Absolute retinal blood flow in healthy eyes and in eyes with retinal vein occlusion.

PURPOSE: To measure non-invasively retinal venous blood flow (RBF) in healthy subjects and patients with retinal venous occlusion (RVO). METHODS: The prototype named AO-LDV (Adaptive Optics Laser Doppler Velocimeter), which combines a new absolute laser Doppler velocimeter with an adaptive optics fundus camera (rtx1, Imagine Eyes®, Orsay, France), was studied for the measurement of absolute RBF as a function of retinal vessel diameters and simultaneous measurement of red blood cell velocity. RBF was measured in healthy subjects (n = 15) and patients with retinal venous occlusion (RVO, n = 6). We also evaluated two softwares for the measurement of retinal vessel diameters: software 1 (automatic vessel detection, profile analysis) and software 2 (based on the use of deep neural networks for semantic segmentation of vessels, using a M2u-Net architecture). RESULTS: Software 2 provided a higher rate of automatic retinal vessel measurement (99.5 % of 12,320 AO images) than software 1 (64.9 %) and wider measurements (75.5 ± 15.7 µm vs 70.9 ± 19.8 µm, p < 0.001). For healthy subjects (n = 15), all the retinal veins in one eye were measured to obtain the total RBF. In healthy subjects, the total RBF was 37.8 ± 6.8 µl/min. There was a significant linear correlation between retinal vessel diameter and maximal velocity (slope = 0.1016; p < 0.001; r2 = 0.8597) and a significant power curve correlation between retinal vessel diameter and blood flow (3.63 × 10-5 × D2.54; p < 0.001; r2 = 0.7287). No significant relationship was found between total RBF and systolic and diastolic blood pressure, ocular perfusion pressure, heart rate, or hematocrit. For RVO patients (n = 6), a significant decrease in RBF was noted in occluded veins (3.51 ± 2.25 µl/min) compared with the contralateral healthy eye (11.07 ± 4.53 µl/min). For occluded vessels, the slope between diameter and velocity was 0.0195 (p < 0.001; r2 = 0.6068) and the relation between diameter and flow was Q = 9.91 × 10-6 × D2.41 (p < 0.01; r2 = 0.2526). CONCLUSION: This AO-LDV prototype offers new opportunity to study RBF in humans and to evaluate treatment in retinal vein diseases.

The retinal venous pressure at different levels of airway pressure measured with a new method.

PURPOSE: This study is to investigate the increase in retinal venous pressure (RVP) induced by a stepwise increase in airway pressure (AirP) using the new IOPstim method, which is designed to artificially increase the intraocular pressure (IOP) and thus to stimulate vascular pulsation. METHODS: Twenty-eight healthy subjects were examined in the left eye. The RVP was measured at baseline and at four different levels of AirP (10, 20, 30, and 40 mmHg) using the new IOPstim method: a half balloon of 8 mm diameter is inflated laterally to the cornea under observation of the central retinal vein. As soon as the vein pulsates at a certain AirP level, the IOP is measured with a commercially available tonometer, which then corresponds to the RVP. RESULTS: Spontaneous venous pulsation was observed in all study participants. The mean RVP values at baseline and at the AirP levels of 10, 20, 30, and 40 mmHg were 17.6 ± 2.8 mmHg; 20.1 ± 3.0 mmHg; 22.1 ± 3.5 mmHg; 24.3 ± 3.7 mmHg, and 26.6 ± 4.2 mmHg, respectively. The mean RVP values of each AirP level were statistically significantly different from each other in pairwise comparison. In a linear mixed model, the effect of AirP on RVP was highly significant (p < 0.001). In the model, a 10-mmHg increase in AirP resulted in a linear increase in RVP of 2.2 mmHg. CONCLUSION: An increase in AirP was accompanied by a linear increase in RVP. The influence of AirP on RVP, and thus on retinal perfusion pressure during the Valsalva maneuver, is less than was assumed based on previous studies in which contact lens dynamometry was used.

Liquid-Driven Microinjection System for Precise Fundus Injection.

Microinjection is usually applied to the treatment of some retinal disorders, such as retinal vein cannulation and displaced submacular hemorrhage. Currently, the microinjection procedure is usually performed by using the viscous fluid control of a standard vitrectomy system, which applies a fixed air pressure through foot pedal activation. The injection process with the fixed pressure is uncontrollable and lacks feedback, the high flow rate of the injected drug may cause damage to the fundus tissue. In this paper, a liquid-driven microinjection system with a flow sensor is designed and developed specifically for fundus injection. In addition, a PID sliding mode control (SMC) method is proposed to achieve precise injection in the injection system. The experimental results of fundus simulation injection demonstrate that the microinjection system meets the requirements of fundus injection and reduces the impact of the injection process on the fundus tissue.

Endothelial contraction of retinal veins.

We have previously reported that porcine retinal veins can be contracted by vasoactive factors such as endothelin-1, but it is still unknown which cells play the major role in such contraction responses. This study seeks to confirm whether retinal vein endothelial cells play a significant role in the endothelin-1 induced contraction of porcine retinal veins. This is a novel study which provides confirmation of the endothelial cells' ability to contract retinal veins using a live vessel preparation. Retinal veins were isolated from porcine retina and cannulated for perfusion. The vessels were exposed to extraluminal delivery of endothelin-1 (10-8 M) and change in vessel diameter recorded automatically every 2 s. A phase contrast objective lens was also used to capture images of the endothelial cell morphometries. The length, width, area, and perimeter were assessed. In addition, vein histology and immuno-labeling for contractile proteins was performed. With 10-8 M endothelin-1 contractions to 63.6% of baseline were seen. The polygonal shape of the endothelial cells under normal tone became spindle-like after contraction. The area, width, perimeter and length were significantly reduced by 54.8%, 48.1%, 28.5% and 10.5% respectively. Three contractile proteins, myosin, calponin and alpha-SMA were found in retinal vein endothelial cells. Retinal vein endothelial cells contain contractile proteins and can be contracted by endothelin-1 administration. Such contractile capability may be important in regulating retinal perfusion but could also be a factor in the pathogenesis of retinal vascular diseases such as retinal vein occlusion. As far as we are aware, this is the first study on living isolated veins to confirm that endothelial cells contribute to the endothelin-1 induced contraction.

Analyze of factors and prognosis of eyes lost to follow-up in retinal vein occlusive disease patients receiving anti-vascular endothelial growth factor therapy.

BACKGROUND: Patients with macular edema (ME) secondary to retinal vein occlusion (RVO) who received at least one intravitreal injection of anti-vascular endothelial growth factor therapy (VEGF) and lost to follow-up (LTFU) for more than six months were analyzed to investigate the factors contributing to the LTFU and the prognosis. METHOD: This was a retrospective, single-center study to analyze the causes and prognosis of LTFU over six months in RVO-ME patients treated with intravitreal anti-VEGF injections at our institution from January 2019 to August 2022 and to collect patients' baseline characteristics along with the number of injections before LTFU, primary disease, best corrected visual acuity (BCVA) before LTFU and after return visit, central macular thickness (CMT), months before LTFU and after LTFU, reasons for LTFU, and complications, to analyze the factors affecting visual outcome at a return visit. RESULTS: This study included 125 patients with LTFU; 103 remained LTFU after six months, and 22 returned after LTFU. The common reason for LTFU was "no improvement in vision" (34.4%), followed by "transport inconvenience" (22.4%), 16 patients (12.8%) were unwilling to visit the clinic, 15 patients (12.0%) had already elected to seek treatment elsewhere, 12 patients (9.6%) were not seen in time due to the 2019-nCov epidemic, and 11 patients (8.8%) cannot do it due to financial reasons. The number of injections before LTFU was a risk factor for LTFU (P < 0.05). LogMAR at the initial visit (P < 0.001), CMT at the initial visit (P < 0.05), CMT before the LTFU (P < 0.001), and CMT after the return visit (P < 0.05) were influential factors for logMAR at the return visit. CONCLUSION: Most RVO-ME patients were LTFU after anti-VEGF therapy. Long-term LTFU is greatly detrimental to the visual quality of patients; thus, the management of RVO-ME patients in follow-up should be considered.

Retinal Periphlebitis May Be a Marker for Subphenotype in Multiple Sclerosis.

Retinal periphlebitis (RPP) is a long-known entity in patients with multiple sclerosis (MS) and has not been revisited in the context of recent developments in MS pathogenesis and heterogeneity. We present six cases of RPP in three female and three male MS patients. They all have relapsing-remitting MS and did not have or had minor ocular symptoms. It is important to perform a thorough retinal examination in patients with MS, as peripheral and sectorial lesions could be unseen. A better knowledge on the concomitant involvement of retinal veins contributes to the understanding of immunopathology, with potentially distinct autoantigenic targets. RPP might serve as a subphenotype marker that may influence treatment choices in MS. Further research is needed.

Alterations in the choroidal thickness and retinal vascular caliber in keratoconus.

PURPOSE: To compare the choroidal thickness (CT) and retinal vascular caliber in the differentiation of patients who have keratoconus (KC) from those of astigmatic and normal patients. METHODS: This was a prospective, cross-sectional study. A total of 72 patients who had KC, 70 who had astigmatism, and 83 healthy control subjects were enrolled in this study. All the patients were examined using the Sirius topography system and spectral domain optical coherence tomography with enhanced depth imaging. Using the digital fundus photographs, the retinal vascular calibers were calculated. The measurements were also analyzed between the KC stages according to the Amsler-Krumeich classification. RESULTS: The CT measurements were significantly higher in the KC group, when compared with the other 2 groups, in each location (P < 0.05). No statistically significant difference was observed with regards to the central retinal artery equivalent (CRAE) values (P = 0.959), while significant differences were noted in the central retinal vein equivalent (CRVE) among the groups (P = 0.011). Significant increases were noted in the CT as the stage of KC progressed, except at temporal 3000 µm (P = 0.603). No statistically significant difference was observed with regards to the CRAE among the stages (P = 0.901). However, the CRVE changes increased remarkably as the stages advanced (P < 0.001). CONCLUSION: The patients who had KC seemed to have a thicker CT and higher CRVE values than the healthy individuals, and these differences were progressively increased as the stages of KC advanced. Reflecting the vascular effects of inflammation, the high CRVE supported theories based on the inflammatory component of KC.

Acute effects of caffeine and glucose intake on retinal vessel calibres in healthy volunteers.

PURPOSE: To evaluate the acute effects of caffeine and glucose intake on retinal vascular calibre of healthy adults. METHODS: This prospective crossover study was conducted at the Centre for Eye Research Australia (Melbourne, Australia). Standardized doses of 300 mg caffeine (approximately 3 cups coffee), 30 g glucose or 300 ml of water, were each given to 19 healthy subjects on separate days. Retinal photographs and blood pressure measurements were taken at baseline, 30-, 60- and 120-min after ingestion of each solution. Central retinal artery and vein equivalents (CRAE, CRVE) and the arterio-venule ratio were measured using computer-assisted software. The mean retinal vascular calibre measurements were compared between pre- and post-ingestion images. RESULTS: After caffeine intake, significant reductions were observed in mean CRAE of - 9.3 µm, - 10.4 µm and - 8.5 µm and CRVE of - 16.9 µm, - 18.7 µm and - 16.1 µm at 30-, 60- and 120-min after intake when compared with baseline (p ≤ 0.002 for all; paired t test). No significant changes were observed in mean retinal vascular calibre measurements after intake of either glucose or water when compared to baseline (p ≥ 0.072 for all). When controlling for baseline characteristics and blood pressure measurements, only caffeine intake had a significant effect on reducing both CRAE and CRVE at all time points post ingestion (p ≤ 0.003 for all, multiple linear regression model). CONCLUSION: Caffeine is associated with an acute vasoconstrictive effect on retinal arterioles and venules in healthy subjects. Factors other than blood pressure-induced autoregulation play a significant role in caffeine-associated retinal vasoconstriction.

RETINAL VASCULAR BED AREA IN EYES WITH RETINAL VEIN OCCLUSION ON ULTRA-WIDEFIELD FLUORESCEIN ANGIOGRAPHY: WAVE Study.

PURPOSE: To compute retinal vascular bed area (RVBA) in square millimeters on distortion corrected ultra-widefield fluorescein angiography images in eyes with retinal vein occlusion (RVO). METHODS: Prospective observational study. The peripheral distortion of baseline ultra-widefield fluorescein angiography (Optos 200Tx) images of 30 patients with RVO from the WAVE study (NCT01710839) and 13 control eyes of normal subjects was corrected using the stereographic projection method to compute RVBA in square millimeters. RESULTS: In comparison with age- and sex-matched normal control eyes, eyes with RVO had a decreased global RVBA for the entire retina (50.5 ± 20.4 mm 2 vs. 62.6 ± 12.2 mm 2 , P = 0.023). Eyes with RVO and the unaffected fellow eye had a similar RVBA globally (50.5 ± 20.4 mm 2 vs. 46.2 ± 18.9 mm 2 , P = 0.523). The RVBA was observed to negatively correlate with nonperfusion area (R = -0.47, P = 0.009). However, RVBA was not related to the severity of macular edema ( P > 0.05). CONCLUSION: Eyes with RVO have a similar RVBA to the unaffected fellow eyes but with a reduction when compared with normal control eyes. Retinal vascular bed area appears to be a surrogate biomarker of retinal ischemia on ultra-widefield fluorescein angiography but not the extent of macular edema.

Von Hipple-Lindau disease complicated with central retinal vein occlusion: a case report.

BACKGROUND: Central Retinal Vein Occlusion (CRVO) is a rare complication of von Hipple-Lindau (VHL) disease. This report presents the first case of VHL disease complicated with CRVO caused by VHL c.208G > A mutation. CASE PRESENTATION: A 20 s man whose left eye visual acuity gradually declined for half a year. The visual acuity of the left eye is counting fingers. Fundus examination revealed that retinal hemangioblastoma was also found in addition to typical CRVO signs such as tortuous expansion of retinal veins and flame-shaped hemorrhage of the retina. Liver tumor, cerebral infarction and erythrocytosis were found during systemic examination, and the diagnosis of polycythemia was confirmed by bone marrow smear. Furthermore, both family history and genetic analysis indicated that the patient had VHL disease caused by VHL c.208G > A. In this patient, a large number of bone marrow erythrocytes proliferated due to VHL disease, which led to the increase of blood viscosity and erythrocyte vascular adhesion, resulting in the obstruction of central retinal vein blood flow, and finally CRVO. For CRVO and its pathogenic factor polycythemia, patient received laser retinal photocoagulation and phlebotomies. After a 1-year follow-up, the vision in the left eye improved to 0.2 logMAR. CONCLUSIONS: This is a rare case of polycythemia complicated by CRVO in patient with VHL disease. It reminds us that the systemic disease factors should be fully considered in the diagnosis of young patients with CRVO, and that treatment requires a coordinated effort of physicians.

At the Pulse of Time: Machine Vision in Retinal Videos.

Spontaneous venous pulsations (SVP) are a common finding in healthy people. The absence of SVP is associated with rapid progression in glaucoma and increased intracranial pressure. Traditionally, SVP has been documented qualitatively by clinicians during biomicroscopy. Nowadays numerous imaging devices recording the fundus exist. Hence, video data for objectification of SVP is readily available. Still, these clinical datasets are afflicted with various quality issues and artifacts. In this machine vision based study, we explore methods to overcome challenges in identifying SVP in fundus videos of varying quality and provide a detailed protocol thereof. Hereby, we aim to lower the burden of access of implementing machine vision in clinical video datasets and quantification of SVP.

Comparison of retinal vascular arcade trajectory between eyes with an idiopathic macular hole and the healthy fellow eye.

PURPOSE: We aimed to present a method to evaluate the retinal arcade vascular trajectory by measuring the distance between the retinal veins in eyes with idiopathic macular hole (IMH) and comparing this measurement with healthy fellow eyes. METHODS: In this cross-sectional study 18 patients with unilateral IMH were enrolled. We used standard fundus photographs, which were obtained from each eye with a digital fundus camera using a 55-degree lens. The calculation of the retinal arcade vascular trajectories was done by drawing and measuring five vertical lines within the macular area. RESULTS: The mean age of the patients was 65 ± 9 years. The between-groups differences of each vertical line were not statistically significant, except for the differences between the most temporal line, which was greater in the diseased group (9388 vs. 8322 µm; P = 0.034). The ratio between the fifth (most temporal) and the third (fovea-center) vertical lines was greater than 1 (V-shape) in 72% of eyes with a macular hole, whereas it was less than one (U-shape) in 78% of control eyes (P = 0.003). CONCLUSIONS: We demonstrated that in eyes with an IMH the vascular arcade has more tendency to diverge on its path temporal to the fovea.

Defective endothelial cell migration in the absence of Cdc42 leads to capillary-venous malformations.

Formation and homeostasis of the vascular system requires several coordinated cellular functions, but their precise interplay during development and their relative importance for vascular pathologies remain poorly understood. Here, we investigated the endothelial functions regulated by Cdc42 and their in vivo relevance during angiogenic sprouting and vascular morphogenesis in the postnatal mouse retina. We found that Cdc42 is required for endothelial tip cell selection, directed cell migration and filopodia formation, but dispensable for cell proliferation or apoptosis. Although the loss of Cdc42 seems generally compatible with apical-basal polarization and lumen formation in retinal blood vessels, it leads to defective endothelial axial polarization and to the formation of severe vascular malformations in capillaries and veins. Tracking of Cdc42-depleted endothelial cells in mosaic retinas suggests that these capillary-venous malformations arise as a consequence of defective cell migration, when endothelial cells that proliferate at normal rates are unable to re-distribute within the vascular network.

Altered retinal oxygen metabolism in patients with combined ocular and central nervous system sarcoidosis.

OBJECTIVE: To evaluate retinal oxygen metabolism by retinal oximetry for ocular and CNS diseases in a cross-sectional study of sarcoidosis. METHODS: Overall 201 eyes from 103 biopsy-verified sarcoidosis patients were included and divided into four groups depending on the organ affection: (i) sarcoidosis without ocular or CNS affection, (ii) ocular sarcoidosis, (iii) CNS sarcoidosis, and (iv) combined ocular and CNS sarcoidosis. Retinal oximetry was obtained and analysed, with the mean retinal arteriolar and venular saturation as well as arteriovenous difference as principal outcomes. Comparison between groups was done in a multi linear regression model adjusted for age, sex, duration of sarcoidosis, best corrected visual acuity and retinal oximetry quality. RESULTS: Mean (s.d.) age was 50.5 (13.4) (95% CI: 47.9, 53.1) years and 52.2% were males. Eyes of the combined Ocular/CNS group had a higher retinal arteriovenous difference than eyes of the Non-ocular/no-CNS group (42.1% vs 37.7%, P = 0.012) but did not differ between other groups. Eyes in the four groups (Non-ocular/no-CNS, Ocular, CNS and Ocular/CNS) did not differ according to retinal arterial (94.5%, 93.5%, 93.5% and 94.5%, respectively) or venular (57.5%, 56.4%, 55.0% and 52.5%, respectively) oxygen saturation. CONCLUSIONS: The results of this study suggest that eyes of sarcoidosis patients with combined ocular and CNS affection have an altered oxygen metabolism indicating a subclinical eye affection that is not recognized by conventional screening methods.

INTERVORTEX VENOUS ANASTOMOSIS IN Pachychoroid-RELATED DISORDERS.

PURPOSE: To evaluate the choroidal vascular patterns of patients with pachychoroid-related diseases in eyes images with wide-field indocyanine green angiography. METHODS: Retrospective study of wide-field indocyanine green angiographic images of patients with pachychoroid, peripapillary pachychoroid syndrome, central serous chorioretinopathy, and pachychoroid-associated neovascularization that were evaluated for anastomoses between vortex vein systems, which are ordinarily separated by a watershed zone. RESULTS: There were 21 subjects with a mean age of 57.4 years and 15 were male. Among the 42 eyes evaluated, central serous chorioretinopathy was found in 24 eyes (57.1%), peripapillary pachychoroid syndrome in 5 (11.9%), pachychoroid associated neovascularization in 7 (16.7%), and pachychoroid in 6 (14.3%). Every eye showed anastomosis between the superonasal, superotemporal, and inferotemporal vortex vein systems. The inferonasal vortex vein system was less likely to demonstrate anastomosis except for peripapillary pachychoroid syndrome, which showed anastomosis in all eyes. The anastomotic connections were prominent in the central macula in the central serous chorioretinopathy and pachychoroid-associated neovascularization cases, and around the nerve in the peripapillary pachychoroid syndrome cases. Although the large choroidal veins were particularly prominent in the neovascular cases, the number was fewer in the macular region than in other pachychoroid-related diseases in this series. Compared with a control group of nine eyes, the inferotemporal-superotemporal-superonasal anastomotic connections were more common in the case group (P < 0.001) and inferonasal quadrant (P = 0.023 right eye; P = 0.01, left eye). CONCLUSION: Intervortex venous anastomosis is common in pachychoroid, central serous chorioretinopathy, peripapillary pachychoroid syndrome, and pachychoroid-associated neovascularization. This finding has important implications concerning pathogenesis and classification of disease.

ASSOCIATION BETWEEN PLATELET INDICES AND RETINAL VEIN OCCLUSION: A Systematic Review and Meta-Analysis.

PURPOSE: Platelet count, mean platelet volume, platelet distribution width, and plateletcrit are standard indices of platelet activation that have been studied in retinal vein occlusion (RVO) and its subtypes: branch retinal vein occlusion and central retinal vein occlusion. This systematic review and meta-analysis aimed to assess the association between these platelet parameters and RVO. METHODS: We searched for studies investigating the association between these platelet indices and RVO in multiple online databases from inception to August 2020. Mean differences and the associated confidence intervals were obtained and calculated for each included study and pooled using random-effects inverse variance modeling. Meta-regression was used to explore interstudy and intrastudy heterogeneity. RESULTS: Thousand three hundred and twenty-five unique studies were screened, from which 24 studies encompassing 2,718 patients were included. Mean platelet volume and platelet distribution width were significantly elevated in RVO, with pooled mean differences of 0.45 fL (95% CI 0.24-0.66, P < 0.0001) and 1.43% (95% CI 0.57-2.29, P = 0.0011), respectively. Platelet count and plateletcrit were not significantly associated with RVO. Mean platelet volume was also independently elevated in branch retinal vein occlusion and central retinal vein occlusion. CONCLUSION: Mean platelet volume and platelet distribution width are significantly elevated in RVO. Further research is required to explore the independence and potential prognostic significance of these associations.

NONPERFUSION ASSESSMENT IN RETINAL VEIN OCCLUSION: Comparison Between Ultra-widefield Fluorescein Angiography and Widefield Optical Coherence Tomography Angiography.

PURPOSE: To compare widefield optical coherence tomography angiography (OCTA) to ultra-widefield fluorescein angiography (UWFA) in the assessment of nonperfusion in retinal vein occlusion (RVO). METHODS: A cross-sectional study of 43 eyes of 43 patients with RVO examined using both widefield OCTA (PLEX Elite, Carl Zeiss Meditec, Dublin, CA) with a panoramic montage of five 12 × 12-mm images and UWFA (Optos, 200°). Qualitative analysis was performed according to nonperfusion areas (cutoff: three disk areas) on widefield OCTA. The quantitative analysis assessed the vascular density on the widefield OCTA and ischemic index on UWFA. RESULTS: The ischemic index on UWFA and vascular density in the superficial and deep plexus correlated significantly (P = 0.019, r = 0.357 and P < 0.013, r = 0.375, respectively). The qualitative classification on widefield OCTA and ischemic index on UWFA correlated significantly (P < 0.001, r = 0.618). For the detection of marked nonperfusion (ischemic index ≥ 25%), widefield OCTA had a sensitivity of 100% and a specificity of 64.9%. CONCLUSION: The presence of nonperfusion on UWFA correlated with widefield OCTA. Optical coherence tomography angiography could help to identify high-risk RVO patients who might benefit from a further evaluation using fluorescein angiography.

NONPERFUSION AREA QUANTIFICATION IN BRANCH RETINAL VEIN OCCLUSION: A Widefield Optical Coherence Tomography Angiography Study.

PURPOSE: To precisely quantify retinal nonperfusion areas (NPAs) in branch retinal vein occlusion using widefield optical coherence tomography angiography (OCTA) and examine their association with neovascular complications. METHODS: We enrolled 26 patients with treatment-naïve branch retinal vein occlusion and prospectively examined them for 12 months. After 3 monthly ranibizumab injections to treat macular edema, each patient underwent ultra-widefield (UWF) fluorescein angiography (FA) and OCTA. Ultra-widefield FA was additionally performed at Month 12. For UWF FA, the retinal NPA was measured using the equipment's built-in software. For OCTA, we used panoramic image montaged from 5 single 12 × 12 mm2 images and quantified the retinal NPA using a Gullstrand eye with a grid scale at each patient. Measurements were expressed in terms of actual values and disc area units. RESULTS: The retinal NPAs as measured using single OCTA and panoramic OCTA were significantly associated with that measured using UWF FA (P < 0.001 for both). Retinal neovascularization lesions were observed in 4 (15.4%) of 26 eyes. For patients with accompanying neovascularization, the retinal NPA measured using UWF FA, single OCTA, and panoramic OCTA were 187.9 ± 39.5 mm2 (109.9 ± 21.4 disc area), 34.3 ± 13.7 mm2 (19.9 ± 7.7 disc area), and 106.6 ± 24.5 mm2 (62.4 ± 13.6 disc area), respectively, which were larger than for those without neovascularization (P < 0.001, 0.014, and <0.001, respectively). CONCLUSION: Using widefield OCTA, we could quantify the retinal NPA of eyes with branch retinal vein occlusion. These could serve as valid references to assess the risk of neovascular complications.

ROLE OF DILATED SUBFOVEAL CHOROIDAL VEINS IN EYES WITH MYOPIC MACULAR NEOVASCULARIZATION.

PURPOSE: To investigate the dilated choroidal veins (DCVs) at or around myopic macular neovascularizations (MNVs) and to determine whether there is a hemodynamic relationship between them. METHODS: Fifty-eight eyes of 57 patients with myopic MNVs were examined. Dilated choroidal veins were defined as choroidal veins whose diameter was 2X larger than adjacent veins. Indocyanine green angiography and swept-source optical coherence tomography images were reviewed to detect DCVs that crossed the subfoveal area. The filling sequence of the DCVs and MNVs was determined. RESULTS: Patients' mean age was 71.4 ± 10.6 years. The mean axial length was 29.3 ± 1.8 mm. Dilated choroidal veins below or around the MNV were found in 17 eyes (29.3%). Emissaries of the short posterior ciliary arteries were seen at or around MNVs in 8 of the 17 eyes. In these eyes, the short posterior ciliary artery was filled first or almost simultaneously with the filling of the MNV, followed by a laminar filling of the DCVs. In one eye, afferent arterioles from the short posterior ciliary arteries and efferent venules connected to DCVs were seen. CONCLUSION: Dilated choroidal veins are present below or around MNVs in about 30% of eyes with myopic MNVs. Our findings suggest that an MNV might be a vascular unit consisting of short posterior ciliary arteries, afferent arterioles, efferent venules, and DCVs.

Comparison of Static Retinal Vessel Caliber Measurements by Different Commercially Available Platforms.

SIGNIFICANCE: Commercially available platforms show good agreement in clinical outcomes for retinal vessel caliber measurements, despite differing absolute values. Tighter agreement is observed when right and left eye data are averaged, suggesting an approach suitable for clinical practice. PURPOSE: The purpose of this study was to compare the retinal vessel caliber measurements generated by different commercially available platforms and their associations with systemic blood pressure and age. METHODS: A total of 209 participants were recruited from a UK optometric practice. After a routine eye examination, participants had disc-centered retinal photographs and systemic blood pressure taken. Retinal vessel calibers (central retinal artery equivalent, central retinal vein equivalent, and arteriovenous ratio) were calculated using both MONA REVA and VesselMap. RESULTS: An inverse Pearson correlation was observed between central retinal artery equivalent and mean arterial blood pressure on both platforms (r = -0.275 [P ≤ .001] and r = -0.388 [P ≤ .001] for MONA REVA and VesselMap, respectively); this correlation was also observed with arteriovenous ratio and blood pressure. An inverse correlation was observed between central retinal artery equivalent and age (r = -0.362 [P ≤ .001] and r = -0.404 [P ≤ .001] for MONA REVA and VesselMap, respectively); this was also seen between central retinal vein equivalent and age (r = -0.322 [P ≤ .001] and r = -0.369 [P ≤ .001]). Arteriovenous ratio remained independent from age for both platforms. Bland-Altman plots demonstrated good agreement between the platforms for all three variables. CONCLUSIONS: Although absolute caliber measurements differed between the platforms, the correlations observed were of similar magnitudes, with good agreement between the two platforms. Tighter spaced limits of agreement were observed when right and left eye data were averaged for each subject. In the absence of localized ocular pathology, this approach should be used.