Peak Systolic Velocity Of Central Retinal Artery Research Articles

Prediction of poor prognosis using the peak systolic velocity and early diastolic velocity of the central retinal artery in patients with post‐cardiac arrest syndrome

AbstractIntroductionMonitoring intracranial pressure (ICP) in patients with post‐cardiac arrest syndrome (PCAS) is crucial for effective management and prognosis assessment. However, continuous ICP monitoring is rarely practiced. Increased ICP is often associated with the impairment of brain autoregulation. This study investigated whether central retinal artery (CRA) flow velocity, autoregulation status according to mean arterial pressure (MAP), and the optic nerve sheath diameter (ONSD)/eyeball transverse diameter (ETD) ratio could predict poor prognosis related to increased ICP in PCAS patients.MethodsIn this multicenter prospective observational study, transocular ultrasonography of the optic nerve sheath was performed on 38 PCAS patients treated with targeted temperature management from December 2021 to November 2022. CRA peak systolic velocity (PSV), early diastolic velocity (eDV), MAP, CRA‐PSV changes following MAP changes (autoregulation), and ONSD/ETD ratio were measured repeatedly from days 0 to 4 post‐admission.ResultsUnivariable analysis indicated that CRA‐PSV, nonpositive or flat CRA‐eDV, and disrupted autoregulation correlated with a poor prognosis (Cerebral Performance Category 4 or 5). In multivariable analysis, nonpositive CRA‐eDV or disrupted autoregulation was the most significant predictor of poor prognosis (odds ratio, 40.576; p = 0.002), with an area under the curve of 0.774. The ONSD/ETD ratio did not show a significant correlation.ConclusionsNonpositive CRA‐eDV, CRA‐PSV and disrupted autoregulation can predict poor prognosis in PCAS patients. Transocular Doppler ultrasonography of the CRA and autoregulation assessment may aid in ICP monitoring and management in PCAS patients.

Sonographic Evaluation of Doppler Parameters Within the Central Retinal Artery: A Cohort Study

Objective: The objective of this study was to assess the Doppler parameters, associated within the central retinal artery (CRA), based on a cohort of Nigerian participants. Materials and Methods: A total of 66 participants were recruited and consented at a medical clinic in Calabar, Nigeria, and presented from August 2019 to December 2023. The diagnostic data points recorded on this cohort were their fasting blood glucose (FBG) (mmol/L), CRA peak systolic velocity (PSV), CRA end-diastolic velocity (EDV), the resistive index (RI), and pulsatility index (PI). The data analysis was completed to provide descriptive information, as well as correlations. The statistical significance was set at P < .05. Results: In this cohort, the women demonstrated a higher PSV and EDV, based on the vascular flow within the right CRA (Rt. PSV [20.8 ± 6.0 SD] and Rt. EDV [5.8 ±2.1 SD]), as well as the left CRA (Lt. PSV [20. 6 ± 4.4 SD] and Lt. EDV [6.2 ± 2.0 SD]). This was compared to the men’s data taken on the vascular flow within the right CRA (Rt. PSV [19.6 ± 5.3 SD] and Rt. EDV [5.2 ± 1.8 SD]), as well as their left CRA (Lt. PSV [19.2± 4.7 SD] and Lt. EDV [5.3 ± 1.3 SD]). The participants’ FBG levels did not correlate with their respective Doppler parameters. The Doppler parameters, based on the flow within the right CRA, showed moderate to weak positive correlations compared with the left CRA. The PSV recorded in the right CRA was varied across the specific participant age groups of 17 to 25 and 26 to 34 years. Conclusion: Potential sex and age-related variations in the Doppler velocities, recorded within the CRA, were specific to this cohort, and the sample size may have compromised the overall study’s statistical power. A replication of this research is needed, and data from a larger cohort of participants are needed.

Orbital blood vessels changes on color duplex imaging in diabetics with and without diabetic retinopathy

To compare changes in ophthalmic artery (OA) and its branches in diabetics with and without diabetic retinopathy (DR) using color duplex imaging (CDI), and to correlate these changes with the disease variables. 60 eyes of 60 diabetic patients were enrolled, divided into 3 groups: without DR (Group A), with Non-Proliferative DR (Group B) and with Proliferative DR (PDR) (Group C). Laboratory testing including HbA1c was done. Patients underwent CDI, by which OA, Central Retinal Artery (CRA) and Ciliary Arteries were identified; for each of them we measured Peak systolic velocity (PSV), End Diastolic velocity (EDV) and Resistivity Index (RI). Results were compared to clinical, laboratory and fundus examination. OA EDV was significantly lower and OA RI was found to be significantly higher in Group C (p = 0.027 and 0.025 respectively). CRA PSV and EDV were significantly lower in Group C (p = 0.017 and 0.001 respectively). PCA RI was significantly higher in Group C (p = 0.008). HbA1c was negatively correlated with CRA PSV (p = 0.041), also it was negatively correlated with CRA EDV (p = 0.0001), as well as with PCA EDV (p = 0.002). There was direct significant correlation between HbA1c and PCA RI (p = 0.012). Duration since diagnosis was negatively correlated with CRA EDV (p = 0.004). Multivariate linear regression showed that DR is an independent predictor for low OA EDV, high OA RI, low CRA EDV and high PCA RI. DR is an independent risk factor for orbital and ocular vessels flow alteration, thus can be used as a prognostic tool in diabetic patients. CDI can be reliably used in diabetics to predict early changes or progression of DR.

The impact of obesity on ocular hemodynamics and choroidal thickness.

Obesity affects microvascular structures. The effect of obesity on the ocular vascular system can be evaluated by changes in the choroidal thickness (CT) and retrobulbar blood flow (RBF). To evaluate the CT and RBF parameters in obese patients with various body mass index (BMI) values and compare these parameters with normal weight, healthy subjects. A prospective study. The study included 102 eyes of 102 female patients. Patients were divided into three groups according to BMI as group 1 with a BMI of 18.5-24.99 (n = 32), normal weight group; group 2 with a BMI of 30-34.99 (n = 35), as obese class I; and group 3 with a BMI of 35-39.99 (n = 35), as obese class II. The peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index, and pulsatility index values of the central retinal artery (CRA) and ophthalmic artery (OA) were evaluated with color Doppler ultrasonography. CT was measured at the subfoveal area and at 500-µm intervals nasal and temporal to the fovea up to a distance of 1500 µm by using the enhanced depth imaging technique of optical coherence tomography. Intraocular pressure (IOP) was measured with a Goldmann applanation tonometry. There was a significant difference in IOP values within the groups with the highest values in group 3 (17.6 ± 2.1 mmHg) and the lowest in group 1 (12.4 ± 1.7 mmHg). The CT in groups 2 and 3 was found to be statistically significantly lower than that in group 1 at all measurement points (p < 0.001). There was a statistically significant negative correlation between CT at all measurement points and BMI (p < 0.001). The mean CRA PSV, EDV, and OA EDV values were statistically significantly lower in each obese group than those values in group 1 (p < 0.001). The OA PSV values were significantly lower in group 3 (36.5 ± 5.9 cm/s) than those in group 2 (43.8 ± 4 cm/s) and group 1 (44.6 ± 5.2 cm/s) (p < 0.001). Also, significant associations were found between BMI and CRA PSV, CRA EDV, and OA PSV values (p < 0.001). Obesity may predispose to eye pathologies by changing the ocular vascular circulation.

Analysis of the Optic Nerve Head Microcirculation Using Optical Coherence Tomography Angiography and the Upstream Macrocirculation Using Color Doppler Imaging in Low-Tension and High-Tension Glaucoma Patients

Introduction: The aim of the study was to analyze the optic nerve head (ONH) microcirculation using optical coherence tomography angiography (OCT-A) and the upstream macrocirculation using color Doppler imaging (CDI) in low-tension and high-tension glaucoma (LTG and HTG, respectively). Methods: This cross-sectional study included 67 eyes of 67 HTG patients, 55 eyes of 55 LTG patients, and 42 eyes of 42 healthy controls. We recorded the complete ophthalmological examination, visual fields, retinal nerve fiber layer (RNFL) thickness, ONH vessel density (VD) measured using OCT-A, peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) measured using CDI. SPSS software was used for data analysis. Data are presented as mean ± standard deviation or median (interquartile range) and compared using t test or Mann-Whitney U test, as appropriate. Pearson χ2 test or Fisher’s exact test was used for comparisons, as appropriate. Pearson correlation analysis was used to evaluate the correlations between variables. p < 0.05 was considered statistically significant. Results: The ONH VD and RNFL thickness were considerably lower in glaucomatous eyes than in healthy eyes (both p < 0.001). Compared with the HTG group, the LTG group had lower VD in the peripapillary region (p = 0.027). Compared with the healthy group, the HTG group had lower PSV (p = 0.029 and = 0.023, respectively), lower EDV (p = 0.023 and <0.001, respectively), and higher RI (p = 0.019 and = 0.006, respectively) of the internal carotid artery (ICA) and central retinal artery (CRA). The LTG group had lower PSV (p = 0.015 and <0.001, respectively) and EDV (p = 0.047 and = 0.001, respectively) of the ophthalmic artery (OA) and CRA. The LTG group had lower PSV of CRA than the HTG group (p = 0.034). In glaucomatous eyes, peripapillary VD had a significant association with the mean defect (p < 0.001) and RNFL thickness (p < 0.001), but not with the other CDI indices (all p > 0.05). Conclusion: The ONH microcirculation and upstream macrocirculation of the large arteries exhibited differences in the blood flow characteristics between the LTG and HTG groups. These differences may improve our understanding of glaucoma. There was no correlation between the characteristics of the ONH microcirculation and the upstream macrocirculation of large vessels in the LTG and HTG groups.

Retrobulbar ocular blood flow and choroidal vascular changes in patients recovering from COVID-19 infection

BackgroundTo evaluate the effects of COVID-19 infection on the ocular vascular structure including choroidal thickness and retrobulbar blood flow values in comparison with healthy subjects. MethodsNinety eyes of 90 patients were included in this study. Participants were divided into Group 1 (n = 30) with mild COVID-19 infection, Group 2 (n = 31) with moderate disease, and Group 3 with age- and sex-matched healthy subjects (n = 29). Choroidal thickness was measured at the subfoveal area and at 500-µm intervals nasal and temporal to the fovea up to a distance of 1500 µm, using the enhanced depth imaging (EDI) technique of spectral coherence tomography (SD-OCT). The peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI), and pulsatility index (PI) values of the central retinal artery (CRA) and ophthalmic artery (OA) were evaluated with color Doppler ultrasonography (CDU). ResultsThe choroidal thickness was significantly thinner in Group 1 and Group 2 than in Group 3 at all measurement points (p <0.001). This difference was not present between Group 1 and Group 2 who had COVID-19 disease of different severity (p>0.05).Among the retrobulbar blood flow parameters, OA PSV value was significantly lower in Group 1 and Group 2 compared to Group 3 (p = 0.025, p = 0.016, respectively). However, the CRA PSV and EDV and OA EDV values, and the CRA and OA PI and RI values were not statistically different between the groups (p> 0.05). ConclusionCOVID-19 infection may predispose patients to ocular vascular pathologies by affecting both choroidal and retrobulbar blood flow.

Effect of calcium dobesilate on retrobulbar blood flow and choroidal thickness in patients with non-proliferative diabetic retinopathy.

Diabetic retinopathy is one of the most common causes of blindness in work-aging adults and develops in one third of diabetic patients. Calcium dobesilate (CaD) treatment have protective effects on blood retinal barrier (BRB) and anti-oxidant as well as anti-inflammatory properties. To assess effects of CaD administration on retrobulbar blood flow and choroidal thickness in patients with diabetic retinopathy. In this quasi-experimental study, diabetic patients with diabetic retinopathy (DR) were recruited from Shahid Motahari and Poostchi ophthalmology clinic affiliated to Shiraz University of Medical Sciences. Patients were treated with CaD, 1 gr per day for seven days. Before and after CaD administration, retrobulbar blood flow and subfoveal choroidal thickness were assessed. Retrobulbar blood flow were evaluated by measuring peak systolic velocity (PSV), end diastolic velocity (EDV) and resistive index (RI) of ophthalmic artery (OA), central retinal artery (CRA) and short ciliary artery (SCA). In this study, 26 DR patients with a mean age of 56.15 ± 8.93years and mean diabetes mellitus duration of 15.04 ± 7.64years were enrolled. Subfoveal choroidal thickness was significantly increased from 316.08 ± 61.69 to 327.81 ± 58.03 after CaD treatment (P value < 0.001). PSV of CRA and EDV of all arteries were significantly increased after CaD administration. In addition, RI of all arteries was significantly reduced after CaD treatment (P < 0.001). CaD treatment may improve the ophthalmic blood flow and increase the subfoveal choroidal thickness in DR patients. These results may be suggestive of protective effects of CaD on endothelium function as well as microvascular circulation.

Comparison of Color Doppler Imaging Criteria for the Ophthalmic Artery and Central Retinal Artery in Infants with Retinopathy of Prematurity with and Without Plus Disease

Background: Color Doppler imaging (CDI) is a non-aggressive and safe technique for the clinical management of retinal diseases. Recently, the number of infants with retinopathy of prematurity (ROP) has increased due to the incidence of premature births. Objectives: This study aimed to compare the CDI criteria for the ophthalmic artery (OA) and central retinal artery (CRA) in ROP infants with and without plus disease. Patients and Methods: In this case-control study, 42 premature infants (21 infants with plus disease and 21 infants without plus disease) underwent CDI. The arterial CDI parameters, including end-diastolic velocity (EDV), pulsatility index (PI), resistance index (RI), and peak systolic velocity (PSV), were measured in these patients. After collecting the data, t-test and chi-square tests were used for data analysis. P &lt; 0.05 was considered to be statistically significant. Results: The mean EDV of CRA in patients with and without plus disease was 4.35 ± 1.00 and 5.27 ± 1.02 cm/sec, respectively (P = 0.005). The mean PSV of CRA in patients with and without plus disease was 15.65 ± 3.35 and 18.39 ± 4.39 cm/sec, respectively (P = 0.029). However, no significant difference was found between the two groups in terms of PSV or EDV of OA (P &gt; 0.05). Also, no significant difference was observed between the two groups considering the RI and PI of CRA and OA (P &gt; 0.05). Conclusion: According to the findings of this study, CDI criteria, such as EDV and PSV of CRA, were significantly lower in infants with plus disease as compared to those without plus disease. Since detecting the early stages of plus disease is a challenge for ophthalmologists, assessment of these criteria can be helpful for differentiation of these two subgroups of patients. However, further studies with a larger sample size are needed to determine the cutoff value.

Intima-media thickness of the common carotid arteries as a marker of retinopathy and nephropathy in sickle cell disease.

PurposeThis study was conducted to test the hypothesis that the carotid intima-media thickness (CIMT) is higher in patients with sickle cell disease (SCD) than in the normal population, and to determine the relationships of the CIMT with central retinal artery (CRA) and renal artery Doppler indices.MethodsForty-four confirmed steady-state SCD patients aged 16 years and above were recruited consecutively. The Doppler velocimetric indices of their right renal artery and both CRAs were obtained. The CIMT was also measured on each side via B-mode ultrasonography. The subjects were categorized by age and sex. Mean and median values for each group were determined. The Spearman correlation test was used to quantify the relationships between CIMT and the Doppler parameters.ResultsThe participants had a median age of 24.50 years (interquartile range, 12.50 to 36.50 years). Twenty-three were men (52.3%) and 21 were women (47.7%). The median CIMT was 0.70 mm (IQR, 0.50 to 0.90 mm). Significant correlations with the CIMT were found for the CRA peak systolic velocity (r=0.312, P=0.003), the renal artery resistivity index (RI) (r=0.284, P=0.007), and the renal artery pulsatility index (PI) (r=0.273, P=0.010). There was no significant relationship between the CIMT and the CRA end-diastolic velocity, CRA RI, or CRA PI.ConclusionCIMT in SCD patients was higher than in the previously reported age groups of the reference populations. In addition, the CIMT was significantly correlated with the CRA peak systolic velocity, the renal artery RI, and the renal artery PI.

Reduced Central Retinal Artery Blood Flow Is Related to Impaired Central Visual Function in Retinitis Pigmentosa Patients

ABSTRACTPurpose: We evaluated the test-retest repeatability of blood flow velocities in the retrobulbar central retinal artery (CRA) and explored whether reduced blood flow is related to the degree of visual function loss in retinitis pigmentosa (RP) patients with wide range of disease severity.Materials and Methods: We measured CRA peak systolic velocity (PSV) and end diastolic velocity (EDV) to calculate mean flow velocity (MFV) in 18 RP patients using color Doppler imaging with spectral flow Doppler (GE Logiq7 ultrasound) twice in each eye at each of two visits within a month. At each of these two visits, we measured ETDRS visual acuity (VA), quick Contrast Sensitivity Function (qCSF), Goldmann visual fields (GVF), 10–2 Humphrey visual fields (HVF), and dark-adaptation at 5° from fixation with the AdaptDx; multifocal electroretinography (mfERG) was obtained at a single visit.Results: Mean coefficients of variation for PSV, EDV and MFV were 16.1–19.2% for within-visit measurements and 20.1–22.4% for between-visit measures. Across patients, greater visual function loss assessed with VA (p = 0.04), extinguished versus measurable amplitude in ring 1 for mfERG (p = 0.001), and cone-only versus rod function with the AdaptDx (p = 0.002) were statistically significantly correlated with reduced MFV in the CRA when included a multilevel multivariate regression model along with the qCSF and HVF results, which all together accounted for 47% of the total variance in MFV. GVF log retinal areas (V4e and III4e; p = 0.30 and p = 0.95, respectively) and measurable far peripheral vision during GVF testing (p = 0.66) were not significantly related to MFV.Conclusions: MFV in the CRA decreased with impaired central vision due to loss of both rod and cone function, had good test-retest repeatability, and may serve as a biomarker outcome to determine the potential physiological basis for improvements in RP clinical trials of therapies with indirect effects on blood flow to the retina.

Multimodality Imaging Assessment of Ocular Ischemic Syndrome.

Objectives To assess the underlying mechanisms of OIS and confirm the haemodynamic and retinal structure changes of early OIS. Methods An observational cross-sectional study was conducted of 60 internal carotid artery (ICA) stenosis patients, and they were divided into OIS and control group. Colour doppler imaging, optical coherence tomography, and fundus fluorescein angiography were performed. Results The middle cerebral artery (MCA) stenosis differs significantly between the two groups. More OIS patients had new collateral patency of posterior communicating artery (PCoA) and retrograde flow via the ophthalmic artery (OA) (p < 0.001). The peak systolic velocity (PSV) in central retinal artery (CRA) and choroidal thickness (CT) was significantly reduced in OIS patients (p = 0.001 and p < 0.001). The arm-retina time (ART) and the retinal arteriovenous passage time (AVP) were prolonged in OIS patients (p < 0.001 and p = 0.001). CT, ART, and PSV of the CRA showed high sensitivity, while ART and ICA stenosis grade showed high specificity for the diagnosis of OIS according to ROC curve. Conclusions Patients who suffered from severe ipsilateral ICA stenosis, new collateral patency of PCoAs, and MCA stenosis may be more susceptible to OIS. The most sensitive sign is PSV of CRA and CT, and the most specific sign is ART.

Surgical Indications of Exploring Optic Canal and Visual Prognostic Factors in Neurosurgical Treatment of Tuberculum Sellae Meningiomas.

Background:Tuberculum sellae meningiomas (TSMs) present a special symptom because of the adherence and compression to the optic nerve, optic artery, and the chiasm. A significant number of patients with TSMs appear visual deficits. This study aimed to investigate the surgical indications of exploring the optic canal and visual prognostic factors in the neurosurgical treatment of TSMs.Methods:Totally 21 patients with TSM, who were operated from September 2007 to August 2011 in the Department of Neurosurgery, Tongren Hospital were enrolled in this study. Results of orbital computed tomography (CT) and magnetic resonance imaging (MRI), visual acuity, Goldmann visual field test, orbital color Doppler flow imaging (CDI) test in these patients were retrospectively analyzed.Results:Visual deficit and optic canal involvement (OCI) were detected in all the 21 patients. Fourteen patients had bone proliferation within the area of the optic canal. After the operation, visual outcomes were improved in 13 patients, unchanged in 7 patients, and deteriorated in 1 patient. All the 21 patients performed orbital CDI test preoperatively, the results showed that if the peak systolic velocity (PSV) of central retinal artery (CRA) value was ≤8 cm/s, the visual outcome would be better.Conclusions:The surgical indications of exploring optic canal in TSM cases included: (1) The neuroimaging evidences of OCI (CT and/or MRI); (2) PSV of CRA in orbital CDI test was ≤8 cm/s; (3) visual acuity was below 0.1; (4) visual field deficit. The PSV of CRA in CDI test could be a prognostic factor for visual outcomes of TSMs.

Ocular blood flow and retinal electrogenesis in retinitis pigmentosa

to investigate correlations between changes in ocular hemodynamics revealed by color Doppler flow mapping (CDFM) and pulsed-wave (PW) Doppler imaging, one the one hand, and electrical activity of the retina, on the other, in patients with early, moderate, and severe retinitis pigmentosa (RP). A total of 20 patients (40 eyes) aged from 16 to 40 years (28.4 ± 8.2 years on average) with retinitis pigmentosa were enrolled. The control group consisted of 20 healthy volunteers of the same age range. All participants underwent full-field electroretinography (ERG), flicker ERG, and macular ERG as well as blood flow assessment in the ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary arteries (SPCA) by means of CDFM and PW-Doppler. Ocular blood flow in CRA and SPCA appeared disturbed in patients with early RP. In cases of moderate and severe RP, the peak systolic velocity of CRA and SPCA blood flow was significantly decreased. Systolic and end diastolic blood flow velocities in CRA and SPCA has been shown to be directly related to full-field ERG a-wave and b-wave amplitudes, correspondingly, but negatively correlated with their implicit times. The revealed decrease in CRA and SPCA blood flow indices proves retinal and choroidal circulation deficit in patients with advanced RP. As shown, moderate blood flow changes are already present in early RP and progress as retinal photoreceptors and bipolar cells become suppressed, which may be useful for RP diagnosis and monitoring.

No Evidence for Retinal Damage Evolving from Reduced Retinal Blood Flow in Carotid Artery Disease.

Introduction. Carotid artery disease (CAD) comprising high-grade internal carotid artery stenosis (CAS) or carotid artery occlusion (CAO) may lead to ipsilateral impaired cerebral blood flow and reduced retinal blood supply. Objective. To examine the influence of chronic CAD on retinal blood flow, retinal morphology, and visual function. Methods. Patients with unilateral CAS ≥ 50% (ECST criteria) or CAO were grouped according to the grade of the stenosis and to the flow direction of the ophthalmic artery (OA). Retinal perfusion was measured by transorbital duplex ultrasound, assessing central retinal artery (CRA) blood flow velocities. In addition, optic nerve and optic nerve sheath diameter were measured. Optical coherence tomography (OCT) was performed to study retinal morphology. Visual function was assessed using high- and low-contrast visual paradigms. Results. Twenty-seven patients were enrolled. Eyes with CAS ≥ 80%/CAO and retrograde OA blood flow showed a significant reduction in CRA peak systolic velocity (no-CAD side: 0.130 ± 0.035 m/s, CAS/CAO side: 0.098 ± 0.028; p = 0.005; n = 12). OCT, optic nerve thicknesses, and visual functional parameters did not show a significant difference. Conclusion. Despite assessable hemodynamic effects, chronic high-grade CAD does not lead to gaugeable morphological or functional changes of the retina.

Short-term effects of intravitreal triamcinolone acetonide injection on ocular blood flow evaluated with color Doppler ultrasonography.

To evaluate the changes in ocular blood flow with color Doppler ultrasonography (CDU) after intravitreal triamcinolone acetonide (IVTA) injection. A total of 46 patients who underwent IVTA (4 mg/0.1 mL) injection for diabetic macular edema (DME) (n=22), central retinal vein occlusion (CRVO) (n=12) and choroidal neovascular membrane (CNVM) (n=12) were included in the study. Peak systolic velocity (PSV), end diastolic velocity (EDV) and resistivity index (RI) were measured from the ophthalmic artery (OA), the central retinal artery (CRA) and the posterior ciliary artery (PCA) of each patient with CDU before, at the end of the first week and at the end of the first month following IVTA injection. In the DME group, PSV of OA at the first of the first month (mean±SD) (37.48±10.87 cm/s) increased compared to pre-injection value (31.39±10.84 cm/s) (P=0.048). There was a statistically significant decrease (P=0.049) in PSV of CRA at the end of the first month (7.97±2.67 cm/s) compared to the pre-injection (9.47±3.37 cm/s). There was not any statistically significant difference on the other parameters in the DME group. Also, there was not any statistically significant difference on the ocular blood flow values in the CRVO and CNVM groups. We observed that 4 mg/0.1 mL IVTA increased PSV of OA and decreased PSV of CRA in DME patients and did not have any effect on ocular blood flow values of CRVO and CNVM patients.

Color Doppler Imaging Analysis of Retrobulbar Blood Flow Velocities in Diabetic Patients Without or With Retinopathy: A Meta-analysis.

To analyze hemodynamic changes in retrobulbar blood vessels using color Doppler imaging in diabetic patients without or with retinopathy. Pertinent publications were retrieved from 3 databases. Changes in peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) of the ophthalmic artery, central retinal artery, and short posterior ciliary artery of diabetic eyes without or with retinopathy and healthy controls were evaluated by color Doppler imaging. Comparisons were conducted in 3 groups: group 1, no retinopathy versus control; group 2, retinopathy versus control; and group 3, no retinopathy versus retinopathy. In group 1, eyes without retinopathy had a significant increase in ophthalmic artery PSV (P = .002), with no heterogeneity (Pheterogeneity = 0.09; inconsistency index [I(2)] = 46%); however, significant reductions in central renal artery PSV and EDV were shown (P = .002; P = .007, respectively), with significant heterogeneity (Pheterogeneity < .00001; I(2) = 85%; Pheterogeneity = .008, I(2) = 68%). A significant increase in ophthalmic artery RI (P = .02) was found in eyes without retinopathy, with heterogeneity (Pheterogeneity = .0009; I(2) = 74%). In group 2, central retinal artery PSV and EDV in eyes with retinopathy decreased significantly (P < 0.00001). Similar results were found for ophthalmic and short posterior ciliary artery EDVs (P= .0003; P< .00001). Ophthalmic artery RI was significantly higher in eyes with retinopathy than controls (P = .0008), with heterogeneity (Pheterogeneity < .00001; I(2) = 84%). In group 3, ophthalmic artery PSV was lower in eyes with retinopathy (P= .04) than eyes without, and central retinal artery PSV and EDV decreased significantly (P = .004; P < .00001) in eyes with retinopathy compared to eyes without. Differences in ophthalmic and central retinal artery RIs were also found in eyes with retinopathy (P = .05; P < .00001). Significant changes in retrobulbar blood flow were found in eyes without and with diabetic retinopathy, especially those with retinopathy.

Doppler Ultrasound of the Central Retinal Artery in Microgravity

Ocular changes have been noted during long-duration spaceflight; we studied central retinal artery (CRA) blood flow using Doppler before, during, and after long-term microgravity exposure in astronauts compared with data from a control group of nonastronauts subjected to head-down tilt (HDT). Available Doppler spectra of International Space Station (ISS) crewmembers were obtained from the NASA Lifetime Surveillance of Astronaut Health database, along with 2D ultrasound-derived measurements of the optic nerve sheath diameter (ONSD). CRA Doppler spectra and optic nerve sheath images were also obtained from healthy test subjects in an acute HDT experiment at 20 min of exposure (the ground-based analogue). HDT CRA peak systolic velocity in the ground-based analogue group increased by an average of 3 cm -s(-1) (33%) relative to seated values. ONSD at 300 of HDT increased by 0.5 mm relative to supine values. CRA Doppler spectra obtained on orbit were of excellent quality and demonstrated in-flight changes of +5 cm x s(-1) (50%) compared to preflight. ONSD increased in ISS crewmembers during flight relative to before flight, with some reversal postflight. A significant ONSD response to acute postural change and to spaceflight was demonstrated in this preliminary study. Increases in Doppler peak flow velocities correlated with increases in ONSD. Further investigations are warranted to corroborate the relationship between ONSD, intracranial pressure, and central retinal blood flow for occupational surveillance and research purposes.

RETINAL DETACHMENT AND PROLIFERATIVE VITREORETINOPATHY

To analyze if endothelin 1 may have an effect on central retinal artery (CRA) blood flow velocities and intraocular pressure (IOP) in retinal detachment. Using radioimmunoassay, immunoreactive endothelin 1 levels were tested in both plasma and subretinal fluid specimens from patients with retinal detachment, while only plasma specimens from healthy subjects were tested. Central retinal artery Doppler sonography parameters and IOP were measured in eyes with retinal detachment, with and without proliferative vitreoretinopathy, their respective healthy fellow eyes, and normal eyes. Retinal detachment eyes had lower CRA peak systolic velocity and end-diastolic velocity, lower IOP, and higher plasma immunoreactive endothelin 1 levels than normal eyes (P < 0.0001). Eyes with proliferative vitreoretinopathy had lower CRA peak systolic velocity and end-diastolic velocity, higher resistivity index, lower IOP, higher plasma immunoreactive endothelin 1 levels, and higher subretinal fluid immunoreactive endothelin 1 than eyes without proliferative vitreoretinopathy (P < 0.0001). A statistically significant linear correlation was found among CRA parameters, IOP, and subretinal fluid immunoreactive endothelin 1 measurements. Endothelin 1 has shown a close relationship with IOP and CRA blood flow changes associated to retinal detachment as well as with proliferative vitreoretinopathy complications.

Impact of intravitreal triamcinolone acetonide versus intravitreal bevacizumab on retrobulbar hemodynamic in patients with diabetic macular edema

Purpose: To evaluate and compare retrobulbar hemodynamic changes measured with color Doppler imaging (CDI) in diabetic patients receiving intravitreal triamcinolone acetonide (IVTA) versus bevacizumab.Methods: Patients with diffuse diabetic macular edema were assessed prospectively by CDI following intravitreal injection of triamcinolone acetonide (group I, 12 eyes) versus bevacizumab (group II, 14 eyes). CDI was used to measure the peak systolic velocity (PSV), end diastolic velocity (EDV) and the resistive index (RI) of the central retinal artery (CRA), ophthalmic artery (OA) and posterior ciliary arteries (PCA) one day preoperatively and one week postoperatively.Results: In group I, EDV of OA and CRA decreased significantly (p = 0.007 and 0.018, respectively). The PSV and RI of PCA decreased significantly (p = 0.035 and 0.002, respectively). In group II, both the PSV and EDV of the CRA decreased significantly (p = 0.000). Comparing the percentage of change in both groups, PSV of the CRA decreased significantly in group II (p = 0.034), while IVTA has more significant effect on the ophthalmic artery hemodynamic parameters as EDV decreased and RI increased significantly (p = 0.045 and 0.043, respectively)Conclusion: Intravitreal injections of triamcinolone acetonide and bevacizumab have a significant effect on the ocular hemodynamic. The effect of bevacizumab is statistically significant on the PSV of CRA compared to IVTA.

Pentoxifylline treatment for protecting diabetic retinopaty in children with type 1 diabetes

The purpose of this study was to determine whether oral pentoxifylline (PTX) would improve retinal microvascular hemodynamics in children with type 1 diabetes mellitus (DM). Non-invasive ultrasonographic measurements were made in 56 type 1 diabetic patients. The diabetic patients were matched first in terms of age, diabetes duration, then one individual within each pair was randomized into a pentoxifylline group and a control group. Pentoxifylline was administered for 6 months. We investigated the change of peak systolic velocity (PSV), end diastolic velocity (EDV), pulsatility index (PI), and resistivity index (RI) of central retinal artery (CRA) at 6 months after pentoxifylline. We investigated the relationship between PI, RI and carotide cross-sectional compliance (C-CSC). In comparison to changes in CRA measurements between the two groups, the pentoxifylline treatment group had significantly lower PI values (p=0.01). The RI, PSV and EDV were lower in pentoxifylline group but not statistically different. There was a positive correlation between CRA PSV and carotid Vmax (cm/s) (r=0.29, p=0.02) and also C-CSC (r=0.27, p=0.03). In addition, there was a positive correlation between PI and C-CSC (r=0.3, p=0.02). In the pentoxifylline group there was a significant reduction in systolic blood pressure, diastolic blood pressure, microalbuminuria and an increase in HDL level. Our results suggest that pentoxifylline may have a protective action for diabetic retinopathy and might modulate risk factors for atherosclerosis in type 1 diabetes.