Deep Retinal Plexus Research Articles

Study of the retina macular region microvascular bed parameters in healthy people of the older age group according to optical coherence tomography with angiography function

BACKGROUND: To date, there is insufficient data on normal blood flow indicators in the retinal choroid plexuses in healthy people of the older age group. AIM: To create a normative basis for average indicators of vessel density in the superficial and deep plexuses of the retina, parameters of the foveal avascular zone and retinal thickness in the macular region in healthy people of the older age group according to optical coherence tomography with angiography. MATERIAL AND METHODS: The retrospective study included 73 people (146 eyes) aged from 58 to 79 years with preserved visual functions and somatic parameters corresponding to the age norm. Optical coherence tomography with angiography function analyzed the density of vessels in the superficial and deep retinal plexuses, the area and perimeter of the foveal avascular zone, the density of vessels in the area up to 300 μm from the foveal avascular zone, and the thickness of the retina. Statistical processing of the data was performed in MS Office Excel 2016. The data was presented in the format M±σ, where M was the average value of the indicator, σ was the standard deviation. RESULTS: In the study group, the overall average retinal thickness in the macular area was 279.9±14.8 µm. The overall average density of vessels of the superficial retinal plexus in the macular zone of the retina was 48.7±2.5%. The overall average density of vessels in the deep retinal plexus in the macular area was 51.9±3.7%. The area of the foveal avascular zone in healthy people was on average 0.322±0.123 mm2; the density of vessels within 300 µm from the foveal avascular zone was 53.8±3.3%. CONCLUSION: The age-related physiological norm for blood flow indicators in the retinal choroid plexuses in healthy people of the older age group has been established.

The characteristics of acute macular neuroretinopathy following COVID-19 infection

BackgroundIn this study, we report a case series of acute macular neuroretinopathy (AMN) associated with COVID-19 infection.MethodsThis retrospective observational study was conducted at Beijing Tongren Hospital. We reviewed patients who were diagnosed with AMN within one month of testing positive for COVID-19 using real-time reverse transcription-polymerase chain reaction (RT-PCR).ResultsA total of 11 AMN patients (20 eyes) were included in the study. The mean age was 33.8 ± 12.6 years. The average interval between a positive COVID-19 PCR test and the onset of ocular symptoms was 2.8 ± 2.5 days. The mean follow-up period for the patients was 12.5 ± 3.8 weeks. Imaging characteristics of AMN patients following COVID-19 infection included areas of low reflectivity on near-infrared reflectance (NIR) imaging, hyperreflective lesions at the level of the outer plexiform layer (OPL) and outer nuclear layer (ONL) and disruption of the ellipsoid zone (EZ) on spectral domain optical coherence tomography (SD-OCT) B-scans. Visual field examinations revealed parafoveal scotomas that closely corresponded to the clinical lesions. Optical coherence tomography angiography (OCT-A) demonstrated impaired perfusion in the deep retinal vascular plexus. Fluorescein angiography (FA), indocyanine green angiography (ICGA), and spontaneous fundus autofluorescence showed no significant abnormalities. During follow-up, partial improvement in retinal lesions was observed in NIR imaging and SD-OCT in some patients, but a proportion of patients still exhibited persistent retinal damage and no improvement in visual field scotomas.ConclusionCOVID-19-related AMN share similar clinical and imaging features with AMN due to other causes, as evidenced by the persistent presence of visual field scotomas over a longer duration.Trail registrationhttps://www.chictr.org.cn/; identifier: ChiCTR2100044365

Retinal biomarkers in vascular occlusion

Objective: To clarify the diagnostic and prognostic values of the biomarkers detected by multimodal imaging procedures as coloured fundus imaging, fluorescein angiography, near infra‐red imaging, fundus Autofluorescence, SD‐OCT, and OCT angiography to predict the prognosis and the response to therapy in retinal vascular occlusions (artery or vein).Recently, there has been an interest in determining the prognostic value of changes on optical coherence tomography (OCT) in retinal vein occlusion as it allows both quantitative and qualitative analysis of imaging biomarkers such as central retinal thickness, choroidal thickness, intraretinal hyper‐reflective foci (HRF), disorganization of the inner retinal layers (DRIL), external limiting membrane (ELM) disruption, ellipsoid zone (EZ) disruption. Also classifying the intraretinal edema if sponge‐like or cystoid or serous retinal detachment (and detecting its height). Also signs of ischemia can be detected such as prominent middle limiting membrane (p‐MLM), paracentral acute middle maculopathy (PAMM), as well as hyperreflectivity of the inner retinal layers (HIRL) which is commonly seen in cases of acute retinal artery occlusion. Internal limiting membrane detachment (ILMD) which is a novel biomarker that can be detected in some cases of acute CRAO.OCT Angiography has added more information about the assessment of microvascular alterations, especially vessel density in the deep retinal vascular plexus, the foveal avascular zone and of areas with no capillary perfusion. Biomarkers of ultra‐widefield angiography, such as peripheral ischemia (ischemic index) and neovascularization are essential for retinal laser treatment decision.Finally, FAF has been a very useful tool in monitoring the disease progression and response to treatment.The speaker will present examples of multimodal imaging of different retinal biomarkers in retinal vascular occlusion that help in predicting the prognosis.

Retina hypoperfusion in multiple sclerosis: Is it only a consequence of atrophy?

Aims/Purpose: To study if there are vascular changes in patients with multiple sclerosis (MS) when compared healthy controls, analysing oct and OCT‐angiography findings (choroidal thickness and retinal vascular density) at the macular level.Methods: The study compared two groups (controls and patients) and it analysed whether there were statistically significant differences in the different parameters studied using OCT: choroidal thickness and in the vascular macular plexuses, using OCT‐angiography. Any patient has an optic neuritis history. It was also studied whether there was a statistically significant correlation between anatomical parameters (radial nerve fibre layer, RNFL and ganglion cell layer, GCL) and vascular parameters matching cases and controls by age and sex.Results: We found a statistically significant reduction in macular choroidal thickness in patients when compared to controls. The study of retinal vascular plexuses showed that the superficial and deep retinal vascular plexuses and the choriocapillaris plexus showed significantly lower vascular density in the patients group. Variations in anatomical parameters between anatomical parameters and in vascular parameters between vascular parameters pairing cases and controls show direct correlations. Regarding the correlation between the differences in anatomical versus vascular parameters, we only observed a low direct correlation between the difference in the papillary RFNL and that of the superficial macular vascular plexus between case and control group.Conclusions: The density of macular vascular plexus and choroidal thickness proved to be significantly lower in MS patients than in healthy subjects. To date, it is not known to what extent hypoperfusion in MS is a cause or consequence of the brain disease or whether it is a simply association. Vascular parameters could be used as useful markers in the diagnosis and follow‐up of MS.

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.

Modifications in ocular microperfusion after transcatheter aortic valve implantation

Cerebral embolization is a known complication of transcatheter aortic valve implantation (TAVI) but the effect of the procedure on the ocular perfusion is currently unclear. Thus, we investigated post-procedural morphologic and perfusion changes of the retina and choroid, using optical coherence tomography angiography (OCTA) and color fundus photography (CFP) in a prospective cohort study. Ophthalmic examinations were conducted pre- and post-TAVI. OCTA images were analyzed quantitatively based on vessel density and skeleton density of the superficial and deep retinal plexus as well as the signal intensity and flow deficits in the choriocapillaris. CFP images were assessed for presence of acute retinal ischemia, optic nerve swelling, vessel emboli, hemorrhages and cotton wool spots. Data was analyzed using linear mixed models. Twenty patients (9 women; 11 men) at a mean age of 81 ± 6 years were included. Pre- and post-interventional ocular imaging data were available for 32 eyes. The analysis revealed a significant impairment of the choriocapillaris perfusion after TAVI with an increased proportion of flow deficits (p = 0.044). When controlling for blood pressure, the average size of choriocapillaris flow voids was significantly increased (systolic and diastolic, p = 0.039 and 0.029). Qualitatively, focal areas of retinal ischemia were detected on OCTA in 33% of participants. Silent emboli or cotton wool spots were identified on CFP in 21%. Our findings indicate a reduced choroidal perfusion as well as areas of retinal ischemia and embolization in a considerable proportion of patients following TAVI. Pending confirmation in a larger sample, these complications merit monitoring as well as inclusion in consent procedures for TAVI.

Macular Microvascular Perfusion Status in Hypertensive Patients with Chronic Kidney Disease.

To compare retinal microvascular perfusion between the eyes of hypertensive patients with and without chronic kidney disease (CKD), the vessel density (VD) and fractal dimension (FD) of the superficial (SVP) and deep retinal vascular plexus (DVP) were analyzed on 6 × 6 mm fovea-centered optical coherence tomography angiography (OCTA) images of patients with hypertension. The retina was divided into an inner ring (IR) and outer ring (OR) according to the Early Treatment of Diabetic Retinopathy Study grid. The glomerular filtration rate (GFR) was determined and CKD was diagnosed (GFR < 60 mL/min/1.73 m2). Ninety-six eyes from 52 patients with hypertension were included in this analysis. Twenty patients (n = 37 eyes) were diagnosed with CKD. The mean age was 69 ± 11.7 years and 60.4 ± 9.2 years in the CKD group and in the control group, respectively. The univariate model revealed a significant difference in VD between patients without and with CKD in the superficial IR (0.36 ± 0.03 vs. 0.34 ± 0.04, p = 0.03), the superficial OR (0.35 ± 0.02 vs. 0.33 ± 0.04, p = 0.02), the deep OR (0.24 ± 0.01 vs. 0.23 ± 0.02, p = 0.003), and the FD in the SVP (1.87 ± 0.01 vs. 1.86 ± 0.02, p = 0.02) and DVP (1.83 ± 0.01 vs. 1.82 ± 0.01, p = 0.006). After adjusting for age and sex, these differences did not remain statistically significant. Similar results were observed for the FD in the SVP and DVP. In our cohort, patients with hypertension and CKD did not differ from patients without CKD in regard to microvascular perfusion status in the macular area as assessed using OCTA.

Secretogranin III Selectively Promotes Vascular Leakage in the Deep Vascular Plexus of Diabetic Retinopathy.

Diabetic retinopathy (DR), a leading cause of vision loss in working-age adults, induces mosaic patterns of vasculopathy that may be associated with spatial heterogeneity of intraretinal endothelial cells. We recently reported that secretogranin III (Scg3), a neuron-derived angiogenic and vascular leakage factor, selectively binds retinal vessels of diabetic but not healthy mice. Here, we investigated endothelial heterogeneity of three retinal vascular plexuses in DR pathogenesis and the therapeutic implications. Our unique in vivo ligand binding assay detected a 22.7-fold increase in Scg3 binding to retinal vessels of diabetic mice relative to healthy mice. Functional immunohistochemistry revealed that Scg3 predominantly binds to the DR-stressed CD31- deep retinal vascular plexus but not to the relatively healthy CD31+ superficial and intermediate plexuses within the same diabetic retina. In contrast, VEGF bound to healthy and diabetic retinal vessels indiscriminately with low activity. FITC-dextran assays indicated that selectively increased retinal vascular leakage coincides with Scg3 binding in diabetic mice that was independent of VEGF, whereas VEGF-induced leakage did not distinguish between diabetic and healthy mice. Dose-response curves showed that the anti-Scg3 humanized antibody (hAb) and anti-VEGF aflibercept alleviated DR leakage with equivalent efficacies, and that the combination acted synergistically. These findings suggest: (i) the deep plexus is highly sensitive to DR; (ii) Scg3 binding to the DR deep plexus coincides with the loss of CD31 and compromised endothelial junctions; (iii) anti-Scg3 hAb alleviates vascular leakage by selectively targeting the DR-stressed deep plexus within the same diabetic retina; (iv) combined anti-Scg3 and anti-VEGF treatments synergistically ameliorate DR through distinct mechanisms.

Assessment of macular microvascular changes in children following treatment of anisometropic myopic amblyopia using optical coherence tomography angiography

PurposeTo evaluate macular microvascular changes in the form of foveal avascular zone (FAZ) area and vessel density in the superficial, deep capillary plexuses, and choriocapillaris using optical coherence tomography angiography (OCTA) in children with anisometropic myopic amblyopia before and after treatment.MethodsThis prospective observational study included 32 patients younger than 12 years old with anisomyopic amblyopia. OCTA was done before patients’ treatment with optical correction with or without patching and was repeated after successful amblyopia treatment. Outcomes included superficial, deep, and choriocapillaris vessel density (VD) and superficial and deep FAZ areas.ResultsThe study included 13 males (40.6%) and 19 females (59.4%), and the mean age was 9.52 ± 1.33 years. Fifty-three percent (53%) of patients needed only optical correction, and the remaining 47% needed additional patching therapy. After successful treatment, there was a significant improvement in amblyopic eyes in best-corrected visual acuity (p < 0.001), with higher VD values in superficial capillary plexuses (p < 0.001), deep capillary plexuses (p < 0.001), and foveal choriocapillaris (p = 0.030). In the glasses with patching subgroup, the difference between pre-treatment and post-treatment parameters revealed a significant improvement in vessel density in superficial retinal plexuses (foveal and parafoveal; p values 0.023 and < 0.001, respectively) and deep retinal plexuses (whole image, foveal, and parafoveal; p values 0.003, < 0.001, and 0.002, respectively). While amblyopic eyes treated with glasses alone had a significantly greater difference in choriocapillaris foveal VD (p value = 0.022).ConclusionAfter effective amblyopia treatment, amblyopic eyes exhibited improved best-corrected visual acuity and better macular perfusion along the superficial, deep vascular density, and choriocapillaris foveal VD.Clinical trial registrationCinicalTrials.gov Identifier: NCT05223153.

OCT Angiography in Noninfectious Uveitis: A Description of Five Cases and Clinical Applications.

Optical coherence tomography angiography (OCTA) is a noninvasive imaging modality used to analyze the retinochoroidal vasculature and detect vascular flow. The resulting images can be segmented to view each vascular plexus individually. While fluorescein angiography is still the gold standard for the diagnosis of posterior uveitis, it has limitations, and can be replaced by OCTA in some cases. This case series describes five patients with posterior noninfectious uveitis and their description by OCTA. Cases included lupus retinopathy (n = 1) for which OCTA showed ischemic maculopathy as areas of flow deficit at the superficial and deep capillary plexus; choroidal granulomas (n = 1) with a non-detectable flow signal in the choroid; active punctate inner choroiditis and multifocal choroiditis (n = 1) with OCTA that showed active inflammatory chorioretinal lesions as non-detectable flow signals in choriocapillaris and choroid; dense type 2 inflammatory secondary neovascularization (n = 1) associated with active choroiditis; and acute posterior multifocal placoid pigment epitheliopathy (APMPPE) (n = 1) without flow abnormalities at the superficial and deep retinal plexuses but non-detectable flow at the levels of the choriocapillaris and choroid. Ophthalmologists can use OCTA to identify inflammatory changes in retinal and choroidal vasculature, aiding in the diagnosis, management, and monitoring of posterior uveitis.

Atrophy of retinal vessels in neovascular age-related macular degeneration following long-term treatment with 20 intravitreal anti-VEGF injections

BackgroundThe study aimed to evaluate the changes in retinal vascular density in exudative age-related macular degeneration (AMD) after long-term anti-VEGF treatment using optical coherence tomography angiography (OCT-A), and to compare these changes with the vascular density in AMD treated for one year and healthy eyes.MethodsIn our cross-sectional study OCT-A was performed on 60 eyes of 60 patients. Group AMD 20 × consisted of patients receiving long-term (minimum 20 injections) aflibercept therapy (n = 17), and Group AMD one year consisted of patients treated for one year with a treat & extend protocol (n = 25). The vascular density values obtained with OCT-A were compared with an age-matched control group of 18 healthy eyes. We examined the central retinal thickness (CRT), the vascular density of the fovea and parafovea in the superficial and deep retinal plexus, and evaluated the extent of the non-flow area and the foveal avascular zone (FAZ) on a 3 × 3 mm macular region. Kruskal–Wallis test was performed for statistical analysis.ResultsIn Group AMD 20x, the vascular density of superficial retinal plexus in the fovea (p = 0.0022) and parafovea (p < 0.0001) was significantly lower compared to Group one year and control group. In the deep retinal plexus, vascular density in the fovea (p = 0.0033) was significantly lower in both AMD groups compared to the control group, with no difference in the parafoveal region (p = 0.0774). The extent of non-flow area (p = 0.0003) and FAZ (p = 0.0008) were significantly larger in both AMD groups compared to the control group. There was a significant difference in CRT between those treated for one year and control eyes (p = 0.0036).ConclusionsIn our study, we demonstrated that macular vessel density was lower in the foveal area in the superficial retinal plexus in AMD patients after one year and long-term anti-VEGF treatment. These vascular density changes were absent in the parafoveal and whole areas of the deep retinal plexus. Our results indicate that long-term anti-VEGF treatment reduces the vascular density of the superficial retinal plexus to a greater extent compared to the deep retinal plexus.

Optical coherence tomography angiography findings in patients with essential hypertension

AbstractPurpose: To study the variation of retinal and choroidal density in patients with essential hypertension using Swept Source Optical Coherence Tomography Angiography (SS‐OCT A).Methods: Prospective cross‐sectional study carried out at the Ophthalmology department of Habib Thameur University Hospital of Tunis between June, 1st 2021 and March, 30th 2022. Fifteen volunteer healthy patients (30 eyes) were included. All patients underwent complete ophthalmic examination, measurements of resting systolic and diastolic blood pressure and 3 × 3 and 4.5 × 4.5 SS‐OCT A angiograms in both eyes. Perimeter of avascular central zone (ACZ), superficial retinal plexus density (SRPD), deep retinal plexus density (DRPC) and choriocapillaris capillary vessel density (CVD) were calculated on exported jpg format images using the Fiji Software. Comparative Mann Whitney and Spearman tests were performed using 21.0 SPSS.Results: Eleven males and four females were eligible for the study. Mean age was 53.33 ± 9.73 years. Eight patients (53.3%) with chronic essential hypertension were compared to seven healthy volunteers (46.7%). Mean ACZ, SRPD, DRPD and CVD were respectively 2.62 ± 0.52 mm, 13.20 ± 2.10%, 17.14 ± 1.17% and 51.05 ± 0.85%. Mean systolic blood pressure was 13 ± 5 mmHg and mean diastolic blood pressure was 7.67 ± 5.16 mmHg. CVD was lower in patients with chronic hypertension than in the control group (50.59 vs 51.41, p = 0.047). There were no significant differences between hypertension group and normal group in ACZ, SRPD and DRPC measurements (p = 0.089, p = 0.90 and p = 0.70, respectively). No correlations were found between resting blood pressure values and ACZ measurements.Conclusions: Chronic hypertension does not affect retinal vessels and capillaries quantitative parameters. However, it may alter choroidal vascular structures by decreasing choriocapillaris vessel density. Larger studies are needed to strengthen these results.

Vascular parameters after vitrectomy for rhegmatogenous retinal detachment, an optical coherence tomography angiography study

AbstractPurpose: To analyse vascular changes such as the postoperative foveal avascular zone (FAZ) area, the superficial vessel density (sVD) and deep vessel density (dVD) and their correlation with functional (best‐corrected visual acuity, metamorphopsia) and anatomical outcomes (foveal macular thickness, FMT) after surgery for rhegmatogenous retinal detachment (RRD) repair.Methods: Patients with RRD eyes, successfully treated with a single pars plana vitrectomy (PPV) with gas or silicone oil tamponade and a minimum 6 months follow‐up, were re‐examined. For patients where silicone oil was applied, measures were taken after its removal. Foveal avascular zone (FAZ) area, sVD, dVD and FAZ area were evaluated by using optical coherence tomography angiography (OCTA) and compared to fellow eye. Moreover, anatomical association was tested between areas of reported metamorphopsias and vascular changes in the corresponding area.Results: Twenty‐one patients with macula‐on and 24 with macula‐off RRD were included in the study. In both groups, no significant difference in macular thickness and FAZ area was found compared to fellow eyes. In macula‐on RRD eyes, a lower total dVD (p &lt; 0.05) was detected; FAZ area was not related to FMT, and the postoperative BCVA was correlated with total DVD (p &lt; 0.05) or FAZ area. In macula‐off RRD eyes, sDV (p = 0.012), and dVD (p = 0.05 and p &lt; 0.05, respectively) were observed when compared to fellow eyes. The prevalence of metamorphopsia in macula‐on group was 42.86% (9/21), whereas in macula ‐off this number increased to 62.5% (15/24). For both of these groups, we found significant association between sDV and presence of metamorphopsia but only in the inferior paramacular area (p = 0.01).Conclusions: Rhegmatogenous retinal detachment eyes successfully treated with PPV had lower vessel density in the superficial and deep retinal plexus compared to fellow healthy eyes; BCVA was related to vessel density but not FAZ area. Metamorphopsias were also related to lower vessel density inferiorly of the macula.

Evaluation of the effect of cigarette smoking on retina and choroid: An optical coherence tomography angiography study

AbstractPurpose: To study the effect of active cigarette smoking on retinal and choroidal micro‐vascularization using Swept Source Optical Coherence Tomography Angiography (SS‐OCT A).Methods: This is a cross‐sectional, observational, comparative study carried out at the Ophthalmology department of Habib Thameur University Hospital of Tunis. Twelve eyes of “healthy” smokers, 10 eyes of former smokers (less than 3 years after quitting smoking) and 6 eyes of healthy non‐smokers controls were included. SS‐OCT A 3 × 3 mm angiograms were exported and analysed with image J, Fiji Software. Perimeter of avascular central zone (ACZ), superficial retinal plexus density (SRPD), deep retinal plexus density (DRPC) and choriocapillaris capillary vessel density (CVD) were calculated and analysed. Comparative Kruskal Wallis and Spearman tests were performed using 21.0 SPSS.Results: Volunteers with a smoking history had an average of 13.75 ± 10.26 pack‐years. The mean smoking period was 3.2 ± 5.13 years and mean smoking cessation period was 1.28 ± 0.85 years. Mean ACZ, SRPD, DRPD and CVD were respectively 2.62 ± 0.52 mm, 13.20 ± 2.10%, 17.14 ± 1.17% and 51.05 ± 0.85%. There was no significant difference between the three groups for the measurements of ACZ, SRPD, DRPD and CVD (p = 0.57, p = 0.97, p = 0.53 and p = 0.07; respectively). However, there was a significant positive correlation between the smoking cessation period and the DRPD (p = 0.003, r = 0.865).Conclusions: Despite the known effects of nicotine and other chemical substances in cigarettes on peripheral vascular structures, no significant difference in quantitative analysis of retinal and choroidal networks could be found. Deep retinal plexus density seems to increase after long smoking cessation periods.

Normative Vascular Features on OCT Angiography in Healthy Nepalese Eyes.

To establish normative data on morphological characteristics and quantitative parameters of Foveal Avascular Zone (FAZ) as well as their systemic and ocular associations using OCT angiography (OCT-A) in healthy Nepalese subjects. A prospective, cross-sectional, population-based study recruiting 210 healthy samples (420 eyes) aged 10 to 70 years was conducted. All the samples underwent detailed comprehensive eye examination followed by Optical Coherence Tomography Angiography (OCTA) and Enhanced Depth Imaging performed in each eye using Spectral Domain Optical Coherence Tomography. Foveal avascular zone area and vessel density in superficial and deep retinal plexus and Sub foveal Choroidal Thickness (SFCT) were evaluated. Ocular and systemic associations of these parameters were also studied in a multivariate analysis utilizing linear regression. The mean superficial and deep FAZ area was 459.96 ± 124.75 μm (95% confidence interval [CI], 443.08-476.83) and 589.0 ± 141.39 μm (95% CL, 570.77-609.02), respectively. The vessel density in superficial capillary plexus was 54.03 ± 9.34% (95% CL, 53.98-54.11) while the vessel density in deep capillary plexus was 25.91 ± 38% (95% CL, 25.85-25.96). The mean SFCT in this study was 308.89 ± 68.87μm (95% CL, 299.64-318.14 μm). There was no statistically significant inter-eye difference in the FAZ parameters. Myopic eyes had smaller FAZ, lesser vessel density and thinner SFCT. Association was observed between superficial FAZ area and systolic blood pressure, and deep FAZ area and diastolic blood pressure. This study reports the normative data on FAZ parameters in healthy Nepalese subjects which can serve as references for interpreting these parameters in different retinal-choroidal diseases.

Biomarkers in the treatment of retinal vein occlusion

Retinal vein occlusion, subdivided into central retinal and branch retinal vein occlusion, is one of the most frequent vascular diseases of the retina. Biomarkers of optical coherence tomography (OCT), OCT-angiography and (ultra-widefield) fluorescein angiography are of exceptional importance in the initial diagnosis and also in the treatment of complications associated with retinal vascular occlusion, particularly macular edema. A systematic literature review was carried out in PubMed with the keywords central retinal vein occlusion, branch retinal vein occlusion, biomarker, OCT, OCT angiography, ultra-widefield fluorescein angiography with prioritization of the most important aspects. Relevant biomarkers in OCT include central retinal thickness (CRT), macular fluid, the integrity of the photoreceptor bands (external limiting membrane and ellipsoid zone), disorganization of retinal inner layers (DRIL), hyperreflective foci, choroidal thickness and signs of ischemia, such as a prominent middle limiting membrane (p-MLM), paracentral acute middle maculopathy (PAMM) as well as hyperreflectivity of inner retinal layers (HIRL). The importance of OCT-angiography lies particularly in the assessment of microvascular alterations, especially vessel density in the deep retinal vascular plexus, the foveal avascular zone and of areas with no capillary perfusion. Biomarkers of ultra-widefield angiography, such as peripheral ischemia (ischemic index) and neovascularízation are essential with respect to treatment decisions for retinal laser. A multitude of simple and complex biomarkers currently enable an effective individualized evaluation of treatment and prognosis in retinal vein occlusion. A shift from invasive to noninvasive biomarkers can be observed.

The Effects of chronic smoking on retinal vascular densities and choroidal thicknesses measured by optical coherence tomography angiography.

To examine the effects of chronic smoking on vascular density in superficial and deep retinal vascular plexuses and choroidal thicknesses. Superficial and deep vessel densities and choroidal thicknesses of smoking volunteers and healthy non-smoking volunteers were measured with the Topcon DRI OCT-1 Tritron® device and compared with each other. This study included 108 eyes of 54 smoking volunteers and 108 eyes of 54 healthy volunteers as a control group. The average superficial vascular density index and deep vascular density indexes of smokers were found to be 39.81 ± 1.5% and 42.53 ± 1.9%, respectively (P = 0.53), while the non-smoking control group was 40.09 ± 1.3% and 41.57 ± 1.6%, respectively (P = 0.006). Average choroidal thicknesses were 284.22 ± 59 in smokers and 270.72 ± 61 in the control group (P = 0.247). Also, smoking quantity per day x years was found to be significantly negatively correlated with average choroidal thicknesses. (P = 0,011). In this study, it was determined that chronic smoking increases deep retinal vascular densities on retinal vascular plexus. However, the cumulative effect of smoking was found to be negatively correlated with choroidal thicknesses. Smoking has microvascular effects on vessels such as vasodilatation, vasoconstriction, increased platelet aggregation, endothelial dysfunction. However, studies in the literature are in dispute with the effects of smoking on choroidal and retinal vessels. This study may show that chronic smoking may have different vascular effects on the superficial and deep plexuses and choroidal vessels, as well as different effects from acute use.

Long term high glucose exposure induces premature senescence in retinal endothelial cells.

Purpose: Features of cellular senescence have been described in diabetic retinal vasculature. The aim of this study was to investigate how the high glucose microenvironment impacts on the senescence program of retinal endothelial cells. Methods: Human retinal microvascular endothelial cells were cultured under control and high glucose conditions of 5 mM and 25 mM D-glucose, respectively. Isomeric l-glucose was used as the osmotic control. Cells were counted using CASY technology until they reached their Hayflick limit. Senescence-associated β-Galactosidase was used to identify senescent cells. Endothelial cell functionality was evaluated by the clonogenic, 3D tube formation, and barrier formation assays. Cell metabolism was characterized using the Seahorse Bioanalyzer. Gene expression analysis was performed by bulk RNA sequencing. Retinal tissues from db/db and db/+ mice were evaluated for the presence of senescent cells. Publicly available scRNA-sequencing data for retinas from Akimba and control mice was used for gene set enrichment analysis. Results: Long term exposure to 25 mM D-Glucose accelerated the establishment of cellular senescence in human retinal endothelial cells when compared to 5 mM D-glucose and osmotic controls. This was shown from 4 weeks, by a significant slower growth, higher percentages of cells positive for senescence-associated β-galactosidase, an increase in cell size, and lower expression of pRb and HMGB2. These senescence features were associated with decreased clonogenic capacity, diminished tubulogenicity, and impaired barrier function. Long term high glucose-cultured cells exhibited diminished glycolysis, with lower protein expression of GLUT1, GLUT3, and PFKFB3. Transcriptomic analysis, after 4 weeks of culture, identified downregulation of ALDOC, PFKL, and TPI1, in cells cultured with 25 mM D-glucose when compared to controls. The retina from db/db mice showed a significant increase in acellular capillaries associated with a significant decrease in vascular density in the intermediate and deep retinal plexuses, when compared to db/+ mice. Senescent endothelial cells within the db/db retinal vasculature were identified by senescence-associated β-galactosidase staining. Analysis of single cell transcriptomics data for the Akimba mouse retina highlighted an enrichment of senescence and senescence-associated secretory phenotype gene signatures when compared to control mice. Conclusion: A diabetic-like microenvironment of 25 mM D-glucose was sufficient to accelerate the establishment of cellular senescence in human retinal microvascular endothelial cells.

Correlation between optical coherence tomography angiography macular parameters with optical coherence tomography structural parameters in primary open angle glaucoma (a longitudinal descriptive study)

Background: There is growing evidence indicating that glaucoma pathogenesis is attributed to vascular dysfunction.Aim: compare the macular circulation in normal individuals and glaucomatous patients in the superficial as well as the deep retinal plexuses, to determine and characterize macular circulation deficits in glaucoma along with correlating them with structural macular OCT parameters Methods: descriptive study included 100 eyes of 100 participants who were selected randomly from attendants of ophthalmology outpatient clinic in Beni-suef university hospital Participants were subjected to 24-2 SITA- standard automated VF test using SAP ,OCT ONH examination and OCTA (Macula) Results: IOP showed significant negative moderate to strong linear correlation with all the Macular Parameters in Glaucoma Participants. These correlations were highly significant; (p-values &lt;0.001). All measurements of superficial and deep macular venues plexuses by studied macular OCTA was statistically significantly lower in glaucomatous as compared to non-glaucomatous participants; (p-values &lt;0.001). Conclusion: There was a reduction in VD in particular that of superficial layer in POAG patients in macular region, according to OCTA measurements. Glaucomatous eyes have a significantly sparser superficial VD in the macula when compared to healthy eyes, and these VD assessments are significantly accompanied by the severity of VF destruction and OCT structural affection.

Changes in chorioretinal flow index after cataract surgery: an optical coherence tomography angiography study.

Pseudophakic cystoid macular edema (CME) occurs in up to 2% of uneventful cataract surgeries. This study evaluates changes in macular blood flow succeeding uneventful phacoemulsification cataract extraction among otherwise visually healthy subjects. This prospective study included 18 eyes of 18 patients undergoing routine phacoemulsification. Optical coherence tomography angiography (OCT-A) was performed using the Angio-Retina 6 × 6mm protocol with the XR Avanti Angio-Vue system (Optovue Inc., Fremont, California) prior to the surgery and 4-8weeks thereafter. Exclusion criteria included motion artifacts, segmentation errors and signal strength index (SSI) < 40. The main outcome measure was change in flow index (FI) measured in all 4 retinal segmentation layers within an area of 1mm diameter around the foveal center. Following surgery, a significant increase in SSI (46.65 ± 8.62 versus 53.12 ± 8.07, p = 0.01), superficial plexus FI (0.98 ± 0.23 versus 1.16 ± 0.16, p = 0.02) and deep plexus FI (0.54 ± 0.46 versus 0.93 ± 0.39, p = 0.01) was found. No significant changes were noted in the outer retina or the choriocapillaris. The study demonstrates a significant increase in FI in the superficial and deep retinal plexus following uneventful cataract surgery, with the greatest changes occurring in the latter. These findings corroborate evidence from structural imaging and support the vascular etiology of pseudophakic CME.