Optic Density Research Articles

Optic flow density modulates corner-cutting in a virtual steering task for younger and older adults.

There is a critical need to understand how aging visual systems contribute to age-related increases in vehicle accidents. We investigated the potential contribution of age-related detriments in steering based on optic flow, a source of information known to play a role in navigation control. Seventeen younger adults (mean age: 21.1 years) and thirteen older adults (mean age: 57.3 years) performed a virtual reality steering task. The virtual environment depicted movement at 19 m/s along a winding road. Participants were tasked with maintaining a central lane position while experiencing eight repetitions of each combination of optic flow density (low, medium, high), turn radius (35, 55, 75 m), and turn direction (left, right), presented in random order. All participants cut corners, but did so less on turns with rotational flow from distant landmarks and without proximal optic flow. We found no evidence of an interaction between age and optic flow density, although older adults cut corners more on all turns. An exploratory gaze analysis revealed no age-related differences in gaze behavior. The lack of age-related differences in steering or gaze behavior as a function of optic flow implies that processing of naturalistic optic flow stimuli when steering may be preserved with age.

CNSC-07. OLIGODENDROGLIAL IMPAIRMENT IN WHITE MATTER TRACTS FOLLOWING NEUROFIBROMATOSIS TYPE 1 (NF1) GERMLINE MUTATION OR CARBOPLATIN TREATMENT

Abstract Neurofibromatosis type 1 (NF1) is a cancer predisposition syndrome due to mutations in the NF1 gene. The disease affects 1 in 2500-3000 people worldwide and patients are predisposed to neoplasms such as optic pathway glioma, plexiform neurofibroma. In addition, NF1 patients often experience neurological issues such as learning difficulties. Unfortunately, there is no cure for NF1 yet. Chemotherapy (e.g., carboplatin) remains the first-line treatment for NF1-associated low-grade glioma; while effective in reducing tumor burden, it does not reliably restore neuronal function. In this study, we sought to determine how chemotherapy and Nf1 germline mutations influence neurological function, using genetically engineered mice of NF1. Nf1-heterozygous mice received carboplatin (60 mg/kg/day) or vehicle every other day for one week. Their optic nerves were collected and processed for immunofluorescence and transmission electron microscopy (EM). We found that carboplatin treatment reduces the density of oligodendrocytes in Nf1-heterozygous mice and impairs myelination. Moreover, a similar effect of carboplatin was observed in wild-type mice, suggesting that carboplatin impairs oligodendroglia independent of the NF1 status and the effect of carboplatin should also be evaluated in the non-NF1 context. In another set of experiments, we sought to understand how germline Nf1 mutations influences oligodendroglia. Whereas we did not observe a difference in optic nerve oligodendrocyte density in mice with an engineered mutation targeting the GTPase-activating protein-related domain (GRD) domain of the Nf1 gene, a reduction of oligodendrocyte density was observed in mice harboring a patient-derived mutation (R1809C), which localizes outside of the GRD. A similar effect was observed in the corpus callosum of Nf1+/R1809C mice together with myelin impairment, suggesting a RAS-independent mechanism of Nf1 regulation of oligodendrocytes. Together, these findings indicate that both Nf1 germline mutations and chemotherapy could contribute to oligodendrocyte and myelin deficits in white matter tracts.

Retinal vasculature changes in patients with internal carotid artery stenosis.

To evaluate the retinal vasculature in patient with internal carotid artery (ICA) stenosis and to highlight association between ICA stenosis severity and retinal vasculature changes. Seventy-five subjects were included in this prospective study. Twenty-five healthy subjects were included in the Group 1, 25 subjects with 1-49% ICA stenosis were included in the Group 2, and 25 subjects with 50-69% ICA stenosis were included in the Group 3. Visual acuity, intraocular pressure (IOP), and anterior and posterior segment examinations were performed. Macular superficial and deep capillary density, optic nerve head capillary density, and choroidal thickness data were measured using optic coherence tomography angiography. There was a statistically significant difference between the three groups regarding superficial vascular density, deep vascular density, vascular density of radial peripapillary capillary and choroid thickness (p < 0.05 for all). Mean parafoveal and perifoveal area vascular density of the superficial capillary plexus was significantly lower in the Group 3 than Group 1 (p < 0.05 for all). Mean whole area vascular density of the deep capillary plexus was significantly lower in Group 3 than both groups (p < 0.05 for all). Mean parafoveal area vascular density of the deep capillary plexus was significantly lower in the Group 3 than Group 1 (p < 0.05). Mean subfoveal choroid thickness in group 3 was significantly lower in the Group 3 than both groups (p < 0.05 for all). Compared to healthy controls, patients with moderate ICA stenosis revealed decreased density of superficial, deep and radial peripapillary capillary vasculature and subfoveal choroidal thickness.

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

BackgroundThis 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.MethodsA 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.ResultsThe 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.ConclusionThere 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.

Dynamics of Nakaseomyces glabratus biofilm formation

Formation of biofilms of microorganisms, including those of Nakaseomyces glabratus, is responsible for the development of local and systemic pathologies in humans and animals. The system of gene expression coordination (quorum sensing) in the representation of signaling molecules allows regulation of the amount and composition of biofilm populations thus expanding the adaptive capacity of microorganisms. In the presence of gingivitis and odontolithiasis clinical signs in dogs, excessive growth of gram-positive yeast microorganisms is a differential sign of the decreased resistance of the digestive system mucous membranes to colonization. Examination of the densitometric and morphometric parameters revealed general patterns of biofilm formation, regardless of the source of Nakaseomyces glabratus isolates. Depending on the time of cultivation of the microorganisms, a gradual increase in the optic density absolute values was established. Intercellular communications were achieved by coaggregation of the heteromorphic structures, which formed clusters with rounded liquid-containing formations detected among them. The population immobilization of the architectonics of the mature three-dimensional biofilm, as consistent with cultivation conditions, was accompanied by the differentiation of numerous cells of different sizes and shapes depending on the stage of the cell cycle. Results of the examination of the general patterns of the heterogeneous micromycete population development are promising for expanding the boundaries of knowledge of the adaptation mechanisms of ubiquitous microorganisms to long-term in vivo and in vitro persistence. Methods for studying morphometric and densitometric indicators avoiding interfering into the natural biofilm architectonics are recommended to optimize the long-term and retrospective mycological studies, as well as to develop effective mycosis treatment and prevention regimens.

OCT angiographic evaluation of changes in macula and optic nerve head vessel density after a water drinking test in glaucomatous and healthy eyes.

To evaluate the effects of a water drinking test (WDT) on the intraocular pressure (IOP) and vascular density of the optic nerve head and macula in healthy individuals and those with primary open glaucoma using optical coherence tomography angiography. In this prospective comparative study, 30 healthy patients and 44 POAG subjects were divided into two groups. The study's outcome measures were the IOP and vessel density of the optic nerve and macular area. After ingesting 1000ml of water in 5min, the effect of the WDT on the IOP and the vascular density of the macular area and optic nerve head were measured at baseline and then 20, 40, and 60min later at intervals of 20min. The initial IOP in the healthy and glaucomatous eye groups was comparable (15.94 ± 2.6 and 16.87 ± 4.21mmHg, respectively, P = 0.506). The IOP of both groups peaked at 40' measurements. POAG eyes had significantly higher IOP elevation (4.34 ± 0.30 vs. 2.24 ± 0.30mmHg, P < 0.001). The glaucomatous eyes had lower radial peripapillary capillary (RPC) and whole macular superficial capillary plexus (SCP) densities at baseline (48.55 ± 5.99 vs. 51.33 ± 3.75) and (48.92 ± 3.41 vs. 45.29 ± 5.29), respectively (P < 0.001). After the WDT, the change in vessel density between groups in the RPC, whole superficial, and deep capillary plexuses was insignificant (SCP and DCP of 0.66 and 0.70, respectively, P = 0.16). The WDT caused a significant IOP jump in both glaucomatous and healthy eyes, but generally, the alterations in the glaucomatous eyes were more pronounced. The changes in vascular density in the macula and optic nerve head were similar between the groups.

Impact of dexmedetomidine as an adjuvant to peribulbar anesthesia on the retinal vasculature in glaucoma patients: an optical coherence tomography angiography study

Objectives To assess Dexmedetomidine’s effect as an adjuvant to peribulbar anesthesia on the retinal vasculature in patients with glaucoma undergoing cataract extraction surgery via optical coherence tomography angiography (OCT-A). Participants Thirty-nine glaucoma participants planned for phacoemulsification were allocated into two groups. A 10 ml mixture of peribulbar anesthesia was administered to group I. This anesthetic mixture consisted of 4.5 ml of lidocaine 2% mixed with 4.5 ml of bupivacaine 0.5%,1 ml of dexmedetomidine (50 µg), and 150 IU hyaluronidase. Group II was administered a peribulbar anesthetic mixture consisting of 4.5 ml of lidocaine 2% combined with 4.5 ml of bupivacaine 0.5%,150 IU of hyaluronidase, and 1 ml of normal saline, totaling 10 ml. Optical coherence tomography angiography was used 10 mi before and 10 min after injection to scan optic disc total vessel density, foveal superficial deep capillary plexuses (DCP) density, radial peripapillary capillary network density, and total vessel density plus foveal avascular zone (FAZ) diameter. We also checked the intraocular pressure (IOP) before and 10 min after the anesthetic injection. Results After the administration of the peribulbar anesthetic, group II demonstrated a notably higher significance in the DCP fovea median percent change (–43.7%) compared with group I (-2%) (P&lt;0.001). Additionally, group II experienced a considerably greater median percent change in DCP total density (–22.4%) postinjection compared to group I (–0.8%) (P value &lt; 0.001). The postinjection median percent changes in foveal total vessel density and superficial vessel density were −16.2% and −56.8% in group II, and −1% and −2.4% in group I, respectively, with a P value less than 0.001. Moreover, following the injection, the median percentage change in the diameter of the foveal avascular zone was significantly higher in group II (–40.6%) than in group I (–2.3%) (P value &lt; 0.001). Additionally, there was a noteworthy increase in the optic disc’s total vessel density and the median percentage shift in radial peripapillary capillary network density in group II (–13.1 and −13.7%, respectively) compared with group I (–1.2 and −1%, respectively, P value &lt; 0.001). IOP before and after injecting the anesthesia was insignificantly different between the studied groups (P =0.198 and 0.069, respectively). Conclusion The addition of dexmedetomidine to the peribulbar anesthesia demonstrates a protective effect on the retinal microvasculature against the ischemic impact of anesthetic drugs with no significant effect on the IOP. This effect holds significant implications for glaucoma patients.

Effect of pan retinal photocoagulation on Macular and optic nerve capillary density and foveal avascular zone area in patients with diabetic retinopathy An OCT angiography study

Effect of pan retinal photocoagulation on Macular and optic nerve capillary density and foveal avascular zone area in patients with diabetic retinopathy An OCT angiography study

Repeatability, interocular correlation and agreement of optic nerve head vessel density in healthy eyes: a swept-source optical coherence tomographic angiography study.

To assess the repeatability, interocular correlation, and agreement of quantitative swept-source optical coherence tomography angiography (OCTA) optic nerve head (ONH) parameters in healthy subjects. Thirty-three healthy subjects were enrolled. The ONH of both eyes were imaged four times by a swept-source-OCTA using a 3 mm ×3 mm scanning protocol. Images of the radial peripapillary capillary were analyzed by a customized Matlab program, and the vessel density, fractal dimension, and vessel diameter index were measured. The repeatability of the four scans was determined by the intraclass correlation coefficient (ICC). The most well-centered optic disc from the four repeated scans was then selected for the interocular correlation and agreement analysis using the Pearson correlation coefficient, ICC and Bland-Altman plots. All swept-source-OCTA ONH parameters exhibited certain repeatability, with ICC>0.760 and coefficient of variation (CoV)≤7.301%. The obvious interocular correlation was observed for papillary vessel density (ICC=0.857), vessel diameter index (ICC=0.857) and fractal dimension (ICC=0.906), while circumpapillary vessel density exhibited moderate interocular correlation (ICC=0.687). Bland-Altman plots revealed an agreement range of -5.26% to 6.21% for circumpapillary vessel density. OCTA ONH parameters demonstrate good repeatability in healthy subjects. The interocular correlations of papillary vessel density, fractal dimension and vessel diameter index are high, but the correlation for circumpapillary vessel density is moderate.

Can optic disc vessel density help in cases of residual disc elevation after shunt surgery in cases of idiopathic intracranial hypertension?

AimTo detect if we can use the reduction in the optic disc vessel density as an indicator to the reduction in intracranial tension in patients with residual optic disc elevation after shunt surgery as fundus examination in those cases is not conclusive.Patients and method21 patients with papilledema due to idiopathic intracranial hypertension underwent shunt surgery. Full neurological and ophthalmological assessments were done. The optic disc vessel density was measured before and 3 months after surgery. Patients were then divided according to the resolution of papilledema into 2 groups: 1) Residual disc elevation group. 2) Completely resolved disc edema group. CSF pressure was measured via lumber puncture preoperative for all patients and 3 months post-operative only for patients with residual disc edema. A comparison between both groups was done.ResultsThere was a highly statistically significant difference between the two groups as regard the papilledema grade (the residual disc elevation group had a higher grade of papilledema) with P-value=0.000. As regard the difference in the preoperative optic disc vessel density between the two groups, there were statistically significant differences (optic disc vessel density was more in the residual disc elevation group). As regard the postoperative optic disc vessel density, there were non-significant differences between the two groups in whole image, inside disc and peripapillary vessel density (either in macro or microvasculature).ConclusionThe optic disc vessel density decreased with normal postoperative CSF opening pressure in cases with residual disc elevation postoperatively. Thus, in cases of residual optic disc swelling after shunt surgery, we can detect the reduction of intracranial pressure by the reduction in the optic disc vessel density which is a safe non-invasive technique. That may help in cases of residual disc elevation.

Rate of Initial Optic Nerve Head Capillary Density Loss and Risk of Visual Field Progression

Rapid initial optic nerve head capillary density loss may be used to assess the risk of glaucoma visual field progression. To investigate the association between the rate of initial optic nerve head capillary density loss from optical coherence tomography angiography (OCTA) and visual field progression. This was a retrospective study of a longitudinal cohort at a glaucoma referral center. A total of 167 eyes (96 with primary open-angle glaucoma and 71 with glaucoma suspect) of 109 patients were monitored for a mean (SD) of 5.7 (1.4) years from January 2015 to December 2022. Data analysis was undertaken in April 2023. The rates of initial capillary density and average retinal nerve fiber layer loss were calculated from the first 3 optic nerve head OCTA and OCT scans, respectively, during the initial follow-up (mean [SD], 2.0 [1.0] years). Based on the median rate, eyes were categorized into fast and slow progressor groups. The association between initial capillary density change or retinal nerve fiber layer thinning and visual field progression was evaluated using linear-mixed and time-varying Cox models. A total of 167 eyes of 109 patients (mean [SD] age, 69.0 [11.1] years; 56 [51.4%] female and 53 [48.6%] male) were assessed. Eighty-three eyes were slow OCTA progressors, while 84 eyes were fast with mean capillary density loss of -0.45% per year and -1.17% per year, respectively (mean difference, -0.72%/year; 95% CI,-0.84 to -0.60; P < .001). Similarly, 83 eyes were slow OCT progressors, while 84 eyes were fast with mean retinal nerve fiber layer thinning of -0.09 μm per year and -0.60 μm per year, respectively (mean difference, -0.51 μm/year; 95% CI,-0.59 to -0.43; P < .001). The fast OCTA and OCT progressors were associated with more rapid visual field loss (mean difference, -0.18 dB/year; 95% CI,-0.30 to -0.06; P = .004 and -0.17 dB/year; 95% CI,-0.29 to -0.06; P = .002, respectively). Fast OCTA progressing eyes were more likely to have visual field progression (hazard ratio, 1.96; 95% CI, 1.04-3.69; P = .04). Seventeen of 52 eyes (32.7%; 95% CI, 32.5-32.8) with fast OCTA and OCT progression developed subsequent visual field likely progression. Rapid initial optic nerve head capillary density loss from OCTA was associated with a faster rate of visual field progression and a doubling of the risk of developing event progression in this study. These findings may support clinical use of OCTA and OCT optic nerve head measurements for risk assessment of glaucoma progression.

Reduction of Optic Disc Microvasculature and Retinal Nerve Fiber Layer Thinning in Patients With Glaucoma

PurposeTo assess the relationship between the change of optic disc vessel density (ODVD) and retinal nerve fiber layer (RNFL) thinning in primary open-angle glaucoma (POAG) patients. DesignRetrospective case series. MethodsFor 105 POAG patients, ≥ 5 consecutive optical coherence tomography (OCT) and OCT angiography (OCTA) images were obtained during ≥ 2 years of follow-up.Based on enface OCTA imaging, ODVD was calculated as the ratio of pixels occupied by vessels below the internal limiting membrane within the temporal area of the optic cup, and ODVD reduction was determined when there was a statistically significant negative slope (P < 0.05) for any of the global, superior, or inferior sectors. The association between the rates of ODVD change and RNFL thinning was assessed by multivariable longitudinal linear mixed-effects model vs. time. ResultsDuring 2.9 ± 0.3 years of follow-up on the 105 participants with visual field mean deviation at baseline of 5.7 ± 4.8 dB, 46 (43.8%) showed ODVD reduction. Faster global RNFL thinning was associated with the smaller Bruch's membrane opening area (ß = 0.381; 95% confidence interval (CI), 0.120 to 0.646; P = 0.006), optic disc hemorrhage (ß = -0.567; 95% CI, -0.909 to -0.228; P = 0.002) and faster rate of global ODVD change (ß = -0.090; 95% CI, -0.139 to -0.042; P = 0.001). ConclusionsReduction of optic disc microvasculature was associated with rapid RNFL thinning in POAG. This suggests a role for deep ONH circulation in the glaucoma pathogenesis.

Smoking Intensity is Associated With Progressive Optic Nerve Head Vessel Density Loss in Glaucoma.

A lifetime history of greater smoking consumption was associated with faster vessel density loss over time. Smoking intensity should be considered when assessing the risk of glaucoma progression, as well as its management. To investigate the relationship of smoking and smoking intensity, with the rate of optic nerve head (ONH) whole image capillary density (wiCD) loss in primary open angle glaucoma (POAG) and glaucoma suspect patients. In this longitudinal study, patients with POAG who had at least 2 years of follow-up and optical coherence tomography angiography (OCTA) performed at a minimum of 4 visits were selected for study. The smoking intensity was calculated as the pack-year at the baseline OCTA. Univariable and multivariable linear mixed models were used to determine the effect of each parameter on the rates of wiCD loss over time. Nonlinear least-squares estimation with piecewise regression model was used to investigate the cutoff point for the relationship between wiCD loss and smoking intensity. One hundred sixty-four eyes (69 glaucoma suspect and 95 POAG) of 110 patients were included with a mean (95% CI) follow-up of 4.0 (3.9 to 4.1) years. Of the 110 patients, 50 (45.5%) had a reported history of smoking. Greater smoking intensity was associated with faster wiCD loss [-0.11 (-0.23 to 0.00)] %/year per 10 pack-year higher; P =0.048) after adjusting for covariates. The wiCD thinning became significantly faster when smoking intensity was greater than 22.2 pack-years. Smoking had no effect on the rate of wiCD thinning in patients who smoked <22.2 pack-years during their lifetime. A history of greater smoking consumption was associated with faster vessel density loss, suggesting smoking intensity as a potential risk factor for glaucoma.

Comparison of macular and optic disc vessel density in thyroid orbitopathy: a comparative octa study.

To determine the microvascular and structural changes in the peripapillary and macular areas observed in patients with active thyroid orbitopathy(TO) before and after steroid treatment and compare with inactive TO and the control group by optical coherence tomography angiography (OCTA). This cross-sectional study included 34 eyes of 17 active TO patients, 108 eyes of 54 inactive TO patients, and 60 eyes of 30 healthy controls. Central macular thickness (CMT), ganglion cell layer-inner plexiform layer (GCL-IPL) thickness, central choroidal thickness (CCT), retinal nerve fiber layer (RNFL) thickness, choroidal thickness in the peripapillary region, superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris vessel densities were determined by OCTA in before and after 12-week steroid treatment of active TO cases, inactive TO and control groups. Between the three groups in macula OCTA, a statistically significant difference was observed in the inferior and nasal quadrants in SCP (all p = 0.01) and only in the temporal quadrant choriocapillaris (p = 0.005). In peripapillary OCTA, a statistically significant difference was found only in the central choriocapillaris (p = 0.03). In the comparison of the active group before and after treatment, there was a statistically significant decrease in CMT and CCT; a statistically significant increase was observed in GCL-IPL (all p < 0.01). There was a statistically significant decrease in SCP and DCP only in the central (all p < 0.01). There was a statistically significant increase was found in the lower quadrant macular SCP vessel density and mean macular DCP in post-treatment measurements (p = 0.01 and p = 0.03, respectively). Peripapillary SCP and DCP vessel density was increased after treatment (p < 0.01). Active TO group had lower vessel density than inactive group and after treatment, vessel density was increased. Non-invasive quantitative analysis of retinal and optic disc perfusion using OCTA could be useful in early treatment before complications occur and monitoring patients with TO.

Optical coherence tomography angiography value for detection of early retinal microvascular changes in systemic hypertension

Purpose The aim of this study was to assess the macula and optic disc vessel density (VD) and perfusion and the anatomical alterations at the fovea and optic nerve in chronic treated hypertension (HTN) patients who exhibited no signs of hypertensive retinopathy using optical coherence tomography angiography (OCTA). Patients and methods This is a prospective case–control study that included 37 participants. They were subdivided into two groups: the hypertensive group that included 22 patients (mean age=51.9±5.9 years), with no clinically evident signs of hypertensive retinopathy, and the control group that included 15 individuals (mean age=48.8±3.7 years) with no known history of HTN or other chronic systemic diseases. OCTA scans covering a 6.0×6.0 mm area for the macula and a 4.5×4.5 mm region for the optic nerve head were performed to evaluate the VD, the foveal avascular zone area, macular thickness, and retinal nerve fiber layer (RNFL) thickness. The correlation of the VD measurements with the RNFL thickness was evaluated. Results The hypertensive patients exhibited a significantly lower overall mean macular VD (45.8±6.0) compared to the control group (48.5±2.9, P=0.017). In addition, they exhibited a significantly lower superficial VD in the superior hemifield (46.4±5.3 and 48.6±2.9, respectively, P=0.030). On the other hand, the deep vascular density in the superior hemifield showed no significant difference between the two groups. In addition, the hypertensive patients were found to have a significantly lower average RNFL thickness (103.2±17.8 μm) compared to the control group (117.1±14.1 μm, P=0.001), with specific statistically significant reductions in the superior (P=0.002) and inferior (P=0.004) sectors. Although the central ganglion cell-inner plexiform layer thickness did not reach statistically significant difference between the two groups (HTN: 50.7±12.0 μm vs. control: 55.7±8.8 μm, P=0.055), the hypertensive group exhibited statistically significant reductions in the ganglion cell-inner plexiform layer thickness in the superior (P&lt;0.001), inferior (P=0.002), nasal (P=0.003), and temporal (P=0.001) sectors compared to the controls. There was no statistically significant difference in the size of the foveal avascular zone between the two groups. Conclusion OCTA revealed subclinical alterations in the retinal microvasculature parameters among the hypertensive patients without clinical signs of hypertensive retinopathy, in comparison to normotensive individuals.

Evaluation of glaucomatous macular and optic nerve vascular damage by optical coherence tomography angiography

Purpose The aim of this study was to compare the macular and optic nerve head vessel perfusion density in mild primary open-angle glaucoma (POAG) and moderate–severe POAG patients to normal eyes as a control cohort. Patients and methods This is a retrospective comparative case–control study that included 80 eyes of 46 participants. The study included 60 eyes of 36 POAG patients and 20 eyes of 10 healthy participants (control group). The patients underwent 3.0×3.0 mm optical coherence tomography angiography (OCTA) scans centered on the macula and 4.5×4.5 mm scans on the optic disc. Results The OCTA scans of the glaucomatous eyes revealed a reduction in microvasculature in the peripapillary area, which was absent in the control cohort. The whole disc vessel density (VD) was significantly less in the glaucomatous eyes (mean=38.02±8.74) compared to the control cohort (mean=50.41±2.58, P&lt;0.001). The severity of glaucoma was linked to a decrease in macular VD percentage, with a mean superficial VD of 36.09±5.67 in the glaucoma cohorts and 46.64±5.53 in the control cohort (P&lt;0.001), which was more pronounced than in the deep layer (P&lt;0.008). There was no statistically significant difference in the foveal avascular zone size between the control and glaucoma cohorts at any stage (P=0.999). Conclusion The OCTA vascular density accurately distinguished the glaucoma from healthy eyes, with superior performance in the peripapillary region. The foveal avascular zone size did not indicate glaucoma severity. The OCTA noninvasive assessment of the capillary networks showed a potential for managing the glaucoma patients by characterizing the retinal vascular changes.

Development of an indirect ELISA for the serodiagnosis of canine infection by Onchocercalupi

Onchocercalupi is a zoonotic filarioid parasite of dogs and cats with widespread distribution. A specific non-invasive diagnostic assay for the detection of O.lupi infections remains unavailable. This study aimed to assess the accuracy, specificity, and sensitivity of an ELISA test designed using nine peptides from two O.lupi proteins. Sera (n = 54) collected from O.lupi infected dogs from endemic areas (Portugal and USA), alongside sera from dogs positive for Dirofilariaimmitis, D.repens, Cercopithifilariabainae, and Acanthocheilonemareconditum (n = 53) from a non-endemic area for O.lupi, as well as from helminth-free dogs (n = 60), were tested. The checkerboard titration method was applied for the optimization of peptide concentrations and conjugate anti-dog dilutions. Sensitivity, specificity, and optimal cut-off values were calculated using ROC curve analysis. All peptides reacted against sera of O.lupi, with no correlation between optic density (OD) values and microfilariae (mfs) loads. Sensitivity and specificity values ranging from 85.45 to 100%, and 88.89% to 100%, respectively, were recorded for all peptides examined, with 100% specificity and sensitivity observed for peptides 40_3, 40_5, 130_3, 120_3 and 40_1, 130_5, respectively. The maximum cut-off value was observed for peptides 40_5 (0.765) and 40_3 (0.708). Testing of sera from dogs positive for other filarioids resulted in lower OD values (up to 1.565) for peptides 40_3 and 40_5 when compared with O.lupi (up to 2.929). The availability of this assay will be of value in epidemiological studies of canine O.lupi infection in both endemic and non-endemic areas, and in assessing the risk for zoonotic transmission.

Unveiling Tetraselmis subcordiformis lipidome dynamics during large-scale cultivation in open raceway pond

A local microalgal strain of Tetraselmis subcordiformis was cultivated at large-scale using open raceway pond. The temporal influence on the growth and lipidomic profile of the strain was investigated using optic density (OD) measurement and ultra-high pressure liquid chromatography. Results showed that triglycerides represented 57% of the total lipids on day 11 (exponential phase) and stayed consistently high until stationary phase, without affecting the biomass quantity. Moreover, a high expression of monounsaturated fatty acids and polyunsaturated fatty acids such as ω-3 eicosapentaenoic acid (20:5), docosahexaenoic acid (22:6), palmitic (16:0) and palmitoleic acid (16:1) was observed by stationary phase. Carotenoid analysis also revealed the increase in lutein (65.2%) and β-carotene (71.4%) from day 6 to day 15. Our study showed that T. subcordiformis contained the highest amounts of valuable lipids, fatty acids and pigments in the stationary phase, which started on day 15 of culture.

Antifungal Activity of a Wireless Electroceutical Dressing

Background:Fusarium and Mucor are two filamentous fungus strains that can cause infections in humans. Fusarium is known for causing corneal infections. Patients who have diabetes mellitus or are immunocompromised are at a higher risk of mucormycosis. Wireless electroceutical dressing (WED) contains embedded silver and zinc nanoparticles in a geometric pattern. Both zinc and silver have been known to be antimicrobial; yet the combination results in a weak electric field when exposed to an electrolyte-containing solution. WED has been found to have antifungal effects against Candida albicans and Aspergillus fumigatus.&#x0D; Methods:We investigated the antifungal effect of WED against Fusarium and Mucor growth and survival through daily radial growth and optic density readings.&#x0D; Results:Our results show that the WED weakly inhibits radial growth of Fusarium strains and strongly inhibits radial growth of Mucor strains, with greater inhibition near physiologic temperatures. Although zinc and silver-only fabric inhibited the radial growth of Mucor, no growth occurred on WED (Ag-Zn) plates for Mucor strains. Optic density readings had mixed results; Ag-Zn liquid cultures had reduced absorbance than control cultures for both strains. Zone of inhibition studies of Fusarium showed no growth on Ag-Zn fabrics with full coverage on all other control and metal containing plates. WED had a greater effect on reducing Mucor growth than Fusarium.&#x0D; Conclusions:WED utilizes a weak electrical field created by silver and zinc nanoparticles to create an antifungal effect. This leads to strong inhibition of Mucor, Candida, and Aspergillus growth and weak inhibition of Fusarium growth. Further studies are needed to determine the specific effect of WED on fungal viability, the mechanism, and in vivo efficacy. This work could increase patient treatment options for fungal wound infections.

Meta-Analysis: Characteristics of Retinal Vasculature in Obstructive Sleep Apnea Syndrome Humans.

The objective of this study is to determine optic nerve head vascular changes in patients with obstructive sleep apnea-hypopnea syndrome (OSAS) by utilizing an optical coherence tomography angiography (OCTA) device. A detailed studies search was screened in the PubMed, Embase, the Cochrane Library, and Web of Science databases from inception to August 2023. We reviewed and examined optic nerve head vascular density in eyes with OSAS and controls. The mean difference and 95% confidence interval were calculated to evaluate continuous outcomes. Review Manager version 5.4.1 was applied for analysing pooled data. Six eligible studies were included in our meta-analysis. The radial peripapillary capillary (RPC) whole enface vessel density (VD) measured by OCTA in the mild-to-moderate and severe OSAS groups was significantly lower compared to the controls (MD = -0.96, P = 0.03; MD = -1.42, P = 0.001, respectively). For RPC peripapillary VD, eyes in mild-to-moderate OSAS showed a trending decrease compared to the controls (MD = -1.71, P = 0.05), and there was a remarkable difference between eyes with severe OSAS and the controls (MD = -3.08, P = 0.004). In addition, the RPC inside disc VD was decreased in severe OSAS eyes than in the controls (MD = -0.07, P = 0.94). Our results revealed that peripapillary vascular density was attenuated in patients with OSAS. Moreover, on the basis of these findings, we suggest that optic nerve head vascular density measured by OCTA may be used as a potential tool to diagnose and monitor the severity of patients with OSAS.