Central Retinal Vein Occlusion after COVID-19 Infection.

INTRODUCTION: Central retinal vein occlusions are not well-known complications of SARS-CoV-2 infection. We describe a case of central retinal vein occlusion secondary to COVID-19, and a review of the literature was performed. HISTORY AND SIGNS: A 47-year-old woman with no underlying ocular or medical condition presented to the hospital complaining about sudden onset of multiple scotomas in her left eye. A COVID-19 infection was confirmed 2 days previously by a PCR test that was performed 2 days after the onset of symptoms. Medical history revealed no risk factors and no oral contraception. Her best-corrected visual acuity was 1.0 in the right eye and 0.04 in the left eye. Clinical exam showed a left relative afferent pupillary defect and a nasally localized papilledema on fundoscopy of the left eye. Multiple dot and blot hemorrhages were also present. Optical coherence tomography revealed cystoid macular edema and paracentral acute middle maculopathy. The results of the fluoresceine angiography were consistent with central retinal vein occlusion. Laboratory workup later revealed an elevated fibrinogen level, corresponding to the COVID-19-induced hypercoagulable state. No other prothrombotic conditions were found. The patient immediately received an intravitreal injection of Lucentis (ranibizumab) after diagnosis. Complete resolution of the retinal hemorrhages and papilledema was observed 1.5 months after treatment and the final visual acuity was 1.25 in the left eye. CONCLUSION: Coagulation abnormalities are frequently observed in infectious diseases such as COVID-19 infection and the resulting prothrombotic state can sometimes lead to retinal vascular complications, including central retinal vein occlusion, irrespective of the presence of other classical risk factors. The consideration of this information could help clinicians establish a prompt diagnosis and therefore appropriate treatment, which could hopefully lead to complete healing of retinal lesions.

Time course study of optical coherence tomography angiography in patients with methanol induced optic neuropathy.

INTRODUCTION: In countries where alcoholic beverages are legally prohibited, methanol toxicity usually occurs due to ingesting homemade alcoholic drinks. The initial ophthalmologic symptoms of methanol toxicity typically appear 6-48 h after ingestion, and the severity of symptoms varies widely from mild and painless decreased vision to no-light perception vision. METHODS: This prospective study examines 20 patients with acute methanol poisoning within 10 days of use. Patients underwent ocular examinations, BCVA (Best Corrected Visual Acuity) recording, and OCTA (Optical Coherence Tomography Angiography) of the macula and optic disc. BCVA measurement and imaging were repeated one month and three months after intoxication. RESULTS: There was a statistically significant reduction in superficial parafoveal vascular density (P-value = 0.026), inner retinal thickness (P-value = 0.022), RNFL (Retinal Nerve Fiber Layer) thickness (P-value = 0.031), and an increase in cup to disc ratio (P-value < 0.001), and central visual acuity (P-value = 0.002) in this time course. However, there was no statistically significant difference in FAZ (Foveal Avascular Zone) area (P-value = 0.309), FAZ perimeter (P-value = 0.504), FD-300 (Foveal density, vascular density within a 300 µm wide region of the FAZ) (P-value = 0.541), superficial vascular density (P-value = 0.187), deep foveal vascular density (P-value = 0.889), deep parafoveal vascular density (P-value = 0.830), choroidal flow area (P-value = 0.464), total retinal thickness (P-value = 0.597), outer retinal thickness (P-value = 0.067), optic disc whole image vascular density (P-value = 0.146), vascular density inside the disc (P-value = 0.864), or peripapillary vascular density (P-value = 0.680) at different times. CONCLUSION: Over time, methanol poisoning can cause changes in retinal layers thickness, vasculature, and optic nerve head. The most important changes include cupping of the optic nerve head, reduction in RNFL thickness, and inner retinal thickness.

Management of autoimmune retinopathy treated with intravitreal dexamethasone implant.

PURPOSE: The purpose of this study is to evaluate clinical outcomes of autoimmune retinopathy (AIR) in the patients treated with intravitreal dexamethasone implant (IDI). METHOD: Twenty-one eyes of 11 AIR patients treated with at least 1 injection of IDI were retrospectively reviewed. Clinical outcomes before and after treatment, including best corrected visual acuity (BCVA), optic coherence tomography (OCT), fundus autofluorescence (FAF), full-field electroretinography (ff-ERG), and visual field (VF) at last visit within 6 and/or 12 months, were recorded. RESULTS: Among all the patients, 3 had cancer-associated retinopathy (CAR) and 8 had non-paraneoplastic-AIR (npAIR) with mean followed up of 8.52 ± 3.03 months (range 4-12 months). All patients achieved improved or stable BCVA within 6 and/or 12 months after the treatment. Cystoid macular edema (CME) in 2 eyes and significant retinal inflammation in 4 eyes were markedly resolved after single injection. Central retinal thickness (CFT) in all eyes without CME, ellipsoid zone (EZ) on OCT in 71.4% of eyes, ERG response in 55% of eyes, and VF in 50% of eyes were stable or improved within 6 months after treatment. At last visit within 12 months, both BCVA and CFT remained stable in the eyes treated with either single or repeated IDI; however, progression of EZ loss and damage of ERG response occurred in some patients with single IDI. CONCLUSION: Clinical outcomes, including BCVA and parameters of OCT, ERG, and VF, were stable or improved after IDI in a majority of AIR patients. Local treatment of AIR with IDI was a good option to initiate the management or an alternative for the patients' refractory to the systemic therapy but with limited side effect.

Assessment of early and long-COVID related retinal neurodegeneration with optical coherence tomography.

PURPOSE: The aim of this study is to investigate short-term and long-term effects of coronovirus 19 disease (COVID-19) at inner and outer retinal layers of patients recovered from COVID-19 with Spectral Domain Optical Coherence Tomography (SD-OCT) and compare these to healthy subjects. METHODS: Twenty-seven patients recovered from COVID-19, and age- and gender-matched 27 healthy controls were included in this study. Macular and peripapillary retinal nerve fiber layer (RNFL), ganglion cell-inner plexiform layer (GCIPL), inner nuclear layer (INL), outer plexiform layer (OPL) and outer nuclear layer (ONL) were analyzed with SD-OCT 1 month (V1 visit) and 12 months (V2 visit) after negative result of reverse transcriptase-polymerase chain reaction test. RESULTS: Macular RNFL thickness in outer ring was thinner at V1 and V2 visits than healthy control (p = 0.049 and p = 0.005). Central and inferonasal quadrants of peripapillary RNFL thicknesses were reduced at V1 and V2 visits compared to controls (p = 0.001 and p = 0.024 for V1 visit; p = 0.001 and p = 0.006 for V2 visit). Thinning in ONL thickness in inner ring was observed at V1 and V2 visits than healthy subjects (p = 0.006 and p = 0.001). CONCLUSION: Subclinical localized changes in macular and peripapillary RNFL and outer nuclear layer were demonstrated in early and 12-months follow-up after COVID-19 recovery.

Tomographic Findings in the Retina of Unvaccinated Patients with COVID Pneumonia: Prospective Longitudinal Study.

There is no definitive evidence on the extent of SARS-CoV-2's effect on the retina. This study aims to determine if the natural history of SARS-CoV-2 infection affects tomographic findings in the retina of patients with COVID-19 pneumonia. This is a prospective cohort study of patients hospitalized with COVID-19 pneumonia. The patients underwent ophthalmological explorations and optical coherence tomography during the acute phase of the infection and at a follow-up 12 weeks later. The primary outcomes were the central retinal thickness and central choroidal thickness, which were compared longitudinally and with non-COVID-19 historical controls. No statistically relevant differences were observed in the longitudinal analysis of the thickness of the central retina (p = 0.056), central choroid (p = 0.99), retinal nerve fiber layer (p = 0.21), or ganglion cell layer (p = 0.32). Patients with acute COVID-19 pneumonia showed significantly greater central retinal thickness than non-COVID controls (p = 0.006). In conclusion, tomographic measures of the retina and choroid are not influenced by the phase of COVID-19 infection and remain stable during 12 weeks. The central retinal thickness may increase in the acute phase of COVID-19 pneumonia, but more epidemiological studies using optical coherence tomography in the early stages of the disease are needed.

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.

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.

Evaluation of vascular and perfusional changes in the retina and choroid of children with multisystem inflammatory syndrome.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is hyperinflammation following coronavirus disease 2019 (COVID-19), which affects many organs. The retina and choroid are affected by COVID-19 through microangiopathy and thrombosis but the literature on MISC-C is limited. METHODS: Thirty children (60 eyes) with MIS-C (the study group, or SG) and 32 age-and gender-matched healthy children (64 eyes) (the control group, or CG) were included in the prospective case-control study. Complete ophthalmological examinations, measurements of the vessel densities of the retinal layers, and flow area of the outer retina and choriocapillaris in both groups were conducted with optical coherence tomography angiography (OCT-A). RESULTS: The mean age of the SG was 11.9 ± 3.9 and that of the CG was 12.5 ± 4.6 years (p = 0.197). In this study we found that the vessel density of the deep layer of the inner retina was decreased significantly and was reduced in the outer retina of flow area in the SG in comparison with the CG (p < 0.05, for all). However, there was no significant difference between the groups regarding other measurements. CONCLUSIONS: In MIS-C patients, vessel densities in the deep layer of the inner retina and in the flow area of the outer retina decreased significantly. This OCTA-A finding suggests that MIS-C is related to endothelial thrombotic condition problems in small branches of the retinal artery. The results of this study support the idea that there is a need for screening of MIS-C patients for the presence of these microangiopathic and perfusional complications.

Pseudophakia as a surprising protective factor in neovascular age-related macular degeneration.

PURPOSE: To assess the impact of lens status on macular function among patients treated for neovascular age-related macular degeneration (nvAMD) in whom scheduled intravitreal injections were delayed. METHODS: We reviewed demographic and clinical data as well as macular optical coherence tomographic images of 34 patients (48 eyes) who did not follow their injection schedule during the first wave of COVID-19 in Israel. Functional worsening was defined as a loss of at least 0.1 in decimal best-corrected visual acuity (BCVA). Morphological worsening was defined as new or increased subretinal/intraretinal fluid or a new hemorrhage. OCT indices of quality were used as a measure for cataract density and progression. RESULTS: Pseudophakia was associated with a better functional outcome than phakic status: there was a loss of 0.06±0.12 vs. 0.15±0.10 decimal BCVA in the pseudophakic and phakic eyes, respectively (P=.001). A similar trend was observed for morphological changes over the same period: there was an increase in macular thickness of 9±26% vs.12±40%, respectively (P=0.79). During the first wave of COVID-19, the index of OCT quality remained stable for phakic eyes (26±3.6 before the first wave of COVID-19, 26±2.9 afterward; P=1) and pseudophakic eyes (30±2.4 before the first wave of COVID-19, 30±2.6 afterward; P=1). CONCLUSION: Pseudophakic eyes with nvAMD that missed their scheduled intravitreal injections experienced fewer morphological and functional complications than phakic eyes with nvAMD.

Retinal microvascular changes in patients recovered from COVID-19 compared to healthy controls: A meta-analysis.

PURPOSE: To investigate changes in retinal microcirculation in patients recovered from COVID-19 infection compared to healthy controls, using optical coherence tomography-angiography. METHODS: Meta-analysis of eligible studies comparing retinal microcirculation between patients recovered from COVID-19 infection and healthy controls up to 7th of September 2022 was performed, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 guidelines. The following search algorithm was used: (COVID-19 OR coronavirus) AND (retina OR optical coherence tomography OR optical coherence tomography angiography OR vessel density OR foveal avascular zone). Standardized Mean Difference (SMD) with 95% confidence interval (CI) was calculated to compare continuous variables. Revman 5.3 was used for the analysis. RESULTS: 12 studies were included in our analysis. Foveal avascular zone (FAZ) area was larger in patients recovered from COVID-19 infection compared to healthy controls, while there was no statistically significant difference in FAZ perimeter between the two groups. The foveal, parafoveal and whole image vessel density in the superficial capillary plexus showed no significant difference between the two groups. The foveal, parafoveal and whole image vessel density in the deep capillary plexus was statistically lower in patients recovered from COVID-19 compared to healthy controls. CONCLUSION: FAZ area was enlarged and foveal, parafoveal and whole image vessel density in deep capillary plexus were reduced in patients recovered from COVID-19 infection compared to healthy controls, suggesting that COVID-19 infection may induce long-term retinal microvascular changes in patients recovered from the virus infection.

Retinal tissue and microvasculature loss in COVID-19 infection.

This cross-sectional study aimed to investigate the hypothesis that permanent capillary damage may underlie the long-term COVID-19 sequela by quantifying the retinal vessel integrity. Participants were divided into three subgroups; Normal controls who had not been affected by COVID-19, mild COVID-19 cases who received out-patient care, and severe COVID-19 cases requiring intensive care unit (ICU) admission and respiratory support. Patients with systemic conditions that may affect the retinal vasculature before the diagnosis of COVID-19 infection were excluded. Participants underwent comprehensive ophthalmologic examination and retinal imaging obtained from Spectral-Domain Optical Coherence Tomography (SD-OCT), and vessel density using OCT Angiography. Sixty-one eyes from 31 individuals were studied. Retinal volume was significantly decreased in the outer 3 mm of the macula in the severe COVID-19 group (p = 0.02). Total retinal vessel density was significantly lower in the severe COVID-19 group compared to the normal and mild COVID-19 groups (p = 0.004 and 0.0057, respectively). The intermediate and deep capillary plexuses in the severe COVID-19 group were significantly lower compared to other groups (p < 0.05). Retinal tissue and microvascular loss may be a biomarker of COVID-19 severity. Further monitoring of the retina in COVID-19-recovered patients may help further understand the COVID-19 sequela.

OCTA evaluation of posterior ocular blood flow in patients after COVID-19 infection without pneumonia.

INTRODUCTION: We aimed to demonstrate the changes in optic nerve and retinal microvascular structures with Optical Coherence Tomography Angiography (OCTA) in patients who had COVID-19 infection. METHODS: Prospective study. Retina, choroid and optic nerve head microvascular flow and vascular densities of both groups were measured by OCTA. RESULTS: OCTA measurements of 122 right eyes of a total of 122 patients, including 72 patients in the COVID-19 group and 50 patients in the control group, were included in the study. The Deep Capillary Plexus (DCP) Flow Area (FA) in the COVID-19 group was 1.42±0.23 mm2, in the control group was 1.50±0.15 mm2, Choriocapillary Plexus FA was 1.89±0.04 mm2 in the COVID-19 group, was 1.91±0.05 mm2 in the control group, and a statistically significant difference was found between the two groups (respectively; P=0.03; P=0.02). DCP Whole Vascular density (VD) values were 56.76±4.16% in the COVID-19 group, 58.28±3.88% in the control group; difference between the values was statistically significant (P=0.04). There was no statistically significant difference between the two groups in terms of optic nerve head flow areas and other parameters examined according to quadrants. CONCLUSIONS: Results show that the retinal microcirculation in subjects with mild disease is affected. Even if the disease is mild, patients may need to be followed up for retinal changes that may develop in the future.

Effects of COVID-19 on Retinal and Choroidal Thickness by Optical Coherence Tomography.

PRCIS: The aim of our study was to evaluate the subclinical changes in the macula, retinal nerve fiber layer (RNFL), and choroidal thickness after coronavirus disease 2019 (COVID-19) infection using spectral domain optical coherence tomography. METHODS: Our study was prospectively designed and involved 170 eyes of 85 patients. Patients with polymerase chain reaction (PCR)-positive COVID-19 infection were examined in the ophthalmology clinic before and after infection were included. All included patients had mild COVID-19 with no hospitalization and no need for intubation. Control ophthalmic examination was repeated at least 6 months after PCR positivity. Macular and choroidal thickness and RNFL parameters were compared before and at least 6 months after PCR-positive COVID-19 infection using optical coherence tomography. RESULTS: When the mean macular thickness data were evaluated, a significant decrease was detected in the inner (mean difference, -3.37 µm; 95% CI: -6.09 to -0.65, P = 0.021) and outer (mean difference, -6.56 µm; 95% CI: -9.26 to -3.86, P < 0.001) temporal segments and the inner (mean difference, -3.39 µm; 95% CI: -5.46 to -1.32, P = 0.002) and outer (mean difference, -2.01 µm; 95% CI, -3.70 to -0.31, P = 0.018) su p erior segments in the post-COVID-19 measurements compared with pre-COVID-19 measurements. Similarly, on RNFL evaluation, some thinning was evident in the temporal superior (mean = 1.14 µm, P = 0.004) and temporal inferior (mean = 1.30 µm, P = 0.032) regions. All choroidal regions, including central, nasal 500 µm and 1500 µm and temporal 500 µm and 1500 µm, exhibited significant thinning ( P < 0.001). CONCLUSION: At least 6 months after mild COVID-19 infection, significant thinning was seen in the temporal and superior quadrants of the macula, the temporal superior and temporal inferior regions of the RNFL, and all measured areas of choroidal regions.

Retinal microvascular signs in COVID-19.

BACKGROUND/AIMS: To explore if retinal findings are associated with COVID-19 infection. METHODS: In this prospective cross-sectional study, we recruited participants positive for COVID-19 by nasopharyngeal swab, with no medical history. Subjects underwent retinal imaging with an automated imaging device (3D OCT-1 Maestro, Topcon, Tokyo, Japan) to obtain colour fundus photographs (CFP) and optical coherence tomographic (OCT) scans of the macula. Data on personal biodata, medical history and vital signs were collected from electronic medical records. RESULTS: 108 patients were recruited. Mean age was 36.0±5.4 years. 41 (38.0%) had symptoms of acute respiratory infection (ARI) at presentation. Of 216 eyes, 25 (11.6%) had retinal signs-eight (3.7%) with microhaemorrhages, six (2.8%) with retinal vascular tortuosity and two (0.93%) with cotton wool spots (CWS). 11 eyes (5.1%) had hyper-reflective plaques in the ganglion cell-inner plexiform layer layer on OCT, of which two also had retinal signs visible on CFP (CWS and microhaemorrhage, respectively). There was no significant difference in the prevalence of retinal signs in symptomatic versus asymptomatic patients (12 (15.0%) vs 13 (9.6%), p=0.227). Patients with retinal signs were significantly more likely to have transiently elevated blood pressure than those without (p=0.03). CONCLUSION: One in nine had retinal microvascular signs on ocular imaging. These signs were observed even in asymptomatic patients with normal vital signs. These retinal microvascular signs may be related to underlying cardiovascular and thrombotic alternations associated with COVID-19 infection.

Structural alterations of the choroid evaluated using enhanced depth imaging optical coherence tomography in patients with coronavirus disease.

PURPOSE: To assess choroidal changes using enhanced depth imaging optical coherence tomography in coronavirus disease (COVID-19). METHODS: Thirty-two patients with moderate COVID-19 and 34 healthy subjects were included in the study. Choroidal thickness was measured at 3 points as follows: at the subfovea, 1500 mm nasal to the fovea, and 1500 mm temporal to the fovea. The total choroidal area, luminal area, stromal area, and choroidal vascular index were measured with Image-J. All the measurements were performed during the disease and at 4 months after remission. RESULTS: In the patient group, the subfoveal, nasal, and temporal choroidal thicknesses were decreased as compared with those in the controls, but without statistically significant differences (p=0.534, p=0.437, and p=0.077, respectively). The mean total choroidal, stromal, and luminal areas and choroidal vascular index were statistically significantly decreased in the patient group (p<0.001, p=0.001, p=0.001, and p=0.003; respectively). At 4 months after remission, the choroidal structural parameters and choroidal vascular index revealed statistically significant increases as compared with the baseline measurements in the patients with COVID-19 (all p<0.001 and p=0.047, respectively). CONCLUSION: The choroidal vascular and stromal parameters showed significant transient decreases during the disease course of COVID-19.

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.

Evaluation of acute effects of pulmonary involvement and hypoxia on retina and choroid in coronavirus disease 2019: An optic coherence tomography study.

PURPOSE: We investigated the acute subclinical choroidal and retinal changes caused by Coronavirus Disease 2019 (COVID-19) in patients with and without pulmonary involvement, using spectral domain optic coherence tomography. METHODS: This prospective case-control study included COVID-19 patients: 50 with pulmonary involvement and 118 with non-pulmonary involvement. All patients were examined 1 month after recovering from COVID-19. The changes were followed using optic coherence tomography parameters such as choroidal and macular thickness and retinal nerve fibre layer and ganglion cell complex measurements. RESULTS: All choroidal thicknesses in the pulmonary involvement group were lower than in the non-pulmonary involvement group and the subfoveal choroidal thickness differed significantly (p=0.036). Although there were no significant differences between the central and average macular thicknesses in the two groups, they were slightly thicker in the pulmonary involvement group (p=0.152 and p=0.180, respectively). A significant decrease was detected in the pulmonary involvement group in all ganglion cell complex segments, except for the outer nasal inferior segment (p<0.05). In addition, a thinning tendency was observed in all retinal nerve fibre layer quadrants in the pulmonary involvement group compared to the non-pulmonary involvement group. CONCLUSION: In COVID-19 patients with pulmonary involvement, subclinical choroidal and retinal changes may occur due to hypoxia and ischemia in the acute period. These patients may be predisposed to ischemic retinal and optic nerve diseases in the future. Therefore, COVID-19 patients with pulmonary involvement should be followed for ophthalmological diseases.

Investigation of changes in retinal vascular parameters and choroidal vascular index values during the early recovery period of COVID-19: The COVID-OCTA study.

BACKGROUND: COVID-19 effects microvasculature in many tissues. This study investigated whether the choroidal structure is also affected. METHODS: This cross-sectional study included 80 patients with COVID-19 and the same number of age- and gender-matched healthy individuals. All participants' right eye measurements were examined. Optical coherence tomography angiography (OCTA) was used for imaging. Otherwise, two independent researchers used the Choroidal vascular index (CVI) for choroidal parameters calculation. RESULTS: Superior and deep flow values were lower in the COVID-19 group than in the control group, and vascular density (VD) values were lower in all regions in this group. Except for the superior mean VD, there was no statistically significant difference (p = 0.003). However, the COVID-19 group had significantly lower subfoveal choroidal thickness (SFChT) measurements than the control group (p = 0.001). In addition, no significant difference was observed between the groups in evaluating mean CVI values (p>0.05). CONCLUSION: Noninvasive diagnostic tools such as OCTA and EDI-OCT can be used to monitor early changes in diseases affecting microvessels, such as from COVID-19.

Evaluation of retinal and optic disc vascular structures in individuals before and after Pfizer-BioNTech vaccination.

INTRODUCTION: We conducted this study to detect possible changes in posterior segment structures using the optical coherence tomography angiography (OCTA) in individuals vaccinated with the Pfizer-BioNTech vaccine. MATERIALS AND METHODS: The study included healthcare professionals who presented to the Ophthalmology Clinic of Health Sciences University Antalya Training and Research Hospital, who were scheduled to receive the first dose of the Pfizer-BioNTech vaccine. The exclusion criteria were any eye pathology (e.g., glaucoma, uveitis, diabetic retinopathy, amblyopia), myopia with the absolute value of refractive error >6, axial length >26 mm, history of eye surgery, and presence of systemic disease.OCTA was performed to 40 healthcare professionals before vaccination and on the third day after vaccination. RESULTS: After Pfizer-BioNTech vaccination, there was a statistically significant decrease in the total vascular, foveal vascular, parafoveal vascular and perifoveal vascular density of the superficial capillary plexus and the perifoveal vascular density of the deep capillary plexus and a statistically significant increase in the retinal foveal thickness and total retinal parafoveal thickness compared to the pre-vaccination values (p < 0.0001, p = 0.009, p < 0.0001, p = 0.001, p = 0.04, p = 0.03, and p = 0.05, respectively). CONCLUSION: We consider that the decrease in the retinal vascular density may be due to vascular endothelial damage and inflammation in vaccinated people. It can be suggested that increased inflammation plays a role in the retinal thickness in vaccinated people similar to patients with a history of COVID-19. We also consider that spike protein may be effective in these processes.

Optical coherence tomography-based assessment of macular vessel density, retinal layer metrics and sub-foveal choroidal thickness in COVID-19 recovered patients.

Purpose: The primary objective of the study was to assess the macular retinal vessel density, subfoveal choroidal thickness, and retinal layer metrics by optical coherence tomography angiography (OCTA), enhanced-depth imaging optical coherence tomography (EDI-OCT), and spectral domain optical coherence tomography (SD-OCT), respectively, in recovered COVID-19 patients and its comparison with the same in control subjects. The secondary objective was to evaluate differences in OCTA parameters in relation with the severity of COVID-19 disease and administration of corticosteroids. Methods: A case-control study was performed that included patients who had recovered from COVID-19 and age-matched healthy controls. Complete ocular examination including OCTA, SD-OCT, and EDI-OCT were performed three months following the diagnosis. Results: Three hundred sixty eyes of 180 subjects were enrolled between the two groups. A decreased mean foveal avascular zone area in both superficial capillary plexuses (P = 0.03) and deep capillary plexuses (P < 0.01), reduced average ganglion cell layer-inner plexiform layer thickness (P = 0.04), and increased subfoveal choroidal thickness (P < 0.001) were observed among cases in comparison to the control group. A significant correlation was found between sectoral macular vessel density in relation to disease severity and a decrease in vessel density with greater severity of the disease. Conclusion: OCTA detected retinal microvascular alterations following SARS-CoV-2 infection in subjects with the absence of any clinical ocular manifestation or systemic thrombotic events. These parameters could be used to help identify patients with a higher incidence of systemic thromboembolism on longer follow-ups and identify the impact of corticosteroids on retinal architecture.