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.

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.

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.