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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.
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Purpose: To observe the effects of caffeine intake on vessel densities in macular and peripapillary regions and to analyze the correlations of vascular properties of these two interlinked regions in healthy volunteers using optical coherence tomography angiography (OCTA). Methods: In this prospective randomized, double?masked, placebo?controlled study, 120 participants were grouped into two groups: sixty subjects as a study group, which received caffeine and sixty subjects as a placebo group, which received a placebo. OCTA imaging was performed at baseline and 1 h after drug intake. Changes in macular and radial peripapillary capillary (RPC) vessel densities (VD) and foveal avascular zone (FAZ) parameters and correlation of these parameters were analyzed. Results: Baseline macular and RPC VD and FAZ parameters showed no significant difference between study and placebo groups (P > 0.05 for all). VD parameters in all segments of superficial and deep macular regions and peripapillary region showed a statistically significant decrease after caffeine intake (P < 0.001 for all). All macular superficial VD parameters showed a positive correlation with deep perifovea VD (P < 0.05 for all). Also, superficial perifovea VD was positively correlated with all deep macular VD parameters except deep fovea VD (P < 0.05 for all). Conclusion: We show that caffeine causes a decrease in macular and peripapillary vessel densities in healthy subjects, and correlations were observed between macular and peripapillary VD parameters. We believe that future studies are needed to support the effect of caffeine on peripapillary VD and the idea of using deep perifovea VD as the main parameter to estimate superficial macular parameters.
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@#AIM: To observe the changes of macular microvascular parameters and their correlation with best corrected visual acuity(BCVA)in patients with branch retinal vein occlusion(BRVO)by using optical coherence tomography angiography(OCTA).<p>METHODS: The superficial retinal capillary layer in the posterior pole of 29 patients with BRVO was scanned by OCTA. Macular vascular density including vessel density(VD), perfusion density(PD), foveal avascular zone(FAZ), and morphological index were obtained at baseline, 1 and 6mo respectively.<p>RESULTS: The FAZ area in BRVO group was 0.32±0.08mm<sup>2</sup>, significantly larger when compared to the fellow eyes(0.21±0.06mm<sup>2</sup>)(<i>t</i>=-6.958, <i>P</i><0.001). The VD of full area of 3mm×3mm and 6mm×6mm was lower in BRVO eyes compared to fellow eyes(<i>P</i><0.05). As for PD, a difference was found between the two groups in the central and inter area in the 3mm×3mm scan pattern(<i>P</i><0.001), while a significant difference was found in central, the outer, and the full area in the 6mm×6mm scan pattern(<i>P</i><0.05). The BCVA at baseline was significantly better than that at 6mo(<i>t</i>=2.43, <i>P</i><0.05); BCVA(LogMAR)was positively correlated with VD and PD of centre area in 3mm×3mm mode, and PD of central and full area in 6mm×6mm model, but negatively correlated with PD in the outer area in 6mm×6mm mode.<p>CONCLUSION: As a non-invasive examination, quantitative OCTA measurements confirm vascular density changes in the superficial vascular networks in eyes with BRVO. Moreover, vascular density and FAZ area appear to correlate with visual function.
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@#AIM:To investigate the distribution characteristics of retinal nerve fiber layer(RNFL)thickness and vessel density(VD)in macular area of eyes with high myopia(HM), using optical coherence tomography angiography(OCTA).<p>METHODS:Forty eyes in 20 patients diagnosed with HM, age 29.90±7.92 years old, with a spherical equivalent(SE)of -8.95±2.01 D, were recruited. The RNFL thickness and the VD of the superficial retinal capillary plexus(SCP), deep retinal capillary plexus, and choroidal capillary(CC)were measured by OCTA. Macular regions within a 6 mm diameter circle were divided into 9 subfields: the central subfield, and the pericentral and peripheral regions of superior, inferior, nasal, and temporal quadrants. The RNFL thickness of different subfields were compared, and their relationships with SE, axial length, and VD were analyzed.<p>RESULTS:In the pericentral region, the RNFL thickness of the superior quadrant was the lowest, whereas thickness was highest in the inferior quadrant(all <i>P</i><0.05). In the peripheral region, the RNFL thickness of the temporal quadrant was the lowest(all <i>P</i><0.05). A negative correlation was found between the RNFL thickness and SE(<i>r</i>=-0.356, <i>P</i>=0.024)in the peripheral superior subfield. The VD of SCP was positively correlated with RNFL thickness in the nasal and inferior quadrants of the pericentral region and in the superior, nasal, and inferior quadrants of the peripheral region(<i>r</i>=0.314, 0.408, 0.467, 0.655, and 0.737 respectively; all <i>P</i><0.05), whereas the VD of CC was negatively correlated with RNFL thickness in the peripheral superior subfield(<i>r</i>=-0.356, <i>P</i>=0.024).<p>CONCLUSION:The RNFL of macular areas is not uniformly distributed in HM. As the SE increases, the RNFL thickness decreases in certain areas, which correlates with the VD of SCP and CC layers.
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Purpose: To evaluate age-related changes in macular vessels and their perfusion densities using optical coherence tomography angiography (OCTA). Methods: A total of 108 eyes of 54 healthy subjects between the age group of 11 to 60 years having unaided visual acuity of 20/20 were studied on spectral domain OCTS using 3 * 3 mm macula protocol. These subjects were divided into 5 groups; Group 1: 11–20 years, Group 2: 21–30 years, Group 3: 31–40 years, Group 4: 41–50 years, and Group 5: 51–60 years. An early treatment diabetic retinopathy study (ETDRS) grid overlay at the macula was used to calculate changes in different quadrants of the superficial retinal plexus. Results: A total of 98 eyes of 49 patients were considered for the final analysis. The vessel density values decreased from the second to the sixth decade in all four quadrants (except the third decade, where a slight increase was noted). The total vessel density decreased from 168 ± 78 mm-1 (group 1) to 131.47 ± 18.32 mm-1 (group 5). A similar reduction pattern in perfusion density was seen in each quadrant from the second to the sixth decade. The total perfusion density reduced from 309 ± 15.63% (group 1) to 283.05 ± 45.23% (group 5). The foveal avascular zone area was 0.18 ± 0.09 mm2 in group 1, 0.33 ± 0.13 mm2 in group 2, 0.30 ± 0.10 mm2 in group 3, 0.38 ± 0.05 mm2 in group 4, and 0.46 ± 0.06 mm2 in group 5. Conclusion: In our population, macular vessel density appears to decrease noticeably from the fourth decade onwards but a statistically significant decrease was observed only from the fifth decade onwards. However, it was not uniform along with all the quadrants. Similarly, the percentage of perfusion density dropped from the fourth decade but these values also varied among the different quadrants.