Retrobulbar Blood Flow Research Articles

Eye microcirculation in glaucoma. Part 1. Diagnostic methods

Glaucoma is a socially significant disease, which is a wide group of polyetiological diseases. In the etiology of primary glaucoma, in addition to the mechanical theory, a vascular mechanism is also distinguished, and therefore, the search and development of the most informative and accurate method for studying ocular blood flow continues. Existing methods are divided into invasive and non-invasive. Invasive methods include angiography with intravenous fluorescein and indocyanine. Non-invasive methods include ultrasound Doppler mapping and pulsed Doppler modes, optical coherence tomography with angiography and laser speckle flowography. The review presents data on modern methods for ocular hemodynamics in glaucoma and ocular hypertension with technologies for studying retrobulbar blood flow and intraocular hemocirculation.

Correlation of retrobulbar perfusion deficits with glaucomatous visual field defects.

This study is to evaluate the correlation between retrobulbar perfusion deficits and glaucomatous visual field defects. Eighty-four patients with glaucoma and 17 normal subjects serving as controls were selected. Color Doppler imaging (CDI) was used to measure the changes in blood flow parameters in the retrobulbar ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary arteries (SPCAs). Visual field testing was performed using a Humphrey perimeter, categorizing the visual field deficits into four stages according to the Advanced Glaucoma Intervention Study (AGIS) scoring method. Subsequently, the correlation of retrobulbar hemodynamic parameter alterations among glaucomatous patients with varying visual field defects was examined. The higher the visual field stage, the lower the peak systolic velocity (PSV) of the OA, CRA, and SPCAs in glaucomatous patients. The CRA had the highest sensitivity to changes in its PSV. The PSV of the temporal SPCA (TSPCA-PSV) was lower in advanced glaucoma than in early-stage glaucoma. The PSVs of the OA, CRA, and TSPCA, as well as the resistance index of the CRA (CRA-RI), were positively correlated with the visual field index and the mean deviation. Except for that of OA, the PSV of the retrobulbar vessels was negatively correlated with the pattern standard deviation (PSD). The OA-PSV and end-diastolic velocity (EDV) of the CRA and TSPCA were lower in patients with superior visual field defects than in those with inferior visual field defects. Greater severity of visual field defects corresponded to poorer retrobulbar blood flow in glaucomatous patients. Patients suffered significant perfusion impairments in the CRA at the early stage, accompanied by SPCA perfusion disorder at the advanced stage. The presence of a bow-shaped defect in the superior or inferior region of the visual field in moderate-stage glaucoma was closely correlated with retrobulbar vascular EDV. ChiCTR2200059048 (2022-04-23).

Ultrasound indicators of blood flow in the eyes and orbits at different durations of type 1 diabetes mellitus in childhood and adolescence

Diabetic retinopathy is a complication of type 1 diabetes mellitus with high social significance, especially in childhood and adolescence.Aim: To evaluate ultrasound indicators of retrobulbar blood flow at different durations of type 1 diabetes mellitus in childhood and adolescence.Material and Methods. Ultrasound examinations were performed in 70 patients with type 1 diabetes mellitus aged from 5 to 18 years, with disease duration of up to 5 years, from 5 to 10 years, and more than 10 years. The analysis included an assessment of the linear velocity of blood flow and the index of peripheral resistance in the ophthalmic arteries, central arteries and retinal veins, posterior short ciliary arteries, and ophthalmic veins at different times of the duration of type 1 diabetes mellitus.Results. The study revealed a decrease in blood flow velocity in the central retinal arteries, in the posterior short ciliary arteries with an increase in the duration of type1 diabetes mellitus. The greatest decrease in blood flow velocity was recorded in the group with duration of diabetes mellitus of more than 10 years.Conclusion. The obtained data on a decrease in blood flow velocity in the retrobulbar arteries can be used for the assessment and dynamic monitoring of early disorders of the blood supply to the eye and orbit in patients with type 1 diabetes mellitus in childhood and adolescence.

Correlation between choroidal vascularity and retrobulbar ocular blood flow changes and thyroid-associated ophthalmopathy activity: a cross-sectional study

ObjectiveTo evaluate the alterations in retrobulbar color Doppler imaging (CDI) parameters and retinal/choroidal optical coherence tomography angiography (OCTA) parameters and their association with the clinical activity and severity in thyroid-associated orbitopathy (TAO) patients.MethodsIn this study, the retrobulbar flow parameters including resistance index (RI), Pulsatile Index(PI), peak systolic velocity (PSV) and end diastolic velocity (EDV) in posterior ciliary artery (PCA), central retinal artery (CRA) and ophthalmic artery (OA) were determined by CDI. Moreover, the retina and choroidal vascularity including the superficial vessel density (SVD), deep vessel density (DVD), choroidal thickness (ChT) and choroidal vascularity, including total choroidal area (TCA), luminal area (LA), stromal area (SA) and Choroidal Vascularity Index (CVI), were determined by OCTA. All patients grouped as active TAO and inactive TAO based on Clinical activity score (CAS). We picked the severe eye among the subjects and compared all parameters between two groups. We analyzed the correlations among those parameters.ResultsThere was a significant difference in CAS score, proptosis value, ChT, LA, CVI between patients with active TAO and inactive TAO. In the active group, PSV and EDV of PCA were significantly higher than the inactive group. On logistic regression analysis, CAS was closely associated with PSV-PCA. On multiple linear regression, proptosis value was closely associated with ChT, LA, SA and CVI.ConclusionChoroidal vascularization and retrobulbar blood flow were concurrently higher in active TAO patients and several variables in choroid circulation was closely related to TAO clinical features.

Dynamics of ultrasound indicators of retrobulbar blood flow at different durations of type 1 diabetes mellitus in childhood and adolescence

The results of a study of the dynamics of ultrasound parameters of blood flow in the eye and orbit in patients with type 1 diabetes mellitus in childhood and adolescence are presented. The study included data from 70 patients aged 5 to 18 years, with disease duration up to 5 years, from 5 to 10 years, and more than 10 years. Ultrasound indicators of linear blood flow velocity and peripheral resistance index were analyzed in the ophthalmic arteries, central arteries and veins of the retina, posterior short ciliary arteries, and superior ophthalmic veins at different periods of the duration of type 1 diabetes mellitus. The study revealed a decrease in blood flow velocity in the central retinal arteries and in the posterior short ciliary arteries with increasing duration of type 1 diabetes. The greatest decrease in blood flow velocity was recorded in the group with a duration of diabetes mellitus of more than 10 years. The data obtained can be used to assess and dynamically monitor early disorders of the blood supply to the eye and orbit in patients with type 1 diabetes mellitus in childhood and adolescence.

Measurement of Retrobulbar Blood Flow and Vascular Reactivity—Relevance for Ocular and Cardiovascular Diseases

Abnormal retrobulbar hemodynamics have been linked to the development of various ocular diseases, including glaucoma, age-related macular degeneration, and diabetic retinopathy. Additionally, altered retrobulbar blood flow has been observed in patients with severe cardiovascular diseases, including carotid artery occlusion, stroke, heart failure, and acute coronary syndrome. Due to the complex and intricate anatomy of retrobulbar blood vessels and their location behind the eyeball, measurement of retrobulbar blood flow and vascular reactivity, as well as the interpretation of the findings, are challenging. Various methods, such as color Doppler imaging, computed tomography angiography or magnetic resonance imaging, have been employed to assess retrobulbar blood flow velocities in vivo. Color Doppler imaging represents a fast and non-invasive method to measure retrobulbar blood flow velocities in vivo. While no information about vessel diameter can be gained performing this method, computed tomography angiography and magnetic resonance imaging provide information about vessel diameter and detailed information on the anatomical course. Additionally, ex vivo studies, such as myography, utilizing genetically modified animal models may provide high optical resolution for functional vascular investigations in these small vessels. To our best knowledge, this is the first review, presenting a detailed overview of methods aiming to evaluate retrobulbar blood flow and vascular reactivity in both humans and laboratory animals. Furthermore, we will summarize the disturbances observed in retrobulbar blood flow in retinal, optic nerve, and cardiovascular diseases.

State-of-the-art methods of qualitative and quantitative assessment of eye microcirculation

Circulatory disorders in eye vessels play an important role in the development of ophthalmic pathologies, in particular socially significant diseases such as glaucoma, age-related macular degeneration, diabetic retinopathy, and retinal vascular occlusion. Eye hemodynamics features are an important diagnostic criterion for both ocular and systemic diseases. A comprehensive assessment of blood flow in various structures of the eyeball offers additional information on the pathogenesis of the diseases and helps develop new approaches to monitoring the effectiveness of treatment and vascular pathology prognostication. Thanks to the improved technologies, we have today a variety of invasive and non-invasive techniques for examining ocular hemoperfusion, including those intended for retrobulbar blood flow and intraocular blood circulation evaluation. The review article is focused on the state-of-the-art techniques: fluorescein angiography, ultrasound examination involving blood flow assessment by colour Doppler mapping and Dopplerography, optical coherence tomography in the angiographic mode and laser speckle flowgraphy. The role of these techniques in the diagnosis of vascular pathology and their advantages and disadvantages when used in ophthalmological practice is considered.

Влияние употребления кофе на гемодинамику глаза в режиме цветного допплеровского картирования

The most common methods for studying ocular blood flow include the method of color Doppler imaging (CDI). Purpose. To evaluate the effect of drinking coffee on the indicators of retrobulbar blood flow in healthy people using color doppler and to predict the possible impact of this factor on the results of the study of ocular blood flow in pathology of the organ of vision. Material and methods. The total number of observations is 16: 8 healthy people (8 eyes) before drinking coffee and an hour after drinking it, 8 healthy people (8 eyes) of the control group. The age of the subjects was 28 ± 2 years. As a control feature, a cup of made coffee (150 ml) was used, which was drunk one hour before the examination. The control group included persons who underwent a study of retrobulbar blood flow with an hour interval without drinking coffee. The calculations were carried out using the STATISTICA 13.0 software. Results. Analyzing the dynamics of the CDI indicators, there was an increase in the diastolic blood flow velocity and the average blood flow velocity in the ophthalmic artery one hour after drinking coffee (p < 0.05) compared with the control group. When assessing the indicators of the resistance index and the pulse index, their increase was found, but these changes turned out to be reliably insignificant, which indicates a change in blood flow in a certain period of cardiac output, but does not affect the total blood flow in the ophthalmic artery. Conclusion. Thus, the data obtained during the CDI indicate a change in ocular blood flow in the ophthalmic artery to a certain cardiac output one hour after drinking coffee, without affecting the true blood flow velocity and peripheral resistance in the ophthalmic artery. The CDI values in the central retinal artery did not change. Keywords: ophthalmic artery, central retinal artery, color Doppler imaging, drinking coffee

Early effects of inactivated (CoronaVac) SARS-CoV-2 vaccine on retrobulbar vascular blood flow and retinal vascular density

AimsWe aimed to investigate the early effects of inactivated SARS-CoV-2 vaccine on retrobulbar vascular blood flow and retinal vascular density in healthy subjects. MethodsThirty-four eyes of 34 healthy volunteers who received the CoronaVac (Sinovac Life Sciences, China) were included in this prospective study. Resistive index (RI), pulsatility index (PI) and peak systolic velocity (PSV) of the ophthalmic artery (OA), central retinal artery (CRA), and the temporal and nasal posterior ciliary arteries (PCA) were evaluated with color Doppler ultrasonography (CDUS) before vaccination, at the 2nd and 4th weeks after vaccination. Superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density (VD), foveal avascular zone (FAZ), and choriocapillaris blood flow (CCF) measurements were made using optical coherence tomography angiography (OCTA). ResultsWhen compared to the pre-vaccination values, there was no significant change in OA-PSV, temporal-nasal PCA-PSV, CRA-EDV, temporal-nasal PCA-EDV at 2nd and 4th weeks after vaccination. However statistically significant reductions were found in the OA-RI, OA-PI, CRA-RI, CRA-PI, temporal-nasal PCA-RI, temporal-nasal PCA-PI values, CRA-PSV at post-vaccination 2nd week (p<0.05 for all). While there was sustained reduction in OA-RI, OA-PI, CRA-PSV, and nasal PCA-RI values at 4th week after vaccination, the change in CRA-RI, CRA-PI, temporal PCA-RI, temporal-nasal PCA-PI values were not significant compared to pre-vaccination values. There was no statistically significant difference in the SCP-VD, DCP-VD, FAZ and CCF measurements. ConclusionsOur findings demonstrating that CoronaVac vaccine did not affect retinal vascular density in the early period, but it caused alterations in the retrobulbar blood flow.

Color doppler ultrasound analysis of pathological myopia induced changes in retrobulbar blood flow and its relationship with characteristic changes in myopia.

To analyze changes in retrobulbar blood flow in patients with pathological myopia using color doppler ultrasound (CDU), and to explore the relationship of these changes with the characteristic changes resulting from myopia. One hundred and twenty patients who met the selection criteria in the ophthalmology department of He Eye Specialist Hospital from May 2020 to May 2022 were included in this study. Patients with normal vision (n=40) were considered Group-A, patients with low and moderate myopia (n=40) were considered Group-B, and patients with pathological myopia (n=40) were considered Group-C. All three groups underwent ultrasonography. The peak systolic blood flow velocity (PSV), end-diastolic blood flow velocity (EDV), and resistance index (RI) of the ophthalmic artery, central retinal artery, and posterior ciliary artery were recorded and compared, and the characteristics of these parameters and myopia severity were analyzed. Pathological myopia resulted in significantly lower PSV and EDV of the ophthalmic artery, central retinal artery and posterior ciliary artery and higher RI values than patients with normal vision and low/moderate myopia (P<0.05). Pearson correlation analysis showed that retrobulbar blood flow changes were significantly correlated with age, eye axis, best corrected visual acuity, and retinal choroidal atrophy. CDU can objectively evaluate the retrobulbar blood flow changes in pathological myopia, and such blood flow changes are significantly correlated with the characteristic changes of myopia.

Retrobulbar Blood Flow Parameters in Patients With Anisometropic Amblyopia.

Introduction We aim to compare retrobulbar blood flow parameters between the amblyopic eye and the fellow eye in patients with anisometropic amblyopia. Methods Peak systolic velocity (PSV) and end-diastolic velocity (EDV) of the ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery (PCA) were measured by color Doppler imaging (CDI), and the resistivity index (RI) and pulsatility index (PI) were calculated in 62 patients aged 12-40 years with anisometropic amblyopia. Results The mean PSV values of OA, CRA, and PCA in amblyopic and fellow eyes were 30.38 ± 10.34, 8.45 ± 2.27, and 8.03 ± 2.77, and33.73 ± 14.46, 8.35 ± 2.05, and 8.81 ± 2.77, respectively. The mean EDV values of OA, CRA, and PCA in amblyopic and fellow eyes were 6.86 ± 2.64, 1.47 ± 1.59, and 1.94 ± 2.03, and 8.57 ± 4.30, 1.80 ± 1.73, and 2.32 ± 1.20, respectively. The mean RI values of OA, CRA, and PCA in amblyopic and fellow eyes were 0.77 ± 0.10, 0.85 ± 0.14, and 0.78 ± 0.15, and 0.75 ± 0.07, 0.79 ± 0.20, and 0.74 ± 0.13, respectively. OA-PSV and OA-EDV values were significantly lower in the amblyopic eye than in the healthy eye (p < 0.05). OA-RI values were significantly higher (p < 0.05) in the amblyopic eye than in the healthy eye. Conclusions Considering the decrease in PSV and EDV and the increase in RI, which are the blood flow parameters of the amblyopic eye, our study may provide guidance to focus on increasing blood flow in the treatment of amblyopia.

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.

Efficacy of dorzolamide in improving ocular blood flow in patients with open-angle glaucoma: The Indian carbonic anhydrase inhibitor trial.

Impaired ocular blood flow is an important risk factor in the pathogenesis of open-angle glaucoma (OAG). Studies have reported that dorzolamide 2% may be effective in improving ocular blood flow (OBF) in OAG patients. The objective of this study was to determine the efficacy of dorzolamide 2% (DORZOX, Cipla Ltd.) in improving retrobulbar blood flow in an Indian setting. The study was conducted as an interventional pilot project in 24 healthy subjects and 19 OAG patients. Baseline OBF measurements were done for all glaucoma patients with color Doppler imaging (CDI). Baseline ocular perfusion pressure (OPP) was calculated for all participants. Glaucoma patients were given dorzolamide 2% thrice daily for 12 weeks. The primary efficacy endpoints were mean changes in the CDI parameters of the retrobulbar vessels and OPP posttreatment. The secondary endpoint was mean change in the intraocular pressure (IOP) and adverse events, if any. In comparison to healthy subjects, glaucoma patients displayed significantly reduced baseline OPP (P = 0.002). Treatment with dorzolamide 2% for 12 weeks led to a significant increase in OPP (P < 0.001) and a significant increase in end diastolic velocity (EDV) in all major ophthalmic arteries like ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary artery (SPCA) (P < 0.001, P = 0.04, and P = 0.0075, respectively). A significant reduction in the intraocular pressure (IOP; P = 0.007) was observed posttreatment, with no adverse events reported. Dorzolamide 2% significantly improved parameters such as the EDV and OPP in major ophthalmic arteries. This pilot study shows promising results on using dorzolamide for treating Indian patients with OAG.

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.

Quantitative evaluation of retinal and choroidal vascularity and retrobulbar blood flow in patients with myopic anisometropia by CDI and OCTA

AimsTo investigate the association between the myopic severity and retinal microvascular density, choroidal vascularity and retrobulbar blood flow in adult anisomyopes.MethodsThis study comprised 90 eyes of 45 myopic anisomyopes who...

Retrobulbar blood flow velocity in systemic lupus erythematosus assessed by color Doppler imaging.

To analyze the blood flow in retrobulbar vessels in systemic lupus erythematosus (SLE) by color Doppler imaging (CDI) and to investigate the associations between immunological markers, retinal abnormalities, disease activity, and vascular parameters. We examined 30 patients with SLE who were aged 32.1 ± 11.6years with a disease duration of 68.0 ± 55.6months and 30 participants in a control group. The peak systolic velocity (PSV), end diastolic velocity (EDV), pulsatility index (PI), and resistive index (RI) of the ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary arteries (PCAs) were determined. Physical and ophthalmic examinations with assessments of immunological markers were performed. All parameters were compared between SLE patients and normal controls while the correlations among parameters were analyzed. In the SLE group, CDI confirmed blood flow abnormalities in the CRA and PCAs, with significantly lower blood flow velocities and increased RI and PI (p < 0.05). There was a significantly negative correlation between disease duration and EDV in the CRA, PCA, and OA (p = 0.0423, 0.0453, 0.0448). There was also a significant relationship between the SLE Disease Activity Index and the PI of the OA (p = 0.0367). The patients who had received biological agents (Rituximab) had lower EDV in the CRA and PCA (p = 0.0026, 0.028). SLE patients with kidney or CNS involvement had a significant increase in the PI in the OA (p = 0.0287). The PSV and EDV in the CRA were significantly related to creatinine (p = 0.0007 and 0.0418). We also noted a significant decreased EDV in the CRA and an increased RI in the OA among participants positive for anti-dsDNA antibodies (p = 0.0331 and 0.0228). Retrobulbar circulatory disturbances were detected in SLE patients by CDI. These findings seem likely to affect smaller vessels like the CRA and PCA. However, the presence of measurable changes in the OA is generally indicative of a coexistent nephropathy or central nervous system (CNS) vasculitis. Creatinine, the disease activity index, being positive for anti-dsDNA, and receiving biological agents were associated with measurable changes on the retrobulbar blood flow.

A study on effect of diabetes mellitus and hypertension on ocular blood flow by colour doppler ultrasonography

Background: Diabetes mellitus (DM) and hypertension (HT) have been the two major medical and public health issues for over 40 years worldwide. Colour doppler imaging (CDI) is widely used to evaluate ocular circulation. It is non-invasive, safe, and useful tool, most commonly used to investigate circulatory parameters in retrobulbar blood vessels. The aim was to study ocular blood flow (OBF) velocity in the ophthalmic artery (OA), central retinal artery (CRA) and central retinal vein (CRV) in patients with DM and HT by CDI. Materials and methods: A cross-sectional observational study was done for 6 months (June 2021–November 2021) on 40 patients of age 40 years and above with DM and/or HT of a minimum 6 months duration. Retrobulbar circulation was assessed in all subjects bilaterally. Subjects were further divided into groups with or without retinopathy. Results: Of the total number of 40 participants, 26 (65%) were male, and 14 (35%) were female. 16 (40%) participants were diabetics, 8 (20%) were hypertensive, and 16 (40%) had both DM and HT. 57.5% were diagnosed with retinopathy changes. The mean values of the pulsatile index (PI) were: 1.23 in patients with DM, 1.30 in patients with HTN, and 1.33 in patients with DM and HTN. Conclusion: Our study showed reduced blood flow velocity and increased resistivity index (RI) in patients with DM and/or HT. Significant changes were noted in retrobulbar blood flow in patients with retinopathy. These results can potentially provide prognostic values in times to come regarding altered OBF even before retinopathy develops.

Evaluation of the impact of childhood obesity on retrobulbar hemodynamics and retinal microvasculature.

To evaluate changes in retrobulbar ocular blood flow parameters by using Colour Doppler Imaging (CDI) and changes in foveal microvasculature by using Optical Coherence Tomography Angiography (OCTA) in pediatric obese patients and to compare them with a group of healthy children. Children diagnosed with obesity without hypertension and diabetes (39 subjects, obese group) and age-matched healthy controls (26 subjects, control group) underwent CDI and OCTA imaging. Peak systolic velocity, end-diastolic velocity and resistivity index from ophthalmic, central retinal and posterior ciliary arteries on CDI; superficial and deep capillary plexus vascular density and foveal avascular zone area on OCTA imaging were obtained in each group. Central foveal and subfoveal choroidal thicknesses were also measured. CDI and OCTA parameters were compared between two groups. Peak systolic and end-diastolic velocities were found to be significantly lower in obese children than in controls in all three examined arteries (p < 0.05). Resistivity index values were similar between the groups. OCTA imaging did not reveal significant changes in superficial and deep capillary plexus vascular densities and foveal avascular zone area across analysed retinal regions between the groups. Subfoveal choroid was thicker in obese group than in control group (325.89 ± 52.77 µm vs. 304.52 ± 21.76 µm, p = 0.04). An apparent decrease was present in retrobulbar hemodynamics in obese children. This arises the possibility of early ocular macrovascular compromise rather than retinal microvascular impairment in childhood obesity.

Ocular microcirculation after revascularization of the internal carotid artery in the early postoperative period

To study the impact of CEA and CAS interventions on ocular blood flow in patients with clinically significant ICA stenosis in the early postoperative period. Thirty-two patients with hemodynamically significant stenosis (≥75%) of the left or right ICA were examined using optical coherence tomography angiography (OCT-A) and flowmetry before and after CEA or CAS in order to assess the changes in ocular blood flow parameters. There were no significant differences in hemodynamic parameters in the eyes on the side of the stenotic and non-stenotic ICA before revascularization. In the early postoperative period (3-7 days) in the ipsilateral eyes, there was an increase in blood flow density and vascular density at the level of the superficial and deep plexuses in the macular area (p≤0.05), as well as an increase in the ocular blood flow volume, the level of tolerated intraocular pressure (p≤0.05) and a decrease in intraocular pressure (p≤0.05) bilaterally. In the contralateral eyes, after ICA revascularization there was a partial improvement in microcirculation parameters according to OCT-A (p≤0.05). Peripapillary blood flow density and peripapillary vessel density did not change significantly either on the ipsilateral or the contralateral side. In patients with clinically significant ICA stenosis, ICA revascularization by stenting or endarterectomy contributed to an improvement in retinal microcirculation and retrobulbar blood flow in both eyes. OCT-A and flowmetry allow non-invasive assessment of retinal microvessels and retrobulbar blood flow, and the measurements provided by these methods can serve as valuable biomarkers for predicting and monitoring hemodynamic changes in patients who undergo CEA and CAS surgeries.

ET‐1 plasma levels and scleral rigidity as risk factors in neovascular age‐related macular degeneration

AbstractPurposeTo study the ocular blood flow, the corneal biomechanics, the scleral rigidity and the endothelin‐1 (ET‐1) plasma levels in patients with neovascular age‐related macular degeneration (ARMD).MethodsWe enrolled 20 patients with ARMD and 20 age‐matched control patients. Retrobulbar blood flow was examined by Colour Doppler Aplio 500 (Toshiba Medical System, Tokyo, Japan). Peak systolic velocity (PSV) and resistivity index (RI) was measured from ophthalmic artery (OA), central retinal artery (CRA) and posterior ciliary arteries (PCA’s). The corneal hysteresis CH and the corneal resistance force (CRF) values were achieved by Ocular Response Analyzer (ORA). Scleral rigidity (E) was determined by using Friedenwald nomograms. ET‐1 plasma levels were determined using a specific radioimmunoassay (Sigma‐Aldrich, Merck, Germany).ResultsWe found a statistically significant difference in the CRF between patients with ARMD and control subjects (ARMD 11.23 ± 1.30 vs. Controls 9.82 ± 1.37; p&lt;0.0025) was found. The CH index between patients with ARMD and control subjects was not statistically significant (ARMD 10.15 ± 1.25 vs. Controls 10.02 ± 1.70; p&lt;0.617). With CDI in PCA’s we found PSV (ARMD 12.37 ± 2.80 cm/sec vs. Controls 15.44 ± 3.59 cm/sec; p&lt;0.0063); RI (ARMD 0.80 ± 0.03 vs Controls 0.74 ± 0.02; p&lt;0.0001). The E had a significant increase in ARMD group (ARMD 0.0358 ± 0.004 vs. Controls 0.0328 ± 0.004; p&lt;0.008) as well as ET‐1 plasma levels (ARMD 2.060 ± 0.276 vs. Controls 1.492 ± 0.0.560; p&lt;0.001). Finally, in ARMD we found that the decrease of PSV and the increase of RI in PCA’s was correlated with the ET‐1 plasma levels (PSV r‐0.615; p&lt;0.0039 and r 0.764; p&lt;0.0001) and not with the values of E, CH and CRF.ConclusionsOur data indicate that patients with neovascular ARMD had a significant increase of RI in all vessels examined with increased corneal CRF index, scleral rigidity values and ET‐1 plasma levels. The decreased blood flow in APC’s was correlated to the increase of ET‐1 plasma levels. These data indicate that elevated plasma ET‐1 and not the scleral rigidity may be an important risk factor in the development of neovascular ARMD.