Retinal Microvascular Impairment in COVID-19 Bilateral Pneumonia Assessed by Optical Coherence Tomography Angiography

COVID-19 and retinal layer thickness: A bidirectional Mendelian randomization study

BACKGROUND

Observational studies have reported that COVID-19 is associated with alterations in retinal layer thickness, including changes in the ganglion cell inner plexiform layer (GCIPL) and retinal nerve fiber layer (RNFL). However, the causal relationships remain unknown. Therefore, we assessed the direction and strength of the causal relationship between COVID-19 and GCIPL and RNFL thicknesses using a bidirectional two-sample Mendelian randomization (MR) design.

METHODS

Data were obtained from a large-scale COVID-19 Host Genetics Initiative (Nsample = 6,512,887), GCIPL dataset (Ncase = 31,434), and RNFL dataset (Ncase = 31,434). The inverse-variance weighted (IVW) method is the primary approach used to estimate causal effects. MR Egger, weighted median, weighted mode, MR Egger (bootstrap), and penalized weighted median methods were applied. Sensitivity analyses were implemented with RadialMR, MRPRESSO, MR-Egger regression, Cochran's Q statistic, leave-one-out analysis, and the funnel plot.

RESULTS

Forward MR analysis revealed that genetically identified COVID-19 susceptibility significantly increased the risk of GCIPL thickness (OR = 2.428, 95 % confidence interval [CI]:1.493-3.947, PIVW = 3.579 × 10-4) and RNFL thickness (OR = 1.735, 95 % CI:1.198-2.513, PIVW = 3.580 × 10-3) after Bonferroni correction. Reverse MR analysis did not indicate a significant causal association between GCIPL and RNFL thicknesses and COVID-19 phenotypes. No significant horizontal pleiotropy was found in the sensitivity analysis.

CONCLUSIONS

The host genetic liability to COVID-19 susceptibility was causally associated with increased GCIPL and RNFL thicknesses. Documenting this association increases our understanding of the pathophysiological mechanisms underlying COVID -19 susceptibility in retinopathy.

Optic nerve head alterations after COVID-19: an optical coherence tomography angiography-based longitudinal study

OBJECTIVE

To evaluate longitudinal changes in peripapillary vessel density (VD) following coronavirus disease 2019 (COVID-19) using optical coherence tomography angiography.

METHODS

As part of a prospective longitudinal observational study, we studied healthy individuals with a history of mild COVID-19 confirmed via real-time polymerase chain reaction. After recovery, we used the Optovue RTVue XR Avanti machine to perform optic nerve head (ONH) imaging. We also assessed the VD of all vessels and of small vessels in the disc and the radial peripapillary capillary (RPC) network at 1 and 3 months post-recovery.

RESULTS

We included 17 patients (34 eyes; mean age: 36.9 ± 10.2 years, range: 24-62 years) who had recovered from COVID-19. No changes were observed in the ONH parameters. However, there was a noticeable trend of increased small vessel VD values in the RPC. These increases were significant for the peripapillary whole, superior hemifield, inferior-temporal, temporal-superior, and superior-temporal small vessels. Moreover, the evaluation of all vessel VD values in the RPC revealed a significant decrease in the inside disc and a significant increase in a grid-based inferior region.

CONCLUSION

COVID-19 may affect VD of the RPC in the ONH, and should be considered in ONH evaluations.

The neurovascular retinal involvement in a large population of patients recovered from COVID-19: an OCT and OCT angiography study

BACKGROUND

This study aimed to assess the neuronal and microvascular retinal and choroidal involvement in COVID-19 recovered patients using optical coherence tomography (OCT) and OCT angiography (OCTA).

METHODS

This observational cross-sectional study recruited patients recovered from COVID-19 and a group of healthy controls for comparisons. OCT (peripapillary scan and macular map) and OCTA (macular map) were performed to obtain: the central subfield thickness (CST), the macular volume (MV), the peripapillary retinal nerve fibre layer (pRNFL) thickness, the vessel area density (VAD), vessel length fraction (VLF), vessel diameter index (VDI) and fractal dimension (FD) of the superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP), and the vessel density (VD), stromal density (SD) and vascular/stromal (V/S) ratio of the choriocapillaris (CC) and choroid (Ch). Data regarding disease severity, administered therapy and prior comorbidities were collected.

RESULTS

We recruited 676 eyes from 338 patients and 98 eyes from 49 healthy controls. VAD of all the three retinal plexuses, VLF and VDI of ICP and DCP and VD of CC were significantly reduced in patients versus controls. No differences were found in CST, MV and pRNFL. A multivariate analysis showed that oxygen therapy, previous cardio/cerebrovascular events and hypertension negatively influenced vascular parameters.

CONCLUSION

A microvascular retinal and choriocapillaris damage may be identified secondary to SARS-CoV-2 infection, even after recovery. OCTA may represent a reproducible and non-invasive tool to assess microangiopathy in these patients, with particular regard to those with previous cardio/cerebrovascular events, hypertension and those who received oxygen therapy.

New findings on retinal microvascular changes in patients with primary COVID-19 infection: a longitudinal study

Purpose

To investigate the longitudinal alterations of retinal microvasculature in patients with primary coronavirus disease 2019 (COVID-19) infection.

Methods

A cohort of participants, who had never been infected with COVID-19, was recruited between December 2022 and May 2023 at Peking Union Medical College Hospital in Beijing, China. Participants underwent comprehensive ophthalmologic examinations and fundus imaging, which included color fundus photography, autofluorescence photography, swept-source optical coherence tomography (SS-OCT) and SS-OCT angiography (SS-OCTA). If participants were infected with COVID-19 during the study, follow-ups with consistent imaging modality were conducted within one week and two months after recovery from the infection.

Results

31 patients (61 eyes), with a mean age of 31.0 ± 7.2 years old, were eligible for this study. All participants contracted mild COVID-19 infection within one month of baseline data collection. The average period was 10.9 ± 2.0 days post-infection for the first follow-up and 61.0 ± 3.5 days for the second follow-up. No clinical retinal microvasculopathy features were observed during the follow-ups. However, SS-OCTA analysis showed a significant increase in macular vessel density (MVD) from 60.76 ± 2.88% at baseline to 61.59 ± 3.72%(p=0.015) at the first follow-up, which subsequently returned to the baseline level of 60.23 ± 3.33% (p=0.162) at the two-month follow-up. The foveal avascular zone (FAZ) remained stable during the follow-ups with areas of 0.339 ± 0.097mm2, 0.342 ± 0.093mm2, and 0.344 ± 0.098mm2 at the baseline, first follow-up (p=0.09) and second follow-up (p=0.052), respectively. Central macular thickness, cube volume and ganglion cell-inner plexiform layer showed a transient decrease at the first follow-up(p<0.001, p=0.039, p=0.002, respectively), and increased to baseline level at the two-month follow-up(p=0.401, p=0.368, p=0.438, respectively).

Conclusion

Mild COVID-19 infection may temporarily and reversibly impact retinal microvasculature, characterized by a transient increase in retinal blood flow during the early recovery phase, which returns to the pre-infection level two months post-infection.

The prone position in COVID-19 impacts the thickness of peripapillary retinal nerve fiber layers and macular ganglion cell layers

The prone position reduces mortality in severe cases of COVID-19 with acute respiratory distress syndrome. However, visual loss and changes to the peripapillary retinal nerve fiber layer (p-RNFL) and the macular ganglion cell layer and inner plexiform layer (m-GCIPL) have occurred in patients undergoing surgery in the prone position. Moreover, COVID-19-related eye problems have been reported. This study compared the p-RNFL and m-GCIPL thicknesses of COVID-19 patients who were placed in the prone position with patients who were not. This prospective longitudinal and case-control study investigated 15 COVID-19 patients placed in the prone position (the "Prone Group"), 23 COVID-19 patients not in the prone position (the "Non-Prone Group"), and 23 healthy, non-COVID individuals without ocular disease or systemic conditions (the "Control Group"). The p-RNFL and m-GCIPL thicknesses of the COVID-19 patients were measured at 1, 3, and 6 months and compared within and between groups. The result showed that the Prone and Non-Prone Groups had no significant differences in their p-RNFL thicknesses at the 3 follow-ups. However, the m-GCIPL analysis revealed significant differences in the inferior sector of the Non-Prone Group between months 1 and 3 (mean difference, 0.74 μm; P = 0.009). The p-RNFL analysis showed a significantly greater thickness at 6 months for the superior sector of the Non-Prone Group (131.61 ± 12.08 μm) than for the Prone Group (118.87 ± 18.21 μm; P = 0.039). The m-GCIPL analysis revealed that the inferior sector was significantly thinner in the Non-Prone Group than in the Control Group (at 1 month 80.57 ± 4.60 versus 83.87 ± 5.43 μm; P = 0.031 and at 6 months 80.48 ± 3.96 versus 83.87 ± 5.43 μm; P = 0.044). In conclusion, the prone position in COVID-19 patients can lead to early loss of p-RNFL thickness due to rising intraocular pressure, which is independent of the timing of prone positioning. Consequently, there is no increase in COVID-19 patients' morbidity burden.

Ocular repercussions in COVID-19 patients: structural changes of the retina and choroid

BACKGROUND

Neurotropic capabilities of SARS-COVs allow viruses to reach the central nervous system by hematogenous neuronal dissemination. The human retina, as an extension of the Central Nervous System, may have some neurodegenerative and/or vascular modifications related to COVID-19.

OBJECTIVES

To evaluate choroidal and inner neural layers in participants previously recovered from COVID-19 compared to the control group using optical coherence tomography.

METHODS

With a cross-sectional approach, the sample (n = 96), constituted by patients who have recovered from COVID-19 (n = 56) and healthy participants control group (n = 40) were ophthalmologically characterized. The neurodegenerative and vascular histological assessment was performed using SD-OCT and the mean thickness was measured in Early Treatment Diabetic Retinopathy Study (ETDRS) subfields. Retinal nerve fiber layer, Ganglion cell layer and subfoveal choroidal thickness were obtained through semi-automatic measurement.

RESULTS

A total of 40 controls (27 women [67.5%]) and 56 COVID-19 participants (34 women [60.8%]) were included in this first report. There were retinal thickness significant differences in nearly all inner ETDRS subfields: nasal 3 mm (p = .025), I3 (p = .049), and temporal 3 mm (p = .009). Also, a decrease in neural layers was found in the nasal 3 mm (p = .049) and temporal 3 mm (p = .029) during ganglion cell layer assessment. The peripapillary retinal nerve fiber layer thickness was thinner in the COVID-19 group in superior temporal (p = .019), nasal (p = .002), inferior temporal (p = .046) and global (p = .014). Concerning the subfoveal choroidal measurement, an increase was observed in the COVID-19 group (p = .002).

CONCLUSION

Participants who had recovered from COVID-19 showed a non-glaucomatous neuropathy trend pattern. We found differences closer to the classic description of the "bow-tie" observed in other neurological as compressive neuropathies at the chiasma location. OCT assessment also showed an increase in choroidal thickness as a result of vascular changes.

Effects of COVID-19 infection on retinal vascular density and choroidal thickness measured by optical coherence tomography angiography

AIM

The present study evaluates the possible effects of COVID-19 on choroid thickness, the Foveal Avascular Zone (FAZ) and retinal vascular indices in the same individuals who had Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA) data prior to the COVID-19 pandemic.

METHODS

The OCT and OCTA images of the same individuals with no known ophthalmic pathology who developed a COVID-19 infection were obtained were retrieved retrospectively from the database and compared with the repeated images of OCT and OCTA images 1-2 months after COVID-19 infection.

RESULTS

Eighty eyes of 40 patients (26 female [65%], 14 male [35%]) who had developed a prior Covid-19 infection were included in the study. When comparing the measurements of the same participants before and after Covid-19 infection, no significant difference was detected in the mean average choroidal thicknesses (p=0.998), average superficial (p=0.425) and deep (p=0.333) retinal vascular densities, and superficial (p=0.991) and deep (p=0.075) FAZ measurements.

CONCLUSIONS

No significant effect of COVID-19 on choroid thickness, FAZ or retinal vascular densities was noted in the present study, although there are some studies in literature with equivocal results.

Retinal Microvasculature Image Analysis Using Optical Coherence Tomography Angiography in Patients with Post-COVID-19 Syndrome

Several optical coherence tomography angiography (OCT-A) studies have demonstrated retinal microvascular changes in patients post-SARS-CoV-2 infection, reflecting retinal-systemic microvasculature homology. Post-COVID-19 syndrome (PCS) entails persistent symptoms following SARS-CoV-2 infection. In this study, we investigated the retinal microvasculature in PCS patients using OCT-angiography and analysed the macular retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL) thickness via spectral domain-OCT (SD-OCT). Conducted at the Manchester Royal Eye Hospital, UK, this cross-sectional study compared 40 PCS participants with 40 healthy controls, who underwent ophthalmic assessments, SD-OCT, and OCT-A imaging. OCT-A images from the superficial capillary plexus (SCP) were analysed using an in-house specialised software, OCT-A vascular image analysis (OCTAVIA), measuring the mean large vessel and capillary intensity, vessel density, ischaemia areas, and foveal avascular zone (FAZ) area and circularity. RNFL and GCL thickness was measured using the OCT machine's software. Retinal evaluations occurred at an average of 15.2 ± 6.9 months post SARS-CoV-2 infection in PCS participants. Our findings revealed no significant differences between the PCS and control groups in the OCT-A parameters or RNFL and GCL thicknesses, indicating that no long-term damage ensued in the vascular bed or retinal layers within our cohort, providing a degree of reassurance for PCS patients.

Comprehensive Assessment of Eyes in Kidney Transplant Recipients after Recovering from COVID-19

INTRODUCTION

Patients after organ transplantation with COVID-19 have a higher risk of morbidity and mortality than patients in the general population. There are single studies that assess the eyes of COVID-19 patients, but there are no such studies on organ transplant recipients. The purpose of this study was to comprehensively examine the eyes of kidney transplant recipients (KTR) after recovery from mild to moderate SARS-CoV-2 infection.

METHODS

A total of 40 KTR after COVID-19 and 20 KTR without clinical and immunological symptoms of SARS-CoV-2 infection as a control group was qualified for the cross-sectional study. A total of 76 eyes from 38 KTR on an average of 7 weeks after COVID-19 and 36 eyes from 18 KTR from the control group were studied. The participants underwent an ophthalmological examination, and the retinal and choroid vessels and nerves were assessed by optical coherence tomography angiography.

RESULTS

We found a lower vessel density (VD) in the deep capillary plexus in the central part of the retina (VD deep central) of the study group. Women had significantly lower VD deep central in the study group (15.51 vs. 18.91, p < 0.001). Multivariate linear regression analysis confirmed an independent, negative impact of COVID-19 (p < 0.001) and female gender (p = 0.001) on VD deep central.

CONCLUSION

The results of our study confirmed that changes in microcirculation induced by SARS-CoV-2 infection may affect the retinal vessels in KTR. Mild to moderate COVID-19 in KTR resulted in a significant reduction in VD deep central of the retina, with these changes being more common in females.

Effects of Sinovac-Coronavac and Pfizer-BioNTech mRNA vaccines on choroidal and retinal vascular system

PURPOSE

To evaluate the effects of Sinovac-Coronavac and Pfizer-BioNTech mRNA vaccines on choroidal and retinal vascular system using enhanced depth imaging optical coherence tomography (EDI-OCT) and optical coherence tomography angiography (OCTA).

METHODS

In this prospective cross-sectional study, 63 healthy participants (29 with Pfizer-BioNTech, 34 with Sinovac-CoronaVac) were evaluated after the first dose of vaccination. Vessel density (VD) of the superficial (SCP), deep capillary plexus (DCP) and choriocapillaris (CC) were measured with OCTA. Choroidal thickness (CT) were measured with EDI-OCT. Measurements were performed at the 2nd week and the 4th week after vaccinations and compared to pre-vaccination values.

RESULTS

Regarding Pfizer-BioNTech vaccination, CT in the subfoveal and nasal region significantly increased between the pre-vaccination and post-vaccination 2nd week and then significantly decreased to pre-vaccine values at 4th week. The SCP-VD (whole image, fovea, parafovea, perifovea temporal) variables showed a significant decrease at 2nd week. The DCP-VD inferior hemi, parafovea inferior hemi, parafovea inferior variables demonstrated a significant decrease at 2nd week. The perifovea DCP-VD variables also showed a significant decrease at 2nd week, and these variables returned to pre-vaccination values after 4 weeks. The CC-VD variables showed a significant decrease between pre-vaccine and 2nd week post-vaccination. Regarding the Sinovac-CoronaVac vaccination, there was no statistically significant difference in CT and VD values before and after vaccination (p> 0.05).

CONCLUSION

Our study showed significant alterations in retinal vascular density and CT for the Pfizer-BioNTech vaccine at the 2nd week, and these parameters became compatible with pre-vaccination values at the 4th week. In contrast, no differences were observed after the Sinovac-Coronovac vaccination.

Retinal microvascular abnormalities, cotton wool-like lesions, and macular edema following COVID-19 in a patient previously vaccinated with AstraZeneca and idiopathic myopathy

In this case study, the authors describe peculiar bilateral cotton wool-like retinal lesions associated with macular edema in a patient with COVID-19 who was vaccinated with a single dose of AstraZeneca one month earlier. This patient had no pulmonary or systemic cardiovascular complications from COVID-19, as reported in other papers that found retinal lesions. However, the patient was diagnosed with idiopathic myopathy when discovering the SARS-CoV-2 infection. The patient was a 22-year-old white female with no previous history of morbidity, complaining of blurred vision in both eyes seven days after testing positive for SARS-CoV-2 by PCR (using nasal and oral swab) and confirmed through ELISA blood test (IgM positive). There was no ancillary test revealing diabetes mellitus. The patient presented with scattered whitish cotton wool-like lesions and a few hemorrhages on the posterior pole in fundus examination. On spectral domain optical coherence tomography (SD-OCT), there were hyperreflective lesions in the nerve fiber layer, ganglion cell layer, inner nuclear layer, and inner and outer plexiform layers at the site corresponding to the whitish cotton wool-like lesions in the posterior fundus photos. Moreover, the macula of both eyes had intraretinal and subretinal fluid, reversible with corticosteroid therapy. In conclusion, COVID-19 has been associated with capillary disorders at different target sites such as retina, lungs, and central nervous system. Similarly, vaccination against SARS-CoV-2 has been linked to retinal complications in the literature; however, cotton wool-like lesions have not yet been reported. There are many questions yet to be answered about the implications of COVID-19 infection and its vaccines.

Post COVID-19 Retinal Evaluation Using Optical Coherence Tomography Angiography: A Case Control Study

PURPOSE

To study the effect of coronavirus disease of 2019 (COVID-19) on retinal vasculature by Optical Coherence Tomography Angiography (OCTA).

METHODS

Macular OCTA images of patients recovered from COVID-19 infections were studied including foveal avascular zone (FAZ), capillary vascular densities (CVD) of the superficial and deep capillary network (SCP, DCP), and central foveal thickness (CFT).

RESULTS

The FAZ area was significantly larger in post COVID-19 cases compared to the healthy controls (p=0.032). Post COVID-19 cases had significant lower CVDs in perifoveal quadrants of the SCP. They also had lower CVD in the whole area, parafoveal, temporal and inferior perifoveal areas in the DCP. The parafoveal DCP area showed a positive correlation with disease duration (r=0.249, p-value=0.018). The whole SCP was significantly larger in cases with lymphopenia (p-value=0.004).

CONCLUSION

This study found asymptomatic retinal vascular affection in post COVID-19 eyes showing a relation with disease clinical and laboratory features.

Neuro-Ophthalmic Visual Impairment in the Setting of COVID-19

We set out to describe in detail the afferent neuro-ophthalmological complications that have been reported in association with coronavirus disease 2019 (COVID-19) infection. We describe and elaborate on mechanisms of disease, including para-infectious inflammation, hypercoagulability, endothelial damage, and direct neurotropic viral invasion. Despite global vaccination programs, new variants of COVID-19 continue to pose an international threat, and patients with rare neuro-ophthalmic complications are likely to continue to present for care.Afferent complications from COVID-19 include homonymous visual field loss, with or without higher cortical visual syndromes, resulting from stroke, intracerebral hemorrhage, or posterior reversible leukoencephalopathy. Optic neuritis has frequently been reported, sometimes along with acute disseminated encephalomyelopathy, often in association with either myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) or less commonly aquaporin-4 seropositivity or in newly diagnosed multiple sclerosis. Ischemic optic neuropathy has rarely been reported. Papilledema, resulting either from venous sinus thrombosis or idiopathic intracranial hypertension in the setting of COVID-19, has also been described.Observed afferent neuro-ophthalmic associations need to be confirmed though larger comparative studies. Meanwhile, the range of possible complications should be recognized by neurologists and ophthalmologists alike, to facilitate faster diagnosis and treatment of both COVID-19 and its neuro-ophthalmic manifestations.

Reduced Vessel Density and Enlarged Foveal Avascular Zone in the Macula as a Result of Systemic Hypoxia Caused by SARS-CoV-2 Infection

Infection with SARS-CoV-2 can lead to various long-term consequences, including those of an ophthalmic nature. This paper reviews the results of optical coherence tomography angiography (OCTA) performed among COVID-19 patients. The review included papers evaluating short- and long-term outcomes following the SARS-CoV-2 infection. Some differentiated the obtained retinal and choroidal vascularization parameters according to gender. Following COVID-19, patients reveal changes in retinal and choroidal vascular parameters based on OCTA, such as reduced vascular density and an increased foveal avascular zone, which can persist for several months. Routine ophthalmic follow-up with OCTA should be considered in patients after SARS-CoV-2 infection to assess the effects of inflammation and systemic hypoxia in COVID-19. Further research is needed to understand whether infection with particular viral variants/subvariants may vary in the risk of effects on retinal and choroidal vascularization and whether and to what extent these risks may also differ in relation to reinfected and vaccinated individuals.

Analysis of Microvasculature in Children Recovered from COVID-19 Using Swept-Source OCT/OCTA Technology

PURPOSE

To analyze structural and vascular changes of the retina and choroid in pediatric patients with coronavirus disease 2019 (COVID-19) using optical coherence tomography (OCT)/OCT angiography (OCTA).

METHODS

This comparative cross-sectional study consists of the COVID-19 group including pediatric COVID-19 patients and the control group including healthy children. Vessel density (VD), central macular thickness,, and choroidal thickness (ChT) measurements were performed using swept-source OCT/OCTA 12 weeks after the recovery from COVID-19.

RESULTS

The mean VD measurements in the central fovea and nasal quadrants of all three retinal layers and choriocapillaris showed insignificantly lower values in the COVID-19 group when compared to the control group (0:002 < p < 0:05 for all). Similar to VD measurements, insignificant lower ChT measurements were obtained in the central fovea and nasal points in the COVID-19 group.

CONCLUSION

OCTA can be used as a non-invasive and valid biomarker in the assessment of early microvascular dysfunction associated with COVID-19.

Evaluation of the retina with optical coherence tomography angiography (OCTA) in patients with coronavirus (COVID-19) infection

PURPOSE

The goal of this study is to compare the optical coherence tomography angiography (OCTA) findings in Coronavirus (COVID-19) positive adult and pediatric patients with those of healthy volunteers with the same demographic characteristics.

METHODS

The right eye of 157 adults infected with covid, 168 healthy adult volunteers, 40 children (6-18 years of age) infected with covid, and 44 healthy children (6-18 years of age) were included in this prospective study. All participants underwent ophthalmological examination and OCTA. The OCTA findings were evaluated.

RESULTS

Deep nasal density (DND), deep inferior density (DID), and deep parafoveal density (DPD) were significantly lower in the pediatric covid-affected group (PCAG) than in the pediatric healthy control group (PHCG) (P=0.034, P=0.029, P=0.022 respectively). On the other hand, radial peripapillary capillary vessel density (RPCVD) intra-disc measurements were significantly higher in the PCAG compared to the PHCG (P=0.025). There was no significant difference between the OCTA measurements of the adult covid-affected group (ACAG) and the adult healthy control group (AHCG).

CONCLUSION

In our study, significant differences were found in OCTA measurements between the covid group and the healthy control group in children. Retinal microvascular changes may occur in patients with covid infection, and these patients might be followed for long-term retinal changes.

Analysis of Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA) Parameters in Young Adults after SARS-CoV-2 Infection (COVID-19) Compared with Healthy Young Controls

Purpose: To compare retinal changes in young adults with previous SARS-CoV-2 infection with healthy young controls using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). Methods: This prospective single-center study was conducted at the University Hospital of Zurich, Zurich, Switzerland. Participants were imaged from May to November 2021 using the SOLIX device (Visionix International SAS, Pont-de-l’Arche, France). We performed 12 mm × 12 mm, 6.4 mm × 6.4 mm, 6 mm × 6 mm and 3 mm × 3 mm OCT and OCTA scans, as well as fundus photography of each participant’s eyes. Results: In total, 466 participants were imaged. Of these, 233 were healthy controls with negative RT-PCR tests for SARS-CoV-2, 168 were young adults who had a SARS-CoV-2 infection at least 180 days previously, 19 were participants who had a SARS-CoV-2 infection < 180 days previously, and 46 were participants with asymptomatic SARS-CoV-2 infection (i.e., serologically positive but with no symptoms). Compared with healthy controls, statistically significant differences were found for OCTA recordings of the optic disc for the whole image (WI) and WI capillary vessel density, with both being higher in the SARS-CoV-2 group. Conclusion: Statistically significant results were only observed for selected variables, and in parts, only unilaterally, with relatively large p values (p = 0.02–0.03). Thus, we did not interpret these as clinically significant, leading to the conclusion that young and otherwise healthy individuals (mainly men) seem to recover from mild COVID-19 infections with no ophthalmological residues.

Macular optical coherence tomography angiography analysis in diabetes mellitus patients with a history of Covid-19

PURPOSE

There is evidence of decreased vessel density in optical coherence tomography angiography (OCTA) after Covid-19. We aimed to investigate whether the outcome of retinal vasculopathy would be worse if patients with diabetes mellitus (DM) were infected with coronavirus using OCTA to assess retinal vessels.

METHODS

One eye of each subject was included in the study. Diabetic patients without retinopathy and non-diabetic controls were divided into four groups according to their Covid-19 history: group 1=DM(-)Covid-19(-); group 2=DM(+)Covid-19(-); group 3=DM(-)Covid-19(+); and group 4=DM(+)Covid-19(+). All Covid-19 patients were not hospitalised. Macular OCTA scans were performed in a 6 × 6 mm area.

RESULTS

Diabetes had no effect on the area of the foveal avascular zone (FAZ), but Covid-19 caused an increase in FAZ area. Diabetes and Covid-19 had an effect on both the superficial capillary plexus (SCP) and the deep capillary plexus (DCP) in the fovea. Eta squared (ƞ2) is a measure of effect size. The effect size of Covid-19 (ƞ2=0.180) was found to be greater than that of diabetes (ƞ2=0.158) on the SCP, whereas the effect size of diabetes (ƞ2=0.159) was found to be greater than that of Covid-19 (ƞ2=0.091) on the DCP.

CONCLUSIONS

The percentage of vessel density was lower in the fovea and the FAZ area was enlarged in the diabetic patients who recovered from Covid-19. In diabetic patients Covid-19 may lead to deterioration of vascular metrics.

The effect of various types of COVID-19 vaccines on the retinal microvasculature

PURPOSE

To detect the effect of various types of COVID-19 vaccine on macular and optic disc microvasculature.

METHOD

One hundred subjects receiving various types of COVID-19 vaccine (AstraZeneca, Sinopharm, Sinovac, Pfizer, and Moderna) were included in this study. A complete ophthalmic examination was done which included best-corrected visual acuity measurement, slit-lamp biomicroscopy, intraocular pressure measurement with Goldmann applanation tonometry, and fundus examination. Optical coherence tomography angiography (OCT-A) was done before and 1 week after receiving the vaccine. Superficial and deep macular capillary densities were measured in the form of the whole image, fovea, parafoveal, and perifoveal capillary density. Optic disc vessel density in the form of the whole disc, inside disc, and peripapillary were also measured.

RESULTS

The superficial macular vessel densities, (whole image, fovea, parafoveal, and perifoveal) showed statistically non-significant changes with P-values (0.269, 0.167, 0.346, and 0.476) respectively. Also, the deep macular vessel densities showed statistically non-significant changes with P-values (0.491, 0.096, 0.724, and 0.386) for the whole image, fovea, parafoveal, and perifoveal respectively. Moreover, RPC (radial peripapillary capillary) density showed no significant changes either (the whole disc, inside disc, or peripapillary) with P-values (0.807, 0.141, 0.883) respectively.

CONCLUSION

Various types of COVID-19 vaccines had no statistically significant effects on macular or optic disc microvasculature.

The Comparison of Retinal Microvascular Findings in Acute COVID-19 and 1-Year after Hospital Discharge Assessed with Multimodal Imaging-A Prospective Longitudinal Cohort Study

This study aimed to quantify possible long-term impairment of the retinal microcirculation and microvasculature by reassessing a cohort of patients with acute COVID-19 without other known comorbidities one year after their discharge from the hospital. Thirty patients in the acute phase of COVID-19 without known systemic comorbidities were enrolled in this prospective longitudinal cohort study. Fundus photography, SS-OCT, and SS-OCTA using swept-source OCT (SS-OCT, Topcon DRI OCT Triton; Topcon Corp., Tokyo, Japan) were performed in the COVID-19 unit and 1-year after hospital discharge. The cohort's median age was 60 years (range 28-65) and 18 (60%) were male. Mean vein diameter (MVD) significantly decreased over time, from 134.8 μm in the acute phase to 112.4 μm at a 1-year follow-up (p < 0.001). A significantly reduced retinal nerve fiber layer (RNFL) thickness was observed at follow-up in the inferior quadrant of the inner ring (mean diff. 0.80 95% CI 0.01-1.60, p = 0.047) and inferior (mean diff. 1.56 95% CI 0.50-2.61, p < 0.001), nasal (mean diff. 2.21 95% CI 1.16-3.27, p < 0.001), and superior (mean diff. 1.69 95% CI 0.63-2.74, p < 0.001) quadrants of the outer ring. There were no statistically significant differences between the groups regarding vessel density of the superior and deep capillary plexuses. The transient dilatation of the retinal vessels in the acute phase of COVID-19, as well as RNFL thickness changes, could become a biomarker of angiopathy in patients with severe COVID-19.

Quantitative analysis of preclinical ocular microvascular changes in Multisystemic Inflammatory Syndrome in Children (MIS-C) detected by optical coherence tomography angiography

OBJECTIVES

To evaluate the macular and optic nerve head (ONH) vascular density, foveal avascular zone area, and outer retina and choriocapillaris flow in Multisystemic Inflammatory Syndrome in Children (MIS-C) using optical coherence tomography angiography (OCTA).

METHODS

Thirty-four eyes of 34 patients with MIS-C and 36 age and sex-matched healthy controls were investigated in this prospective, cross-sectional study. The superficial capillary plexus (SCP) and deep capillary plexus (DCP), ONH, FAZ parameters, the flow area of the outer retina, and choriocapillaris were evaluated using OCTA.

RESULTS

All VD parameters in SCP were significantly lower in MIS-C patients. There was no significant difference between the groups in VD parameters of both DCP and ONH, as well as FAZ area and FAZ perimeter. However, foveal density (FD-300) was significantly decreased in the MIS-C group. (p = 0.024). The outer retina flow area at 1 mm, 2 mm, and 3 mm radius and CC flow area at 1 mm and 2 mm radius were significantly lower in the MIS-C group than in the control group. Although CC flow area at 3 mm radius was decreased in the MIS-C group compared to healthy controls, the difference was not statistically significant.

CONCLUSIONS

We demonstrated a decreased vessel density in SCP, choriocapillaris flow area, and outer retinal flow area in MIS-C patients. Hence, we proposed that OCTA could reveal retinal and choroidal microvascular changes in MIS-C patients who were completely healthy before the diagnosis of MIS-C.

Retinal Findings in Hospitalized COVID-19 Patients, Is Routine Ophthalmological Examination Required after Discharge? Prospective Case-Control Study

OBJECTIVES

To investigate retinal findings by comparing patients hospitalized for COVID-19 with the control group.

METHODS

In this prospective study, 188 eyes of 94 recovered COVID-19 patients and 108 eyes of 54 healthy participants as a control group were evaluated. Patients were divided into three groups, those with mild, moderate, and severe COVID-19. Refractometry, tonometry, optical biometry, optical coherence tomography (OCT) measurements, and complete ophthalmological examinations were performed on healthy volunteers and COVID-19 patients on average 2 weeks after discharge. Pulse O₂ and vital parameters were also assessed. Primary outcomes were evaluated, such as retinal findings, and secondary outcomes as retinal thickness, choroidal thickness (CT), retinal nerve fiber layer thickness, and ganglion cell layer thickness.

RESULTS

There was no difference between the groups in terms of demographic data, ocular biometry, and intraocular pressure (p > 0.05). Pulse O₂ was lower in the study group (p < 0.001). Retinal findings were detected in 68 (36.1%) of 188 eyes in the study group and 28 (25.9%) of 108 eyes in the control group (p = 0.07). The two most common retinal findings were hypertensive retinopathy and retinal pigment epithelium alterations and/or drusen in both groups. In OCT measurements, significant thinning was observed in nasal macular thickness and superior 2 mm CT in the study group compared to the control group (p < 0.05). In patients divided into subgroups according to disease severity, no significant difference was found between the groups in any OCT parameter (p > 0.05).

CONCLUSION

It has been observed that COVID-19 infection does not cause a specific and sensitive finding in the ocular tissues, especially the retina, and does not produce a reproducible measurement result. Recommending routine eye exam after COVID-19 does not seem cost-effective.

Early-term Optical Coherence Tomography Angiographic Findings in Pediatric Patients Infected with COVID-19

PURPOSE

The aim of this study was to investigate possible vascular changes in pediatric patients infected with COVID-19 and to compare these with an age-matched control group.

METHODS

All patients underwent an ocular assessment and optical coherence tomography angiography examination. Two vascular networks were analyzed as the superficial and deep regions.

RESULTS

Evaluation was made of 40 eyes of 20 patients who had recently recovered from COVID infection and 80 eyes of 40 healthy individuals. The DCP-VD values of the COVID group were significantly lower than the control group in most quadrants. The FAZ PERIM and FAZ area values in the COVID patients were higher than the control group, but not statistically significant (p>.05).

CONCLUSION

Pediatric cases of COVID-19 may differ from adults based on structural and immune response differences, and that OCTA can be a noninvasive guide for analysis of the end-organ effects of pediatric COVID disease.

AT, Rao KC, Chhabra K, Saxena S, Manchanda V, Sharma S. Optical Coherence Tomography Angiography Parameters of the Retina in SARS-CoV-2 Recovered Subjects

INTRODUCTION

This study aims to evaluate retinochoroidal optical coherence tomography angiography (OCTA) parameters in patients recovered from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

This study was an observational study that included 80 subjects being discharged after having negative reports on the reverse transcription-polymerase chain reaction (RT-PCR) test for SARS-CoV-2 to evaluate OCTA parameters of the retina. The subjects underwent an ophthalmic evaluation that included best-corrected visual acuity (BCVA), intraocular pressure (IOP), color vision (CV), contrast sensitivity (CS), and optical coherence tomography (OCT) parameters. OCTA was done for all patients and was evaluated for foveal avascular zone (FAZ) area, perimeter, and circularity index, and vessel density (VD) in superficial capillary plexus (SCP), deep capillary plexus (DCP), outer retina (OR), outer retina chorio-capillaries (ORCC), chorio-capillaries (CC), and choroid (C) using 3 x 3 mm scans. The OCTA parameters were compared with normative data of the Indian population for various parameters in question.

RESULTS

The subjects included 54/80 (67.5%) males and 26/80 (32.5%) females having a mean age of 52.40 ± 15.71 (18-60) years. The systemic evaluation revealed 38.75% of subjects had hypertension, 30% had diabetes, 20% had kidney disease, 5% had tuberculosis, and 3.75% had coronary artery disease. The mean distance BCVA was logarithm of the minimum angle of resolution (LogMAR) (1.17 ± 0.22), mean IOP was 17.0 ± 4.0 mmHg, mean CS was 2.13 ± 0.36, 50.62% of subjects had normal CV on Farnsworth test while 47% had tritanopia, and none of the subjects had red-green CV defect on Ishihara plates. The OCT scan was normal in 90% of eyes while the posterior vitreous detachment was seen in 4% of eyes, broad vitreomacular adhesion in 2.5% of eyes, and the globally adherent epiretinal membrane was seen in 2.5% of eyes. The mean central macular thickness (CMT) measured 245.14 ± 28.41 micrometers. The mean FAZ area measured 0.37 ± 0.15 mm², the perimeter was 3.28 ± 1.08 mm, and the circularity index measured 0.41 ± 0.10. The average VD in SCP measured 16.06 ± 12.29, in DCP measured 9.11 ± 8.75, in OR measured 6.38 ± 7.37, in ORCC measured 42.53 ± 12.46, in CC measured 25.83 ± 16.31, and in C measured 25.52 ± 17.49. The VD in coronavirus disease 2019 (COVID-19) subjects was significantly lesser than that in the healthy Indian population in all layers except ORCC.

CONCLUSIONS

The SARS-CoV-2 recovered subjects have a reduced VD in retinochoroidal layers from COVID-19, an underlying systemic disease, or both. The CS values fall within normal limits. Several subjects show tritanopia on the Farnsworth test but no red-green CV defect on Ishihara plates.

The Effect of Post-Coronavirus Disease 2019 Infection on the Retinal Microvasculature

Purpose

To evaluate the short-term microvasculature changes of the macula and optic disc following coronavirus disease 2019 (COVID-19).

Methods

This study included 150 eyes (50 eyes of healthy controls and 100 eyes of patients) during the 1st month following COVID-19 recovery, as evidenced by two negative polymerase chain reactions. A complete ophthalmic examination and optical coherence tomography angiography were performed to detect the deep and superficial macular vessel density (VD). In addition, the VD of the optic disc was evaluated.

Results

Deep VD (DVD) showed a statistically significant decrease in post-COVID-19 patients, particularly those with severe COVID-19. This reduction occurred in the whole image, parafoveal, and perifoveal VD (P = 0.002, P = 0.002, and P < 0.001, respectively). Concerning the superficial VD (SVD), only the superior hemisphere of the whole image density was statistically significantly reduced (P = 0.037). There was no statistically significant difference in foveal VD (both deep and superficial vessel) among the study groups (P = 0.148 and P = 0.322, respectively). Regarding the foveal avascular zone (FAZ), there was no statistically significant among groups (P = 0.548). Regarding the optic disc, the whole image VD and redial peripapillary capillary VD demonstrated a highly significant decrease, particularly in cases of severe COVID-19. Conversely, inside disc VD showed a nonsignificant change among the study groups.

Conclusions

According to the findings of the current study, retinal microvasculature was affected in the 1st month following recovery from COVID-19. DVD was significantly reduced more than SVD. In addition, peripapillary VD decreased, whereas the FAZ was unaffected.

Ocular manifestations of COVID-19 in pediatric patients

The coronavirus disease-19 (COVID-19) infection may remain asymptomatic or may have several different presentations. Although this disease primarily affects the respiratory system, systemic manifestations affecting the gastrointestinal, cardiovascular, neurological, otorhinolaryngologic, and ophthalmic systems have been reported. Ophthalmic signs may be the first and only sign of COVID-19 infection in children. In the current narrative review, we report the ophthalmic manifestations of COVID-19 in the pediatric age cohort. We performed a comprehensive literature search for the publications on ophthalmic manifestations of COVID-19 in children between 1 March 2020 and 1 January 2022 and compiled the ophthalmic manifestations of this entity among the pediatric population. Conjunctivitis is the most common ophthalmic manifestation in children and can develop at any stage of the disease. Ophthalmic manifestations are seen more commonly in children with severe systemic disease. Long-term and indirect consequence of the COVID-19 disease is the rise of myopia among children. Ophthalmic signs may be the first and only sign of COVID-19 infection in children. Pediatricians, as well as ophthalmologists, must keep observing all children with COVID-19 closely for ophthalmic signs.

Relationship of the main indicators of systemic COVID-associated endotheliopathy with the morphofunctional state and hemodynamics of the retina and chorioid in the acute period of the disease

BACKGROUND: Nonspecific angio- and retinopathy is one of the clinical manifestations of a new coronavirus infection. The frequency of occurrence of these changes in people with severe COVID-19 does not exceed 55%. The causes, course and consequences of these microcirculatory disorders of the retina are currently not well understood. AIM: To study and compare of retinal morphometric parameters and systemic endothelial dysfunction markers, as well as the main clinical and laboratory parameters in patients with moderate and severe coronavirus infection during convalescence. MATERIALS AND METHODS: The study involved 44 patients (86 eyes) who had COVID-19 during the previous 3 months, who were divided into 2 groups: with moderate and severe disease. The control group consisted of 18 healthy volunteers (36 eyes). All patients underwent a standard ophthalmological examination and optical coherence tomography, which included an assessment of the choroidal thickness (CT) and measurement of the mean diameter of the peripapillary arteries (MAD) and veins (MVD). During hospitalization, all patients underwent a laboratory study of venous blood parameters, as well as an assessment of the microcirculation of the sublingual plexus by examining the density of the endothelial glycocalyx (PBR) using the GlycoCheck. RESULTS: In patients who underwent COVID-19, there was a significant increase in CT relative to the control group, amounting to 308, 344 and 392 m, respectively. The most pronounced difference was observed between MVD in patients with severe infection and the control group (119.1 m vs. 99.2 m). In patients with moderate and severe COVID-19, MAD and MVD were positively correlated with TC, with r = 0.389 and r = 0.584, respectively. MVD also correlated with the level of leukocytes (r = 0.504), the ESR value (r = 0.656). Correlations between MVD and data characterizing the state of the glycocalyx in the sublingual vascular plexus were revealed: the filling of small capillaries with erythrocytes (r = 0.587), as well as the marginal perfusion value in large capillaries 2025 m (r = 0.479) and PBR (r = 0.479). Only significant differences and correlations are shown (p 0.005). CONCLUSIONS: In patients who underwent moderate and severe COVID-19 during the convalescence period (up to 30 days), an increase in the diameter of peripapillary vessels and TC is observed, proportional to the severity of COVID-19, laboratory markers of systemic inflammation and hypercoagulation (the number of leukocytes, the ESR value, D-dimer and prothrombin), which indicates the inflammatory nature of the changes. The severity of postcovid retinal microangiopathy correlates with indicators detecting a decreasing of the endothelial glycocalyx thickness in the sublingual capillary plexus, which indirectly indicates a connection with systemic endotheliopathy.

The impact of acute COVID-19 on the retinal microvasculature assessed with multimodal imaging

PURPOSE

To quantify retinal microvascular findings in the acute phase of COVID-19 using multimodal imaging and compare them with healthy, age-matched controls.

METHODS

Hospitalized patients in the acute phase of COVID-19 without known systemic comorbidities (n = 75) and healthy controls (n = 101) aged 18-65 were enrolled in this prospective cross-sectional study. The retinal microcirculation and microvasculature impairments were assessed using fundus photography, swept-source optical coherence tomography, and swept-source optical coherence tomography angiography in the COVID-19 unit and compared with healthy, age-matched controls.

RESULTS

Retinal findings were predominately observed in patients with severe disease (P = 0.006). Patients with severe disease were shown to have increased both mean vein diameter (Coef. = 19.28, 95% CI: 7.34-31.23, P = 0.002) and mean artery diameter (Coef. = 11.07, 95% CI: 0.84-21.67, P = 0.044). Neither blood vessel diameters were correlated with any confounding variables (age, sex, treatment with oxygen, LDH, or ferritin). Patients with severe COVID-19 were shown to have significantly increased retinal nerve fiber layer thickness in the superior and inferior quadrants both in the inner (S: P = 0.046; I: P = 0.016) and outer (S: P = 0.026; I: P = 0.014) ring and significantly increased GCL thickness in the outer temporal quadrant (P = 0.038). There were no statistically significant differences in vessel density or the foveal avascular zone area between the groups.

CONCLUSION

The severity of COVID-19 was significantly correlated with the presence of retinal microangiopathy, which could become a biomarker of angiopathy in patients with COVID-19.

Retinal Microvascular Changes in COVID-19 Bilateral Pneumonia Based on Optical Coherence Tomography Angiography

The purpose of this study was to evaluate retinal and choroidal microvascular alterations with optical coherence tomography angiography (OCTA) in COVID-19 patients hospitalized because of bilateral pneumonia caused by SARS-CoV-2. The vessel density (VD) and foveal avascular zone (FAZ) of 63 patients with SARS-CoV-2 pneumonia who had positive polymerase chain reaction (PCR) tests and who recovered after receiving treatment and 45 healthy age- and gender-matched controls were evaluated and compared using OCTA in the superficial capillary plexus (SCP) and deep capillary plexus (DCP). The VD was also estimated in both groups in the choriocapillaris (CC). In COVID-19 patients, there was a statistically significant difference between the patients and a control group in both superficial (FAZs) and deep (FAZd) avascular zone (p = 0.000). The VD was significantly lower in the foveal area in choriocapillaris (p = 0.046). There were no statistically significant changes in the VD in the superior, inferior, nasal, and temporal quadrants in superficial and deep plexus, or in the choriocapillaris. The VD was not significantly lower in the foveal area in superficial or deep plexus. COVID-19 may affect the retinal vasculature, causing ischemia, enlargement of the FAZ, and lowering of the VD in the choriocapillaris area. Routine ophthalmic examination after SARS-CoV-2 infection should be considered in the course of post-infectious rehabilitation.

Spectral-domain optical coherence tomography assessment of retinal and choroidal changes in patients with coronavirus disease 2019: a case-control study

Objectives

This study aimed to evaluate the retinal and choroidal changes in the macular region of patients with Coronavirus Disease 2019 (COVID-19) using structural spectral-domain optical coherence tomography (SD-OCT) analysis.

Methods

This cross-sectional observational case-control study included patients recovered from COVID-19. The COVID-19 in all participants was confirmed using the reverse transcription-polymerase chain reaction (RT-PCR) technique. The participants had mild to moderate degree of disease without a history of hospitalization, steroid usage, or blood saturation below 92%. Macular SD-OCT was performed at least two weeks and up to one month after recovery from systemic COVID-19. Quantitative and qualitative changes detected by macular SD-OCT imaging were evaluated in COVID-19 recovered patients and compared with the results of age-matched normal controls.

Results

Participants in this study included 30 cases (60 eyes) and 60 healthy controls (120 eyes). In total, 17 (28.3%) eyes in patient group showed at least one abnormal finding indicated by macular SD-OCT imaging included hyperreflective lesions in different retinal layers. In addition, dilated choroidal vessels and retinal pigment epitheliopathy were evident in 41 (68.3.6%) and 4 (6.6%) eyes in patient group, respectively, and their OCT findings resembled those with pachychoroid spectrum. No statistically significant differences were observed in retinal layers or retinal volume between the two groups. The mean ± SD subfoveal choroidal thickness (SFCT) was determined at 380.3 ± 12.40 μm, which was significantly thicker than that in control group (310.7 ± 57.5 μm) (P < 0.001).

Conclusion

Regarding retinal thickness, no significant change was observed in different retina layers of patients with COVID-19; however, there were striking qualitative changes, such as hyperreflective lesions in different retinal layers. The evaluation of choroidal structure and thickness demonstrated remarkable abnormal pachyvessels and significant thickening of the SFCT but the clinical significance of these findings is unknown.

Retinal microvascular impairment in COVID-19 patients: A meta-analysis

Background

The coronavirus disease 2019 (COVID‐19), caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has led to a global pandemic in an unprecedented time frame. Systemic vascular involvement in COVID‐19 has been identified, and SARS‐CoV‐2 has also been found to cause multiple organ ischemia and posterior ocular segment disease in mammals, raising concerns about the human retinal microvascular involvement in SARS‐CoV‐2.

Objective

To objectively assess the presence of retinal microvascular impairment in COVID‐19 patients by optical coherence tomography angiography (OCTA), so as to facilitate the clinical system management of COVID‐19 patients.

Methods

We searched PubMed, Cochrane Library, EMBASE, Ovid, CBM to collect eligible studies. The main outcomes included the vessel density (VD), area or perimeter of foveal avascular zone (FAZ), central foveal thickness (CFT), subfoveal choroidal thickness (SCT) in our meta‐analysis.

Results

We eventually included five studies with a total of 401 participants. Our meta‐analysis showed that nonacute infectious COVID‐19 or post‐COVID‐19 patients presented significantly lower foveal VD of deep capillary plexus (WMD = −4.22, 95% CI [−8.00, −0.43]) and thinner SCT (WMD = −10.33, 95% CI [−19.08, −1.57]) than healthy controls. The foveal VD and parafoveal VD of superficial capillary plexus, parafoveal VD of deep capillary plexus, CFT, area, and perimeter of FAZ showed no significant differences between the groups.

Conclusion

The patients of nonacute infectious COVID‐19 or post‐COVID‐19 displayed alterations in the retinal microvasculature and choroidal vessels, including a significantly lower foveal VD in deep capillary plexus and thinner SCT. The impairment may be a medium to long‐term process. Close ophthalmic surveillance is necessary for COVID‐19 patients or post‐COVID‐19 patients.

Use of Imaging Technology to Assess the Effect of COVID-19 on Retinal Tissues: A Systematic Review

PURPOSE

To evaluate the effect of COVID-19 on retinal tissues by conducting a systematic review and meta-analysis of the current literature.

BACKGROUND

The novel coronavirus disease is not yet well understood. The orbit provides a window into the body's microvasculature, and as such, it is a non-invasive opportunity to analyse the systemic circulation in vivo. By analysing the current literature, we test the hypothesis that non-invasive imaging of the retina could provide insight into the effect of COVID-19 on the retinal microvasculature.

METHODS

For this systematic review and meta-analysis, we screened PubMed databases and LitCOVID19 using the search criteria: (OCTA or Optical Coherence Tomography Angiography) AND (COVID-19 or corona or SARS-CoV-2) AND (retina or fundus). Databases were searched on 11 January 2022. The primary study outcomes were studies that utilised OCTA to analyse the retina; secondary outcomes involved studies that involved other imaging modalities such as OCT, fundus photography, and fundus autofluorescence.

FINDINGS

The total number of studies included in this review was 32. Optical coherence tomography angiography scans show reduced central retinal vascular density, a thinner ganglion cell layer, a thicker retinal nerve fibre layer, and an enlarged foveal avascular zone. Optical coherence tomography scans demonstrate a thicker central macular thickness and other changes to the macula, ganglion cell, and inner nuclear layers. Many fundus photographs depicted cotton wool spots, microhaemorrhages, and vascular occlusions. Non-invasive imaging technology has demonstrated that COVID-19 can profoundly affect the retina. Therefore, there is a requirement for long-term follow-up of COVID-19 patients to assess whether the retinal damage caused by COVID-19 is reversible.

A Pediatric COVID-19 Study: Retinal Nerve Fiber Layer, Ganglion Cell Layer, and Alterations in Choroidal Thickness in Swept-Source OCT Measurements

Purpose To investigate early covid measurements of central macular thickness (CMT), retinal nerve fiber layer (RNFL), ganglion cell layer (GCL) thickness, and choroidal thickness (ChT) in children recovered from coronavirus disease 2019 (COVID-19).

Methods This cross-sectional study was carried out 4 weeks after completed COVID-19 treatment. The diagnosis of the Alpha variant COVID-19 was made by the polymerase chain reaction test after prediagnosis with clinical, laboratory, and radiological findings. A total of 46 children were included in the study. Pediatric patients who received COVID-19 treatment comprised the COVID-19 group (24 children), and healthy children were enrolled in the control group (22 children). Only the right eyes of the participants were enrolled in the study. All pediatric patients in the COVID-19 group required hospitalization without the need for intubation. Swept-source optical coherence tomography (SS-OCT) was used to measure CMT, RNFL, and GCL thickness, and ChT measurements.

Results The COVID-19 and control groups had similar mean values of visual acuity, intraocular pressure, spherical equivalent, axial length, and CMT (p > 0.05 for all). RNFL thickening, GCL, and choroidal thinning were observed in all SS-OCT measurements of COVID-19 children. However, RNFL thickening was significant only in the global and nasal peripapillary quadrants. GCL thinning was significant in the nasal/inferior sector (p < 0.002 for all). Some significant correlations were observed between the mean levels of inflammatory markers and OCT measurements (p < 0.002).

Conclusion This study may be among the first reports of SS-OCT examination of COVID-19 children. OCT measurements showed changes in retinal and ChT in the COVID-19 children as in adult patients.

Acute macular neuroretinopathy as the first stage of SARS-CoV-2 infection

Introduction

To report two cases of Acute Macular Neuroretinopathy (AMN) presented as the first stage of SARS-CoV-2 infection in two European countries during the third wave of pandemic viral infection in the early months of 2021.

Observations

A unilateral case of type 1 AMN in a man and a bilateral case of type 2 AMN in an otherwise heathy patients were reported. Sudden onset of paracentral scotoma characterized the cases with no systemic symptoms. Structural optical coherence tomography (OCT) shows multifocal middle and inner retinal hyperreflective infarctions. OCT-Angiography showed the presence of hypoperfusion of the deep capillary plexus (DCP) corresponding to the hyperreflective lesions visible on structural OCT, confirming the diagnosis.

Conclusions and importance

Type 1 and type 2 AMN may be the first stage of SARS-CoV-2 infection. We suggest testing all patients with AMN for SARS-CoV-2. In our cases, the natural history of AMN associated with SARS-CoV-2 infection was similar to already described cases of AMN.

COVID-19-Related Retinal Micro-vasculopathy - A Review of Current Evidence

PURPOSE

To evaluate the occurrence of retinal microvasculopathy in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and who developed coronavirus disease (COVID-19).

DESIGN

Systematic review and meta-analysis.

METHODS

The Pubmed and Embase databases were comprehensively searched to identify studies that reported retina vascular changes in eyes with COVID-19. Two independent reviewers selected papers and extracted data for analysis. Data of interest were extracted and analyzed in RevMan Web versions 3.3. Quality of evidence was assessed using the National Institute of Health quality assessment tool for a case-control study.

RESULTS

Thirty-one studies reporting on 1373 subjects (972 COVID-19 and 401 controls) were included. Only case-control studies were included in the pooled analysis. There was a significantly higher likelihood of retinal microvasculopathy in subjects with COVID-19 compared to controls (odds ratio [95% confidence interval], 8.86 [2.54-27.53], P < .01). Optical coherence tomography angiography (OCTA) revealed reduced vessel density and enlarged foveal avascular zone in subjects with COVID-19 compared to controls.

CONCLUSIONS

The results suggested that COVID-19-related retinal microvasculopathy is a significant ocular manifestation of COVID-19 and may herald future retinal complications. These microvascular impairments might have occurred antecedent to clinically visible changes and could be detected earlier by OCTA. These findings are significant, due to the large numbers with COVID-19, and need to be recognized by ophthalmologists as a potential long-term sequalae of the disease.

Retinal findings of COVID-19 patients using Ocular coherence tomography angiography two to three months after infection: Ocular appearance recovered COVID-19 patient

Purpose

The aim of this study was to evaluate the ocular disorders in COVID-19 patients, two to three months after infection.

Methods

In this cross-sectional, historically controlled study, fifty-one COVID-19 patients were compared with thirty-seven age, and gender-matched healthy individuals. After complete ophthalmological examination, all participants underwent peripapillary and macular optical coherence tomography, and optical coherence tomography angiography (OCTA) measurements (OptoVue Inc, Freemont, CA, USA).

Results

The time between the initial onset of symptoms, and ophthalmologic examination was 63.31±15.21 (40–95 days). Ophthalmic examination of all the recovered COVID-19 patients was within normal range. None of the peripapillary and macular OCTA parameters were significantly different between the two groups with pairwise comparisons, but after adjusting for age, gender, axial length, and signal strength index (SSI), recovered COVID-19 eyes showed a significant increase in peripapillary retinal nerve fiber (RNFL) thickness, superficial, and deep macular vessel densities in parafoveal and perifoveal regions compared with healthy control eyes (p<= 0.05). Inner retinal thickness overall is higher in recovered COVID-19 eyes compared to healthy eyes after adjustment.

Conclusion

Patients with moderate-intensity SARS-CoV-2 pneumonia had altered peripapillary and macular vessel density compared to healthy subjects. Further investigation is warranted to analyze the correlation of these changes with disease severity as well as evolution of these changes over time.

Persistent reduction of retinal microvascular vessel density in patients with moderate and severe COVID-19 disease

OBJECTIVE

This study aims to analyse the possible recovery or worsening in retinal microvasculature after 8 months in a previously studied COVID-19 cohort.

METHODS AND ANALYSIS

A cross-sectional case-control study and a prospective longitudinal cohort study. Participants were the subjects of our previous study who re-enrolled for a new examination including a fundus photograph (retinography), an optical coherence tomography (OCT) scan and an OCT angiography. COVID-19 diagnosed patients were divided into three groups: group 1: mild disease, asymptomatic/paucisymptomatic subjects who received outpatient care; group 2: moderate disease and group 3: severe disease, both of which required hospital admission because of pneumonia. Statistical analyses were performed using SPSS software (V.23.0). Cross-sectional intergroup differences were analysed by means of analysis of variance for normally distributed variables and the Kruskal-Wallis test for non-normally distributed ones. In reference to the prospective part of the study (intragroup differences, baseline with 8-month comparison), a paired t-test was used for normally distributed data and Wilcoxon signed ranks sum for non-normally distributed data.

RESULTS

The fovea-centered superficial and deep vascular densities were significantly diminished in severe cases compared with mild cases (p=0.004; p=0.003, respectively, for superficial and deep) and to controls (p=0.014; p=0.010), also in moderate cases to mild group (p=0.004; p=0.003) and to controls (p=0.012; p=0.024). In the longitudinal study, no significant statistical differences were found between baseline and 8-month follow-up vessel density values.

CONCLUSION

We demonstrated persistent reduction in the central vascular area over time in patients with moderate and severe COVID-19.

Posterior segment manifestations and imaging features post-COVID-19

Background

To report the posterior segment (uvea and retinal) manifestations and imaging characteristics of eyes of patients with and after coronavirus disease 2019 (COVID-19).

Methods

We searched the PubMed/MEDLINE database to identify relevant articles using the following search terms: COVID-19, SARS-CoV-2, retina, uvea, optic nerve, retinal findings, posterior segment manifestations, and endophthalmitis. Articles published from December 1, 2019, to May 30, 2021, and indexed in PubMed/ MEDLINE were screened.

Results

For the purpose of this review, we included clinical features of 26 case reports and 8 case series. The posterior segment manifestations reported included cotton wool spots, retinal hemorrhages, central serous retinopathy, papillophlebitis, optic neuritis, panuveitis, multifocal retinitis, necrotizing retinitis, central retinal artery/vein occlusion, and Purtschner like retinopathy. In this review, we have also included optical coherence tomography angiography (OCTA) features that have been described in COVID-19 patients with pneumonia.

Conclusions

COVID-19 patients can experience uveo-retinal manifestations even after recovery. These patients, even if asymptomatic for eye symptoms, should undergo an eye evaluation to rule out posterior segment involvement. OCTA performed in these patients revealed microvascular changes in the superficial and deep retinal plexuses. Some of these patients may require anticoagulant or antiplatelet therapy.

Evaluation of Macular Retinal Vessels and Histological Changes in Two Cases of COVID-19

The purpose of this study was to assess vascular and histological alterations in two COVID-19 and three control post-mortem retinas. The macular areas of flat-mounted samples were processed for immunofluorescence. Lectin and collagen IV positive vessels were captured under confocal microscopy, and endothelium loss and tortuosity were analyzed. Expression of ACE2 (angiotensin-converting enzyme 2) (the receptor for SARS-CoV-2), Iba1 (ionized calcium-binding adaptor molecule 1) and GFAP (glial fibrillary acidic protein) were quantified in retinal sections. The number of lectin vessels in COVID-19 retinas decreased by 27% compared to the control (p < 0.01) and the tortuosity increased in COVID-19 retinas (7.3 ± 0.2) vs. control retinas (6.8 ± 0.07) (p < 0.05). Immunofluorescence analysis revealed an increase in ACE2 (2.3 ± 1.3 vs. 1.0 ± 0.1; p < 0.0001) and Iba1 expression (3.06 ± 0.6 vs. 1.0 ± 0.1; p < 0.01) in COVID-19 sections whereas no changes in GFAP were observed. Analysis of the COVID-19 macular retinal tissue suggested that endothelial cells are a preferential target of SARS-CoV-2 with subsequent changes through their ACE2 receptor expression and morphology. Thus, microglial activation was hyperactive when facing an ensuing immunological challenge after SARS-CoV-2 infection.

Macular vessel density reduction in patients recovered from COVID-19: a longitudinal optical coherence tomography angiography study

Background/aims

To quantify the longitudinal changes of the macular microvasculature and the foveal avascular zone (FAZ) parameters in patients recovered from coronavirus disease-2019 (COVID-19) using optical coherence tomography angiography (OCTA) analysis.

Methods

This observational, longitudinal study was performed on patients recovered from COVID-19. The OCTA images were recorded at baseline and after 1 and 3 months at the follow-up examination. Vessel density (VD) of the retinal superficial (SCP) and deep capillary plexus (DCP), as well as the area of the FAZ of patients who had recovered from COVID-19, were measured.

Results

In total, 36 eyes of 18 patients (62.2% female) with a mean age of 34.5 ± 7.5 years old were included. Regarding SCP, while the VDs of the whole image, fovea, and parafovea were comparable at different time points, the mean VDs in inferior hemifield, as well as superior and inferior regions of perifovea, underwent significant reductions at month 3, compared to the baseline. In DCP, the mean of VD in the whole image was 54.3 ± 2.7 at the first visit which significantly decreased to 52.1 ± 3.8(P = 0.003) and 51.4 ± 2.7(P = 0.001) after 1 and 3 months, respectively. The VDs in all regions of parafovea and perifovea revealed a significant reduction after 1 and 3 months, compared to the first visit. The mean FAZ area was 0.27 ± 0.08 mm², 0.26 ± 0.08 mm², and 0.27 ± 0.08 mm² at the baseline, month 1, and month 3, respectively (P > 0.05).

Conclusion

Based on the results, the patients who had recovered from COVID-19 had a progressive decrease of VD at the follow-up visit 3 months after COVID-19 infection.

Persistent Retinal Microvascular Impairment in COVID-19 Bilateral Pneumonia at 6-Months Follow-Up Assessed by Optical Coherence Tomography Angiography

The purpose of this study was to evaluate the long-term evolution of retinal changes in COVID-19 patients with bilateral pneumonia. A total of 17 COVID-19 patients underwent retinal imaging 6 months after hospital discharge with structural optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). The parafoveal retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) were significantly thinner in COVID-19 patients at 6 months compared to 0 months (p = <0.001 in both cases). In the optic nerve analysis, a significantly thinner RNFL was observed (p = 0.006) but persisted significantly thickened, compared to controls (p = 0.02). The vascular density (VD) at 6 months persisted significantly decreased when compared to the control group, and no significant differences were found with the 0 months evaluation; in addition, when analyzed separately, women showed a worsening in the VD. Moreover, a significantly greater foveal area zone (FAZ) (p = 0.003) was observed in COVID-19 patients at 6 months, compared to 0 months. The cotton wool spots (CWSs) observed at baseline were no longer present at 6 months, except for one patient that developed new ones. This study demonstrates that some of the previously known microvascular alterations resulting from COVID-19, persist over time and are still evident 6 months after hospital discharge in patients who have suffered from bilateral pneumonia.