Color Doppler ultrasound imaging of the eye and orbit

Multiple Cavernous Sinus Arteriovenous Fistulas

Patients with bilateral cavernous sinus combined with dural arteriovenous fistula in the intercavernous sinus area are very rare. Cavernous sinus dural arteriovenous fistula is mostly associated with venous thrombosis and venous hypertension. It can be treated curatively by the venous route.

The impact of demographics and positioning on the imaging features of the optic nerve sheath and ophthalmic vessels

BACKGROUND

There are significant discrepancies in the optic nerve sheath diameter (ONSD) reported in the literature. We aimed to determine the ultrasonographic imaging features of ONSD and ophthalmic vessels in a healthy population, using a standardized protocol, and to estimate the effect of demographics and positioning changes on imaging measurements.

METHODS

We measured the mean values of the ONSD in supine and sitting position and the Doppler imaging parameters of the ophthalmic, central retinal and short posterior ciliary arteries. Inter-observer reliability was assessed using intraclass correlation coefficient (ICC). Linear regression models were fitted to predict the effect of demographic and clinical determinants on the imaging features.

RESULTS

A total of 50 measurements were obtained for each observer. The mean ONSD was 5.9 mm and there was a mean reduction of 0.2 mm when assessed in sitting position (p < 0.001). Doppler analysis showed higher peak-systolic velocity and resistive index in the ophthalmic artery (35.6 cm/s vs. 12.0 cm/s; 0.78 vs. 0.70) compared to the central retinal artery (p < 0.001). Age, sex, heart rate and systolic blood pressure were significant determinants of the imaging features, with ONSD being larger in males (p < 0.001) and increasing with heart rate (p = 0.001). ICC estimates indicated 'good' inter-observer reliability of the ONSD and the ophthalmic and central retinal arteries velocities and resistance.

CONCLUSIONS

Our findings suggest a significant impact of patient demographics and positioning during ultrasonography on the normal imaging features of the ONSD and ophthalmic vessels. The heterogeneity in methodology and clinical cohorts may justify previous discrepancies in the literature. These findings can assist in the interpretation of imaging features in clinical settings and in the standardization of point of care ONSD ultrasonography.

Glaucoma Surgery and Ocular Blood Flow in Colour Doppler Imaging: Is There a Link?

Glaucoma is a common cause of blindness worldwide. This disease is characterised by increased intraocular pressure (IOP) and the concomitant disruption of ocular haemodynamic. Several studies have demonstrated that trabeculectomy is associated with changes in extraocular blood flow. In this study, we reviewed the available evidence on the use of colour Doppler imaging to evaluate and manage patients with open-angle glaucoma. We present the detailed anatomy of ocular blood flow to provide a background for the research findings. We also discuss the physiological foundations of ocular blood flow and detailed flow characteristics of specific extraocular vessels. Finally, we reviewed published studies that analysed the effects of glaucoma surgery on the blood flow parameters of the eye.

The role of optic nerve sheath ultrasonography in increased intracranial pressure: A systematic review and meta analysis

OBJECTIVES

To review the optimal diagnostic cut-off of ultrasonographic optic nerve sheath diameter (ONSD) in the diagnosis of increased intracranial pressure (IICP).

METHODS

A systematic search was conducted of available studies assessing the use of ONSD ultrasonography in patients with suspected IICP. Meta-analysis of diagnostic accuracy of ultrasonographic ONSD was performed using a bivariate model of random effects to summarize pooled sensitivity and specificity. A summary receiver operating characteristics (SROC) curve was plotted. Accuracy measures associated with ONSD cut-off and predefined covariates were investigated with meta-regression.

RESULTS

We included 38 studies, comprising a total of 2824 patients. A total of 21 studies used invasive techniques as a reference standard estimation of IICP and meta-analysis revealed a pooled sensitivity of 0.90 (95% CI 0.85-0.93) and specificity of 0.87 (95% CI 0.80-0.91). Optimal ONSD cut-off values ranged between 4.1 mm and 7.2 mm. Meta-regression analysis showed that ONSD cut-off values of 5.6 to 6.3 mm were associated with higher pooled specificity compared to cut-off values of 4.9 to 5.5 mm (0.93, 95% CI 0.85-0.97 vs. 0.78, 95% CI 0.65-0.87; p = 0.036).

CONCLUSIONS

Ultrasonography of ONSD shows a high diagnostic accuracy for IICP, with high pooled sensitivity and specificity. Additionally, larger cut-off values seem to significantly increase specificity without compromising sensitivity, which support their use as optimal ONSD cut-off. The overall high sensitivity of ultrasonographic ONSD suggests its usefulness as a screening tool for IIC, which may provide an estimate of when invasive methods are warranted.

CLINICAL RELEVANCE

ONSD ultrasonography is a fast and cost-effective method with a high diagnostic accuracy to detect IICP. The optimum ONSD cut-off hasn't been established before, but we suggest the 5.6 to 6.3 mm range as the best for the diagnosis of IICP.

Association between resistivity index of central retinal artery and severity of diabetic retinopathy

Purpose

Diabetic retinopathy (DR) is a leading cause of ocular morbidity. Its progression depends mainly on retinal vasculature and ocular blood flow. Color Doppler imaging (CDI) is a noninvasive imaging technique that measures blood flow velocity. The resistivity index (RI), calculated by the CDI, reflects the vascular resistance distal to the measuring location. RI is independent of the doppler angle and position of the patient, making it a reliable and reproducible parameter. To the best of our knowledge, there is only one study in literature studying the association between resistivity index (RI) of the central retinal artery (CRA) and severity of DR.

Aim

To determine the association between RI of CRA and severity of DR. To determine the association between RI of CRA and spectral-domain optical coherence tomography (SD-OCT) biomarkers for DR.

Methods

Type II diabetics visiting our OPD underwent DR screening and were graded into three categories according to ETDRS classification which include Group A-No diabetic retinopathy (No DR), Group B-Nonproliferative diabetic retinopathy (Moderate-Severe-Very Severe NPDR), and Group C-Proliferative diabetic retinopathy (PDR). SD-OCT was performed. Ultrasonic color doppler imaging was done. RI of the CRA was noted. It was compared between the three groups and its association with severity of DR and OCT biomarkers (central subfield thickness, cube average thickness and ellipsoid zone disruption) was studied.

Results

56 eyes of 28 patients were included in our study with 20 in Group A,14 in Group B, and 22 in Group C. RI of CRA compared within groups showed statistically significant association with severity of DR (P < 0.001). The presenting BCVA (LogMar) showed positive correlation with RI in all groups. OCT biomarker central subfield thickness showed a positive correlation with RI in Groups A (P < 0.001) and B. Ellipsoid zone (EZ) disruption showed a statistically significant association with RI in Group C (P < 0.001).

Conclusion

The RI of CRA is a reliable biomarker for the assessment of the severity of DR. Patients with high RI of CRA had higher chances of EZ disruption and presented with poor visual acuity.

Retinal nerve fiber layer and ophthalmic artery blood flow parameters in pseudoexfoliation syndrome and pseudoexfoliative glaucoma

OBJECTIVES

To investigate the relationship between ophthalmic artery (OA) blood flow parameters and retinal nerve fiber layer (RNFL) thickness in eyes with pseudoexfoliation (PEX).

METHODS

We compared PEX eyes without glaucoma (group A, n=53) and those with glaucoma (group B, n=18) with control eyes (group C, n=44). Subsequently, eyes in groups A and B were compared. Finally, OA color Doppler imaging measurements were recorded, and peripapillary RNFL analysis was performed.

RESULTS

The total RNFL measurements differed significantly among the groups (P=0.012), being thicker in group C than in group A (P=0.010) and significantly different between group B and groups A and C (both P=0.001). The peak systolic velocity (PSV) and end diastolic velocity (EDV) measurements of groups A and B were lower than those of group C (PSV: P=0.001 and P=0.001, respectively; EDV: P=0.001 and P=0.001, respectively). No significant difference was noted in resistive index (RI) measurements (P=0.370). In group B, significant negative correlations were noted between total RNFL and PSV (r=-0.743; P=0.001) and between total RNFL and EDV (r=-0.691; P=0.001), but not between total RNFL and RI measurements (P=0.548).

CONCLUSIONS

Pseudoexfoliation syndrome (PXS) with or without glaucoma was associated with a decrease in the PSV and EDV values of the OA. An extensive study may be needed to further explore the role of PXS in OA blood flow parameters. Total RNFL thickness values were lower in eyes with PEX than in those without.

Detecting Early Ocular Choroidal Melanoma Using Ultrasound Localization Microscopy

Ocular choroidal melanoma (OCM) is the most common ocular primary malignant tumor in adults, and there is an increasing emphasis on its early detection and treatment worldwide. The main obstacle in early detection of OCM is its overlapping clinical features with benign choroidal nevus. Thus, we propose ultrasound localization microscopy (ULM) based on the image deconvolution algorithm to assist the diagnosis of small OCM in early stages. Furthermore, we develop ultrasound (US) plane wave imaging based on three-frame difference algorithm to guide the placement of the probe on the field of view. A high-frequency Verasonics Vantage system and an L22-14v linear array transducer were used to perform experiments on both custom-made modules in vitro and a SD rat with ocular choroidal melanoma in vivo. The results demonstrate that our proposed deconvolution method implement more robust microbubble (MB) localization, reconstruction of microvasculature network in a finer grid and more precise flow velocity estimation. The excellent performance of US plane wave imaging was successfully validated on the flow phantom and in an in vivo OCM model. In the future, the super-resolution ULM, a critical complementary imaging modality, can provide doctors with conclusive suggestions for early diagnosis of OCM, which is significant for the treatment and prognosis of patients.

Real-time ultrasound elastographic features and color doppler imaging of mitral valve prolapse

Background: The aim of this study was to investigate the elasticity of ocular structures in patients with mitral valve prolapse (MVP). Material and Methods: This prospective study included a total of 35 patients with MVP (study group) and 35 healthy volunteers (control group). The elastography value of the ratio of orbital fat- sclera (ROF/S) was measured with real-time US elastography. For each eye, central retinal artery (CRA), posterior ciliary artery (PCA), and ophthalmic artery (OA) were evaluated, respectively. Results: The mean ages of the patients in the study and the control groups were 31.77 ± 11.40 years, and 30.65 ± 7.45 years, respectively (P =0.511). Mean ROF/S were 1.95 ± 0.81 and 1.37 ± 1.06 (P=0.001) in the study groups and control, respectively. The mean RI of the OA was 0.67 ± 0.05 in the control group, 0.67 ±0.05 (0.55; 0.87) in study group. The mean RI of the PCA was 0.66 ± 0.05 in the control group, 0.68 ±0.06 in study group. . The mean RI of the CRA was 0.66 ± 0.05 in the control group, 0.66 ±0.06 in study group. The RI value was not a significant difference between control and study group (p > 0.05). Conclusion: Scleral elasticity was significantly increased in MVP patients. These could be related to ocular pathologies such as glacouma, kerataconus in MVP.

Ultrasound and Microbubbles for the Treatment of Ocular Diseases: From Preclinical Research towards Clinical Application

The unique anatomy of the eye and the presence of various biological barriers make efficacious ocular drug delivery challenging, particularly in the treatment of posterior eye diseases. This review focuses on the combination of ultrasound and microbubbles (USMB) as a minimally invasive method to improve the efficacy and targeting of ocular drug delivery. An extensive overview is given of the in vitro and in vivo studies investigating the mechanical effects of ultrasound-driven microbubbles aiming to: (i) temporarily disrupt the blood–retina barrier in order to enhance the delivery of systemically administered drugs into the eye, (ii) induce intracellular uptake of anticancer drugs and macromolecules and (iii) achieve targeted delivery of genes, for the treatment of ocular malignancies and degenerative diseases. Finally, the safety and tolerability aspects of USMB, essential for the translation of USMB to the clinic, are discussed.

B-Scan Biometry and Color Doppler Ultrasound Imaging of the Eye in Clinically Normal Donkeys (Equus asinus): Effect of Laterality, Maturity and Gender

Despite the extensive research on ocular ultrasonography, there is paucity of information regarding ocular biometry and color Doppler imaging of the donkey's eye. This study establishes B-scan ocular biometry and color Doppler ultrasonographic reference values in normal donkeys and describes effect of laterality, maturity and gender on ocular biometry and vasculature. Forty (80 eyes) clinically normal immature and mature donkeys of both sexes were included. Transpalpebral ocular ultrasonography was made using a 12-MHz linear transducer. Biometric ocular measurements were made including the anterior chamber depth, central lens thickness, vitreous chamber depth, axial globe length, longitudinal globe length, lens pole diameter and posterior wall thickness. Color Doppler velocimetric measurements including peak systolic velocity and end-diastolic velocity were made. Blood flow indices represented by resistive and pulsatility indices were calculated. Results revealed that laterality and gender did not represent variability factors in ocular biometry (P >.05), while the animal's maturity had an influence on axial globe length (P <.001), longitudinal globe length (P = 0.000) and lens pole diameter (P = .000). Laterality had no effect on velocimetric parameters and indices (P >.05) while gender had significant effect on resistive index (P = .024), pulstality index (P = .000) and volume flow per area (P = .008). The state of maturity had significant effects on peak systolic velocity (P = .027) and blood volume flow per distance (P = .012), and area (P = .048). Ocular biometry and color Doppler ultrasonography provided a clinically useful tool to evaluate the donkey's eye that will be helpful in diagnosing donkeys with ocular diseases.

Magnetically Driven Micro and Nanorobots

Manipulation and navigation of micro and nanoswimmers in different fluid environments can be achieved by chemicals, external fields, or even motile cells. Many researchers have selected magnetic fields as the active external actuation source based on the advantageous features of this actuation strategy such as remote and spatiotemporal control, fuel-free, high degree of reconfigurability, programmability, recyclability, and versatility. This review introduces fundamental concepts and advantages of magnetic micro/nanorobots (termed here as “MagRobots”) as well as basic knowledge of magnetic fields and magnetic materials, setups for magnetic manipulation, magnetic field configurations, and symmetry-breaking strategies for effective movement. These concepts are discussed to describe the interactions between micro/nanorobots and magnetic fields. Actuation mechanisms of flagella-inspired MagRobots (i.e., corkscrew-like motion and traveling-wave locomotion/ciliary stroke motion) and surface walkers (i.e., surface-assisted motion), applications of magnetic fields in other propulsion approaches, and magnetic stimulation of micro/nanorobots beyond motion are provided followed by fabrication techniques for (quasi-)spherical, helical, flexible, wire-like, and biohybrid MagRobots. Applications of MagRobots in targeted drug/gene delivery, cell manipulation, minimally invasive surgery, biopsy, biofilm disruption/eradication, imaging-guided delivery/therapy/surgery, pollution removal for environmental remediation, and (bio)sensing are also reviewed. Finally, current challenges and future perspectives for the development of magnetically powered miniaturized motors are discussed.

Associating the biomarkers of ocular blood flow with lamina cribrosa parameters in normotensive glaucoma suspects. Comparison to glaucoma patients and healthy controls

Purpose

To evaluate association between ocular blood flow biomarkers and lamina cribrosa parameters in normotensive glaucoma suspects compared to glaucoma patients and healthy controls.

Methods

A total of 211 subjects (72 normotensive glaucoma suspects, 70 with primary open-angle glaucoma and 69 controls) were included. Ocular blood flow biomarkers in ophthalmic artery, central retinal artery, as well as in nasal and temporal short posterior ciliary arteries were measured using colour Doppler imaging. Lamina cribrosa position was assessed by measuring its depth, deflection depth, lamina cribrosa shape index and its horizontal equivalent (LCSI_H) on B-scan images obtained using optical coherence tomography.

Results

Ocular blood flow biomarkers in glaucoma patients were statistically significantly reduced when compared to healthy controls in peak systolic velocity (PSV) (P = 0.001 in ophthalmic artery and P<0.001 in central retinal artery) and mean flow velocity (V_m) (P = 0.008 in ophthalmic artery and P = 0.008 in central retinal artery), but not statistically significantly different to that of glaucoma suspects except for PSV in central retinal artery (P = 0.011). Statistically significant correlations corrected for age, central corneal thickness and intraocular pressure were found in glaucoma patients between LCSI_H and end diastolic velocity of central retinal artery (P = 0.011), and of nasal short posterior ciliary artery (P = 0.028), and between LCSI_H and V_m of central retinal artery (P = 0.011) and of nasal short posterior ciliary artery (P = 0.007). No significant correlations were observed between these parameters in glaucoma suspects and healthy controls.

Conclusions

Impaired ocular blood flow associated with the deformation of lamina cribrosa was found in glaucoma patients, whereas glaucoma suspects had similar lamina cribrosa shape to glaucoma patients but that deformation was not associated with ocular blood flow biomarkers.

Retinal vessel oxygen saturation in patients with unilateral internal carotid artery stenosis: a pilot study

PURPOSE

To investigate the retinal vessel oxygen saturation in patients with internal carotid artery stenosis (ICAS).

METHODS

This is a cross-sectional study. Sixteen patients with unilateral moderate or worse ICAS (≥50%) and no fundus diseases were included in the study. Sixteen gender- and age-matched healthy subjects were selected as controls. The mean oxygen saturation and vessel diameters of the retinal arterioles and venules were obtained using a dual-wavelength spectrophotometric retinal oximeter.

RESULTS

In the eye of the stenotic side, the retinal vessel oxygen saturation was 100.14 ± 10.27% in the arterioles and 56.50 ± 10.79% in the venules, and the arteriovenous (A-V) difference was 43.63 ± 7.71%. In the eye of the contralateral side, the oxygen saturation was 96.55 ± 7.50% in the arterioles and 57.42 ± 9.84% in the venules, and the A-V difference was 39.39 ± 6.33%. In healthy subjects, the oxygen saturation was 93.22 ± 5.98% in the arterioles and 56.57 ± 7.05% in the venules, and the A-V difference was 36.65 ± 7.33%. The arteriolar oxygen saturation in the stenotic side was higher than that in the contralateral side (p = 0.025) and that in the healthy subjects (p = 0.027), and the A-V difference in the stenotic side was significantly higher than that in the contralateral side (p = 0.009) and that in the healthy subjects (p = 0.013). The diameters of the arterioles in the stenotic side were smaller than those in the healthy subjects (p = 0.030).

CONCLUSIONS

Patients with ICAS had decreased retinal arteriole diameters and increased retinal vessel oxygen saturation in the arterioles and A-V differences, suggesting the presence of microcirculation disorder and hyperoxia in the retina.

A new stethoscope for pediatric intensivists: Point-of-care ultrasound

In recent years, the use of point-of-care ultrasound by non-radiologist physicians has become widespread. Especially for clinicians working in pediatric emergency departments and pediatric intensive care units, point-of-care ultrasound has almost become a part of physical examinations due to the rapid responses it offers to the problems of critically ill patients. Numerous studies revealed the important clinical benefits of point-of-care ultrasound use by pediatric intensive care providers. In this review, we aimed to give detailed information about different types of point-of-care ultrasound applications in pediatric intensive care units and wanted to draw attention to the increased use and clinical benefits of this noninvasive and radiation free technique.

How to measure retinal microperfusion in patients with arterial hypertension

PURPOSE

Assessment and monitoring of changes in microcirculatory perfusion, perfusion dynamic, vessel structure and oxygenation is crucial in management of arterial hypertension. Constant search for non-invasive methods has led the clinical focus towards the vasculature of the retina, which offers a large opportunity to detect the early phase of the functional and structural changes in the arterial hypertension and can reflect changes in brain vasculature. We review all the available methods of retinal microcirculation measurements including angiography, oximetry, retinal vasculature assessment software, Optical Coherence Tomography Angiography, Adaptive Optics and Scanning Laser Doppler Flowmetry and their application in clinical research.

MATERIALS AND METHODS

To further analyse the applicability of described methods in hypertension research we performed a systematic search of the PubMed electronic database (April 2020). In our analysis, we included 111 articles in which at least one of described methods was used for assessment of microcirculation of the retina in hypertensive individuals.

RESULTS

Up to this point, the methods most commonly published in studies of retinal microcirculation in arterial hypertension were Scanning Laser Doppler Flowmetry followed shortly by Optical Coherence Tomography Angiography and retinal vasculature assessment software.

CONCLUSIONS

While none of described methods enables the simultaneous measurement of all microcirculatory parameters, certain techniques are widely used in arterial hypertension research, while others gain popularity in screening.

Color Doppler Imaging Features of the Lacrimal Sac in Health and Diseased States

PURPOSE

The objective of this study is to present Color Doppler imaging (CDI) features of the lacrimal sac in normal and diseased states.

METHODS

Prospective study was performed on 20 lacrimal sacs of 20 eyes of 10 patients who underwent Color Doppler imaging at a tertiary care Dacryology service over a period of 6 months. All the patients were subjected to Duplex doppler scanning of the lacrimal sacs. Of the 20 lacrimal drainage systems studied, 8 were normal, 8 had primary acquired nasolacrimal duct obstruction (PANDO) and 4 were that of acute dacryocystitis (AcDac). Patient demographics, clinical presentation, duration of the disease and Color Doppler vascular characteristics like peri-sac vascular flow, peak systolic velocity (PSV), end-diastolic velocity (EDV), resistivity index (RI), arterial spectral waveforms and sac dimensions and wall thickness were analyzed.

RESULTS

The vascular flow around the lacrimal sac was increased with higher flow velocities in PANDO as compared to normal and grossly enhanced in AcDac. Flow disturbances were also quite discernible in AcDac. The mean PSV and EDV were 9 & 3.87 cm/sec, 13.07 & 4.63 cm/sec and 18 & 8.5 cm/sec in normal, PANDO and AcDac, respectively. The mean vascular resistivity index increased in patients with PANDO (0.67) and decreased in AcDac (0.53) as compared to the normal (0.57). The arterial spectral waveforms in PANDO and AcDac showed low pulsatility, but the systolic peaks were sharper with more continuous forward flow through diastole in AcDac. This reflects vascular dilatation and reduced resistance to flow in AcDac.

CONCLUSION

Characteristic Color Doppler flow parameters can be demonstrated in patients with PANDO and acute dacryocystitis. Color Doppler techniques have the potential to enhance the understanding of lacrimal drainage pathophysiology.

Optic Nerve Sheath Diameter and Retinal Artery Resistive Index Measurements with Bedside Ophthalmic Ultrasound in Pediatric Patients with Pseudotumor Cerebri Syndrome

Pseudotumor cerebri syndrome (PTCS) is characterized by raised intracranial pressure (ICP) with no neuroradiological abnormalities. Ocular ultrasound has been in use to measure optic nerve sheath diameter (ONSD), and retinal artery Doppler indices have been used for indirect assessment of ICP by pediatric intensivists. Here, we aimed to evaluate the correlation of the lumbar puncture (LP) opening pressure with the ultrasonographic ONSD and retinal resistive index (RRI) measures in patients with PTCS. And we wanted to find an answer to the following question: Can ultrasonographic ONSD measures serve as a follow-up tool in patients with PTCS? A prospective, single-center, case-control study was performed by pediatric intensive care and pediatric neurology departments. A total of 7 patients with PTCS were evaluated as patient group and 15 healthy children were evaluated as control group. The mean age of patient group was 138.8 ± 43.7 months. The mean right ONSD was 6.7 ± 0.5 mm and the mean left ONSD was 6.7 ± 0.6 mm. The mean right RRI value was 0.73 ± 0.03 and the mean left RRI was 0.73 ± 0.09. For the patient group, ONSD and RRI values of both eyes were statistically significant higher values than for the control group. The mean LP opening pressure was 56.57 ± 16.36 cmH ₂ O. We detected strong, positive, and statistically significant correlations between the LP opening pressure and ONSD baseline measures for both the right eye ( r  = 0.882, p  = 0.009) and the left eye ( r  = 0.649, p  = 0.004). There was no correlation between opening pressure in LP and RRI measurements. We detected a statistically significant decrease in the right ONSD and left ONSD values and visual analog scale scores at the third-month follow-up. Our study results demonstrate that ultrasonographic ONSD measurements can be used as a noninvasive tool for assessment of the ICP at first admission and can be used as a follow-up tool in PTSC patients.

Resistive index of central retinal artery is a bioimaging biomarker for severity of diabetic retinopathy

BACKGROUND

The present study was undertaken to assess the resistive index (RI) of central retinal artery (CRA) as a bioimaging biomarker for the severity of diabetic retinopathy (DR), for the first time.

METHODS

Eighty-one consecutive patients of type 2 diabetes mellitus between the ages of 40 and 70 years were included in a tertiary care center-based cross sectional study. Severity of retinopathy was assessed according to Early Treatment Diabetic Retinopathy Study (ETDRS) classification: diabetes mellitus with no retinopathy (No DR) (n = 26); non-proliferative diabetic retinopathy (NPDR) (n = 29); and proliferative diabetic retinopathy (PDR) (n = 26). Twenty-six healthy controls of similar age were also included. Resistive index of CRA was studied using color Doppler and gray scale sonography. Central subfield thickness (CST), cube average thickness (CAT), retinal photoreceptor ellipsoid zone (EZ) disruption, and retinal nerve fiber layer (RNFL) thickness were evaluated using spectral domain optical coherence tomography. Sensitivity and specificity were assessed by receiver operating characteristic (ROC) curve.

RESULTS

Mean RI of CRA for the study groups revealed significant increase with severity of diabetic retinopathy (F = 10.24, P < 0.001). The ROC curve analysis showed diagnostic accuracy of RI of CRA (area under curve = 0.841-0.999; sensitivity = 76-100%, specificity = 95.45-100%, P < 0.001) in discriminating controls and patients. Univariate regression analysis revealed significant association between the study groups and RI of CRA (P < 0.001). RI of CRA correlated positively with CST (r = 0.37), CAT (r = 0.45), EZ disruption (r = 0.43) and negatively with RNFL thickness (r = - 0.35) (P < 0.001).

CONCLUSIONS

Resistive index of CRA is a reliable bioimaging biomarker for the severity of DR.

Optic nerve sonography and ophthalmic artery Doppler velocimetry in healthy pregnant women: an Australian cohort study

PURPOSE

Maternal ocular sonography offers a window into cerebrovascular and intracranial pressure changes in pregnancy. This study aimed to determine the Doppler velocimetric variables of the ophthalmic artery, and the mean diameter of the optic nerve sheath (ONSD), in an Australian cohort of healthy pregnant women.

METHODS

A prospective observational cohort study of healthy women with uncomplicated singleton pregnancies in the third trimester was undertaken in a tertiary maternity service. A single prenatal ultrasonographic examination was performed on all participants, with a postnatal examination performed on a subgroup with uncomplicated deliveries.

RESULTS

Fifty women were examined at a mean gestation of 35 weeks. The mean ± SD Doppler variables in the ophthalmic artery were peak systolic velocity (PSV) 41.89 ± 13.13 cm/s, second peak velocity 20.63 ± 8.97 cm/s, end diastolic velocity 9.29 ± 5.13 cm/s, pulsatility index 1.97 ± 0.53, resistive index 0.78 ± 0.07, peak ratio (second peak velocity/PSV) 0.49 ± 0.12, while the mean ONSD was 4.34 ± 0.4 mm. None of these variables had a demonstrable relationship with gestation or mean arterial pressure (MAP), nor did the sheath diameter have a relationship with any of the Doppler variables.

CONCLUSIONS

The ocular sonographic variables observed in this population are similar to those reported in other cohorts. No clear relationship could be identified in this cohort between ophthalmic artery Doppler variables and the ONSD, and between each of these variables and gestation or MAP.

Guidelines for ultrasound examination in ophthalmology. Part III: Color Doppler ultrasonography

The aim of this article was to present the possibilities of use and application of color-coded Doppler ultrasonography in the diagnosis of various diseases of the eyeball and orbit which result from vascular disorders. Color-coded Doppler ultrasonography is recommended for the assessment of blood flow velocity in the retrobulbar arteries. That is why the article contains current recommendations for Doppler imaging in ophthalmology. The paper provides detailed recommendations for patient's preparation for the examination, presents the scanning technique and safety of the examination, and lists ophthalmological diseases of vascular origin for which color-coded Doppler ultrasonography can be applied. Furthermore, the article also presents other techniques applied in clinical practice for the assessment of blood flow or imaging of vasculature of a given eyeball structure, inter alia: power Doppler ultrasonography, 3D and 4D ultrasonography, magnetic resonance angiography, spiral computer tomography, transcranial ultrasonography and modern microvascular imaging. The authors emphasize the usefulness of color-coded Doppler ultrasonography in the diagnosis of diseases which result from blood flow disorders within the eyeball, such as amaurosis fugax, ocular ischemic syndrome, insufficiency in vessels supplying the carotid and vertebral arteries, posterior ischemic optic neuropathy, glaucoma, age-related macular degeneration, vascular vision disorders, vascular malformations, such as arteriovenous fistula, orbital varices, systemic connective tissue diseases in retinopathy of prematurity, diabetes, thyroid disorders or strabismus. The application of color-coded Doppler ultrasonography is especially important in the assessment of the vasculature of intrabulbar tumorous lesions and in the differential diagnosis of intrabulbar tumors.

The aim of this article was to present the possibilities of use and application of color-coded Doppler ultrasonography in the diagnosis of various diseases of the eyeball and orbit which result from vascular disorders. Color-coded Doppler ultrasonography is recommended for the assessment of blood flow velocity in the retrobulbar arteries. That is why the article contains current recommendations for Doppler imaging in ophthalmology. The paper provides detailed recommendations for patient’s preparation for the examination, presents the scanning technique and safety of the examination, and lists ophthalmological diseases of vascular origin for which color-coded Doppler ultrasonography can be applied. Furthermore, the article also presents other techniques applied in clinical practice for the assessment of blood flow or imaging of vasculature of a given eyeball structure, inter alia: power Doppler ultrasonography, 3D and 4D ultrasonography, magnetic resonance angiography, spiral computer tomography, transcranial ultrasonography and modern microvascular imaging. The authors emphasize the usefulness of color-coded Doppler ultrasonography in the diagnosis of diseases which result from blood flow disorders within the eyeball, such as amaurosis fugax, ocular ischemic syndrome, insufficiency in vessels supplying the carotid and vertebral arteries, posterior ischemic optic neuropathy, glaucoma, age-related macular degeneration, vascular vision disorders, vascular malformations, such as arteriovenous fistula, orbital varices, systemic connective tissue diseases in retinopathy of prematurity, diabetes, thyroid disorders or strabismus. The application of color-coded Doppler ultrasonography is especially important in the assessment of the vasculature of intrabulbar tumorous lesions and in the differential diagnosis of intrabulbar tumors.

Color Doppler imaging of orbital vasculature before and after orbital decompression in thyroid eye disease

Purpose: To measure alterations in orbital blood flow parameters using color Doppler imaging (CDI) before and after orbital decompression in patients with moderate to severe thyroid eye disease (TED). Methods: Resistance index (RI) and maximum and minimum velocity of ophthalmic artery (OA), superior ophthalmic vein (SOV), and central retinal artery (CRA) of 24 eyes (14 patients) with TED were measured before and at least 3 months after cosmetic orbital decompression procedure (single or double walls) using CDI. Complete eye examination was performed to define the severity (EUGOGO classification) and activity (clinical activity score) of TED. Results: Median OA (p = 0.003) and CRA (p = 0.001) resistance indices were significantly reduced postoperatively. Significant differences were found in maximum (p = 0.001) and minimum (p = 0.014) velocity of SOV before and after surgery. While a significant decrease in exophthalmometry was observed after the orbital decompression (p = 0.031), intraocular pressure changes were not significant (p = 0.182). Conclusion: Orbital decompression procedure led to a significant reduction of RI in both CRA and OA in patients with TED.

Color Doppler imaging of ocular hemodynamic changes in patients with rheumatoid arthritis unrelated to disease activity

We aimed to investigate how orbital blood flow rates in patients with rheumatoid arthritis (RA) are affected by the active and remission phase of the disease. This prospective study included a total of 56 patients with RA (study group) and 24 control individuals (control group). All RA patients were divided into two groups, as active (Group 1) and remission (Group 2) according to the disease activity index (DAS 28) score. For each eye, retrobulbar vascular structures were evaluated [central retinal artery (CRA), posterior ciliary artery (PCA), and ophthalmic artery (OA)], respectively. The peak systolic velocity (PSV) and end-diastolic velocity (EDV) values were obtained for each artery and the vascular resistance index (RI) measurement was calculated. The median RI of the OA was 0.70 (0.57; 0.79) in the control group, 0.77 (0.55; 0.87) in group 1, and 0.73 (0.47; 0.87) in group 2. The median RI in the PCA was 0.70 (0.56; 0.82) in the control group, 0.76 (0.52; 0.88) in the group 1, and 0.74 (0.52; 0.86) in the group 2. The median RI of CRA was 0.73 (0.48; 0.81) in the control group, 0.71 (0.64; 0.81) in group 1, and 0.68 (0.61; 0.85) in group 2. The RI value was a significant difference between control and group 1 (p < 0.05). Active and remission RA patients had different effects on the flow rate of eye blood vessels.

The role of the erythrocyte in the outcome of pregnancy with preeclampsia

The objective of this study was to analyze the relationships of osmotic and mechanical stability of erythrocytes with anthropometric, biochemical, hematologic and hemodynamic variables in pregnant women with preeclampsia (PE). The studied population consisted of 20 normotensive patients and 16 patients with PE. Patients with PE presented worse gestational outcome, greater hematologic impairment, erythrocytes osmotically more stable in vitro, but in conditions of isotonicity with the in vivo medium, in addition to hyperflow in orbital territory, when compared to normotensive patients. The correlation analysis between anthropometric, hematologic and hemodynamic variables in patients with PE indicated that erythrocytes with lower volumes and lower levels of hemoglobin favor the occurrence of a better gestational outcome, because they are more stable and because they are associated with a decrease in the hemodynamic changes present in the disease. This should mean that the tendency to microcytosis, probably due to a mechanism of compensatory mechanical selection, is a desirable characteristic in the disease.

The impact of intravitreal dexamethasone implant (Ozurdex®) on retrobulbar hemodynamics in patients with diabetic macular edema and retinal vein occlusions

Objective: To evaluate the effect of single intravitreal dexamethasone implant (Ozurdex^®) on ocular blood flow velocities in patients with diabetic macular oedema (DME) and retinal vein occlusions (RVO). Methods: This prospective non-randomized interventional study included injected and fellow eyes of 12 patients with DME and of 16 patients with RVO treated with intravitreal Ozurdex^®. Colour Doppler Ultrasonography (CDU) measures of the central retinal artery (CRA), posterior ciliary artery (PCA), ophthalmic artery (OA) those are peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI) and pulsatility index (PI) were performed in both injected and uninjected eyes before injection, at one week, one month after injection, and prior to re-injection. Results: Inter-eye comparison of all the measured CDU data (baseline, first week, first month, reinjection) showed no statistically significant difference in both DME and RVO group. PSV and EDV values of the CRA, OA, and PCA showed a decreasing trend in the first week and first-month visits and then increased at reinjection time. RI and PI measures of the CRA, OA, and PCA measures showed minimal alterations in the follow-up. But all these differences were not statistically significant. Significant visual gain and anatomic recovery were obtained by the intravitreal dex-implant both in the DME and RVO group. Conclusions: Single intravitreal dex-implant did not alter ocular blood flow in the treatment of macular oedema due to RVO and diabetes.

Ultrasonography Monitoring of Optic Nerve Sheath Diameter and Retinal Vessels in Patients with Cerebral Hemorrhage

BACKGROUND AND PURPOSE

Evaluation of the diagnostic accuracy of optic nerve sheath diameter (ONSD) and Doppler indices of central retinal arteries and veins for the detection of increased intracranial pressure (ICP) in intracerebral hemorrhage (ICH) and of the usefulness of a second assessment of these variables in the monitoring of ICH.

METHODS

A total of 46 acute ICH patients with (group 1, n = 25) and without (group 2, n = 21) clinical and radiological computed tomography signs of raised ICP and 40 healthy controls were recruited. The median binocular ONSD and Doppler indices of retinal vessels including resistive index (RI) and retinal venous pulsation (RVP) were compared among groups, both at admission and later during ICH monitoring.

RESULTS

Median binocular ONSD showed higher accuracy for the detection of increased ICP (sensitivity and specificity 100%), while Doppler indices were less accurate (sensitivity 48% and specificity 95% for RI; 80% and 62% for RVP). In ICH patients, ONSD was significantly elevated in group 1 both at admission (6.40 mm [interquartile range [IQR] = .70] vs. 4.70 [.40]) and at control time (6.00 [.55] vs. 4.55 [.40]; P < .01), as well as RI (.79 [.11] vs. .77 [.03] and .80 [.06] vs. .75 [.35]; P = .01). RVP was significantly increased in group 1 only at admission (3.20 cm/s [1.05] vs. 2.00 [1.55], P = .02).

CONCLUSIONS

Median binocular ONSD evaluation showed higher accuracy for the estimation of elevated ICP compared with Doppler indices of retinal vessels. The ONSD enlargement detected in the early phase of ICH persists at control time.

Optical coherence tomography angiography (OCTA) flow speed mapping technology for retinal diseases

INTRODUCTION

Optical coherence tomography angiography (OCTA) is a noninvasive imaging modality for depth-resolved visualization of retinal vasculature. Angiographic data couples with structural data to generate a cube scan, from which en-face images of vasculature can be obtained at various axial positions. OCTA has expanded understanding of retinal vascular disorders and has primarily been used for qualitative analysis.

AREAS COVERED

Recent studies have explored the quantitative properties of OCTA, which would allow for objective assessment and follow-up of retinal pathologies. Various quantitative metrics have been developed, such as foveal avascular zone area and vessel density. However, quantitative assessment of the characteristics of retinal blood flow remains limited, as OCTA provides an image depicting either the presence or absence of flow at a particular region without information of relative velocities. The development of variable interscan time analysis (VISTA) overcomes this limitation. The VISTA algorithm generates a color-coded map of relative blood flow speeds. VISTA has already demonstrated utility in furthering our understanding of various retinal pathologies, such as geographic atrophy, choroidal neovascularization, aneurysmal type 1 neovascularization, and diabetic retinopathy.

EXPERT COMMENTARY

VISTA, an OCTA flow speed mapping technique, may have a role in developing the utility of OCTA as a screening tool.

Looking into the eye of patients with chronic obstructive pulmonary disease: an opportunity for better microvascular profiling of these complex patients

Chronic obstructive pulmonary disease (COPD) is a complex disease with many patients suffering from cardiovascular comorbidity. However, cardiovascular diseases remain often undiagnosed in COPD. Assessment of the retinal microvasculature can provide value in cardiovascular profiling of these patients. Retinal microvascular assessment carried out via a noninvasive eye exam represents an easy to use tool when examining patients with COPD. The purpose of this review was to provide an overview of studies assessing structural and functional changes in the retinal microvasculature of patients with COPD. Findings demonstrated that structural and functional microvascular changes were more common and severe in COPD patients as compared to non-COPD controls, although few retinal investigations have been performed in patients with COPD. As cardiovascular comorbidities are highly prevalent in COPD, we advocate more research to investigate the value of an eye exam for microvascular phenotyping of COPD patients.

Retrobulbar hemodynamics and aqueous humor levels of endothelin-1 in exfoliation syndrome and exfoliation glaucoma

Background

Endothelin-1 (ET-1) is the most potent vasoconstrictor in the body. There are reports in the literature correlating plasma levels of ET-1 and its impact on retrobulbar hemodynamics. This study evaluates aqueous humor levels of ET-1 and retrobulbar hemodynamics in patients with exfoliation syndrome (XFS) and exfoliation glaucoma (XFG).

Patients and methods

Patients scheduled for cataract surgery were included. Patients were allocated to non-exfoliation non-glaucoma group (controls), XFG and XFS groups. Peak systolic velocity (PSV), end diastolic velocity, and resistivity index of the ophthalmic artery (OA), short posterior ciliary arteries, and central retinal artery (CRA) were determined preoperatively using color Doppler imaging. Aqueous humor samples obtained at the beginning of cataract surgery were analyzed with enzyme-linked immunosorbent assay.

Results

Sixty-nine participants of similar age were included (controls: n=24, XFG: n=22, XFS: n=23). Multiple regression analysis showed that ET-1, OA-PSV, OA-resistivity index, CRA-PSV, and CRA-end diastolic velocity were influenced by group but not by sex or age. ET-1 for the XFG group (15.93±2.8 pg/mL) was significantly higher than for the XFS (8.92±2.7 pg/mL) and control (8.44±2.6 pg/mL) groups. The difference in ET-1 titers between the control and XFS groups was not statistically significant. All four hemodynamic parameters affected by group status significantly correlated with ET-1 levels in eyes with XFS. In eyes with XFG, two of the four hemodynamic parameters significantly correlated with ET-1 levels. In control eyes, no correlation between ET-1 and hemodynamic parameters affected by group status was detected.

Conclusion

ET-1 aqueous levels in eyes with XFG were significantly higher than those of age-matched controls. Reduced blood flow and increased vascular resistivity were detected in the OA and the CRA in eyes with XFG/XFS. ET-1 levels in eyes with XFG/XFS exhibit a significant correlation with hemodynamic parameters that indicate reduced perfusion.

Resistive index of ophthalmic artery correlates with retinal pigment epithelial alterations on spectral domain optical coherence tomography in diabetic retinopathy

Background

Retinal pigment epithelium (RPE) plays a significant role in maintenance of integrity of retinal photoreceptors and choriocapillaries. RPE derives its blood supply through ophthalmic artery (OA) via choriocapillaries. RPE topographic alterations have been observed to be associated with severity of retinopathy. The present study was undertaken to assess the correlation between resistive index (RI) of the OA with RPE topographic alterations on Spectral-Domain optical coherence tomography (SD-OCT), to our knowledge, it is for the first time.

Methods

A tertiary care center based cross-sectional study was undertaken after informed consent. Sample size was calculated using 95% confidence interval. Seventy five consecutive cases of type 2 diabetes mellitus between the ages of 40 and 70 years were included. The cases were divided into three groups according to Early Treatment Diabetic Retinopathy Study classification: diabetes mellitus with no retinopathy (No DR) (n = 24); non-proliferative diabetic retinopathy (n = 27); and proliferative diabetic retinopathy (n = 24). Healthy control subjects of similar age group were included (n = 24). RI in OA was studied using Color Doppler imaging. Grades of RPE topographic alterations and retinal photoreceptor ellipsoid zone (EZ) disruption were studied using SD-OCT. Data was analysed using Chi square (χ²) test, analysis of variance (ANOVA), Pearson correlation analysis and Neuman–Keuls test.

Results

LogMAR best corrected visual acuity was found to increase significantly with the severity of DR (F = 105.74, p < 0.001). ANOVA revealed a significant increase in RI of OA (F = 14.23, p < 0.001) with severity of diabetic retinopathy. χ² test revealed significant increase in grades of RPE alterations (χ² = 71.83, p < 0.001) and EZ disruption (χ² = 60.59, p < 0.001) with the severity of diabetic retinopathy. Pearson correlation analyses revealed a significant positive correlation between RI of OA with grades of RPE alterations (r = 0.48, p < 0.001) and also between grades of RPE alterations and EZ disruption (r = 0.82, p < 0.001).

Conclusions

Decrease in ocular blood flow resulting from an increase in RI of OA correlates with severity of DR and grades of topographic alterations in RPE. Integrity of EZ was observed to be dependent on RPE.

Are There Differences in the Anthropometric, Hemodynamic, Hematologic, and Biochemical Profiles between Late- and Early-Onset Preeclampsia?

Preeclampsia (PE) is classified as early-onset PE (EOPE) and late-onset PE (LOPE) when present before or after 34 weeks of gestation, respectively. This transversal study aimed to investigate the differences and possible associations existing in the anthropometric, hemodynamic, hematologic, and biochemical profiles of late- and early-onset preeclampsia. The study included 65 volunteers admitted to a tertiary hospital in Brazil: 29 normotensive and 36 with preeclampsia (13 with EOPE and 23 with LOPE). Pregnant women with LOPE presented greater weight gain and borderline increase in body mass index at the end of gestation in relation to the other groups, which is compatible with the metabolic origin, associated with obesity, attributed to this form of the disease. Pregnant women with EOPE presented a borderline reduction in the number of erythrocytes and a significant decrease in the number of platelets, in addition to a significant increase in reticulocytes, serum iron, and ferritin when compared to normotensive pregnant women and pregnant women with LOPE. A significant increase in osmotic stability of erythrocytes was observed in the EOPE group in relation to other groups. Hemodynamic analysis by Doppler ultrasonography of the ophthalmic artery showed that both groups of pregnant women with PE presented alterations compatible with the occurrence of hyperflow in the orbital territory. These hemodynamic changes were associated with changes in hematimetric indices.

Does severe obstructive sleep apnea syndrome alter retrobulbar blood flow? A color Doppler ultrasound study

PURPOSE

To evaluate extraocular orbital vessels with color Doppler ultrasound (CDU) and investigate the effects of severe obstructive sleep apnea (OSA) on retrobulbar blood flow.

METHODS

Between February 2014 and September 2015, 30 patients with severe OSA (apnea-hypopnea index (AHI) > 30) and 28 controls were prospectively included in this study. Intraocular pressure (IOP) was measured with a Goldmann applanation tonometer, and CDU was used to evaluate the retrobulbar vessels.

RESULTS

The mean AHI score for the OSA group was 63.2 ± 21.5 per hour. The IOP values were significantly higher in the severe OSA group (p < 0.05). The central retinal artery peak systolic velocity (PSV) (p < 0.05) and end-diastolic velocity (EDV) (p < 0.02), and the ophthalmic artery (OA) PSV and EDV, were found to be significantly lower in the OSA group (p < 0.05).

CONCLUSION

Severe OSA causes an increase in IOP and a decrease in flow velocity in the retrobulbar circulation.

The Effects of Cyclopentolate on Intraocular Pressure and Retrobulbar Hemodynamics in Patients with Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma

Purpose

To evaluate the changes of intraocular pressure (IOP) and retrobulbar hemodynamics after cyclopentolate administration in patients with pseudoexfoliation syndrome and pseudoexfoliation glaucoma.

Methods

Eighteen patients with pseudoexfoliation syndrome and 18 patients with pseudoexfoliation glaucoma were enrolled in the study. After baseline measurements of IOP, the peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistivity index (RI) of the ophthalmic, central retinal, and posterior ciliary arteries were investigated by color Doppler imaging. Then, 1% cyclopentolate was instilled in one eye of each subject. After 45 minutes of instillation of the cyclopentolate, the measurements of IOP and retrobulbar blood flow velocities were repeated. The results were compared with those of 20 age-matched normal subjects.

Results

Neither IOP nor retrobulbar blood flow velocities changed significantly in control subjects after cyclopentolate administration. IOP increased significantly after cyclopentolate instillation in pseudoexfoliation syndrome (p=0.004). Retrobulbar blood velocities did not change significantly after the cyclopentolate in this group. In pseudoexfoliation glaucoma group, it was observed that basal mean IOP showed a statistically significant increase after cyclopentolate drop (p=0.002). Although blood flow velocities of ophthalmic artery did not change significantly, PSV and EDV of the central retinal and posterior ciliary arteries decreased significantly (p<0.05) and RI of the posterior ciliary artery increased significantly (p=0.01) after cyclopentolate instillation.

Conclusions

On the basis of our findings, pseudoexfoliation appears to be a predictive factor for an IOP rise after cyclopentolate. In pseudoexfoliation glaucoma patients, an increase of IOP after cyclopentolate could lead to a decreased retrobulbar blood flow. IOP must be rechecked after cyclopentolate administration in these patients to avoid further damage to the ganglion cells.

Comparison of Visual Function and Ocular Hemodynamics between Pre- and Post-Menopausal Women

Purpose

The incidence of eye disease increases with age and can often be linked to worsening cardiovascular function and increasing intraocular pressure. Estrogen is known to have vasodilatory effects in the systemic circulation. Decreased estrogen levels during menopause may therefore complicate or contribute to ocular pathologies as estrogen receptors are found in both retinal and choroidal tissue. The purpose of this investigation was to determine the effects of menopause on visual function and cardiovascular and ocular hemodynamics.

Methods

Twelve premenopausal and 24 postmenopausal women were evaluated at the Indiana University School of Medicine during a single study visit. Vision screening and ocular blood flow evaluations were performed, including blood pressure, heart rate, visual acuity, contrast sensitivity, intraocular pressure, and retinal capillary and retrobulbar blood flow imaging. Vision and ocular hemodynamics were compared using unpaired Student t-tests with pp<0.05 regarded as statistically significant.

Results

The premenopausal group had significantly lower heart rate (-16.1 b/m, p=0.0001) and systolic blood pressure (-17.7 mmHg, p=0.003) than postmenopausal subjects. Contrast sensitivity was significantly higher (measured in log units) in premenopausal women in both the right (0.25, p=0.039; 0.16, p=0.039) and left (0.45, p=0.001; 0.27, p=0.032) eyes at 9 and 18 cycles per degree, respectively. Premenopausal women also had significantly lower intraocular pressure in both the right (-2.19 mmHg, p=0.024) and left (-1.74 mmHg, p=0.035) eyes. Total ocular perfusion was not significantly different between groups.

Conclusions

This pilot work suggests that postmenopausal women have lower contrast sensitivity detection and elevated intraocular pressures compared to premenopausal women. Premenopausal women have lower cardiovascular risk factors, while total ocular circulation was similar to post-menopausal women.

Effects of Betaxolol and Latanoprost on Ocular Blood flow and Visual Fields in Patients with Primary Open-Angle Glaucoma

Purpose

To evaluate the effects of betaxolol and latanoprost on ocular blood flow and visual fields in patients with primary open-angle glaucoma (POAG) by means of an obseiver-masked, prospective clinical study.

METHODS

Thirty-two patients with newly diagnosed POAG were included in the study. The patients were randomized into two groups. The first group was treated with betaxolol 0.50% twice daily and the second group with latanoprost 0.005% once daily. Baseline and post-treatment examinations on the first and third months of treatment included intraocular pressure (IOP) measurement, automated visual field testing, and ocular blood flow assessment. For evaluation of visual fields, mean defect and pattern standard deviation indices were used. Ocular blood flow was assessed by means of color Doppler imaging of the central retinal artery (CRA) and the temporal short posterior ciliary artery (PCA). For each vessel, peak systolic (PSV) and end-diastolic (EDV) blood flow velocities were measured and resistivity index (RI) calculated.

Results

After exclusion of one noncompliant patient, the study was completed with 31 eyes of 31 patients. Both drugs significantly reduced IOP (p<0.05). The mean IOP lowering effect of latanoprost was significantly higher than that of betaxolol (p=0.03). Visual field indices exhibited no significant changes in either group (p>0.05). There were no significant changes in PSV or EDV measurements of CRA or PCA in either group (p>0.05). RI decreased in both CRA and PCA with both drugs. The mean changes between baseline and 3 month blood flow measurements were not significantly different between betaxolol and latanoprost (p>0.05).

CONCLUSIONS

Over a treatment period of 3 months, both betaxolol and latanoprost tended to improve ocular blood flow without one of them being superior to the other. The results suggest that the direct (non IOP-dependent) influence on ocular circulation is better for betaxolol than for latanoprost. In addition, neither drug caused significant generalized improvements in visual fields during this period.

Use of Doppler Sonography in Evaluating the Effect of Age in the Central Retinal Artery: A Cohort Study

Intracranial arterial Doppler derived resistive indices (RI), peak systolic velocities (PSV), end diastolic velocities (EDV), and pulsatility indices (PI) have been shown to differ across age groups; therefore, the flow parameters in the central retinal artery (CRA) could also be expected to vary. The aim of this study was to evaluate the effect of age in CRA hemodynamics in a convenience sample of healthy men by using Doppler sonography. A total of 100 healthy adult male participants were recruited prospectively. Hitachi (HI VISION Avius) ultrasound equipment was used to measure the CRA PSV, EDV, RI, and PI within the right eye. Data were analyzed to determine velocity flow differences based on age. The results indicated that the CRA’s PSV and EDV declined with increasing age. The CRA’s RI and PI increased with age. Further research is indicated, specifically employing research designs that are statistically powered and use age matching, to generate clinically useful interpretations.

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.

Doppler ultrasonographic measurement of short-term effects of valsalva maneuver on retrobulbar blood flow

BACKGROUND

To investigate the effects of Valsalva maneuver (VM) on retrobulbar blood flow parameters in healthy subjects.

METHODS

Participants without any ophthalmologic or systemic pathology were examined in supine position with color and pulsed Doppler imaging for blood flow measurement, via a paraocular approach, in the ophthalmic artery (OA), central retinal artery (CRA), central retinal vein (CRV), nasal posterior ciliary artery (NPCA), and temporal posterior ciliary artery (TPCA), 10 seconds after a 35- to 40-mm Hg expiratory pressure was reached. Peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI), and resistivity index (RI) values were recorded for each artery. PSV and EDV values were recorded for CRV.

RESULTS

There were significant differences between resting and VM values of PSV and EDV of CRA, RI of NPCA, and PI, RI, and EDV of TPCA. Resting CRA-EDV, CRV-PSV, and CRV-EDV were positively correlated whereas resting OA-PSV and CRA-PI, and OA-PSV, CRA-PSV, and CRA-EDV during VM, were negatively correlated with age.

CONCLUSIONS

VM induces a short-term increase in CRA blood flow and a decrease in NPCA and TPCA RI. Additional studies with a longer Doppler recording during VM, in a larger population sample, are required to allow definitive interpretation. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:551-555, 2017.

Optical coherence tomography angiography: Technical principles and clinical applications in ophthalmology

Optical coherence tomography angiography (OCTA) is a functional extension of OCT that provides information on retinal and choroidal circulations without the need for dye injections. With the recent development of high-speed OCT systems and efficient algorithms, OCTA has become clinically feasible. In this review article, we discuss the technical principles of OCTA, including image processing and artifacts, and its clinical applications in ophthalmology. We summarize recent studies which qualitatively or quantitatively assess disease presentation, progression, and/or response to treatment.

Effect of intravitreal aflibercept (Eylea®) on retrobulbar hemodynamics in patients with neovascular age-related macular degeneration

PURPOSE

To investigate the short-term effect of single intravitreal aflibercept injection on retrobulbar blood flow in patients with neovascular age-related macular degeneration (nAMD).

METHODS

Twenty eyes of 20 patients with nAMD scheduled for single intravitreal aflibercept (Eylea^®) injection and 20 fellow eyes (uninjected) were enrolled in this prospective interventional study. The hemodynamic parameters of the ophthalmic artery (OA), central retinal artery (CRA) and posterior ciliary artery (PCA) comprising peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) were measured by using color Doppler ultrasonography (CDU) in both injected and uninjected fellow eyes at baseline and 1 week after the injection.

RESULTS

The measured first-week values of PSV and EDV in the CRA, OA and PCA showed a statistically significant reduction when comparing baseline values in both injected and uninjected fellow eyes (p = 0.0001). Also, it was found a significant increase in the post-injection RI values of all the CRA, OA, PCA in injected eye and OA in the uninjected eye (p = 0.0001). There was any significant difference between pre- and post-injection RI values of the CRA and PCA in the fellow eyes (p = 0.137, p = 0.736, respectively).

CONCLUSION

Single intravitreal administration of aflibercept alters retrobulbar blood flow velocities (BFVs) in both injected and uninjected fellow eyes in the short-term period.

Analysis of the blood supply to the post-fracture edentulous mandible: study by colour Doppler sonography

PURPOSE

This study assessed the arterial blood supply to the mandible of edentulous patients treated for mandibular fractures using colour Doppler ultrasound.

METHODS

The blood supply of edentulous patients surgically treated for mandibular fractures (group A) and edentulous fracture-free individuals (group B) was assessed. Only the fractured sides were evaluated in the first group (N = 17), whereas each side was evaluated in the second group (N = 20). The arterial flow of six sites was assessed. The systolic-peak maximum velocity (SPV), final diastolic velocity (FDV), resistive index (RI), pulsatility index (PI), acceleration and flow direction of each artery were obtained. Additionally, the presence of local vascular obstructive factors was evaluated. The differences between groups were analysed using the Kruskal-Wallis test, which was complemented by the Mann-Whitney test, for correlations between the degree of alveolar atrophy and the study factors (p < 0.050).

RESULTS

There was a significant decrease in the flow of certain arteries, especially the submental (SPV, p = 0.007, PI, p = 0.022, and acceleration, p = 0.015), in the fracture group. The facial artery in both groups showed lower values related to local obstructive factors (SPV, p = 0.001, FDV, p = 0.040, and PI, p = 0.030). The submental artery flow was higher (SPV, p = 0.006, and FDV, p = 0.009) in non-atrophic individuals.

CONCLUSIONS

There was a decreased flow mainly in the submental artery, but there were no cases of major vascular injury in edentulous patients treated for mandibular fractures.

In vivo imaging of retinal hemodynamics with OCT angiography and Doppler OCT

Retinal hemodynamics is important for early diagnosis and precise monitoring in retinal vascular diseases. We propose a novel method for measuring absolute retinal blood flow in vivo using the combined techniques of optical coherence tomography (OCT) angiography and Doppler OCT. Doppler values can be corrected by Doppler angles extracted from OCT angiography images. A three-dimensional (3D) segmentation algorithm based on dynamic programming was developed to extract the 3D boundaries of optic disc vessels, and Doppler angles were calculated from 3D vessel geometry. The accuracy of blood flow from the Doppler OCT was validated using a flow phantom. The feasibility of the method was tested on a subject in vivo. The pulsatile retinal blood flow and the parameters for retinal hemodynamics were successfully obtained.

The diagnostic performance of ultrasonographic optic nerve sheath diameter and color Doppler indices of the ophthalmic arteries in detecting elevated intracranial pressure

OBJECTIVES

To assess the diagnostic accuracy of ultrasonographic optic nerve sheath diameter (ONSD) measurement and color Doppler indices of the ophthalmic arteries in detecting elevated intracranial pressure (ICP).

PATIENTS AND METHODS

A total 60 patients with (cases, n=30) and without (controls, n=30) acute clinical and computed tomographic findings of elevated ICP due to intracranial mass/hemorrhage were recruited from a teaching hospital. The mean binocular and maximum ultrasonographic ONSDs, as well as the mean binocular Doppler ultrasound waveform indices of the ophthalmic arteries including pulsatility index (PI), resistive index (RI), end-systolic velocity (ESV), peak systolic velocity (PSV) and end-diastolic velocity (EDV) were compared between the two groups.

RESULTS

Compared to controls, the case group had significantly higher mean binocular ONSD (5.48 ± 0.52 mm vs. 4.09 ± 0.22 mm, p<0.001), maximum ONSD (5.63 ± 0.55 mm vs. 4.16 ± 0.23 mm, p<0.001), mean PI (1.53 ± 0.16 vs. 1.45 ± 0.20, p=0.01), and mean RI (0.76 ± 0.07 vs. 0.73 ± 0.04, p=0.01). The mean EDV, in contrast, was significantly higher in controls (8.55 ± 3.09 m/s vs. 7.17 ± 2.61 m/s, p=0.01). The two groups were comparable for the mean PSV (30.73 ± 7.93 m/s in cases vs. 32.27 ± 10.39 m/s in controls, p=0.36). Among the mentioned variables, the mean binocular ONSD was the most accurate parameter in detecting elevated ICP (sensitivity and specificity of 100%, cut-off point=4.53 mm). The Doppler indices were only moderately accurate (sensitivity: 56.7-60%, specificity: 63.3-76.7%).

CONCLUSION

While the ultrasonographic mean binocular ONSD (>4.53 mm) was completely accurate in detecting elevated ICP, color Doppler indices of the ophthalmic arteries were of limited value.

Color Doppler Imaging Analysis of Ocular Blood Flow Velocities in Normal Tension Glaucoma Patients: A Meta-Analysis

Background. To evaluate the potential diagnostic value of CDI of retrobulbar hemodynamic changes in NTG patients. Methods. Relevant publications which included PSV, EDV, and RI of OA, CRA, NPCA, and TPCA in NTG patients and normal controls measured by CDI were retrieved from the Cochrane Central Register of Controlled Trials, PubMed, the ISI Web of Knowledge, and EMBASE from 1990 to 2014. Subgroup analyses were made based on IOP-lowering medications uses. Result. In OA, there was significant decrease of PSV with moderate heterogeneity (P < 0.00001, I (2) = 49%) and significant decrease of EDV with significant heterogeneity (P = 0.0005, I (2) = 87%) in NTG patients. In CRA, similar results of PSV (P < 0.00001, I (2) = 42%) and EDV (P < 0.00001, I (2) = 80%) were detected. Significant decrease of PSV and EDV with significant heterogeneity was also found in both NPCA (P < 0.0001, I (2) = 70%; P < 0.0001, I (2) = 76%; resp.) and TPCA (P < 0.00001, I (2) = 54%; P < 0.00001, I (2) = 65%; resp.). Statistically significant increases of RI were found in CRA (P = 0.0002, I (2) = 89%) and TPCA (P = 0.02, I (2) = 81%) with significant heterogeneities, though RI in OA (P = 0.25, I (2) = 94%) and in NPCA (P = 0.15, I (2) = 86%) showed no statistical changes with significant heterogeneities. Conclusions. Ischemic change of retrobulbar hemodynamics is one of the important manifestations of NTG. Hemodynamic parameters measured by CDI might be potential diagnostic tools for NTG.

Retrobulbar Hemodynamics and Visual Field Progression in Normal Tension Glaucoma: A Long-Term Follow-Up Study

Purpose. Vascular risk factors are important factors in the pathogenesis of glaucoma. The purpose of this research was to investigate retrobulbar hemodynamics and visual field progression in patients with normal tension glaucoma (NTG). Patients and Methods. 31 eyes of 16 patients with NTG were included in a retrospective long-term follow-up study. Colour Doppler imaging was performed at baseline to determine various CDI parameters in the different retrobulbar vessels. The rate of visual field progression was determined using the Visual Field Index (VFI) progression rate per year (in %). To be included in the analysis, patients had at least 4 visual field examinations with a follow-up of at least 2 years. Results. Mean follow-up was 7.6 ± 4.1 years with an average of 10 ± 5 visual field tests. The mean MD (mean defect) at baseline was −7.61 ± 7.49 dB. The overall VFI progression was −1.14 ± 1.40% per year. A statistical significant correlation between VFI progression and the RI of the NPCA and PSV of the CRA was found. Conclusion. Long-term visual field progression may be linked to impaired retrobulbar hemodynamics in patients with NTG only to a limited degree. Interpretation of the data for an individual patient seems to be limited due to the variability of parameters.