Characteristics of macular microvasculature before and after idiopathic macular hole surgery

AIM: To evaluate the macular microvasculature before and after surgery for idiopathic macular hole (MH) and the association of preoperative vascular parameters with postoperative recovery of visual acuity and configuration. METHODS: Twenty eyes from 20 patients with idiopathic MH were enrolled. Optical coherence tomography angiography (OCTA) images were obtained before, 2wk, 1, and 3mo after vitrectomy with internal limiting membrane peeling. Preoperative foveal avascular zone (FAZ) area and perimeter and regional vessel density (VD) in both layers were compared according to the 3-month best-corrected visual acuity (BCVA). RESULTS: The BCVA improved from 0.98±0.59 (logMAR, Snellen 20/200) preoperatively to 0.30±0.25 (Snellen 20/40) at 3mo postoperatively. The preoperative deep VD was smaller and the FAZ perimeter was larger in the 3-month BCVA<20/32 group (all P<0.05). A significant reduction was observed in FAZ parameters and all VDs 2wk postoperatively. Except for deep perifoveal VD, all VDs recovered only to their preoperative values. The postoperative FAZ parameters were lower during follow-up. Decreases in preoperative deep VDs were correlated with worse postoperative BCVA (Pearson's r=-0.667 and -0.619, respectively). A larger FAZ perimeter (Spearman's r=-0.524) and a lower deep perifoveal VD preoperatively (Pearson's r=0.486) were associated with lower healing stage. CONCLUSION: The status of the deep vasculature may be an indicator of visual acuity in patients with a closed MH. Except for the deep perifoveal region, VD recovers only to preoperative levels.

Idiopathic Epiretinal Membrane: Microvasculature Analysis with Optical Coherence Tomography and Optical Coherence Tomography Angiography

Background: The present study examined the relationships among macular microvasculature, retinal structure, and epiretinal membrane (ERM) and explored the utility of optical coherence tomography (OCT) angiography (OCTA) in idiopathic ERM assessment. Methods: The study sample comprised 276 eyes of 276 patients. A total of 154 eyes with ERM and 122 normal (control) eyes were analyzed. Only one eye of each participant was randomly selected for posterior segment imaging. Each patient underwent OCT and OCTA. Images were analyzed with AngioTool 0.6. Results: Foveal avascular zone was significantly smaller in the ERM group (p = 0.044). Average retinal thickness and foveal thickness were significantly higher in the ERM group (both p = 0.001). Moreover, 64 (41.5%) patients exhibited no metamorphopsia, while 46 (29.8%) and 44 (28.7%) patients exhibited moderate and extensive metamorphopsias, respectively. Meanwhile, FAZ was negatively correlated with central retinal thickness in the ERM group. The vessel area (p = 0.0017) and vessel percentage area (p = 0.044) were significantly greater in the ERM group. Conclusions: Changes observed in the superficial plexus in OCTA are related to the severity of metamorphopsia and can be further evaluated to support decision making regarding the surgical management of idiopathic ERM.

The Impact of COVID-19 Infection on Macular Capillary Perfusion

Purpose: To evaluate the impact of a prior non-severe COVID-19 infection on retinal microcirculation with optical coherence tomography angiography (OCTA).Methods:A total of 83 eyes of 43 patients with a history of non-severe COVID-19 infection confirmed with a positive PCR test (Group 1) and 30 age-matched healthy controls (Group 2) underwent detailed eye examination including Spectral-Domain OCT (Topcon-Triton Swept Source) and OCTA (RTVue-XR Avanti) scanning. OCTA images (6x6mm) images were used to assess vessel densities (VD) in superficial capillary plexus (SCP) and deep capillary plexus (DCP) and foveal avascular zone (FAZ). Results:The mean duration between the COVID-19 positive PCR test and ocular examination was 144.6±82.2 days (range: 30-270). VD of SCP and DCP in the foveal and perifoveal regions were significantly lower in Group 1 compared to Group 2 (p<0.05). Conclusion:Non-severe COVID-19 infection may cause a decrease in VD of retinal SCP and DCP.

Normative data on the foveal avascular zone in a young healthy Irish population using optical coherence tomography angiography

Purpose To establish normative data on the size, shape and vascular profile of the foveal avascular zone (FAZ) in a young, healthy, Irish population, using the Cirrus 5000 HD-OCT. Certain diseases may alter FAZ appearance. Normative databases provide normal baseline values for comparison, thus improving diagnostic ability. Methods One hundred and fifty-four subjects aged 18–35 years old were recruited. Superficial FAZ area, diameter, circularity, ganglion cell layer, central macular thickness (CMT), vascular perfusion and density were measured using the Cirrus 5000. Axial length was measured with the IOL Master and blood pressure was measured using the Omron sphygmomanometer. Results Mean FAZ area was 0.22 ± 0.07 mm2, mean CMT was 263.08 ± 18.73μm. Both were larger in females than males (p = 0.022, p = 0.000). Mean vessel density and perfusion central were 14.11 ± 2.77 mm/mm2 and 24.70 ± 4.96% respectively. Both were lower in females (p = 0.010, p = 0.019). Vessel density and perfusion inner correlated positively with minimum ganglion cell layer plus inner plexiform layer (GCL + IPL) thickness (p = 0.001, p = 0.019). CMT correlated positively with vessel density and perfusion central (p = 0.000 for both) and negatively with FAZ area (p = 0.000). Conclusions This study provides normative data for FAZ appearance and vascularity for the first time in a young, healthy, Irish population, using the Cirrus 5000 HD-OCT. Establishing machine and population specific normative data, particularly in relation to vessel density and perfusion is paramount to the early identification of ocular disease using Optical Coherence Tomography Angiography.

Study of the retina and optic nerve microvascular bed using optical coherence tomography-angiography in post-COVID-19 patients

Introduction. Signs of angioretinopathy are revealed in 7–27.7 % of post-COVID-19 patients. Optical coherence tomographyangiography (OCT-A) allows performing life-time evaluation of structural and microvascular retinal changes in patients after the new coronavirus infection. Aim. To investigate and to compare main microcirculatory parameters of capillary retinal and optic nerve plexuses using OCT-A in patients after COVID-19 of different severity degree. Materials and methods. The main group consisted of 54 people (108 eyes), who recovered from COVID-19 during 3 preceding months. According to the COVID-19 course severity degree, patients were divided into 3 sub-groups. 22 healthy volunteers (44 eyes) were included in the control group. All patients underwent OCT-A. In the angiography regimen, entire vascular density (VD) and that of every sector in the limits of superficial (SCP) and deep (DCP) capillary plexuses, radial peripapillary capillaries (RPC), and in the foveal avascular zone (FAZ). Results. All over parameters investigated no significant differences between control group patients and those of the sub-group with mild COVID-19 course. In patients with moderately severe infectious process course a significant decrease in VD SCP (P<0.01), as well as decrease in VD RPC (P<0.01). In patients with severe and critically severe disease course there was an decrease of VD DCP in the foveal area (P=0.016) and VD FAZ (P<0.01). VD indices correlations with thickness of retinal layers, in which these vascular plexuses are located. In any of the groups, there was no statistically significant enlargement of the FAZ area and no structural optic disc changes. Conclusion. In post-COVID-19 patients, there are signs of capillary blood flow reduction in retinal SCP and RPC, which is proportional to the prior infection severity degree. Associated to COVID-19 microangiopathy is a significant ophthalmologic sign of the new coronavirus infection. Microvascular changes of the retina could play a role of of a new biomarker reflecting the severity degree of the entire vascular system impairment in COVID-19.

The quantitative measurements of choroidal thickness and volume in diabetic retinopathy using optical coherence tomography and optical coherence tomography angiography; correlation with vision and foveal avascular zone

Background To represent choroidal thickness (CT) and choroidal volume (CV) databases in diabetic retinopathy (DR) patients and healthy control participants using optical coherence tomography (OCT) and enhanced depth imaging OCT (EDI-OCT). No study had evaluated CT at all main stages of diabetic retinopathy in a single study. Methods The study included 176 eyes from 93 patients (39–80 years old; 42% females) who were divided into three groups based on DR severity and normal control group: 39 eyes no DR, 64 eyes NPDR, 33 eyes PDR, and 40 eyes normal control. The CT and CV were measured and statistically analyzed. Intra-observer and inter-observer coefficients of repeatability were calculated. Results Subfoveal CT showed persistent thinning from normal group (322.50 ± 69.24) to no-diabetic retinopathy (NDR, 308.33 ± 74.45) to nonproliferative diabetic retinopathy (NPDR, 283.45 ± 56.50) group and then thickening as the patient progressed to proliferative diabetic retinopathy (PDR, 295.17 ± 95.69) (P = 0.087). A significant difference was found between the control group and the NDR, NPDR, and PDR groups in nearly all CT and CV of Early Treatment Diabetic Retinopathy Study macular subfields. Fasting blood sugar (FBS = 189.08 ± 51.3 mg/dl) and diabetes mellitus (DM) duration (13.6 ± 6.5 years) had no noticeable effect on CT. In patients with diabetes, the best-corrected visual acuity (BCVA), diabetic macular edema (DME), and foveal avascular zone (FAZ) were not affected by CT and CV. Conclusions The choroidal thickness decreases from the early stages of diabetic retinopathy up to the NPDR stage, with a subsequent modest rise in CT during the PDR stage. There was no correlation between FBS, diabetes duration, BCVA, DME, and FAZ, and CT.

Time-related OCT-A changes in preclinical retinopathy and their association with systemic factors

Background. Optical coherence tomography angiography (OCT-A) is a promising tool for the detection of microvascular impairment at the preclinical stage of diabetic retinopathy (DR). Evaluation of dynamic OCT-A changes and their association with systemic factors can help to reveal early biomarkers of DR progression.Aim: to evaluate time-related OCT-A changes and their association with systemic factors in type 1 diabetes mellitus (DM1) patients with no apparent DRMaterials and methods. 38 DM1 patients with no apparent DR and 39 healthy volunteers were included in the study. All participants underwent 7-fi eld fundus photography, OCT and OCT-A. We analyzed OCT-A parameters (foveal avascular zone (FAZ) area (mm2), acircularity index (AI), vessel density (VD), skeletonized density (SD)) as well as the results of blood and urea tests.Results. After one year of observation, AI was significantly higher (р = 0.005) and VD0–300 was signifi cantly lower in superfi cial vascular plexus (SVP, p < 0.0001) and deep capillary plexus (DCP, р = 0.032) in DM1 patients. We have also registered a positive correlation between AI and triglycerides (TG) level (r = 0.627, p = 0.007) as well as a negative correlation between ketones and VD (SVP VD0–300: r = –0.695, p = 0.030; intermediate capillary plexus (ICP, VD0–300: r = –0.551, p = 0.041; DCP, VD0–300: r = –0.704, p = 0.003; SVP, VD300–600: r = –0.853, p = 0.001).Conclusions. After one year of observation, we have registered an increase in AI level and a decline in VD in SVP and DCP which can be the earliest signs of DR progression. A signifi cant correlation between these parameters and systemic factors indicates their role as potential DR biomarkers.

Assessment of the degree of restoration of the retinal structure and chorioretinal blood flow after surgical treatment of large-diameter macular holes

The aim: to evaluate the restoration features of the structural relationships of the retina and chorioretinal blood fl ow after surgical treatment of large-diameter macular hole (MH) using a modifi ed technology.Material and methods. A prospective study of 14 patients (14 eyes), 13 women and 1 man, with medium-and large-diameter MH was conducted. The mean age of the patients was 67.7 ± 5.38 (55–80) years. The study included patients with endto-end MH of the 3rd–4th stage according to the classifi cation of J. Gass. All patients underwent surgical treatment of macular rupture according to the proposed method of inverted fl ap of the internal limiting membrane (ILM) and fi lling it into a “pocket” formed between the retina and the ILM.Optical coherence tomography (OCT) was performed along with traditional research methods. The obtained images were used to measure manually the parameters of retinal MH, the thickness of the choroid in the projection of the rupture and the fovea zone before the operation and 1, 3 and 6 months after the operation. In the angio-mode, the foveal avascular zone (FAZ) was evaluated, as well as the density of capillaries of the superfi cial and deep retinal plexus in four quadrants, with the exception of the central zone.Results. In all patients, it was possible to achieve MH blocking. Visual acuity in the eyes with MH varied from 0.02 to 0.3, while in the comparison group, the best corrected visual acuity was from 0.3 to 1.0 (p = 0.002). An increase in the diameter of large choroidal vessels, as well as a pronounced decrease in the diameter of the posterior short ciliary artery, attracted attention. However, despite the improvement in visual acuity, patients retained a signifi cant expansion of the FAZ, which by 6 months exceeded the FAZ area of the paired eye by 25.8 % (p = 0.01).Conclusion. The results obtained indicate that the achievement of an anatomicalreconstructive effect and even a moderate improvement in visual acuity during surgical treatment of macular holes by the modifi ed inverted flap technology of the internal limiting membrane does not determine the restoration of retinal perfusion in full.

Hyperreflective Foci and Subretinal Fluid Are Potential Imaging Biomarkers to Evaluate Anti-VEGF Effect in Diabetic Macular Edema

Purpose: The aim was to investigate the effect and underlying mechanism of anti-vascular endothelial growth factor (anti-VEGF) in diabetic macular edema (DME) by optical coherence tomography angiography (OCTA).Methods: Twenty-five eyes in 18 treatment-naïve patients with DME were included. All eyes were imaged by OCTA at baseline and 1 week after monthly intravitreal aflibercept injection (IAI). Visual acuity was measured as best corrected visual acuity (BCVA). Additional parameters were evaluated by OCTA, including central macular thickness (CMT), the number of hyperreflective foci (HRF), foveal avascular zone (FAZ), vessel density (VD) in the deep capillary plexus (DCP), the en-face area of cystoid edema in DCP segmentation, and subretinal fluid (SRF) height.Results: The mean time between baseline and final follow-up by OCTA was 79.24 ± 38.15 (range, 28–163) days. Compared with baseline, BCVA was increased significantly after the 3rd IAI, while CMT was decreased significantly from the 1st IAI. SRF height and the area of cystoid edema in DCP segmentation were decreased significantly after the 2nd IAI compared with baseline. The number of HRF was decreased significantly after the 1st IAI (8.87 ± 9.38) compared with baseline (11.22 ± 10.63). However, FAZ’s area and perimeter as well as VD in DCP showed no significant changes post-treatment.Conclusion: Anti-VEGF is effective in treating DME, improving visual acuity and decreasing macular edema. The decreased HRF indicates anti-inflammatory effects of aflibercept to deactivate retinal microglia/macrophages. The decreased cystoid edema and SRF height indicated improved drainage function of Müller glial cells and retinal pigment epithelium after IAI.