75%). After initiation of systemic corticosteroids, all the eyes showed resolution of vitreous cells and improvement in the integrity of retinal layers. Mean BCVA improved from an initial 0.80±0.33 logarithm of the minimum angle of resolution (logMAR) to 0.23±0.36 logMAR. Retinal plexus flow deficit (superficial plexus: 0.10±0.12 mm²; deep plexus: 0.29±0.13 mm²) persisted in all eyes and correlated well with initial BCVA (P < 0.05).

CONCLUSIONS

The pathophysiology of dengue maculopathy involves both ischemic and inflammatory components. Early institution of corticosteroid therapy may help in resolution of the inflammation-driven vitreoretinal alterations, but ischemia of the deep retinal plexuses may persist and may be the cause of permanent structural and functional changes.