Foveal Avascular Zone Area Research Articles

COVID-19-related retinal microvasculopathy and systemic implications in patients with severe disease: results from the Methuselah study.

To assess the reversibility of retinal microvascular changes in the long term and to investigate the potential links with other vascular diseases of COVID-19. We designed a prospective multicenter observational study. Patients were enrolled from the Methuselah study cohort. Retinal vascular function was studied in these patients using optical coherence tomography angiography (OCTA); aortic stiffness was measured using aortic pulse wave velocity. These examinations were performed 1 (Visit 1) and 12 (Visit 2) months after the hospital discharge for severe COVID-19. A control subject group matched for age and sex was included to define normal values. A total of 28 control subjects (56 eyes) and 25 patients (50 eyes) completed the scheduled OCTA assessment; 18 patients (36 eyes) also completed the macrovascular examination. Compared to controls, the vessel density of the superficial capillary plexus (SCP) was reduced, whereas the foveal avascular zone area was enlarged at Visit 1 (p = 0.016 and < 0.001, respectively) and was not modified after the 12-month follow-up in COVID-19 patients (p = 0.011 and 0.001, respectively). Higher inflammation and lower renal function during hospitalization were linked to higher aortic stiffness and reduced vessel density of the SCP 1 month after the acute phase of COVID-19. A slower recovery of aortic dysfunction was linked to worse retinal vascular outcomes at Visit 2. Retinal vascular alterations were not reversible 12 months after COVID-19 and were linked to inflammation and renal dysfunction during hospitalization as well as to aortic stiffness measured during follow-up.

Mean Ocular Perfusion Pressure Effect During Pars Plana Vitrectomy on the Foveal Avascular Zone: A Pilot Study.

Purpose: To evaluate the effect of mean ocular perfusion pressure on the foveal avascular zone (FAZ) area in eyes with successful retinal detachment (RD) surgery. Methods: This prospective pilot fellow eye-controlled study measured the intraoperative mean ocular perfusion pressure in eyes having surgery for rhegmatogenous RD (RRD). Postoperatively, the FAZ area was measured; the change was calculated as the difference in the FAZ area between the operated eye and the contralateral control eye. Results: The study comprised 8 patients with a mean age (±SD) of 53.38 ± 13.92 years. The mean superficial FAZ area was not different between operated eyes and control eyes, while the deep FAZ area was significantly larger in operated eyes. There was a strong negative correlation between the mean ocular perfusion pressure and the change in the deep FAZ area (Spearman ρ, -0.73; P = .04); the correlation between the mean ocular perfusion pressure and the change in the superficial FAZ area was not significant (Spearman ρ, -0.24; P = .57). A significant linear regression was found between the mean ocular perfusion pressure and the change in the deep FAZ area (R2 = 0.388). The predicted enlargement of the deep FAZ area was 0.03 mm with every 1 mm Hg decrease in the mean ocular perfusion pressure. Conclusions: Lower intraoperative mean ocular perfusion pressure is associated with enlargement of the deep FAZ area in eyes having successful RRD surgery.

Retinal capillary plexus in Parkinson's disease using optical coherence tomography angiography.

To evaluate the alterations of the retinal microvasculature and foveal avascular zone in patients with Parkinson's disease (PD) using optical coherence tomography angiography (OCT-A). A retrospective study of PD patients examined in the Ophthalmology Department of the General Hospital of Athens, "Georgios Gennimatas" from March 2021 to March 2022 was conducted. Totally 44 patients with PD were included and 18 healthy controls were examined, hence a total of 124 eyes were enrolled in the study. The foveal and parafoveal superficial and deep capillary plexus vascular density (fSCP-VD, fDCP-VD, pSCP-VD, pDCP-CD) and foveal avascular zone (FAZ) were quantified with OCTA. Optical coherence tomography (OCT) was used to measure macular thickness. Our statistical analysis was conducted by using a mixed effect linear regression model. After adjustment for age and gender, the mean parafoveal superficial capillary plexus vascular density (pSCP-VD) and mean parafoveal deep capillary plexus vascular density (pDCP-VD) were significantly decreased in individuals with PD (P<0.001 in both) by -2.35 (95%CI -3.3, -1.45) and -7.5 (95%CI -10.4, -4.6) respectively. fSCP-VD and fDCP-VD didn't approach statistical significance. The FAZ area and perimeter were significantly decreased (P<0.001 in both) by -0.1 mm2 (95%CI -0.13, -0.07) and -0.49 mm2 (95%CI -0.66, -0.32) respectively. Circularity didn't approach statistical significance. Central retinal thickness (CRT) was significantly decreased in individuals with PD (P<0.001) by -23.1 µm (95%CI -30.2, -16) and temporal retinal thickness (TRT) was decreased (P=0.025) by -11 µm (95%CI -22, -1.5) while nasal retinal thickness (NRT) only approached statistical significance (P=0.066). The mean pSCP-VD, pDCP-VD, CRT and TRT are significantly decreased and FAZ is altered in individuals with PD. These findings can be potentially used as biomarkers for the diagnosis and evaluation of early PD.

Retinal neurovascular alteration in type 2 diabetes with renal impairment in association with systemic arterial stiffness

BackgroundDiabetic retinopathy (DR) patients should be alert for subclinical macroangiopathy. We aimed to investigate the association between retinal neurovascular alteration and systemic arterial stiffness in type 2 diabetes mellitus (type 2 DM) patients with varying degrees of renal impairment.MethodsThe study included 170 patients with confirmed diagnosis of type 2 DM aged ≥18 years old. Renal function was assessed by estimated glomerular filtration rate (eGFR). Arterial stiffness was measured by brachial-ankle pulse wave velocity (baPWV) and ankle brachial index (ABI). Retinal neurovascular parameters were derived from Optical Coherence Tomography (OCT)/OCT-Angiography, represented by vessel density (VD Central, Inner, Outer, Full), foveal avascular zone (FAZ area and FAZ perimeter) of the superficial capillary plexus, the average of macular ganglion cell-inner plexiform layer thickness (ave mGC-IPLt) and the average of retinal nerve fiber layer thickness (aveRNFLt). The association between variables among the groups (according to renal function, diabetic retinopathy (DR) severity, and arterial stiffness categories) were analyzed by regression analysis with multiple hypothesis testing commands.ResultsOut of the 265 eyes, the mean DM duration and HbA1c were 6.21 ± 6.37 years and 8.44 ± 2.06% respectively. While the mean of eGFR, baPWV and ABI were 66.78 ± 32.80 ml/min/1.73m2, 15.49 ± 3.07 m/s, and 1.05 ± 0.12, respectively. Patients with more severe renal impairment demonstrated longer DM duration (p < 0.001), higher baPWV (p < 0.0001), and retinal vascular alteration. Proliverative DR group showed the lowest eGFR (p < 0.0001), highest baPWV (p < 0.0001), and retinal neurovascular changes. Significantly lower eGFR and retinal vascular alteration were found in the baPWV > 14 group. Some neurovascular parameters were significantly negatively correlated with baPWV; moreover, retinal neurovascular changes were also noted in the abnormal ABI group.ConclusionsThe strong association between changes in the retinal neurovascular system, DR severity, renal impairment, and arterial stiffness in type 2 DM was confirmed. Patients with more severe renal impairment had higher levels of arterial stiffness, more severe DR and retinal neurovascular alteration. Retinal neurovascular changes seen in OCT/OCTA might mimic renal microvascular alteration and systemic arterial stiffness. Therefore, assessment of baPWV and OCT/OCTA should be integrated in DR screening to enhance cardiovascular risk stratification and prognosis as well as to provide clinically useful early identification of subclinical micro- and macrovascular alterations.

Evaluation of early retinal changes in patients on long-term hydroxychloroquine using optical coherence tomography angiography.

Connective tissue diseases (CTD), including systemic lupus erythematosus and rheumatoid arthritis (RA), have long been treated with hydroxychloroquine (HCQ). However, prolonged HCQ use poses a risk of adverse effects, particularly retinopathy. To detect early retinal changes assessed by optical coherence tomography angiography (OCTA) in CTD patients with long-term HCQ treatment and to explore the relationship between OCTA parameters and the concentrations of HCQ and its metabolites. A cross-sectional study conducted from March 2020 to October 2021 at the First Affiliated Hospital of Anhui Medical University. The area and perimeter of the foveal avascular zone (FAZ), the thickness of the fovea and parafovea, and the vascular density of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in each area of the macula were measured by OCTA in 43 CTD patients treated with HCQ for over 6 months. Meantime, blood concentrations of HCQ and its metabolites were determined by high-performance liquid chromatography-tandem mass spectrometry, and the clinical documents of all 43 involved patients were collected. There is no significant correlation between OCTA outcomes and the patient's age, disease duration, and weight-dependent dose. HCQ cumulative duration positively correlated with FAZ area and perimeter (r = 0.419, p = 0.005 and r = 0.407, p = 0.007, respectively) and negatively correlated with the foveal vessel density in DCP (r = -0.378, p = 0.012). HCQ cumulative dose had a positive correlation with FAZ area and perimeter (r = 0.445, p = 0.003 and r = 0.434, p = 0.004, respectively) and had a negative correlation with foveal vessel density in SCP and DCP (r = -0.383, p = 0.011 and r = -0.424, p = 0.005, respectively). OCTA outcomes did not correlate with HCQ and its metabolite concentrations. OCTA could be used to detect microvascular changes in the macula of CTD patients with long-term HCQ therapy. It was not found the concentrations of HCQ and its metabolites were associated with retinal vascular changes.

Optimizing criterion to reduce the variability between observers in the delimitation of the foveal avascular zone in diabetic patients

Aims/Purpose: To reduce the variability when performing manual segmentation of the foveal avascular zone (FAZ) on retinal optical coherence tomography angiography (OCTA) images, and to find a new accurate FAZ delimitation criterion.Methods: Seventy‐three eyes from healthy subjects, 40 eyes from Type 1 diabetes mellitus (DM1) patients without diabetic retinopathy (DR) and 54 eyes from Type 2 diabetes mellitus (DM2) patients with moderate DR and without diabetic macular oedema (DME) were evaluated using OCTA. A manual FAZ segmentation was performed by different observers of each OCTA image of the superficial (SCP) and deep capillary plexuses (DCP). After comparing the results, a new criterion was established to reduce the variability in the segmentations. The FAZ area and circularity were also studied.Results: The novel criterion produces smaller areas (closer to the real FAZ), as well as a diminution of the standard deviation values, with a factor of 0.5, with lower variability than the different criteria of the explorers in both plexuses for the three groups. This was particularly notorious for the DM2 group with damaged retinas, where it was very difficult to define the FAZ limits. The acircularity values were also slightly reduced with the final criterion in all groups. In the DM2 group a significant reduction in the acircularity mean value of both plexuses was obtained. Looking for a relationship between the FAZ area and the acircularity, we found slightly higher values of acircularity for smaller FAZ areas. The number of extremal values was much higher for the initial method, and when the DCP was evaluated.Conclusions: The implementation of a new criterion for FAZ segmentation produced more consistent results with less variability among observers.

Optical coherence tomography angiography of the foveal avascular zone after successful macula‐off rhegmatogenous retinal detachment repair

Aims/Purpose: To investigate the size and shape of the foveal avascular zone (FAZ) after successful macula‐off rhegmatogenous retinal detachment (RRD) repair using swept source OCT angiography (SS OCTA).Methods: A prospective comparative cross‐sectional study including 21 eyes of 21 patients with macula‐off RRD that were successfully repaired. The size of the superficial FAZ was assessed by its area, length of perimeter, and Feret's diameter, and the shape by the circularity, axial ratio, roundness and solidity. The correlations between each parameter and the clinical and OCT findings were statistically determined. The unaffected fellow eyes were used as controls.Results: The mean initial BCVA was 1.92 ± 0.41 Log MAR (20/2000 Snellen's equivalent). The mean BCVA at OCTA acquisition (3 months) was 0.78 ± 0.39 Log MAR (20/100 Snellen's equivalent) (p &lt; 0.001). FAZ was significantly larger (323.09 ± 129.03 μm2 vs. 245.27 ± 93.15 μm2; p = 0.038), with longer perimeter (2.31 ± 0.35 mm vs. 2.07 ± 0.31 mm; p = 0.048), and irregular shaped (mean circularity: 0.73 ± 0.72 vs. 0.78 ± 0.5; p = 0.019 and mean solidity: 0.90 ± 0.02 vs. 0.93 ± 0.02; p = 0.002) in operated eyes than in the control group. The average Feret's diameter was 0.77 ± 0.10 mm versus 0.71 ± 0.88 mm (p = 0.076). The average axial ratio was 1.25 ± 0.20 versus 1.22 ± 0.22 (p = 0.531), and the average roundness was 0.81 ± 0.11 versus 0.83 ± 0.11 (p = 0.531). Mean central foveal thickness (CFT) was significantly lower in operated eyes than in control eyes (178.23 ± 40.59 μm vs. 247.44 ± 38.2 μm (p &lt; 0.001)). There was a significant inverse correlation between FAZ area and post‐operative outer nuclear layer thickness (r = −0.520, p = 0.016) and CFT (r = −0.571, p = 0.007) in operated eyes. There was no significant correlation between the post‐operative visual acuity and FAZ parameters.Conclusions: Enlargement and irregularities of FAZ after successful macula‐off RRD repair, as demonstrated by SS OCTA, might suggest an ischaemic macular damage caused by RRD that may affect post‐operative functional outcome.

Optical coherence tomography angiography findings after silicone oil tamponade for rhegmatogenous retinal detachment

Aim: To describe retinal structural and microvascular changes using Swept source optical coherence tomography (SS‐OCT) and OCT angiography (OCT‐A) in patients with rhegmatogenous retinal detachment (RRD) treated by vitrectomy (PPV) and silicone oil (SO) tamponade and to identify the final visual acuity (VA) prognostic factors.Methods: In this retrospective study, patients were treated with PPV and SO tamponade for uncomplicated DRR. After SO removal, retinal thickness was assessed by SS‐OCT. The foveal avascular zone (FAZ) area, the fractal dimension (FD), the lacunarity (LAC) and the macular capillary vessel density (VD) in the superficial (PCS) and deep plexuses (PCP) and in the choriocapillaris (CC) were analysed.Results: Thirty‐one eyes were included in this study; 20 eyes (65%) had macula ‘OFF’ RRD. The mean post‐operative final VA was 3.2/10. Outer retinal defect was observed in 74.1% of the operated eyes. Central macular thickness (CMT) and parafoveal thickness were significantly decreased compared with healthy fellow eyes (p = 0.048; p = 0.029). Outer nuclear layer (ONL) and subfoveal choroid were significantly thinned in the operated eyes (p = 0.003; p = 0.017). The FAZ in PCS and PCP and was larger (p = 0.042; p = 0.032), the VD (total, parafoveal and parafoveal) in the PCP were significantly lower (p = 0.004; p = 0.012; p = 0.049) and the lacunarity (LAC) at the PCP level was significantly higher (p = 0.040) in the operated eyes than in the fellow eyes. The final VA was correlated with the defect of the outer retina (p &lt; 0.002) and the VD in PCP (p = 0.0199). The duration of SO tamponade was signifcantly correlated with the outer retinal defect (p = 0.011), the enlargement of FAZ area (p = 0.001) and the VD in DCP (p = 0.002).Conclusion: SIO can lead to structural and vascular retinal ischaemic defect such as enlargement and irregularity of the FAZ and predominant PCP capillary abnormalities. These changes could reflect vascular hypoperfusion in eyes with SO tamponade and may represent a potential cause of retinal thinning and unexplained visual loss.

Exploratory analysis of choriocapillaris vasculature as a biomarker of idiopathic epiretinal membrane.

To investigate the preoperative choriocapillaris perfusion (CCP) as a biomarker in patients with idiopathic epiretinal membrane (iERM). 28 patients (28 eyes) with unilateral iERM who received pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling were included for retrospective observational study. Optical coherence tomography (OCT) and angiography (OCTA) was performed before and after PPV. Area, perimeter, and circularity of superficial foveal avascular zone (FAZ) were analyzed preoperatively in both eyes using OCTA. Preoperative CCP was also analyzed with binarized en-face OCTA images. Measurements of best-corrected visual acuity (BCVA) and central foveal thickness (CFT) by OCT were conducted at the baseline and 6 months following the surgery. The correlations of preoperative OCT parameters with postoperative BCVA and CFT reduction were analyzed. CCP was significantly lower (p < 0.001) and FAZ had shrunk (p < 0.001) in eyes with iERM compared to unaffected fellow eyes before surgery. BCVA and CFT became significantly improved after surgery (p = 0.001, p < 0.001). Multiple regression analysis revealed that preoperative CCP was significantly related with BCVA improvement (β = 0.185, p = 0.005), postoperative BCVA (β = 0.108, p = 0.023) and ratio of post- to preoperative CFT (β = 0.106, p = 0.044). Preoperative CCP is a biomarker for poor functional and anatomical prognosis after surgery in iERM.

Four years follow‐up OCTA changes in long‐term type 1 diabetic patients without diabetic retinopathy

Aims/Purpose: To assess changes in retinal capillary plexuses and choriocapillaris over 4 years' time in long‐term Type 1 diabetic patients (DM1) without diabetic retinopathy (DR).Methods: Twenty‐four eyes of 24 long‐term DM1 patients with no DR lesions were examined by optical coherence tomography angiography (OCTA) over a 4 year follow‐up period. Vascular density (VD) of both superficial and deep retinal capillary plexuses (SCP, DCP) and choriocapillaris (CC) were compared, as well as foveal avascular zone (FAZ) area and diameters.Results: Mean age was 46.84 ± 11.28 years and the average DM1 evolution time was 28.88 ± 8.04 years. Mean HbA1c level was 7.34 ± 0.94% at the last examination. SCP showed a statistically significant increase in VD in all areas except the inferior quadrant. There were no changes in the area or diameters of the FAZ in the SCP. In the DCP, there was a significant increase in VD in the temporal quadrant and a decrease in the inferior quadrant, along with a decrease in the horizontal diameter of the FAZ. The nasal area of the CC showed a significant increase in VD.Conclusions: DM1 patients present changes in the inner retina microvascularization after a follow‐up period of 4 years before displaying any signs of DR, mainly an increase in VD the SCP of the retina, along with a decrease in VD in the inferior quadrant of the DCP.

Relationship between visual function and macular microstructure in highly myopic patients undergoing surgery for rhegmatogenous retinal detachment.

To analyze the relationship between visual function and macular microstructure in highly myopic patients undergoing surgery for rhegmatogenous retinal detachment (RRD). Fifty-eight highly myopic patients treated in the Baoding No. 1 Central Hospital between December 2021 and September 2023 were selected as the research participants for retrospective analysis. All patients were complicated with RRD and underwent retinal reattachment surgery at Baoding No. 1 Central Hospital after diagnosis. Best-corrected visual acuity (BCVA) examinations were performed before and 3 months after surgery, and visual field mean sensitivity (MS) and fixation stability (FS) were measured by microperimetry. Additionally, changes in postoperative macular microstructure and micro blood flow were determined by optical coherence tomography (OCT), and their correlations with visual function were analyzed. Patients showed reduced BCVA, MS, and FS after surgery (all P<0.05), with 70.69% of them presenting with macular microstructural changes, mainly ellipsoid zone disruption and external limiting membrane disruption. Patients with macular microstructural changes exhibited significantly decreased BCVA, MS, and FS than those without (all P<0.05). In terms of micro blood flow, the BCVA, FS, and MS of patients with macular microstructural changes were negatively correlated with the foveal avascular zone (FAZ) area but were positively related to FAZ morphological index, PSCP, and VSCP (all P<0.05). Changes in patients' visual function after surgery for RRD can be effectively evaluated by observing the macular ellipsoid, the integrity of the external limiting membrane, and the alterations in micro-blood flow, enabling the formulation of early and targeted interventions.

Evaluation of Optical Coherence Tomography Angiography in Degenerative and Tractional Lamellar Macular Hole.

This study aims to evaluate the optical coherence tomography angiography (OCTA) findings in cases with degenerative and tractional lamellar macular holes (LMH). Two subtypes of LMH cases were included. Seventeen patients had the degenerative subtype, whereas 18 patients had the tractional subtype of LMH. Twenty healthy individuals were enrolled as the control group. The foveal avascular zone (FAZ) and retinal vascular densities in the superficial, deep capillary, and choriocapillary plexuses were analyzed and compared with fellow eyes and healthy controls using OCTA. The mean FAZ area was wider in the degenerative subtype (0.33 ± 0.14 mm2) compared to the tractional subtype (0.24 ± 0.10 mm2) (p=0.04) and control eyes (0.26 ± 0.10 mm2) (p=0.03). Foveal vessel densities in the superficial and deep capillary plexuses were lower in the degenerative group than in the tractional group, (21.7 ± 9.8% vs. 26.8 ± 6.9%, p=0.01 and 28.5 ± 5.1% vs. 36.9 ± 6.2%, p=0.01). Choriocapillary vascular density in the parafoveal area was also lower in degenerative lamellar macular holes compared to the tractional group (60.4 ± 4.7% vs. 63.7 ± 3.9%, p=0.03). Compared to control eyes, eyes with degenerative and tractional LMH showed lower vessel densities in the parafoveal and perifoveal areas of the SCP, DCP, and all layers of CC (p < 0.05). In the foveal area, the LMH groups showed higher foveal vascular density (FVD) in the SCP than control eyes, while in the DCP, FVD was lower in the degenerative LMH eyes relative to the other groups. The finding of microvascular changes between degenerative and tractional LMH subtypes highlights their distinct pathologies and supports recent changes in the classification and terminology of this macular condition.

Retinal and Choroidal Vascularization Parameters in Patients with Type 2 Diabetes Without Diabetic Retinopathy.

The purpose of this study was to evaluate retinal and choroidal vascularization parameters in patients with type 2 diabetes mellitus (DM), without diabetic retinopathy (DR), and to compare them to healthy controls. Seventy-four eyes from 74 patients (40 eyes in the DM group and 34 eyes in the control group) were included in the study. Optical coherence tomography angiography RTVue XR Avanti was used to obtain 3×3mm scans of the macula. The choroidal vascularity index (CVI), superficial and deep capillary plexus vascular densities (SCP and DCP, respectively), and choroidal thickness (CT) were measured. In the diabetic group, SCP was lower in the superior and nasal segments (48.68 vs 50.62, p=0.02; 45.50 vs 48.82, p=0.02, respectively). The DCP did not differ between the groups. CVI was significantly lower in the study group in all measured segments, including central and parafoveal (31.73 vs 48.86 and 50.32 vs 59.58, p<0.001, respectively). CT was larger in the study group only at the center of the macula (281.89µm vs 268.37µm p<0.001) and in the inferior segment (337.47µm vs 329.40µm, p<0.001). In the multivariate regression, clinical and vascularization parameters affecting CVI and CT were analyzed after adjusting for age and sex. Decreased central CVI was associated with the presence of DM, lower central SCP, and bigger foveal avascular zone area (b=-0.68, b=0.47, b=-0.21). Parafoveal CVI was also negatively affected by DM (b= -0.46) and positively by parafoveal SCP (b= 0.44). Increased central CT was found to be positively associated with higher central SCP (b=0.48) and male sex (b=0.20). The results of our study confirmed a reduction of SCP and CVI in diabetic patients without DR. DM and SCP are age and sex independent parameters affecting CVI. Central CT is affected by SCP and sex, rather than the presence of diabetes.

Optical coherence tomography angiography features of the chorioretinal complex and choriocapillaris perfusion before and after vitrectomy with conventional versus fovea-sparing internal limiting membrane peeling for idiopathic macular hole

Purpose: To assess optical coherence tomography angiography (OCTA)-measured changes in the chorioretinal complex and choriocapillaris perfusion density in the macula before and after vitrectomy with fovea-sparing versus conventional internal limiting membrane (ILM) peeling for idiopathic macular hole (IMH). Material and Methods: Eyes with stage-2 to stage-4 holes as per the classification by Gass received 25-G vitrectomy with conventional or fovea-sparing ILM peeling and gas tamponade with 20% SF6 or 15% С3F8. IMH diameter, foveal avascular zone (FAZ) area in the deep retinal plexus and choriocapillaris perfusion density (CPD) were assessed before and 1 month after surgery. Results: Totally, 70 patients had an IMH surgery in 71 eyes. The mean age ± standard deviation (SD) was 65.7 ± 6.8 years, median IMH duration (interquartile range or IQR), 3.0 (1.0-6.0) months, median best-corrected visual acuity or BCVA (IQR), 0.19 (0.1-0.25), and median maximum IMH diameter (IQR), 673.5 (549.5–1010.5) µm. In eyes with IMH and fellow eyes, the median FAZ area (IQR) was 0.51 (0.15–0.53) mm2, and 0.46 (0.10–0.74) mm2, respectively (р = 0.49), and mean CPD ± SD, 0.11 ± 0.06, and 0.29 ± 0.13 (р = 0.0001), respectively. Thirty-four eyes received conventional ILM peeling and 37 eyes, fovea-sparing ILM peeling, and there was no significant intergroup difference in baseline characteristics. One month after surgery, IMH closure was achieved in 63/71 eyes (i.e., the closure rate was 88.7% for total operated eyes, and 88.2% and 89.2%, respectively, for eyes in conventional ILM peeling and fovea-sparing ILM peeling groups), and median BCVA (IQR) improved to 0.60 (0.4–0.8) (р = 0.00001). After IMH closure, in operated eyes, median FAZ area (IQR) decreased to 0.30 (0.12–0.6) mm2, but the difference was not significant, whereas mean CPD ± SD increased significantly from 0.11 ± 0.06 to 0.25 ± 0.10 (р = 0.0001). No significant difference in OCTA-based retinal microcirculation and choriocappillaris characteristics was observed between the conventional ILM peeling and fovea-sparing ILM peeling groups. Conclusion: The presence of macular hole is accompanied by abnormal perfusion in the choriocapillaris, but the CPD recovers after IMH closure. Postoperative CPD recovery is not influenced by the type (conventional or fovea-sparing) of ILM peeling.

CHANGES IN OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY MEASURES THROUGHOUT THE DAY: Diurnal Variation or Test-Retest Variability?

To evaluate the repeatability and diurnal variation of the retinal vessel density and foveal avascular zone parameters using optical coherence tomography angiography. Forty-one healthy individuals were measured twice in the morning and once in the evening. Foveal avascular zone area, perimetry, foveal density; superficial and deep capillary plexus (superficial capillary plexus, deep capillary plexus) vessel density, and central macular thickness were evaluated with the intraclass correlation coefficient, coefficient of repeatability, and Bland-Altman plots. Repeatability was evaluated with two consecutive scans taken in the morning. The coefficient of repeatabilities (%) was 5.4; 4.3, and 8.8 for the foveal avascular zone area, perimetry, and foveal density, respectively, with excellent intraclass correlation coefficients. Intraclass correlation coefficient was poor for parafovea (0.33), whereas excellent for fovea (0.97) in superficial capillary plexus-vessel density. Coefficient of repeatability for fovea and parafovea was 19.19% and 10.43%, respectively. Intraclass correlation coefficient values were poor (0.3-0.4) with 10% to 16% measurement differences in deep capillary plexus-vessel density parameters. Coefficient of repeatabilities for central macular thickness was between 1% and 2% with excellent intraclass correlation coefficient. The analysis on diurnal variation yielded comparable results. Except for the parafoveal vessel density, optical coherence tomography angiography is a highly reproducible device for measuring foveal avascular zone and vessel density using 6 × 6 scans with undilated pupils. However, variation in optical coherence tomography angiography parameters observed throughout the day could be attributed to test-retest variation rather than diurnal rhythm.

Association of foveal avascular zone change and glaucoma progression

Background/aimsTo investigate the association between longitudinal changes of foveal avascular zone (FAZ) area and the rate of structural and functional progression in glaucoma.MethodsA longitudinal cohort included 115 eyes (46 glaucoma...

Evaluation of retinal and peripapillary vessel density and subfoveal choroidal thickness changes in patients undergoing cardiopulmonary bypass: An OCTA study.

We aimed to investigate hemodynamic changes in the retina, peripapillary area, and choroid in patients undergoing coronary artery bypass grafting (CABG). This prospective case series included 35 eyes of 35 patients. Vessel density (VD) of superficial capillary plexus, deep capillary plexus, radial peripapillary capillary, foveal avascular zone area, and subfoveal choroidal thickness changes were evaluated using optical coherence tomography angiography (OCTA) 1 day before and 2 weeks after surgery. The correlation of these parameters with aortic cross-clamp (ACC) duration and cardiopulmonary bypass (CPB) duration was evaluated. There were no differences in the OCTA measurements of the patients after CABG compared to before surgery (P > 0.05). Inside-disc VD showed a negative correlation with both ACC (P = 0.036) and CPB duration (P = 0.048); peripapillary inferior hernia showed a negative correlation with both ACC (P = 0.042) and CPB duration (P = 0.027). Another negative correlation was observed between mean peripapillary VD and CPB duration (P = 0.039). The CPB procedure had no permanent effect on retinal choroid and optic disc blood flow postoperatively. Prolonged ACC and CPB times seem to be important in terms of optic nerve blood flow. Clinicians should be alert for postoperative ocular complications after long surgeries.

A cross-sectional study of macular displacement after macular hole surgery with ILM peeling in patients with idiopathic macular hole.

To examine the retinal displacement and change in mean superficial foveal avascular zone (FAZ) after successful closure of macular hole (MH) with vitrectomy with internal limiting membrane peeling (ILM) and gas tamponade. A total of 45 patients with idiopathic MH who underwent 23G pars plana vitrectomy with ILM peeling and tamponade with 20% SF6/14% C3F8 were included. Follow-up visits were performed at 2, 4, and 8 weeks. OCT and OCT-A scans were performed along with detailed ocular examination. Distance between optic disc and an easily identifiable vascular bifurcation nasal and temporal to fovea, FAZ, was noted. Chi-square test (categorical data) and Mann-Whitney U test and t tests for other parameters were performed for statistical analysis. The mean displacement (µm) of an easily identifiable vascular bifurcation in the nasal quadrant was 96.58 ± 36.55 at 8 weeks and in the temporal quadrant was 273.07 ± 85.51 at 8 weeks. The change was statistically significant in the temporal quadrant (P = <0.001). The mean BCVA changed from a minimum of 0.08 at the preoperative timepoint to a maximum of 0.23 at 8 weeks (P = <0.001). The mean FAZ area (mm²) decreased from a maximum of 0.37 at the preoperative timepoint to a minimum of 0.19 at 8 weeks (p = <0.001). The retina in the temporal quadrant is displaced significantly more than nasal quadrant after successful closure of macular hole. The mean superficial FAZ also decreases suggesting a centripetal movement of the foveal tissue postoperatively.

Anatomical changes in idiopathic epiretinal membrane at 2-year follow-up assessed using spectral domain optical coherence tomography and optical coherence tomographic angiography.

To evaluate anatomical changes in the low-stage partial attachment-type idiopathic epiretinal membrane (iERM) over 2 years. Data from patients with low-stage partial attachment-type iERM (stage 2) were analyzed. The main outcome measures were anatomical changes, including changes in the foveal avascular zone (FAZ) area, vessel density (VD) in the vascular plexus, and thickness of retinal sublayers during the follow-up period. Thirty patients (mean age: 68±12 years) were included in the study. The FAZ area on the superficial vascular plexus (SVP) significantly decreased from baseline (0.12±0.08 mm2) to month 24 (0.10±0.08 mm2, p=0.024). However, the FAZ area on the deep vascular plexus (DVP) did not significantly decrease from baseline (0.15±0.13 mm2) to month 24 (0.14±0.14 mm2, p=0.099). VDs on both the SVP and DVP did not show significant change from baseline (29.51±8.14% vs. 28.35±5.63%) to month 24 (29.79±9.77%, p=0.564 vs. 28.17±5.75%, p=0.417). Parafoveal ganglion cell and inner plexiform layer (GCIPL) thickness decreased from baseline (108.77±13.61 μm) to month 24 (103.03±15.54 μm, p=0.004). The central total retinal layer thickness did not significantly change from baseline (396.07±64.86 μm) to month 24 (392.04±72.72 μm, p=0.570). Even in low-stage ERM, inner retinal changes, including GCIPL thickness, occurred during follow-up periods, which might be owing to degenerative changes or centrifugal movement.

Comparison of retinochoroidal and optic nerve head microvascular circulation between HIV-positive patients and healthy subjects using optical coherence tomography angiography

To evaluate the retinal, choroidal, and optic disc head microvascular circulation in human immunodeficiency virus (HIV)-infected individuals without retinopathy receiving highly active antiretroviral therapy (HAART) using swept-source optical coherence tomography angiography (SS-OCTA). This cross-sectional study included 100eyes of 100patients with HIV infection but no HIV-related ocular disease and 108 eyes of 108 age- and sex-matched healthy subjects as the control group. SS-OCTA was used to assess foveal avascular zone (FAZ) area, retinal nerve fiber layer thickness (RNFL), choriocapillaris (CC) flow area, outer retinal (OR) thickness, radial peripapillary capillary (RPC) vessel density (VD), ONH VD, and choroidal thickness. No statistically significant difference was found between the two groups except in the foveal VD of the deep capillary plexus (DCP). The foveal VD of the DCP was lower in the HIV-positive group (P=0.011). The mean FAZ area (mm2), perimeter (mm), and CC flow area (mm) values were higher in the HIV-positive group at statistically significant levels (P=0.021, P=0.02, and P=0.039, respectively). However, no statistically significant differences were found between the two groups concerning the OR flow area, subfoveal choroidal thickness, or the VDs of the RPC or ONH. This is the first study in the literature to evaluate the microvascular circulation of the ONH in HIV-positive patients. Although retinal and choroidal microvascular circulation decreased in HIV-positive patients receiving HAART treatment, we found no effect on the microvascular circulation of the ONH or RPC microvascular circulation. Our findings suggest that retinochoroidal microvascular circulation is affected in HIV-positive patients over time.