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.

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.

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.

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.

How does Covid-19 affect the choroidal structures at the early post-infectious period?

PURPOSE: To evaluate choroidal thickness (CT) and choroidal vascularity index (CVI) in patients recovered from COVID-19 using enhanced depth imaging optical coherence tomography in the early postinfectious period. METHODS: Sixty-five patients recovered from COVID-19 and 72 healthy subjects were included in the study. A full ophthalmic examination including best-corrected visual acuity (BCVA), slit lamp biomicroscopy, and dilated fundus examination was performed. CT was measured at 3 points as follows: subfoveal, 1000µm nasal and temporal to the fovea. The total choroidal area (TCA), luminal area (LA), stromal area (SA), and CVI were measured with Image-J. RESULTS: The mean age was 39.09±11.27 years in the COVID-19 group and 39.61±11.43 years in the control group. The mean time from the first positive RT-PCR was 49.54±26.82 days (range 18-120) in the COVID-19 group. No statistically significant difference was detected between the groups with regard to axial length, spherical equivalent, and BCVA (all P>0.05). CT was found to be lower in the COVID-19 group compared to the control group in all quadrants, but this difference was not significant (all P>0.05). The mean TCA, LA, and CVI were statistically significantly reduced in the COVID-19 group (all P<0.001); however, SA showed no statistically significant difference (P=0.064). CONCLUSIONS: In asymptomatic or mild COVID-19, CVI and LA decrease significantly, while CT thins in the early postinfectious period but not significantly.

Evaluation of Retinal Microvascular Impairment after COVID-19 and its Clinical Correlates Using Optical Coherence Tomography Angiography.

Objectives: Retinal vascular complications have been described in patients with coronavirus disease 2019 (COVID-19). This study aimed to analyze retinal microvascular changes and their correlations with clinical findings. Materials and Methods: This case-controlled study was conducted in a university hospital. The right eyes of 52 otherwise healthy patients recovered from COVID-19 and 42 healthy controls were examined with optical coherence tomography angiography. Mann-Whitney U test was used to compare vessel density (VD) and foveal avascular zone (FAZ) parameters. Associations with treatment choices, pneumonia, and laboratory findings were analyzed. Results: Twenty-nine patients (56%) and 18 healthy controls (43%) were men. Mean age of the COVID-19 group was 39.00±13.04 years. Twenty-two patients had pneumonia, 18 (35%) received hydroxychloroquine (HCQ), 17 (33%) received HCQ plus low-molecular-weight heparin (LMWH), and 10 (19%) received favipiravir. The patient group had lower parafoveal VD in the superficial capillary plexus (SCP) and lower parafoveal VD and perifoveal VD in the deep capillary plexus (DCP) than controls (p=0.003, p=0.004, p=0.001). FAZ area did not differ significantly (p=0.953). Perifoveal VD in the DCP was also significantly lower in the HCQ+LMWH group than the HCQ group (p=0.020) and in the presence of pneumonia (p=0.040). C-reactive protein (CRP) and ferritin levels were negatively correlated with perifoveal VD in the DCP (r=-0.445, p=0.023; r=-0.451, p=0.040). Ferritin was also negatively correlated with parafoveal VD in the SCP (r=-0.532, p=0.013). Conclusion: Parafoveal and perifoveal VD was found to be lower in the COVID-19 group. Presence of pneumonia, need for LMWH prophylaxis, and levels of CRP and ferritin were found to be negatively associated with retinal VD. Large-scale studies are needed to evaluate the clinical importance.

Evaluation of choroidal thickness with OCT in COVID-19 patients with high D-dimer levels.

To evaluate retinal and choroidal thickness with optical coherence tomography (OCT) to detect retinal and choroidal pathologies in coronavirus disease 2019 (COVID-19) patients with high D-dimer levels. Thirty patients who were hospitalized in the intensive care unit due to severe acute respiratory syndrome coronavirus 2 and whose D-dimer levels were high during this period, who applied to the internal medicine outpatient clinic between 15 and 30 days after discharge, and 30 healthy volunteers with similar age and gender as the control group was included in the study. After full ophthalmological examination, central foveal and choroidal thicknesses were evaluated using optical coherence tomography. Statistical analysis of the study data demonstrated that there was no significant difference between the groups in terms of age or gender (p > 0.05). There was also no statistically significant difference between the groups in terms of central foveal thickness, central choroidal thickness, or nasal 500, nasal 1500, temporal 500, or temporal 500 micron distances (p > 0.05 for all parameters). Choroidal and retinal vascular thicknesses were not affected in the short term in COVID-19 patients hospitalized in the intensive care unit.

Evaluation of early and late COVID-19-induced vascular changes with OCTA.

OBJECTIVE: To evaluate vascular changes in the early period after coronavirus disease 2019 (COVID-19) infection and at 6-month follow-up. METHODS: This study included 50 eyes of 25 patients who had been hospitalized for polymerase chain reaction-positive COVID-19 infection and 50 eyes of 25 healthy individuals. All subjects underwent optical coherence tomography angiography using a 6 × 6 macular protocol in the early period after hospital discharge and 6 months later. Foveal vessel density (VD) and parafoveal VD values were measured from 4 quadrants (superior, inferior, nasal, and temporal) of the superficial capillary plexus (SCP) and the deep capillary plexus (DCP). The choriocapillaris (CC) flow area and the foveal avascular zone area also were measured. The OCTA measurements of the patient group were compared both between time points and with the control group at each time point. RESULTS: COVID-19 patients showed lower VD values than control subjects in all parafoveal quadrants of both the SCP (superior, p = 0.01; inferior, p = 0.048; nasal, p = 0.003; temporal, p = 0.048) and the DCP (superior, p = 0.001; inferior, p = 0.011; nasal, p = 0.012; temporal, p = 0.018) at the initial checkup and in all parafoveal quadrants of the SCP (superior, p = 0.0001; inferior, p = 0.007; nasal, p = 0.001; temporal, p = 0.017) and in 2 of the parafoveal quadrants of the DCP (superior, p = 0.003; inferior, p = 0.016) at 6-month follow-up. CC flow area values were significantly lower at the 6-month follow-up than at the initial examination (p = 0.044). CONCLUSION: It is important to perform appropriate follow-up for COVID-19 patients because retinal vascular flow changes may persist in the long term.

Retinal microvascular morphology versus COVID-19: What to anticipate?

BACKGROUND: To investigate retinal microvascular morphological changes in previously COVID-19 infected patients using optical coherence tomography angiography (OCTA), and compare the findings to age- and gender-matched healthy subjects. METHODS: In this cross-sectional study, OCTA findings (6.0 × 6.0 mm scan size and scan quality index ≥7/10) from previously COVID-19 infected patients (group 1, 32 patients, 64 eyes) with ≥1 month of complete recovery were compared to healthy subjects (group 2, 33 subjects, 66 eyes) with no history of COVID-19 infection. A positive real-time reverse transcription-polymerase chain reaction test on a naso-pharyngeal swab sample confirmed the diagnosis. The AngioVueAnalytics, RTVue-XR 2017.1.0.155 software measured and recorded OCTA parameters. RESULTS: Group 1 had significantly lower superficial capillary plexus vessel densities in all foveal regions than group 2 (P<0.05). Foveal deep capillary plexus vessel density in group 1 was also significantly lower than in group 2 (P=0.009); however, no significant differences were found in other regions (P>0.05). All foveal avascular zone (FAZ) parameters were higher in group 1 than in group 2, with significant differences in FAZ area (P=0.019) and foveal vessel density 300 µm area around FAZ (P=0.035), but not FAZ perimeter (P=0.054). The outer retina and choriocapillaris flows were significantly lower in group 1 than in group 2 (P<0.05). CONCLUSIONS: Prior COVID-19 infection seems to be associated with significant changes in retinal microvascular density, as well as FAZ and flow parameters, which may be attributed to different pathogenic mechanisms that lead to SARS-CoV-2 infection, such as thrombotic microangiopathy and angiotensin-converting enzyme 2 disruption.

How are central foveal and choroidal thickness affected in patients with mild COVID-19 infection?

The aim of this study was to evaluate the effects of  COVID-19 on central foveal and choroidal thicknesses. Thirty-two patients with a positive SARS-CoV-2 PCR test who received outpatient treatment within the previous two months and 32 healthy controls were included in the study. Patients requiring hospitalization due to COVID-19 as well as the patients who received either intensive care support and/or antiplatelet therapy, smokers, or patients with systemic or ocular diseases were excluded from the study. After full ophthalmological examination, central foveal and choroidal thicknesses were evaluated by using optical coherence tomography. Statistical analysis of the study data demonstrated no significant difference between the groups in terms of age or gender (p>0.05). There was also no statistically significant difference between the groups in terms of central foveal thickness, central choroidal thickness, or nasal 500, nasal 1500, temporal 500, or temporal 500-micron distances (p>0.05 for all parameters). Choroidal and retinal thicknesses were not affected in patients with recent mild COVID 19 without comorbidities.

The Impact of Coronavirus Disease 2019 (COVID-19) on Retinal Microcirculation in Human Subjects.

BACKGROUND: The aim of the study was to assess retinal microcirculation in patients with coronavirus disease 2019 (COVID-19) through the use of optical coherence tomography angiography (OCT-A) and compare the results with those obtained in healthy controls. METHODS: The study enrolled 39 patients who had fully recovered from COVID-19 and 40 healthy controls. OCT-A image acquisitions were obtained using AngioVue software (version 2017.1.0.151) and the RTVue XR Avanti imaging system (Optovue Inc., Fremont, CA, USA). Nonflow area in the superficial capillary plexus (SCP), foveal avascular zone (FAZ) area in the whole retinal vasculature, FAZ perimeter, acircularity index of FAZ, and foveal density were automatically obtained with the FAZ assessment tool. Vessel density (VD) at the SCP and deep capillary plexus were also measured. RESULTS: Compared to the control group, the nonflow area and the FAZ area in the whole retina was greater in the COVID-19 group; however no statistically significant difference was observed (p > 0.05 respectively). As for vessel densities, all superficial parafoveal VD parameters were considerably higher in the COVID-19 group compared to the control group (p < 0.05 respectively). Despite the fact that the vessel densities in the remaining zones were lower in the COVID-19 group, those differences were not statistically significant (p > 0.05 respectively). CONCLUSION: VD at the parafoveal area of the SCP was significantly higher among patients in the late post-recovery period of COVID-19 disease compared to healthy controls. These findings show the impact of COVID-19 on the retinal microvasculature and its possible role as a risk factor for the development of ocular diseases.