Optic nerve and macular optical coherence tomography in recovered COVID-19 patients

Analysis of retinal sublayers in patients with systemic COVID-19 illness with varying degrees of severity

COVID-19 infection has been linked to ocular involvement, particularly retinal microvascular changes. Additionally, prolonged hypoxemia may affect retinal sublayers located within the retinal watershed zone. The aim of this study was to evaluate retinal and optic nerve OCT parameters in patients with COVID-19 illness of varying severity and compare them with controls. In this prospective case-control study, a total of 78 consecutive patients who had recently recovered from SARS-CoV-2 infection (29 outpatients, 32 ward-admitted patients, and 17 ICU-admitted patients) were included, along with 85 controls. All participants had no ocular disease or symptoms. Spectralis SD-OCT scans of the macula and optic nerve were obtained from all participants 6 weeks after initial diagnosis. The central subfield thickness of the macula (CSFT), peripapillary retinal nerve fiber layer thickness (pRNFL), and retinal sublayers' volumes in the total 6-mm ETDRS zone were recorded and analyzed using the ANCOVA test, adjusting for age. The mean CSFT in controls was 271 μm, while in the outpatient, ward-admitted, and ICU-admitted groups, it was 251, 260, and 253 μm, respectively (P = 0.093). No differences were observed in pRNFL between the groups (P> 0.1). However, the outer plexiform layer (OPL) was the only retinal sublayer that demonstrated a significant difference in 6-mm volume across the groups, with volumes of 0.832 μm3 in controls, 0.822 μm³ in the outpatients, 0.814 μm³ in ward-admitted patients, and 0.785 μm³ in ICU-admitted cases (P = 0.006). Our findings suggest that patients with severe COVID-19 illness, especially those requiring respiratory support, may develop ischemia and atrophy of the OPL. This indicates that the OPL might be the most vulnerable retinal sublayer to systemic hypoxemia, a hypothesis that requires confirmation through future studies.

Long-Term Effects of COVID-19 on Optic Disc and Retinal Microvasculature Assessed by Optical Coherence Tomography Angiography

Objectives: To evaluate the long-term effects of coronavirus disease (COVID-19) on optic disc and macular microvasculature. Methods: 40 post-COVID-19 and 40 healthy subjects were included. Optical coherence tomography angiography (OCTA) was performed for all subjects at the first visit and repeated in the fourth and twelfth months. Radial peripapillary capillary (RPC) vessel density (VD), retinal nerve fiber layer (RNFL) thickness, foveal avascular zone (FAZ) area, FAZ perimeter, VDs of the fovea, parafovea, and perifovea at superficial capillary plexus (SCP) and deep capillary plexus (DCP), and central macular thickness (CMT) were evaluated. The OCTA measurements of the COVID-19 group were compared with the control group. Results: The COVID-19 group showed lower VD values than the control group in the nasal parafoveal quadrant of the SCP at all visits (p = 0.009, p = 0.47, p = 0.042) and in the superior perifoveal quadrant of the DCP in the twelfth-month visit (p = 0.014). At all visits, FAZ area and FAZ perimeter were higher (p = 0.02, p = 0.02, p = 0.002; p = 0.002, p = 0.003, p = 0.005), foveal VD values of both SCP and DCP were lower (p < 0.001, p < 0.001, p < 0.001; p = 0.005, p = 0.001, p = 0.001), and CMT was lower (p < 0.001, p = 0.001, p = 0.001) in the COVID-19 group. The COVID-19 group had higher temporal quadrant RPC at all visits (p = 0.003, p = 0.003, p < 0.001) and higher average, superior and inferior RNFL at first and fourth-month visits (p = 0.014, p = 0.020; p = 0.001, p = 0.003; p = 0.021, p = 0.024). Conclusions: There are long-term changes that mainly point to the ischemia in the COVID-19 patients. We emphasize the need for long-term ophthalmologic and systemic follow-up of COVID-19 patients regarding potential complications.

Productive infection of the retinal pigment epithelium by SARS-CoV-2: Initial effects and consideration of long-term consequences

As the SARS-CoV-2 coronavirus continues to evolve and infect the global population, many individuals are likely to suffer from post-acute sequelae of SARS-CoV-2 infection (PASC). Manifestations of PASC include vision symptoms, but little is known about the ability of SARS-CoV-2 to infect and impact the retinal cells. Here, we demonstrate that SARS-CoV-2 can infect and perturb the retinal pigment epithelium (RPE) in vivo, after intranasal inoculation of a transgenic mouse model of SARS-CoV-2 infection, and in cell culture. Separate lentiviral studies showed that SARS-CoV-2 Spike protein mediates viral entry and replication in RPE cells, while the Envelope and ORF3a proteins induce morphological changes. Infection with major variants of SARS-CoV-2 compromised the RPE barrier function and phagocytic capacity. It also caused complement activation and production of cytokines and chemokines, resulting in an inflammatory response that spread across the RPE layer. This inflammatory signature has similarities to that associated with the onset of age-related macular degeneration (AMD), a major cause of human blindness, resulting from RPE pathology that eventually leads to photoreceptor cell loss. Thus, our findings suggest that post-acute sequelae of SARS-CoV-2 infection of the RPE may have long-term implications for vision, perhaps comparable to the increased occurrence of AMD found among individuals infected by HIV, but with greater public health consequences due to the much larger number of SARS-CoV-2 infections.

Retinal and Corneal OCT Results of Patients Hospitalized and Treated in the Acute Phase of COVID-19

Objective: This study aimed to assess changes in the morphology of the retina and cornea in patients treated and hospitalized during the acute active phase of SARS-CoV-2 infection. Methods: A total of 24 patients with symptomatic early COVID-19 disease and 38 healthy participants from a control group were enrolled in our study. Among them, 20 received oxygen therapy at flow rates ranging from 1-10 L, while four received high-flow intranasal oxygen therapy (HFNOT). Some patients were treated with other types of therapy, such as Remdesivir, COVID-19 convalescent plasma therapy, or Tocilizumab. In the study, we focused on the analysis of optical coherence tomography (OCT) images of the cornea and retina including corneal thickness, central retinal thickness, retinal nerve fiber layer (RNFL), and optic disc parameters. The measurements were acquired using Spectral-domain OCT REVO FC 130. Results: The analysis did not show significant changes between the examined ophthalmological parameters before and after therapy. Furthermore, there were no detected significant differences between the tested parameters of the retina and cornea in COVID-19-positive patients compared to the control group. Conclusions: No ophthalmological manifestations of COVID-19 disease were observed during the study. Taking into account the results of other publications, the lack of an unambiguous position on this topic requires further research.

Evaluation of Long-term Posterior Segment Parameters in Children Who Had Recovered From Multisystem Inflammatory Syndrome

BACKGROUND AND OBJECTIVE

To evaluate long-term posterior segment findings in children recovering from multisystemic inflammatory syndrome (MIS-C) associated with severe acute respiratory syndrome coronavirus 2.

PATIENTS AND METHODS

Our study included 22 patients who were admitted to an intensive care unit with a diagnosis of MIS-C between November 2021 and March 2022, and 25 healthy controls. The study included pediatric patients who had an eye examination an average of 12.35 ± 2.18 months after recovery from MIS-C. Detailed eye examinations and measurements of all participants were obtained retrospectively from patient files. Posterior segment parameters were measured using swept-source optical coherence tomography (OCT) and OCT-angiography (OCT-A); these parameters included peripapillary retinal nerve fiber layer (pRNFL) thickness, central macular thickness (CMT), subfoveal choroidal thickness (SCT), macular vascular densities (VD), and foveal avascular zone (FAZ) area.

RESULTS

Mean age was 9.7 ± 3.6 years in the MIS-C group and 10.6 ± 2.8 years in the healthy control group (P = 0.316). There were no statistically significant differences between the MIS-C group and the healthy control group in terms of pRNFL thickness, CMT, and SCT. However, in the MIS-C group, the macular superficial vascular plexus and deep vascular plexus showed significantly lower VD in the superior, inferior, nasal, and temporal quadrants compared to the healthy controls (P < 0.05 for all). A comparison of the superficial and deep FAZ area parameters of both groups showed no statistically significant difference (P > 0.05).

CONCLUSIONS

We showed that patients who had recovered from MIS-C had retinal vascular damage at the long-term follow-up. Following up with these patients after recovery with OCT and OCT-A, which are noninvasive methods commonly used in the detailed evaluation of the posterior segment of the eye, could be beneficial for understanding the long-term effects of MIS-C on retinal microvasculature. [Ophthalmic Surg Lasers Imaging Retina 2024;55:518-526.].

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.

SARS-CoV-2 neurovascular invasion supported by Mendelian randomization

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is known to affect vessels and nerves and can be easily visualized in the retina. However, the effect of SARS-CoV-2 on retinal morphology remains controversial. In the present research, we applied Mendelian randomization (MR) analysis to estimate the association between SARS-CoV-2 and changes in the thickness of the inner retina.

METHODS

Two-sample MR analysis was conducted using summary-level data from 3 open genome-wide association study databases concerning COVID-19 infection (2,942,817 participants) and COVID-19 hospitalization (2,401,372 participants); moreover, the dataset of inner retina thickness, including the macular retinal nerve fiber layer (mRNFL) and macular ganglion cell-inner plexiform layer (mGCIPL), included 31,434 optical coherence tomography (OCT) images derived from healthy UK Biobank participants. All the participants were of European ancestry. The inverse variance weighted (IVW) meta-analysis was used as our primary method. Various complementary MR approaches were established to provide robust causal estimates under different assumptions.

RESULTS

According to our MR analysis, genetically predicted COVID-19 infection was associated with an increased risk of mRNFL and mGCIPL thickness (OR = 1.74, 95% CI 1.20-2.52, P = 3.58 × 10-3; OR = 2.43, 95% CI 1.49-3.96, P = 3.6 × 10-4). The other MR methods produced consistent results. However, genetically predicted COVID-19 hospitalization did not affect the thickness of the inner retina (OR = 1.11, 95% CI 0.90-1.37, P = 0.32; OR = 1.28, 95% CI 0.88-1.85, P = 0.19).

CONCLUSION

This work provides the first genetically predictive causal evidence between COVID-19 infection and inner retinal thickness in a European population. These findings will contribute to further understanding of the pathogenesis of COVID-19 and stimulate improvements in treatment modalities.

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.

Alterations in the optic nerve and retina in patients with COVID-19. A theoretical review

The objective of this research is to identify and systematize the medical conditions generated by SARS-CoV-2 on the optic nerve and retina of young, adult, and elderly adults who suffered from COVID-19 in the period 2019-2022. A theoretical documentary review (TDR) was conducted within the framework of an investigation to determine the current state of knowledge of the subject under study. The TDR includes the analysis of publications in the scientific databases PubMed/Medline, Ebsco, Scielo and Google. A total of 167 articles were found, of which 56 were studied in depth, and these evidence the impact of COVID-19 infection on the retina and optic nerve of infected patients, both during the acute phase and in subsequent recovery. Among the reported findings, the following stand out: anterior and posterior non-arteritic ischemic optic neuropathy, optic neuritis, central or branch vascular occlusion, paracentral acute medial maculopathy, neuroretinitis, as well as concomitant diagnoses such as possible Vogt-Koyanagi-Harada disease, multiple evanescent white dot syndrome (MEWDS), Purtscher-like retinopathy, among others.

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.

Insights into human health from phenome- and genome-wide analyses of UK Biobank retinal optical coherence tomography phenotypes

The human retina is a complex multi-layered tissue which offers a unique window into systemic health and disease. Optical coherence tomography (OCT) is widely used in eye care and allows the non-invasive, rapid capture of retinal measurements in exquisite detail. We conducted genome- and phenome-wide analyses of retinal layer thicknesses using macular OCT images from 44,823 UK Biobank participants. We performed phenome-wide association analyses, associating retinal thicknesses with 1,866 incident ICD-based conditions (median 10-year follow-up) and 88 quantitative traits and blood biomarkers. We performed genome-wide association analyses, identifying inherited genetic markers which influence the retina, and replicated our associations among 6,313 individuals from the LIFE-Adult Study. And lastly, we performed comparative association of phenome- and genome- wide associations to identify putative causal links between systemic conditions, retinal layer thicknesses, and ocular disease. Independent associations with incident mortality were detected for photoreceptor thinning and ganglion cell complex thinning. Significant phenotypic associations were detected between retinal layer thinning and ocular, neuropsychiatric, cardiometabolic and pulmonary conditions. Genome-wide association of retinal layer thicknesses yielded 259 loci. Consistency between epidemiologic and genetic associations suggested putative causal links between thinning of the retinal nerve fiber layer with glaucoma, photoreceptor segment with AMD, as well as poor cardiometabolic and pulmonary function with PS thinning, among other findings. In conclusion, retinal layer thinning predicts risk of future ocular and systemic disease. Furthermore, systemic cardio-metabolic-pulmonary conditions promote retinal thinning. Retinal imaging biomarkers, integrated into electronic health records, may inform risk prediction and potential therapeutic strategies.

An eye to the future: Acute and long-term neuro-ophthalmological and neurological complications of COVID-19

COVID-19 has had a significant impact on the global population and has produced compelling evidence of non-pulmonary organ dysfunction, including the nervous system. It is vital that specialists in ophthalmology and neurology are informed of the potential complications of COVID-19 and gain a deeper understanding of how COVID-19 can cause diseases of the nervous system. In this review we detail four possible mechanisms by which COVID-19 infection may result in neurological or neuro-ophthalmological complications: (1) Toxic and metabolic effects of severe pulmonary COVID-19 disease on the neural axis including hypoxia and the systemic hyper-inflammatory state, (2) endothelial dysfunction, (3) dysimmune responses directed again the neuroaxis, and (4) direct neuro-invasion and injury by the virus itself. We explore the pathological evidence for each of these and how they may link to neuro-ophthalmological disorders. Finally, we explore the evidence for long-term neurological and neuro-ophthalmological complications of COVID-19, with a focus on neurodegeneration.

One-Year Changes in Optic Nerve Head Parameters in Recovered COVID-19 Patients

BACKGROUND

The main purpose was to evaluate the changes in peripapillary retinal nerve fiber layer (RNFL) thickness and vessel density (VD) in post-COVID-19 patients during 12-month follow-up.

METHODS

In this prospective study, patients with COVID-19 who were attended in the Hospital Clinico San Carlos (Madrid, Spain) were included. All patients underwent a complete ophthalmological examination, optic nerve head optical coherence tomography (OCT), and OCT angiography (OCTA) using the Cirrus HD-OCT 5,000 with AngioPlex OCTA 1, 3, and 12 months after laboratory-confirmed diagnosis. Sociodemographic data, medical history, disease severity, and laboratory workup were registered.

RESULTS

A total of 180 eyes of 90 patients with SARS-CoV-2 infection were included; the mean age was 55.5 ± 8.9 years, and 46 patients (51%) were females. The mean visual acuity was 0.76 ± 0.16, and no abnormalities attributable to SARS-CoV-2 were detected in the ocular or fundus examination. No differences in the OCT and OCTA data were found between severity groups in each visit (all P > 0.05). Overall, there was a decrease in RNFL global thickness ( P < 0.001) from the first to the last visit, and an increase in VD and flux index was noted in some sectors at the 12-month examination. A significant correlation was detected at 12 months between vascularization parameters and RNFL thickness.

CONCLUSIONS

One year after SARS-CoV-2 infection, changes in peripapillary RNFL thickness and vascularization occur, possibly indicating a recovery in such parameters.

Analysis of macular structure in age-related cataract patients with different antibody levels of severe acute respiratory syndrome coronavirus-2 vaccine

Objective

To analyze the macular structure of age-related cataract (ARC) patients with different antibody levels after COVID-19 vaccine injection, in order to obtain the effect of COVID-19 vaccine on the macular structure, and speculate whether the COVID-19 vaccine has adverse effects on the macular structure.

Methods

This retrospective study is conducted to analysis on the status of COVID-19 vaccine and the thickness of different layers at different positions in the macular area of ARC patients. In the age, sex and eye axial length matched population, in the un-injection, no-antibody, IgM and IgG positive groups after vaccination, the choroid, ganglion cell complex, nerve fiber layer and retinal thickness at different positions of ETDRS zoning in the macular area were discussed.

Results

A total of 164 patients (164 eyes) were included in the analysis. There were 63 males and 101 females. The average age was 65.99 ± 8.43 years. There was no significant difference in age and sex among the groups (p>0.05). The average axial length of 164 eyes was 23.56 ± 1.46mm, and no significant difference between the groups (p>0.05). Non parametric test and ANOVA test for the thickness of choroid, retina, ganglion cell complex and retinal nerve fiber layer in each division of ETDRS showed no significant difference in the four groups of un-injection, no-antibody, IgM and IgG (p>0.05). There was no correlation between the antibody concentration and the thickness of macular structure (p>0.05).

Conclusion

There was no significant difference in the thickness of choroid, retina, ganglion cell complex and retinal fiber layer in different macular areas after COVID-19 vaccine injection. There was no linear correlation between the thickness of choroid, retina, ganglion cell complex and retinal fiber layer and the antibody concentration produced after COVID-19 vaccine injection. It suggests that the injection of COVID-19 vaccine might have no significant effect on the macular structure of eye.

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.

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.

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.

Peripapillary Nerve Fiber Layer Thickness and Optic Nerve Head Parameters in Patients Recovered from COVID-19: A Longitudinal Study

Purpose

To quantify the longitudinal changes of the optic nerve head (ONH) parameters and peripapillary retinal nerve fiber layer (pRNFL) thickness in patients recovered from coronavirus disease 2019 (COVID-19) using spectral-domain optical coherence tomography (OCT) analysis.

Materials and Methods

In an observational longitudinal study, in patients recovered from COVID-19, ONH OCT images were recorded at least two weeks after recovery from the systemic disease as the baseline and after one and three-month follow-up. Ganglion cell complex (GCC) analysis, ONH parameters, and pRNFL thickness changes were measured.

Results

A total of 36 eyes from 18 recovered COVID-19 patients including eleven (61.2%) females were studied. The average age was 35.5 ± 7.5 years. The pRNFL thickness in the nasal lower sector significantly decreased from 77 ± 18 μm in the first post-COVID-19 month to 74 ± 10 μm in the third month (P=0.8). The average, superior, and inferior pRNFL thickness remained unchanged. The average cup volume significantly decreased from 0.27 ± 0.15 mm³ at baseline to 0.19 ± 0.15 mm³ in the third post-COVID-19 visit (P=0.028). In terms of ONH morphologies including rim, disc and cup to disc area, and the vertical and horizontal ratio, the changes were not significant over the 3-month study period. Focal loss volume and global loss volume values were not changed significantly.

Conclusion

Localized defect in the nasal lower sector of pRNFL is observed in 3-month post-recovery from COVID-19. Larger studies with longer follow-ups are required to reveal the exact changes in ONH parameters.

Retinal nerve fibre layer and ganglion cell layer changes in children who recovered from COVID-19: a cohort study

OBJECTIVE

To investigate the optic nerve and macular parameters of children who recovered from COVID-19 compared with healthy children using optical coherence tomography (OCT).

DESIGN

Cohort study.

SETTING

Hospital Clinico San Carlos, Madrid.

PATIENTS

Children between 6 and 18 years old who recovered from COVID-19 with laboratory-confirmed SARS-CoV-2 infection and historical controls were included.

INTERVENTIONS

All patients underwent an ophthalmological examination, including macular and optic nerve OCT. Demographic data, medical history and COVID-19 symptoms were noted.

MAIN OUTCOME MEASURES

Peripapillary retinal nerve fibre layer thickness, macular retinal nerve fibre layer thickness, macular ganglion cell layer thickness and retinal thickness.

RESULTS

90 patients were included: 29 children who recovered from COVID-19 and 61 controls. Patients with COVID-19 presented an increase in global peripapillary retinal nerve fibre layer thickness (mean difference 7.7; 95% CI 3.4 to 12.1), temporal superior (mean difference 11.0; 95% CI 3.3 to 18.6), temporal inferior (mean difference 15.6; 95% CI 6.5 to 24.7) and nasal (mean difference 9.8; 95% CI 2.9 to 16.7) sectors. Macular retinal nerve fibre layer analysis showed decreased thickness in the nasal outer (p=0.011) and temporal inner (p=0.036) sectors in patients with COVID-19, while macular ganglion cell layer thickness increased in these sectors (p=0.001 and p=0.015, respectively). No differences in retinal thickness were noted.

CONCLUSIONS

Children with recent history of COVID-19 present significant changes in peripapillary and macular OCT analyses.

Retinal OCT Findings in Patients after COVID Infection

PURPOSE

The aim of this study was to assess and compare the optic nerve, retina, and retinal vessel parameters in recovered COVID-19 patients and healthy patients by using optical coherence tomography angiography (OCT-a).

METHODS

In all, 156 eyes of post-COVID-19 patients and 98 eyes of subjects from a control group were enrolled in our study. BCVA, intra ocular pressure (IOP) measurement, fundus examination, and OCT images, including macular cube, OCT-RNFL, and angio-OCT 6 × 6 mm examinations, were performed for both groups. The measurements were acquired using Swept Source OCT DRI OCT Triton. In the post-COVID-19 group, 762 OCT protocols were obtained. For statistical analysis, parameters from only one eye from each subject were taken.

RESULTS

In the measured parameters, no significant differences were observed, i.e., central macular thickness (p = 0.249); RNFL (p = 0.104); FAZ (p = 0.63); and vessel density of superficial retinal vascular plexus in central (p = 0.799), superior (p = 0.767), inferior (p = 0.526), nasal (p = 0.402), and temporal (p = 0.582) quadrants. Furthermore, a slit-lamp examination did not reveal any COVID-19-related abnormalities.

CONCLUSION

OCT examination did not detect any significant changes in morphology or morphometry of the optic nerve, retina, or the retina vessels due to COVID-19.

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.