Retinal vascular changes after Silicon Oil removal in the Eye with Rhegmatogenous Retinal detachment.

BACKGROUND: This study aims to examine vessel density changes in the optic nerve and macula following silicone oil removal (SOR) surgery in eyes with rhegmatogenous retinal detachment (RRD) at different time points by Optical Coherence Tomography Angiography (OCTA) in compared to the contralateral eye. METHODS: A total of 43 eyes from 43 patients with silicone oil in their eyes for 3-9 months underwent OCT-A using AngioVue and optic disc-associated vessel density (VD) and thickness, macular-associated VD and thickness, Foveal avascular zone (FAZ) area, FAZ perimeter (PERIM), Acircularity index (AI), vessel density within a 300 µm wide region of the FAZ were compared between eyes. OCTA scans were performed one week before SOR and one month and three months after SOR. RESULTS: The mean age of participants was 52.8 years (SD = 15.85) and a median visual acuity was 0.8 (range: 0.5-1.0). Notably, male participants constituted 67.4% of the sample. The preoperative mean value BCVA (logMAR) of patients was 0.73, and 3 months post-oil removal was 0.7727. Regarding optic disc parameters, RNFL thickness and vessel density (VD) measurements Peripapillary, whole disc, inside disc, and Disc Angio (superior, Nasal, inferior, temporal) did not change. In analyzing macular thickness parameters, all of them (Whole and Fovea, parafoveal, and Perifovea) remained unchanged. Examining macular vessel density parameters revealed no significant changes across superficial and deep retinal layers. Finally, the comparison of the foveal avascular zone (FAZ) area and flow density (FD) parameters demonstrated consistent measurements with non-significant alterations observed in FAZ size (p = 0.6) and FD values (p = 0.49) over the monitored duration. CONCLUSION: There was no change in peripapillary VD and macular vessel density of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) after silicone oil removal. FAZ and full retinal thickness  remained stable 3 month after SOR.  Clinical trial number: Not applicable.

Predictive value of optical coherence tomography angiography in management of diabetic macular edema.

BACKGROUND: Optical coherence tomography angiography (OCTA) is a relatively new extension of Optical coherence tomography (OCT) that generates non-invasive, depth-resolved images of the retinal microvasculature which allows for the detection of various features of diabetic retinopathy. OBJECTIVES: This study aimed to detect biomarkers that may predict an early anatomical response to the treatment of diabetic macular edema (DME) with intravitreal ranibizumab (IVR) by means of OCTA. PATIENTS AND METHODS: This prospective interventional study was undertaken on 111 eyes of 102 naïve participants who had diabetic macular edema; enrolled patients were evaluated by taking a complete ophthalmologic history, examination and investigations by use of a pre-designed checklist involving Optical Coherence Tomography Angiography. RESULTS: Regarding the best corrected visual acuity (BCVA) the Mean ± SD was 0.704 ± 0.158 preoperatively and 0.305 ± 0.131 postoperatively in good responder patients; and was 0.661 ± 0.164 preoperatively and 0.54 ± 0.178 postoperatively in poor responders. The central macular thickness (CMT) was 436.22 ± 54.66 µm preoperatively and 308.12 ± 33.09 µm postoperatively in good responder patients; and was 387.74 ± 44.05 µm preoperatively and 372.09 ± 52.86 µm postoperatively in poor responders. By comparing the pre injection size of the foveal avascular zone area (FAZ-A) in both groups, it found that the mean ± SD of FAZ-A was 0.297 ± 0.038 mm in good responder patients compared to 0.407 ± 0.05 mm in non-responder patients. The preoperative superficial capillary plexus (SCP) foveal vascular density (VD) was 24.02 ± 3.01% in good responder patients versus 17.89 ± 3.19% um in poor responders. The preoperative SCP parafoveal VD was 43.06 ± 2.67% in good responder patients versus 37.96 ± 1.82% um in poor responders. The preoperative deep capillary plexus (DCP) foveal VD was 30.58 ± 2.89% in good responder patients versus 25.45 ± 3.14% in poor responders. The preoperative DCP parafoveal VD was 45.66 ± 2.21% in good responder patients versus 43.26 ± 2.35% um in poor responders, this was statistically significant. CONCLUSION: OCTA offers an accurate measurement for VD in the macula as well as the FAZ-A which could be used to predict an early anatomical response of anti-VEGF treatment in DME.

Retinal microcirculation changes in prediabetic patients with short-term increased blood glucose using optical coherence tomography angiography.

BACKGROUND: Retinal microcirculation alterations are early indicators of diabetic microvascular complications. Optical coherence tomography angiography (OCTA) is a noninvasive method to assess these changes. This study analyzes changes in retinal microcirculation in prediabetic patients during short-term increases in blood glucose using OCTA. AIM: To investigate the changes in retinal microcirculation in prediabetic patients experiencing short-term increases in blood glucose levels using OCTA. METHODS: Fifty volunteers were divided into three groups: Group 1 [impaired fasting glucose (IFG) or impaired glucose tolerance (IGT)], Group 2 (both IFG and IGT), and a control group. Retinal microcirculation parameters, including vessel density (VD), perfusion density (PD), and foveal avascular zone (FAZ) metrics, were measured using OCTA. Correlations between these parameters and blood glucose levels were analyzed in both the fasting and postprandial states. RESULTS: One hour after glucose intake, the central VD (P = 0.023), central PD (P = 0.026), and parafoveal PD (P < 0.001) were significantly greater in the control group than in the fasting group. In Group 1, parafoveal PD (P < 0.001) and FAZ circularity (P = 0.023) also increased one hour after glucose intake. However, no significant changes were observed in the retinal microcirculation parameters of Group 2 before or after glucose intake (P > 0.05). Compared with the control group, Group 1 had a larger FAZ area (P = 0.032) and perimeter (P = 0.018), whereas Group 2 had no significant differences in retinal microcirculation parameters compared with the control group (P > 0.05). Compared with Group 1, Group 2 had greater central VD (P = 0.013) and PD (P = 0.008) and a smaller FAZ area (P = 0.012) and perimeter (P = 0.010). One hour after glucose intake, Group 1 had a larger FAZ area (P = 0.044) and perimeter (P = 0.038) than did the control group, whereas Group 2 showed no significant differences in retinal microcirculation parameters compared with the control group (P > 0.05). Group 2 had greater central VD (P = 0.042) and PD (P = 0.022) and a smaller FAZ area (P = 0.015) and perimeter (P = 0.016) than Group 1. At fasting, central PD was significantly positively correlated with blood glucose levels (P = 0.044), whereas no significant correlations were found between blood glucose levels and OCTA parameters one hour after glucose intake. CONCLUSION: A short-term increase in blood glucose has a more pronounced effect on retinal microcirculation in prediabetic patients with either IFG or IGT.

Nomogram for predicting short-term response to anti-vascular endothelial growth factor treatment in neovascular age-related macular degeneration: An observational study.

BACKGROUND: Anti-vascular endothelial growth factor (anti-VEGF) therapy is critical for managing neovascular age-related macular degeneration (nAMD), but understanding factors influencing treatment efficacy is essential for optimizing patient outcomes. AIM: To identify the risk factors affecting anti-VEGF treatment efficacy in nAMD and develop a predictive model for short-term response. METHODS: In this study, 65 eyes of exudative AMD patients after anti-VEGF treatment for ≥ 1 mo were observed using optical coherence tomography angiography. Patients were classified into non-responders (n = 22) and responders (n = 43). Logistic regression was used to determine independent risk factors for treatment response. A predictive model was created using the Akaike Information Criterion, and its performance was assessed with the area under the receiver operating characteristic curve, calibration curves, and decision curve analysis (DCA) with 500 bootstrap re-samples. RESULTS: Multivariable logistic regression analysis identified the number of junction voxels [odds ratio = 0.997, 95% confidence interval (CI): 0.993-0.999, P = 0.010] as an independent predictor of positive anti-VEGF treatment outcomes. The predictive model incorporating the fractal dimension, number of junction voxels, and longest shortest path, achieved an area under the curve of 0.753 (95%CI: 0.622-0.873). Calibration curves confirmed a high agreement between predicted and actual outcomes, and DCA validated the model's clinical utility. CONCLUSION: The predictive model effectively forecasts 1-mo therapeutic outcomes for nAMD patients undergoing anti-VEGF therapy, enhancing personalized treatment planning.

Sea-fan retinal neovascularization associated with rickettsial retinitis: a case report.

BACKGROUND: Rickettsial disease has been commonly associated with retinitis, retinal vasculitis, and optic nerve involvement, but the development of retinal neovascularization has been very rarely reported. We herein describe a case of rickettsial retinitis complicated with the development of sea-fan retinal neovascularization documented with multimodal imaging, including fundus photography, SS-OCT, fluorescein angiography, and SS-OCT angiography. CASE PRESENTATION: A 26-year-old female with a history of fever one week earlier presented with sudden decreased vision in the left eye. Best-corrected visual acuity (BCVA) was 20/2000 and the patient was diagnosed with rickettsial retinitis along the superotemporal retinal vascular arcade associated with serous retinal detachment and retinal hard exudates. The indirect immunofluorescence test was positive for Rickettsia conorii, and the patient was treated with oral doxycycline (200 mg/day) and oral prednisone (0.75 mg/kg/day, with gradual tapering). Four weeks after presentation, the retinal infiltrate and associated serous retinal detachment had resolved, but retinal hard exudates had increased. A large sea-fan preretinal fibrovascular neovascularization became apparent along the superotemporal retinal vascular arcade, but there was no associated retinal ischemia on fluorescein angiography. The patient received an adjunctive single intravitreal injection of 1.25 bevacizumab. Sequential follow-up examinations showed shrinking of sea-fan retinal neovascularization, a complete resolution of retinal hard exudates, and the development of a self-limited vitreous hemorrhage. On last follow-up, 30 months after intravitreal bevacizumab injection, BCVA was 20/25. CONCLUSION: Patients with rickettsial retinitis may develop a sea-fan retinal neovascularization, with subsequent vitreous hemorrhage, putatively through inflammatory mechanisms. Multimodal imaging including OCT, fluorescein angiography, and OCT-angiography, is highly useful for accurate diagnosis and reliable monitoring of the evolution of retinitis, retinal neovascularization, and other retinal changes. The use of a combination therapy with oral doxycycline and corticosteroids and intravitreal anti-VEGF can improve outcomes.

Optical coherence tomography angiography findings of systemic lupus erythematosus patients and the effect of neuropsychiatric involvement on it.

AIM: To investigate the radial peripapillary capillary plexus vessel density (RPCP-VD) and peripapillary retinal nerve fiber layer thickness (pRNFLT) of systemic lupus erythematosus (SLE) and neuropsychiatric SLE patients (NPSLE) using disc optical coherence tomography angiography (OCTA) and investigate the association between these parameters and SLE disease activity index (SLEDAI-2K). METHODS: A total of 64 'right eyes (36 SLE patients, 28 healthy controls (HCs)) were included in this cross-sectional case-control study. Ten (27.7%) patients had neuropsychiatric involvement. RPCP-VD and pRNFLT of patients were evaluated in all peripapillary sectors. RPCP-VD and pRNFLT of NPSLE, non-NPSLE, and HCs were compared. The correlation between SLEDAI-2K and OCTA findings was evaluated. RESULTS: SLE patients' RPCP-VDs were significantly lower compared with the HCs except for two sectors (p < .005). There was not a significant difference in pRNFLT of SLE patients and HCs. There was not a correlation between SLEDAI-2K and RPCP-VD in any subsectors but there was a significantly negative correlation between pRNFLT in tempo-inferior and inferior-temporal sectors. When compared with non-NPSLE-patients, NPSLE patients had significantly lower inferior-hemi (p = .001), inferior-nasal VDs (p = .003), and peripapillary (p = .012), superior-hemi (p = .038), inferior-hemi (p = .026), inferior-nasal (p = .002) and inferior-temporal (p = .012) pRNFLTs. A negative correlation was found between NPSLE and pRNFLT. CONCLUSION: SLE patients may have early subclinical vascular involvement leading to decreased RPCP-VD. A negative correlation between the SLEDAI-2K and pRNFLT in the temporal subsectors of all SLE patients may show an association between the disease activity and temporal pRNFL thinning. The presence of neuropsychiatric involvement may also be associated with decreased RPCP-VD and pRNFLT.

Optical coherence tomography angiography of the retina and choroid in systemic diseases.

Optical coherence tomography angiography (OCTA) has transformed ocular vascular imaging, revealing microvascular changes linked to various systemic diseases. This review explores its applications in diabetes, hypertension, cardiovascular diseases, and neurodegenerative diseases. While OCTA provides a valuable window into the body's microvasculature, interpreting the findings can be complex. Additionally, challenges exist due to the relative non-specificity of its findings where changes observed in OCTA might not be unique to a specific disease, variations between OCTA machines, the lack of a standardized normative database for comparison, and potential image artifacts. Despite these limitations, OCTA holds immense potential for the future. The review highlights promising advancements like quantitative analysis of OCTA images, integration of artificial intelligence for faster and more accurate interpretation, and multi-modal imaging combining OCTA with other techniques for a more comprehensive characterization of the ocular vasculature. Furthermore, OCTA's potential future role in personalized medicine, enabling tailored treatment plans based on individual OCTA findings, community screening programs for early disease detection, and longitudinal studies tracking disease progression over time is also discussed. In conclusion, OCTA presents a significant opportunity to improve our understanding and management of systemic diseases. Addressing current limitations and pursuing these exciting future directions can solidify OCTA as an indispensable tool for diagnosis, monitoring disease progression, and potentially guiding treatment decisions across various systemic health conditions.

Acute macular neuroretinopathy following COVID-19 infection: Three case reports.

BACKGROUND: During the Coronavirus disease 2019 (COVID-19) pandemic, a notable increase in acute macular neuroretinopathy (AMN) cases was observed. This study aimed to investigate the potential association between AMN and COVID-19 by examining 3 cases in China. CASE SUMMARY: The first case involved a 30-year-old man who presented with progressive vision loss following a COVID-19 infection. Optical coherence tomography (OCT) and near-infrared imaging identified hallmark AMN lesions, hyperreflective disruptions within the outer plexiform layer, and hyporeflective anomalies in the ellipsoid zone, leading to an AMN diagnosis. Despite partial visual recovery, OCT angiography (OCTA) revealed persistent microvascular changes, specifically a decreased vascular density in the deep capillary plexus. The second case was a 24-year-old woman who experienced blurred vision and exhibited bilateral cotton-wool spots on fundus examination post-COVID-19. Imaging confirmed the presence of AMN along with paracentral acute middle maculopathy (PAMM). Follow-up OCTA found a progressive reduction in vascular density, indicating ongoing microvascular compromise. The third case was a 28-year-old woman who reported sensations of occlusion in her right eye following a COVID-19 infection. Imaging confirmed both AMN and PAMM, revealing similar decreases of microvascular density on OCTA despite a significant improvement in visual acuity. We noted that all 3 patients had received the COVID-19 vaccine prior to the appearance of symptoms. CONCLUSION: The findings highlight the diagnostic utility of advanced ocular imaging in detecting AMN in COVID-19 patients and the importance of comprehensive eye examinations.

Bibliometric analysis of ophthalmic OCT and OCT angiography research trends over the past 20 years.

PURPOSE: Optical coherence tomography (OCT) and OCT angiography (OCTA) are widely used in the diagnosis of ophthalmic diseases. This study aims to provide a comprehensive bibliometric analysis of ophthalmologic OCT and OCT angiography. METHODS: We retrieved publications on ophthalmic OCT and OCTA from 2003 to 2022 from the Web of Science Core Collection and used bibliometric tools to analyze and visualize the distribution, trend, and hotspots. RESULTS: In total, 20,817 articles written by 48,160 authors from 106 countries were selected. The number of publications has significantly increased. In the last two decades, the USA was the most productive country and received the highest citations. The most productive journal was Investigative Ophthalmology and Visual Science and received the highest number of citations. Moorfields Eye Hospital was the most productive institution. Bandello F published the most papers, while Spaide RF was the highest cited author. SPAIDE RF, 2011, AM J Ophthalmology was the most cited document. "OCT", "glaucoma" and "OCTA" were three hotspots in the last two decades. "Vessel density" and "deep learning" would be research hotspots in the future. CONCLUSION: The bibliometric analysis of ophthalmic OCT and OCTA research over the past two decades on keywords, authors, citations, hotspots and trends will provide global researchers with valuable information for future research and cooperation.

Assessment of conjunctival autograft reperfusion after pterygium surgery by optical coherence tomography angiography (OCT-A).

PURPOSE: To investigate the healing process of conjunctival autografts (CAG) following pterygium surgery using optical coherence tomography angiography (OCTA). METHODS: Twenty-one eyes of 21 patients diagnosed with pterygium underwent pterygium excision with CAG without using Mitomycin-C. Over a 12-week follow-up period, changes in vascular density (VD), vascular density index (VDI), and vascular length density (VLD) were assessed at two distinct depths: superficial (<200 µm) and deep (>200 µm) using OCTA. Additionally, the revascularization rate and pattern were evaluated. RESULTS: During the first week, the CAG was edematous and no sign of neovascularization was observed. In 4th week edema decreased and early signs of vascular formation appeared. In the 12th week, the deep vasculature demonstrated a greater density of interconnectivity compared to the superficial layers. VD and VLD significantly increased during the follow-up period (P < 0.05). The CAG blood flow signals exhibited a chaotic pattern, deviating from the expected centrifugal vascular pattern in the surrounding normal conjunctiva. CONCLUSION: OCTA imaging emerges as a reliable tool for the assessment of CAG vascularization, improving the monitoring of the healing process in the postoperative period. The evaluation of CAG revascularization patterns appears to be promising biomarkers that can predict the potential future recurrence.

Macular vascular and photoreceptor changes for diabetic macular edema at early stage.

This study was intended to investigate the macular vascular and photoreceptor changes for diabetic macular edema (DME) at the early stage. A total of 255 eyes of 134 diabetes mellitus patients were enrolled and underwent an ophthalmological and systemic evaluation in this cross-sectional study. Early DME was characterized by central subfoveal thickness (CST) value between 250 and 325 µm, intact ellipsoid zone, and an external limiting membrane. While non-DME was characterized by CST < 250 µm with normal retinal morphology and structure. Foveal avascular zone (FAZ) area ≤ 0.3 mm2 (P < 0.001, OR = 0.41, 95% CI 0.26-0.67 in the multivariate analysis) and HbA1c level ≤ 8% (P = 0.005, OR = 0.37, 95% CI 0.19-0.74 in multivariate analysis) were significantly associated with a higher risk of early DME. Meanwhile, no significant differences exist in cone parameters between non-DME and early DME eyes. Compared with non-DME eyes, vessel diameter, vessel wall thickness, wall-to-lumen ratio, the cross-sectional area of the vascular wall in the upper side were significantly decreased in the early DME eyes (P = 0.001, P < 0.001, P = 0.005, P = 0.003 respectively). This study suggested a vasospasm or vasoconstriction with limited further photoreceptor impairment at the early stage of DME formation. CST ≥ 250 µm and FAZ ≤ 0.3 mm2 may be the indicator for early DME detection.

Evaluation of optical coherence tomography angiography and pattern and flash electroretinography in diabetes mellitus without retinopathy.

PURPOSE: To evaluate the findings and the correlation of optical coherence tomography angiography and pattern and flash electroretinography in diabetes mellitus without retinopathy. METHODS: Seventy-six eyes of 38 diabetic patients and age- and gender-matched control subjects were included in the study. The foveal avascular zone (FAZ), whole, foveal, parafoveal and perifoveal vascular densities of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillary plexus (CCP) layers were analyzed using optical coherence tomography angiography (OCTA). The amplitudes and implicit times of P50 and N95 waves of the pattern ERG (pERG) and the amplitudes and implicit times of the scotopic and photopic b-waves and oscillatory potentials (OP) of the flash ERG (fERG) tests were evaluated using the Metrovision brand monpack model device. RESULTS: The mean age of the patients was 59.7 ± 7.9 [range 43-79] years. Eighteen (47%) of the patients were female and 20 (53%) were male. The mean duration of diabetes was 7.45 ± 6.2 [range 1-20] years. No significant difference in FAZ area was found between study subjects and controls. Vascular density (VD) values of the superficial capillary plexus (SCP) layer were significantly lower (whole VD, 44.7 ± 3.3 vs. 46.6 ± 3.2%, p = 0.01, foveal VD 16.8 ± 6.4 vs. 24.9 ± 6.1%, p < 0.01, parafoveal VD 45.6 ± 4.5 vs. 47.1 ± 4.4%, p = 0.27 and perifoveal VD 45.5 ± 3.3 vs. 47.3 ± 3.1%, p = 0.01, respectively) in the diabetic group except the parafoveal area. VD measurements in deep and choriocapillary plexuses did not significantly differ between the groups (p > 0.05). ERG tests revealed significantly lower scotopic b-wave amplitudes (130.2 ± 39.3 µV vs.163.3 ± 47.8 µV, p < 0.01) and photopic b-wave amplitudes (83.2 ± 20.7 µV vs. 99.6 ± 29.4 µV, p < 0.01) in the diabetic patients. The implicit time of the photopic responses was significantly prolonged (28.9 ± 1.3 ms vs. 27.8 ± 2.1 ms, p = 0.01) in the patients. Oscillatory potentials in all components consisting of O1 to O4 and the sum of the OP potentials were lower in the diabetic group than the control subjects (p < 0.001). The P50 and N95 amplitudes and implicit times were comparable between the groups (p > 0.05). Correlation analysis showed a positive correlation between N95 amplitudes in pERG and the superficial vessel densities in OCTA (r = 0.26, p = 0.04). A negative correlation was found between photopic implicit times in fERG and the choriocapillary vessel densities (r=-0.27, p = 0.03). CONCLUSION: OCTA revealed decreased superficial vascular densities with the onset of the metabolic process of diabetes mellitus. As a result of these structural changes, lower scotopic and photopic amplitudes, decreased OP amplitudes, and prolonged implicit times in flash ERG were obtained.

Macular vascular density alteration patterns in paediatric optic neuritis patients with serum MOG antibody positivity detected by optic coherence tomography angiography.

PURPOSE: The retinal microvascular network plays a crucial role in inflammatory injury in paediatric optic neuritis (PON) with serum MOG antibody positivity (MOG + PON). This study compared retinal microvascular densities and structural alterations in MOG + PON eyes with paediatric isolated optic neuritis (PION) eyes and followed up with the final best-corrected visual acuity (BCVA) after 6 months. METHODS: A total of 29 children (52 eyes) with PON, including 15 MOG + PON cases (28 eyes), 6 PION cases (10 eyes), 2 neuromyelitis optica spectrum disorders associated PON(NMOSD-PON) cases (4 eyes), 6 MOG-associated disease (MOGAD) patients without ON-affected eyes (MOG + NPON) cases (10 eyes) and age- and gender-matched healthy controls (HCs) underwent superficial/deep retinal angiography density (SAD/DAD) by optical coherence tomography angiography (OCTA). Their BCVAs were followed up until 6 months after PON onsets. RESULTS: MOG + PON cases had better final BCVAs than PION and NMOSD-ON. MOG + PON (35.7 ± 10.3 %) and PION (40.1 ± 10.3 %) eyes experienced severe SAD reductions in contrast to MOGAD+NPON (48.7 ± 5.2 %) and HCs eyes (55.6 ± 8.2 %). However, DAD in MOG + PON eyes (48.5 ± 9.2 %) and MOG + NPON eyes (53.1 ± 3.3 %) increased compared to HC eyes (45.7 ± 9.6 %; p = 0.028 and 0.009, respectively). SAD reduction occurred in acute PON and was detected as early as 2 weeks after PON onset. CONCLUSIONS: MOG + PON eyes had better final BCVAs than PION eyes, which displayed superficial retinal microvascular perfusion reductions and deep microvascular perfusion increases. SAD could be a sensitive surrogate for PON attacks in children with MOGAD.

Comparative of OCT and OCTA parameters in patients with early chronic angle-closure glaucoma and early pituitary adenoma.

Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) have the potential application in evaluating pathological structural change of the optic nerve. We aimed to evaluate the value of the OCT and OCTA parameters of the optic disk and macular in differentiating early chronic primary angle-closure glaucoma (CPACG) and early pituitary adenoma (PA) in case of mild visual field defects (the mean defect (MD) > 6 dB). The results showed that regarding OCTA parameters, CPACG patients had lower retinal blood flow density of most layers of the optic disk and macular than PA patients. Regarding OCT parameters, CPACG patients had thinner circumpapillary retinal nerve fiber layer (CP-RNFL) in all quadrants and average CP-RNFL, ganglion cell layer (GCL) and macular ganglion cell complex (GCC) in each quadrant of macular inner and outer rings, and inner plexus layer (IPL) of macular inner ring, superior-outer ring and temporal-outer ring than PA patients. The Z test indicated that OCTA parameters and OCT parameters had similar value in the diagnosis of disease. In conclusion, in the case of similar visual field damage, early CPACG patients have smaller blood flow density and thinner optic disk and macular than early PA. OCTA has similar performance to OCT in diagnosing CPACG and PA.

The role of Perifoveal Arteriolar Tortuosity in Optical Coherence Tomography Angiography (OCTA) images as an early indicator of hypertensive retinopathy.

PURPOSE: To assess the value of increased perifoveal retinal vascular tortuosity in optical coherence tomography angiography (OCTA) images as a biomarker of early hypertensive retinopathy and compare its clinical sensitivity and accuracy with traditional morphological changes used for Scheie classification. METHODS: OCTA images of 81 eyes (40 eyes from 20 hypertensive subjects and 41 eyes from 21 control subjects) were obtained retrospectively. Hypertensive retinopathy changes in randomized eyes were graded according to the Scheie classification, and perifoveal vessels were traced in a masked fashion. Tortuosity values of the perifoveal vessels were then calculated along with interobserver agreement in determining the morphometric values. RESULTS: There were no differences in perifoveal venular tortuosity between the hypertensive and control groups (Mean = 1.13 ± 0.04 vs. 1.13 ± 0.03), but significant differences existed for arterioles (Mean = 1.14 ± 0.05 vs. 1.11 ± 0.04). Tortuosity measurements demonstrated a significant interobserver agreement (p < 0.001), while Scheie ratings had a poor interobserver agreement (p = 0.735). There was a significant difference in Scheie classification between the hypertensive and control groups (Mean = 1.06 ± 0.54 vs. 0.50 ± 0.43, p = 0.005). CONCLUSIONS: OCTA-based perifoveal retinal arteriolar tortuosity may be a potential reliable biomarker with certain advantages for detecting early hypertensive retinopathy than morphological changes used for the Scheie classification. This may have broad applications and establish important parameters in utilizing OCTA for screening protocols, considering the importance of early detection of systemic hypertension.

Foveal avascular zone area measurement in diabetic patients: Superficial, deep or combined retinal vascular complex?

PURPOSE: To compare differences in the foveal avascular zone (FAZ) area, measured in the Superficial Vascular Complex (SVC), Deep Vascular Complex (DVC) and a combined analysis of both (SDVC), using two Spectral Domain OCT angiography (OCT-A) protocols, High Speed (HS) and High Resolution (HR). METHODS: A total of 26 eyes of diabetic patients, with and without macular oedema, were examined with two different fovea centered OCT-A volume scans. The two protocols were HS and HR volume scans, and the foveal avascular zone was manually measured in the SVC, DVC, and SDVC slabs by two masked investigators. Inter and intraoperator variability was analysed using Intraclass Correlation Coefficient (ICC) and differences were compared between the HR and HS acquisitions throughout the different vascular slabs. RESULTS: Intraoperator variability was low in all slabs (ICC > 0.9) and interoperator variability was lower for HR (ICC 0.835-0.911) compared to HS (ICC between 0.604 and 0.865). Comparing HS and HR measurements for the same slab, the correlation was only moderate in SVC and DVC (ICC was 0.640 and 0.568 respectively) but was good in the SDVC (ICC = 0.823). FAZ area measurement in SDVC also showed the smallest bias (mean difference 0.009 mm2) and the narrowest limits of agreement (-0.175 to 0.193 mm2). CONCLUSIONS: Even in cases of diabetic macular oedema, when measuring the FAZ area, the reproducibility was better between HS and HR protocols when using the SDVC slab, compared to the SVC or DVC slabs alone. Further studies should evaluate the use of the combined SDVC slab for the FAZ assessment, compared to the SVC and DVC slabs alone, in the detection and progression of different retinal diseases.

Internal limiting membrane peeling for large macular holes induces only structural remodeling without functional impairment over 12 years.

PURPOSE: To evaluate the very long-term functional and structural outcomes of internal limiting membrane (ILM) peeling for full-thickness macular holes (FTMH). DESIGN: Observational case series nested within a multicenter, randomized, controlled clinical trial (RCT) (ClinicalTrials.gov: NCT00190190). SUBJECTS: Patients who underwent vitrectomy with or without ILM peeling for an idiopathic large FTMH in a tertiary ophthalmology center, with a minimum follow-up of 10 years after surgery. METHODS: Review of charts, spectral domain optical coherence tomography (SD-OCT) scans, OCT-angiography (OCT-A) scans, and microperimetry of patients originally enrolled in the RCT. MAIN OUTCOME MEASURES: Primary outcome was functional assessment in both groups (ILM peeling or not) including the retinal sensitivity (RS), distance and near best-corrected visual acuity (BCVA), number of eyes achieving ≥0.3 logMAR more than 10 years after surgery. Secondary outcomes were structural assessment in the entire 3x3mm and 6x6mm areas, and regionally in the different areas of the ETDRS grid: OCT and OCT-A biomarkers in both groups and fellow eyes. RESULTS: Thirteen eyes of 13 patients with a mean follow-up of 12 ±0.73 years were included. The mean RS and BCVA, or visual improvement did not differ between ILM peeling (n=8) and no peeling (n=5) (all p>0.05). The dissociated optic nerve-fiber layers on en-face OCT were only observed in eyes with ILM peeling, predominantly in temporal parafoveal (20%) and perifoveal (19%) rings. The mean total retinal thickness and inner retinal thickness in the parafoveal ring were significantly lower in peeled eyes (309 ±11 µm and 94 ±9 µm respectively) versus non-peeled eyes (330 ±21 µm and 108 ±11 µm respectively; p=0.037 and p=0.040), without significant difference in ganglion cell or retinal nerve fiber layers. Accordingly, the mean superficial capillary plexus density in the parafoveal ring was significantly lower in eyes with peeling versus without, (39.65 ±3.76 % versus 47.22 ±4.00; p=0.005). The mean foveal avascular zone area was smaller in eyes with peeling versus without (0.24 ±0.05 mm2 versus 0.42 ±0.13 respectively, p=0.005), CONCLUSION: Despite persistent structural changes especially in the parafoveal ring, ILM peeling for idiopathic large FTMH did not appear to impact long-term RS or BCVA over 12 years.

A Comparison of Optical Coherence Tomography Angiography Metrics and Artifacts on Scans of Different Sizes in Diabetic Macular Ischemia: The effect of different size scans on DMI evaluation.

PURPOSE: Changes in the foveal avascular zone (FAZ) metrics over time are key outcome measures for clinical trials in diabetic macular ischemia (DMI). However, artifacts and automatically delineated FAZ measurements may influence the results. We aimed to compare the artifact frequency and FAZ metrics on 3 × 3 versus 6 × 6 mm optical coherence tomography angiography (OCTA) macular scans in patients with DMI. DESIGN: Prospective, comparative image quality analysis with one-year follow-up. METHODS: Patients with diabetic retinopathy (DR) were recruited if they presented with OCTA evidence of DMI, defined as an automated FAZ (aFAZ) ≥0.5 mm2 or parafoveal capillary nonperfusion (CNP) ≥1 quadrant if the aFAZ <0.5 mm2. Only those who had both size scans were included in the analysis. The types of artifacts and FAZ delineation errors were graded before manual correction. After excluding scans with poor quality, the aFAZ, corrected FAZ (cFAZ), whole image superficial vessel density (wiSVD), and whole image deep vessel density (wiDVD) were compared on both size scans. RESULTS: Fifty-seven patients (81 eyes) with paired OCTA 3 × 3 and 6 × 6 mm scans at baseline were included in the image quality analysis. The 6 × 6 mm scan presented with more severe motion artifact (P = .02). Conversely, the 3 × 3 mm scans were more susceptible to mild decentration (P = .009). After removing all the poor-quality images, 55 eyes with both size scans entered the longitudinal analysis. The 3 × 3 mm FAZ was significantly larger than the 6 × 6 mm FAZ using either aFAZ or cFAZ (both P < .05). In contrast, the 6 × 6 mm wiSVD and wiDVD were remarkably higher than those on the 3 × 3 mm scans (both P < .001). There was a steady increase in cFAZ over one year on both size scans (both P < .01). However, the 3 × 3 mm aFAZ decreased numerically at 52 weeks (P = .02). After reviewing all the scans, poor identification of parafoveal CNP was the most common reason for erroneous aFAZ delineation. CONCLUSIONS: In DMI, the FAZ metrics are best evaluated on the 3 × 3 scan due to better resolution. However, manual correction of the FAZ margin is needed. The frequency of artifacts and aFAZ delineation errors suggest that further technical refinement is required.

Harnessing deep learning for detection of diabetic retinopathy in geriatric group using optical coherence tomography angiography-OCTA: A promising approach.

The prevalence of diabetic retinopathy (DR) among the geriatric population poses significant challenges for early detection and management. Optical Coherence Tomography Angiography (OCTA) combined with Deep Learning presents a promising avenue for improving diagnostic accuracy in this vulnerable demographic. In this method, we propose an innovative approach utilizing OCTA images and Deep Learning algorithms to detect diabetic retinopathy in geriatric patients. We have collected 262 OCTA scans of 179 elderly individuals, both with and without diabetes, and trained a deep-learning model to classify retinopathy severity levels. Convolutional Neural Network (CNN) models: Inception V3, ResNet-50, ResNet50V2, VggNet-16, VggNet-19, DenseNet121, DenseNet201, EfficientNetV2B0, are trained to extract features and further classify them. Here we demonstrate:•The potential of OCTA and Deep Learning in enhancing geriatric eye care at the very initial stage.•The importance of technological advancements in addressing age-related ocular diseases and providing reliable assistance to clinicians for DR classification.•The efficacy of this approach in accurately identifying diabetic retinopathy stages, thereby facilitating timely interventions, and preventing vision loss in the elderly population.

Diameter-dependent classification of dermal vasculature using optical coherence tomography angiography.

Background: Dermal blood vessels beneath the epidermis play critical roles in epidermal homeostasis and are functionally divided into several types, such as capillaries. Optical coherence tomography angiography (OCTA) is a powerful tool for the non-invasive assessment of dermal vasculature. However, the classification of vessel types has been limited. To address this issue, we proposed an algorithm for diameter-dependent classification that preserves three-dimensional (3D) information using OCTA. Methods: OCTA data were acquired by a prototype swept-source-type optical coherence tomography (OCT) system, which was processed through several imaging filters: an optical microangiography (OMAG) imaging filter, a vesselness imaging filter, and a diameter map filter. All vessels were visually classified into three types based on their diameters, as micro-vessels, intermediate vessels, and thick vessels. Aging-related alterations and their association with the epidermis were investigated for each vessel type. The measurements were conducted on the cheeks of 124 female subjects aged 20-79 years. Results: The 3D vascular structure was visualized by applying our proposed post-processing filters. Based on visual assessment, the thresholds for the diameters of the micro, intermediate and thick vessels were set at 80 and 160 µm. It was found that micro-vessels were predominantly located in the upper layer of the dermis and thick vessels in the deeper layer. Analysis of vessel metrics revealed that the volume density of the micro-vessels decreased significantly with age (r=-0.36, P<0.001) and was positively correlated with epidermal thickness (r=0.50, P<0.001). In contrast, the volume density of thick vessels significantly increased with age (r=0.2, P<0.05) and was not significantly correlated with epidermal thickness (r=0.13, P≥0.05). Conclusions: In this study, we proposed a 3D quantification method using OCTA for dermal blood vessels and various vessel metrics, such as vessel volume density. This proposed classification will be beneficial for determining the function of the dermal vasculature and its diagnostic applications.