Ocular Blood Flow Parameters Research Articles

Doppler ocular ultrasound in patients with type 2 diabetes mellitus

Purpose: To determine ocular blood flow parameters by Doppler ultrasound scanning in type 2 diabetic patients with different stages of diabetic retinopathy. Material and Methods: In this prospective study, forty-five patients (90 eyes) with type 2 diabetes mellitus were divided into three groups of 15 patients each: no diabetic retinopathy group (DR0), non-proliferative retinopathy (NPDR), and proliferative retinopathy (PDR) groups. Doppler indices such as systolic blood flow velocity (Vs), diastolic blood flow velocity (Vd), time-averaged maximum velocity (TAMXV), pulsatility index (PI) and resistivity index (RI) in the ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary arteries (SPCA) were determined. ANOVA was used for quantitative comparisons between the three groups. Results: There was a significant (р less 0.05) decrease in (a) the Vs from 71.1 +- 20.6 cm/s in the DR0 group to 59.9 +- 16.7 cm/s in the NPDR group and 47.4 +- 16.4 cm/s in the PDR group, (b) Vd from 22.1 +- 6.9 cm/s to 17.0 +- 6.6 cm/s and 12.3 +- 5.9 cm/s, respectively; and (c) TAMXV from 37.2 +- 11.3 cm/s to 31.9 +- 9.1 cm/s and 25.3 +- 9.7 cm/s, respectively, and an increase in the RI from 0.69 +- 0.06 cm/s to 0.71 +- 0.09 cm/s and 0.75 +- 0.08 cm/s, respectively, in the OA. In addition, there was a significant decrease in the Vd from 9.9 +- 5.4 cm/s in the DR0 group to 8.1 +- 3.8 cm/s in the NPDR group and 5.5 +- 3.1 cm/s in the PDR group, and an increase in the PI from 1.34 +- 0.16 cm/s to 1.46 +- 0.28 cm/s and 1.54 +- 0.24 cm/s, respectively, and in the RI from 0.71 +- 0.06 cm/s to 0.75 +- 0.07 cm/s and 0.80 +- 0.05 cm/s, respectively, in the CRA. Moreover, there was a significant decrease in the Vd from 4.3 +- 1.6 cm/s in the DR0 group to 3.2 +- 2.0 cm/s in the NPDR group and 3.1 +- 2.2 cm/s in the PDR group, and an increase in the PI from 1.32 +- 0.21 cm/s to 1.37 +- 0.24 cm/s and 1.54 +- 0.26 cm/s, respectively, and in the RI from 0.76 +- 0.04 cm/s to 0.82 +- 0.06 cm/s and 0.82 +- 0.06 cm/s, respectively, in the SPCA. Conclusion: We found that the arteries examined in patients with diabetic retinopathy tended to have decreased blood flow velocities and increased resistivity and pulsatility indices, with the greatest changes observed in patients with PDR. In addition, the difference in mean values of most Doppler indices between the PDR and NPDR groups was larger than that between the NPDR and DR0 groups.

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.

Changes in ocular hemodynamics in patients recovered from COVID-19

To evaluate the severity of hemodynamic changes in the ocular vessels of patients recovered from COVID-19. The study included 44 patients (88 eyes) aged 28-60 years, among them 24 (54.5%) women and 20 (45.4%) men, with SARS-CoV-2 infection confirmed by PCR no more than 2 months prior to enrollment and with no ophthalmological complaints within 2 months before the disease, as well as 20 healthy volunteers (40 eyes). At the time of the study all patients had a negative PCR result for SARS-CoV-2. The patients were divided into 2 groups. The first group comprised 24 patients who did not take any anticoagulants during the treatment. The second group consisted of 20 patients who received anticoagulants (Rivaroxaban (Xarelto)) at a dosage of 10 mg per day for 1-1.5 months. The maximum systolic (Vs), end-diastolic (Vd) blood flow velocity, as well as resistance index (RI) in the ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary arteries (SPCA) were measured in all study patients with the ultrasound imaging system VOLUSON E8 Expert («Kretz», USA). Additionally, the flowmetry method was used to assess the volumetric ocular blood flow (VOBF) on Ocular Blood Flow Analyzer system («Paradigm Medical Industries, Inc.», USA). In the first group, a decrease in Vs and Vd was noted amid a significant increase of RI in CRA and SPCA, as well as an increase of RI in OA compared with the age-normal values (p<0.05). In the second group, a decrease in Vs and Vd was noted amid a significant increase of RI in CRA, as well as a decrease in Vs in SPCA and an increase of RI in OA relative to the age-normal values (p<0.05). A decrease in VOBF was noted in the first group in comparison to the second group and the age norm (p<0.05). Blood flow velocity parameters in the ocular vessels are reduced in patients recovered from COVID-19 compared to the age-normal values. There was a significant decrease in volumetric ocular blood flow parameters in COVID-19 patients who did not take any anticoagulants compared to the age-normal values. Anticoagulants intake has a positive impact on hemodynamic characteristics in the ocular vessels and volumetric ocular blood flow in patients with COVID-19.

Ocular blood flow and choroidal thickness in ocular hypertension.

Ocular hypertension (OHT) is a clinical entity characterized by elevated intraocular pressure (IOP) without optic nerve damage. In the presence of other risk factors, OHT may progress to glaucoma. This study aimed to evaluate ocular blood flow (OBF) and choroidal thickness (CT), which may be markers and/or risk factors that could assess the progression of OHT to glaucoma. Age and gender matched 60 eyes of 32 patients with OHT and 61 eyes of 31 control patients were included for this study. All participants underwent a detailed ophthalmological examination including best-corrected visual acuity, IOP measurement with Goldmann applanation tonometry, gonioscopy, optic nerve evaluation with 78 D lens, and visual field test with Humphrey visual field analyzer. Retinal nerve fiber layer, ganglion cell complex, and central corneal thickness measurements were performed by optical coherence tomography (OCT). CT was measured with OCT in the fovea, 1.5mm, 2mm, 2.5mm nasal and temporal to the fovea and from nasal and temporal to the optic disk. OBF data including peak systolic velocity (PSV), end-diastolic velocity (EDV), resistivity index (RI) and pulsatility index (PI) were measured with color Doppler imaging (CDI) from the ophthalmic artery (OA), central retinal artery (CRA), medial and lateral branches of short posterior ciliary arteries (MPCA, LPCA). Systolic (SBP) and diastolic arterial blood pressure were also noted. CT measurement at each point in the OHT group compared to the control group were found to be significantly thinner (p = 0.001). There was a decrement in CT from the fovea to the nasal and temporal retina in both groups. In the OHT group, there was a significant decrease in PSV and EDV of OA, CRA, MPCA, and LPCA, and a significant increase in PI and RI of measured arteries. (EDV p = 0.036, PI p = 0.006, RI p = 0.006 for OA and p = 0.001 for other arteries and all OBF measurements). There was a negative correlation between CT and age, IOP and axial length (AL) in OHT group (r = - 0.529, p = 0.001; r = - 0.258, p = 0.047; r = - 0.345, p = 0.007, respectively, for fovea). But there was no statistically significant correlation between CT and other measurements in the control group, except age (r = - 0.860 p = 0.001 for fovea). We found that OBF decrement and choroidal thinning in OHT group compared with controls. Interpretation both of CT measurements with OCT and OBF parameters with CDI and new imaging technologies may help to prevent and reduce the possible optic nerve damage.

Abstract 8881: Comprehensive Assessment of Systemic Atherosclerosis in Relation to the Ocular Resistive Index in Acute Coronary Syndrome Patients

Introduction: It remains unclear how systemic atherosclerosis can affect ocular microvessels. The abnormality of the ocular microvasculatures can be non-invasively detected by measuring ocular arterial blood flow velocity using laser speckle flowgraphy (LSFG). Among the ocular blood flow parameters obtained by LFSG, the ocular blowout time (BOT) and the ocular resistivity index (RI) are used as the index of retinal vascular resistance. The purpose of this study was to investigate the relationship between ocular vascular resistance evaluated by LSFG and cardiac function evaluated by transthoracic echocardiography in patients with acute coronary syndrome (ACS). Methods: We evaluated 53 patients with ACS who were taken to Coronary Care Unit between April 2019 and September 2020. The mean blur rate (MBR), the ocular blowout time (BOT) and the ocular resistivity index (RI) were measured by LSFG. In addition, the age-matched normal subjects were also evaluated the measurement of LSFG in 20 healthy subjects with no ocular disease and no history of cardiovascular disease. Results: Among all ACS patients, there were significant positive correlations between ocular RI and systemic parameters, i.e., IMT(r = 0.34, P = 0.01), PWV(r = 0.41, P &lt; 0.01), BUN(r = 0.27, P = 0.047), cystatin C(r = 0.32, P = 0.020), urinary β2 microglobulin(r = 0.30, P = 0.029), L-FABP(r = 0.28, P = 0.046), and E/e’(r = 0.34, P = 0.013). There was also significant negative correlation between ocular BOT and PWV(r = -0.44, P &lt; 0.01). Age-matched comparing the selective ACS (n=20) with healthy group (n=20), the ocular RI was significantly higher in the ACS group (0.34 ± 0.04 vs 0.38 ± 0.07, P = 0.03). Conclusions: We found that the ocular resistivity index, which was non-invasively obtained by LSFG, was associated with systemic atherosclerosis, early renal dysfunction and cardiac diastolic dysfunction in ACS patients, suggesting that it might be useful index as an non-invasive comprehensive arteriosclerotic markers.

Evaluation of Flowmetry Indicators in Patients with a Wet AMD Form during Antiangiogenic Therapy

Purpose: to assess the effect of aflibercept (Eylea; “Regeneron”, USA) intravitreal injections on ocular blood flow and intraocular pressure parameters in patients with neovascular form of age-related macular degeneration (wet AMD). Currently, neovascular agerelated macular degeneration (wet AMD) is one of the leading causes of irreversible vision loss and blindness among populations over the age of 50 . Material and methods. The study included 35 patients (35 eyes), 10 men and 25 women. Mean patients’ age was 72 ± 6 years. The inclusion criteria were the established diagnosis of a neovascular form of age-related macular degeneration and the level of ophthalmotonus not more than the accepted upper limit of the average norm — IOP 21 mm hg prior to drug administration of the drug. All patients underwent flowmetry with ocular blood flow (OBF) volume determination and intraocular pressure (IOP) measurement. The patients received a singular intravitreal aflibercet injection (2 ml). OBF and IOP were measured at baseline before the injection and the on day 4 and 1 month after the injection. Results. There was no statisticaly significant difference between the IOP level before and after the injection. We revealed a tendency towards OBF decrease in 1 month after the injection, but overall values and the decrease both 4 days and 1 month after the intravitreal injection did not prove to be statistically significant. The absence of statistically significant changes of intraocular pressure level and volumetric ocular blood flow additionally confirms information about the safety of intravitreal administration of aflibercept to patients with a wet form of age-related macular degeneration.

Exercise-Induced Changes in Ocular Blood Flow Parameters in Primary Open-Angle Glaucoma Patients

Purpose: To evaluate exercise-induced changes in ocular blood flow (OBF) parameters in primary open-angle glaucoma (POAG) patients. Methods: A prospective observational study was carried out, in which medically treated patients with POAG were enrolled. Following inclusion, all patients performed a 40-min cycloergometry in a standardized fashion. The following parameters were measured and compared immediately before and 1 and 30 min after the exercise: intraocular pressure (IOP; Goldman applanation tonometry), mean arterial pressure (MAP), ocular pulse amplitude (OPA; assessed by dynamic contour tonometry), and ocular perfusion pressure (OPP; 2/3 MAP – IOP). In addition, we investigated possible factors associated with OBF parameter changes immediately after exercise. Results: A total of 30 eyes (30 patients; mean age was 62.9 ± 1.7 years) were included. Most patients were women (53%), and median visual field mean deviation index was –3.5 dB. Both MAP (mean change, 21%) and IOP (mean change, 17.3%) increased significantly immediately after the workout (p < 0.01), persisting higher than baseline following 30 min (p < 0.01%). Regarding OBF parameters, both OPA (mean change, 58.8%) and OPP (mean change, 21.7%) increased significantly immediately after the workout and persisted higher than baseline 30 min after the workout (p < 0.01). Regression analysis revealed that only age was significantly associated with OPA variation (R² 0.14; p < 0.05). No significant associations were found for OPP (p ≥ 0.19). Conclusion: Aerobic exercise leads to a significant short-time increase in OBF parameters in patients with POAG. Even though IOP seems to present a modest elevation, it is accompanied by a significant increase in MAP, leading to higher OBF measurements. Exercise-induced short-term changes and its possible implications for glaucoma prognosis deserve further investigation.

The short-term effect of acupuncture on different ocular blood flow parameters in patients with primary open-angle glaucoma: a randomized, clinical study.

IntroductionTo investigate the effect of acupuncture on different ocular blood flow (OBF) parameters in patients with primary open-angle glaucoma (POAG).Patients and methodsIn a prospective, randomized study, 56 POAG patients were randomly assigned either to an eye-specific acupuncture (group I, n=28) or to an eye-unspecific acupuncture treatment (group II, n=28). Blood flow parameters were measured before and 10 minutes after treatment. Parapapillary retinal blood flow was determined by the Heidelberg retina flowmeter. Retinal vessel diameters were measured by the dynamic vessel analyzer. Pulsatile ocular blood flow, ocular pulse amplitude, and IOP were investigated by the Langham OBF system. Systemic blood pressure was obtained additionally.ResultsPulsatile ocular blood flow increased significantly after the eye-specific acupuncture treatment from 5.6±4.3 to 6.7±4.9 µL/min (P=0.014). There was no significant change in parapapillary retinal blood flow, retinal vessel diameter, systemic blood pressure, or IOP after treatment in neither of the two groups.ConclusionAn eye-specific acupuncture treatment may affect OBF in POAG patients.

Racial differences in the correlations between structural parameters and ocular blood flow in healthy eyes

Purpose: This study aimed to assess differences in the relationship between structural parameters and ocular blood flow between persons of African (AD) and European descent (ED) with healthy eyes.Methods: The relationship between structural and ocular blood flow parameters was assessed in 46 participants (20 AD, 26 ED) with healthy eyes. Disc area (DA), rim area (RA), and retinal nerve fiber layer (RNFL) thickness were measured. Retrobulbar blood flow was assessed in the ophthalmic (OA), central retinal (CRA), nasal (NPCA) and temporal short posterior ciliary arteries (TPCA). Peak systolic velocity (PSV), end diastolic velocity (EDV) and resistive index (RI) were assessed. Retinal capillary blood flow was also evaluated. Differences between the correlations were determined using the Fisher r-to-z transformation.Results: Significant differences in correlations were observed between the AD and ED groups in the CRA, where PSV and DA were positively correlated in AD (r=0.43) and negatively correlated in ED (r=-0.36) (Δr=0.79; P=0.01). A similar finding was observed for PSV and RA (AD: r=0.39; ED: r=-0.23; Δr=0.62; P=0.04). In the inferior hemifield for ED group only, percentage of avascular space and RNFL thickness were positively correlated (r=0.51, P=0.01) and mean retinal flow and RNFL thickness were negatively correlated (r=-0.50, P=0.01).Conclusion: The relationship between structural parameters and the blood supply to the superficial layer of the retina was significantly different in the healthy eyes of AD compared to ED. More research is required to show how these differences may affect glaucomatous risk.

24 HOUR BLOOD PRESSURE PROFILE IN YOUNG AND MIDDLE-AGED PATIENTS WITH RETINAL VEIN OCCLUSION

Background. Absence of nocturnal decrease (non-dipper) or an extreme decrease of blood pressure (BP) (overdipper) may be a sign of vascular dysregulation. Non-dipper pattern is associated with increased risk of strokes and cardiovascular events. Over-dipper pattern increases the risk of non-arteritic anterior ischemic neuropathy and glaucoma progression. Daily BP profile in young and middle-aged adults with retinal vein occlusion (RVO) has not been previously examined. The target organ damage is determined by BP dynamics, regional microcirculation and associated perfusion pressure decrease, which verifies the relevance of our study. Objective. To evaluate the diurnal BP variation, the prevalence of arterial hypertension (HTN) and its character, ocular blood flow in RVO in young and middle-aged adults. Design and methods. The study included 30 patients with RVO. In all patients, routine ophthalmic examination was performed, as well as an additional ocular blood flow assessment (ophthalmoplethysmography, ophthalmorheography, ophthalmosphygmography, and fluorescein angiography). 24‑hour blood pressure monitoring (BPM) was performed to estimate systemic hemodynamics. Results. Statistically significant differences between eyes were noted in visual acuity (p = 0,001) and retinal thickness in macular area (p &lt; 0,001). Patients with HTN showed lower visual acuity (р = 0,04), ocular blood flow parameters (p &lt; 0,05) and retinal mean sensitivity (RMS) (р = 0,02) according to automated static perimetry. Fluorescein angiography showed zones of peripheral retinal ischemia with a mean area of 103 mm 2 (from 0 to 250 mm 2 ). 8 patients had masked HTN according to ambulatory BPM. Depending on the night decrease of BP 13 patients had an extreme decrease of BP (over-dipper), 12 had non-dipper pattern and 5 had dipper pattern. No relation between evaluated parameters was found. However, non-dippers showed a tendency towards lower hemodynamic and automated static perimetry parameters. Conclusions. The prevalence of HTN was 57%, while 47% demonstrated masked HTN. Lower ocular blood flow parameters and RMS according to automated static perimetry were associated with HTN. Vascular dysregulation is considered as a possible cause of RVO in young and middle-aged adults. Its manifestation is the equal frequency of non-dipper and over-dipper patterns. Ambulatory BPM in patients with RVO can be recommended for the detection of HTN, BP profiles, and indirectly, for the evaluation of ocular perfusion pressure, risk stratification and the selection of adequate and individualized antihypertensive therapy to reduce the risk of developing and progressing cardiovascular diseases and mortality.

Baseline characteristics predictive of structural and functional progression in open-angle glaucoma patients with different demographic characteristics

Purpose: The aim of this study was to examine ocular blood flow parameters that may predict structural and functional disease progression in open-angle glaucoma (OAG) patients of different diabetic status, gender, ethnicity, and body mass index (BMI).Methods: One hundred twelve patients with OAG were assessed for systemic blood pressure (BP), ocular perfusion pressure (OPP), retrobulbar blood flow, capillary blood flow, and optic nerve head morphology at baseline and every six months for a five-year period. Structural progression was monitored with optical coherence tomography and Heidelberg retinal tomography-III. Functional disease progression was monitored with automated perimetry using Humphrey visual fields. Factors associated with OAG structural and functional progression were analyzed using Cox proportional hazards models.Results: The following were associated with shorter time to structural progression: In diabetic patients, larger area of avascular space; in males, lower central retinal artery peak systolic velocity and end diastolic velocity; in patients of African descent, higher systolic BP and OPP; in obese patients, lower ophthalmic artery end diastolic velocity. The following were associated with shorter time to functional progression: In diabetic patients, cup area, cup volume, cup/disc area ratio, linear cup/disc ratio, mean cup depth, cup shape; in males, systolic BP, diastolic BP, mean arterial pressure, systolic PP, diastolic PP, OPP, mean PP; in overweight patients, higher ophthalmic artery and central retinal artery resistive indices; in obese patients, lower central retinal artery resistive index.Conclusions: Structural and functional OAG disease progression may be influenced differently in patients based on diabetic status, gender, ethnicity, and BMI. Mathematical modeling of risk variables that takes into account demographic characteristics may assist in better identifying OAG progression risk.

Ophthalmology and mathematics: crossroad or scientific interface?

Ophthalmology and mathematics: crossroad or scientific interface?

Study on correlation between retinal vessel morphology or ocular hemodynamic parameter and internal carotid artery stenosis

Objective: To analyze the correlation between retinal vascular calibers, ocular blood flow parameters and internal carotid artery stenosis and to evaluate the effect of internal carotid artery stenosis on ocular blood vessels comprehensively. Methods: A retrospective case-control study. The clinical data of 141 patients who underwent head-and-neck computed tomography (CT) angiography examinations of the ICA were collected at Beijing Friendship Hospital, Capital Medical University from January 2014 to January 2016. According to diagnostic criteria, the patients were divided into four groups: the non-stenosis group, the mild stenosis group, the moderate stenosis group, and the severe stenosis andocclusion group. The retinal vascular caliber was measured in color fundus photograph by IVAN software. Color Doppler ultrasonography was used to measure the parameters of ocular blood flow, including the peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI) and pulsatility index (PI). The enumeration data were analyzed with chi-square test, the measurement data were analyzed with rank-sum test, and the correlation test was performed with spearman. Results: The gender ratio of the patients without stenosis, mild stenosis, moderate stenosis, severe stenosis and occlusion was 12/7, 31/19, 28/25, 12/7, χ2 test was not statistically significant (χ2= 0.79, P=0.85); There was no statistically significant difference between the different groups (χ2= 0.15, P=0.68), the age of four groups were (64.1±8.3), (54.3±14.3), (68.9±11.8) and (59.1±8.0) y, respectively. In the no internal carotid artery stenosis group, the arteries diameter is (164.5±15.6) μm ,the vein diameter is (245.6±20.0) μm and the arteriovenous ratio is 0.7±0.1. There is no difference among the mild stenosis group, moderate stenosis group and the severe stenosis (χ2artery caliber=6.92, Partery caliber=0.08; χ2vein diameter=4.16, Pvein diameter=0.25; χ2arteriolar-venular ratio=1.38,Parteriolar-venular ratio=0.71) . The PSV of central retinal artery in the above groups were (14.6±3.6), (34.4±13.2), (35.7±14.6), (42.3±19.0)cm/s respectively, the data were analyzed by rank-sum test and there was a significant difference (χ2=13.44, P< 0.01) ; The PSV of the posterior ciliary artery in the above groups (17.6±6.5), (15.0±4.6), (13.4±4.3) and (11.0±3.2)cm/s respectively, the data were analyzed by rank-sum test and there was a significant difference (χ2=22.71, P<0.01) , EDV were (5.90±2.2), (5.1±2.1), (4.3±1.5) and (4.3±4.8)cm/s respectively and there was a significant difference (χ2=20.36, P<0.01) .There was a correlation between retinal artery diameter, PSV and EDV of the central retinal artery, PSV and EDV of the posterior ciliary artery and the diameter of the internal carotid artery but without linear correlation. (rartery caliber=-0.23, Partery caliber=0.01; rPSV of central retinal artery= -0.29, PPSV of central retinal artery<0.01; rPSV of posteri or ciliary artery=-0.34, PPSV of posterior ciliary artery<0.01, rEDV of posterior ciliary artery=-0.35, PEDV of posterior ciliary artery<0.01). Conclusions: There was a correlation between retinal artery diameter, PSV and EDV of the central retinal artery, PSV and EDV of the posterior ciliary artery and the diameter of the internal carotid artery. PSV of the central retinal artery, PSV and EDV of the posterior ciliary artery changed significantly when the internal carotid artery stenosis existed. (Chin J Ophthalmol, 2016, 52: 905-910).

Value of Structural and Hemodynamic Parameters for the Early Detection of Primary Open-Angle Glaucoma

ABSTRACTPurpose: To compare the diagnostic value of ocular blood flow parameters and choroidal thickness (CT) with standard structural parameters for early glaucoma detection.Methods: A total of 32 patients with pre-perimetric glaucoma were compared with 30 age-matched normal subjects. The thickness of the ganglion cell complex (GCC), retinal nerve fiber layer (RNFL), and the choroid and foveal loss volume (FLV) were measured by means of optical coherence tomography (OCT). Retrobulbar blood velocities (Color Doppler Imaging), corneal compensated intraocular pressure (IOPcc), and corneal hysteresis (CH) were also evaluated. Mean ocular perfusion pressure (MOPP) was calculated by measuring IOP and mean arterial blood pressure as MOPP = ([2/3 diastolic BP + 1/3 systolic BP] × 2/3-IOP). The value of each diagnostic indicator (z-value) was calculated using the Wilcoxon–Mann–Whitney test and the area under the receiver operating characteristic curve (AUC).Results: The following indicators had the largest AUC and diagnostic value (z-value): mean blood flow velocity in the vortex veins (AUC 1.0; z-value 5.35) and central retinal vein (0.85; 3.74), diastolic blood flow velocity in the central retinal artery (0.73; 2.74) and lateral short posterior ciliary arteries (0.71; 2.53), IOPcc (0.74; −2.9), CH (0.69; 2.24), CT (0.69; −2.28), GCC (0.67; 2.05), and FLV (0.66; −1.86) to discriminate pre-perimetric glaucoma from healthy subjects.Conclusions: Interestingly, ocular hemodynamic parameters performed better than structural parameters in detecting early glaucoma. This highlights the potential of techniques to measure ocular blood flow in glaucoma diagnostics independently of the question whether perfusion abnormalities are a cause or a consequence of the disease.

Leuven Eye Study – Baseline and Methods

PurposeGlaucoma is known to be associated with vascular dysfunction. However, integrating this knowledge in the clinical setting has been limited, considering the majority of vascular oriented studies have been either underpowered or only addressed a small segment of the vascular parameters in strictly selected patients. The Leuven Eye Study aims at bridging this gap by prospectively collecting the largest amount of vascular oriented data in a large real‐life glaucoma clinic setting.MethodsProspective, cross‐sectional, case–control hospital‐based study. Patients with primary open‐angle glaucoma (POAG), normal tension glaucoma (NTG), glaucoma suspect or ocular hypertension (OHT) and healthy volunteers were recruited. In addition to an ophthalmological examination, a vascular‐oriented questionnaire was completed and ocular blood flow assessment (color Doppler imaging of retrobulbar vessels, retinal oximetry, dynamic contour tonometry, optical coherent tomography enhanced depth imaging of the choroid) was performed in each subject.Results620 subjects (297 male) were recruited between March and December 2013 (POAG: 214, NTG: 192; glaucoma suspect: 41; OHT: 27; healthy controls: 146). Mean age was 68.4 ± 12.9 years. Other than IOP, there was no difference in demographic variables between glaucoma groups and healthy volunteers. Values for the ocular blood flow parameters are in line with the current literature.ConclusionsThe Leuven Eye study stands as the largest clinical trial on ocular blood flow in glaucoma. The creation of this vast database may help integrate the vascular aspects of glaucoma into the clinical practice of glaucoma.

Leuven Eye Study ‐ Baseline and methods

PurposeGlaucoma is known to be associated with vascular dysfunction. However, integrating this knowledge in the clinical setting has been limited, considering the majority of vascular oriented studies have been either underpowered or only addressed a small segment of the vascular parameters in strictly selected patients. The Leuven Eye Study aims at bridging this gap by prospectively collecting the largest amount of vascular oriented data in a large real‐life glaucoma clinic setting.MethodsProspective, cross‐sectional, case‐control hospital‐based study. Patients with primary open‐angle glaucoma (POAG), normal tension glaucoma (NTG), glaucoma suspect or ocular hypertension (OHT) and healthy volunteers were recruited. In addition to an ophthalmological examination, a vascular‐oriented questionnaire was completed and ocular blood flow assessment (color Doppler imaging of retrobulbar vessels, retinal oximetry, dynamic contour tonometry, optical coherent tomography enhanced depth imaging of the choroid) was performed in each subject.Results620 subjects (297 male) were recruited between March and December 2013 (POAG: 214, NTG: 192; glaucoma suspect: 41; OHT: 27; healthy controls: 146). Mean age was 68.4 ± 12.9 years. Other than IOP, there was no difference in demographic variables between glaucoma groups and healthy volunteers. Values for the ocular blood flow parameters are in line with the current literature.ConclusionsThe Leuven Eye study stands as the largest clinical trial on ocular blood flow in glaucoma. The creation of this vast database may help integrate the vascular aspects of glaucoma into the clinical practice of glaucoma.

Diurnal Variations in Blood Flow at Optic Nerve Head and Choroid in Healthy Eyes

To investigate the diurnal variations of the ocular blood flow in healthy eyes using laser speckle flowgraphy (LSFG), and to determine the relationship of the diurnal variations between the ocular blood flow and other ocular parameters.This prospective cross-sectional study was conducted at Nagoya University Hospital. We studied 13 healthy volunteers whose mean age was 33.5 ± 7.6 years. The mean blur rate (MBR), expressing the relative blood flow, on the optic nerve head (ONH) and choroidal blood flow was determined by LSFG (LSFG-NAVI) every 3 hours from 6:00 to 24:00 hours. The intraocular pressure (IOP), choroidal thickness measured by enhanced depth imaging optical coherence tomography, systolic (SBP) and diastolic (DBP) blood pressure, and heart rate (HR) in the brachial artery were also recorded. We evaluated the diurnal variations of the parameters and compared the MBR to the other parameters using a linear mixed model.The diurnal variations of the MBR on the ONH varied significantly with a trough at 9:00 hours and a peak at 24:00 hours (P < 0.001, linear mixed model). The MBR of choroid also had significant diurnal variations with a trough at 15:00 hours and a peak at 18:00 hours (P = 0.001). The IOP (P < 0.001), choroidal thickness (P < 0.001), SBP (P = 0.005), DBP (P = 0.001), and HR (P < 0.001) also had significant diurnal variations. Although the diurnal variation of the MBR on the ONH was different from the other parameters, that on the choroid was significantly and positively correlated with the DBP (P = 0.002), mean arterial pressure (P = 0.023), and mean ocular perfusion pressure (P = 0.047).We found significant diurnal variations in the ONH and choroidal blood flow. Although the ONH blood flow had its own diurnal variation because of strong autoregulation, the choroidal blood flow was more likely affected by systemic circulatory factors because of poor autoregulation.

Effects of blood flow properties on ocular hemodynamics

to study the effects of blood rheology on ocular blood flow (OBF) parameters and estimated individual normal range of intraocular pressure (IOP). A total of 15 patients (15 eyes) taking warfarin were enrolled. Volumetric parameters and linear velocity of OBF under warfarin treatment and after its cessation were obtained by means of flowmetry (Paradigm's Blood Flow Analyzer) and color Doppler flow mapping (Voluson 730), respectively. On the basis of flowmetry results an individual normal range of IOP was calculated in all patients. Pulsatile OBF does not appear to correlate with warfarin-induced changes in blood rheology (p = 0.09), however, depends on IOP fluctuations (p = 0.02). Resistance index of retinal vessels is found to rise significantly with increasing blood viscosity (p < 0.05). The use of warfarin, an indirect thrombin inhibitor, has no effect on estimated individual normal range of IOP, which is crucial for glaucoma diagnosis and monitoring.

Interaction between leukocytes and erythrocytes in the human retina: Effects of pentoxifylline on hyperoxia‐induced vasoconstriction during increased neutrophil counts

AbstractPurpose We have previously shown that under states of vasoconstriction an interaction between circulating erythrocytes and leukocytes may play a role in the control of blood flow. In the present study we hypothesized that pentoxifylline may alter this interaction during oxygen‐induced vasoconstriction.Methods 24 healthy male subjects participated in this double masked, randomized, placebo‐controlled 2 way cross over trail. In order to increase white blood cell count (WBC) count, 300 μg of G‐CSF was administered intravenously. Vasoconstriction of retinal vessels was induced by oxygen inhalation. 400mg of pentoxifylline or placebo was infused at two different study days. White blood cell flux was assessed with the blue‐field entoptic technique. Vessel calibers were measured with a dynamic vessel analyzer (DVA) and red blood cell velocity (RBCV) was determined with laser Doppler velocimetry (LDV). Retinal blood flow was calculated based on retinal vessel diameters and RBCV.Results Retinal vessel diameter, RBCV, calculated retinal blood flow and white blood cell flow were not altered by administration of pentoxifylline. Hyperoxia induced a pronounced decrease in retinal blood flow parameters. No difference was observed between groups during oxygen breathing in vessel diameters (p=0.54), RBCV (p=0.34), calculated retinal blood flow (p=0.3) and white blood cell flow (p=0.26).Conclusion Our data indicate that short time administration of pentoxifylline does not alter the oxygen‐induced effect on ocular blood flow parameters during leukocytosis.