Search

Purpose. To study state of ocular hemodynamics in pregnant women with disorders of carbohydrate metabolism using color Doppler imaging. Patients and methods. 147 pregnant women were examined: 40 of them had type 1 diabetes mellitus (DM), 87 had gestational diabetes (GD); in 20 — pregnancy proceeded physiologically. Examination of pregnant women with DM was carried out in each trimester and 3 months after delivery, pregnant women with GD and control groups — once in the third trimester. The parameters of hemodynamics in the central retinal artery (CRA) and in the short posterior ciliary arteries (SPCAs) were studied using color Doppler imaging. Results. It was found that the peak systolic velocity (PSV) in the CRA was significantly lower in the GD and DM groups, while PSV in the SPCAs and end-diastolic velocity (EDV) in the CRA were higher in the control group compared to the GD. In SPCAs, the resistive index (RI) was the highest in the DM group, and the lowest in the GD group. Conclusion. In patients with GD in the third trimester of pregnancy, there is a statistically significant decrease in PSV and EDV in the CRA and SPCAs, combined with a decrease in RI in SPCAs, compared with patients with a physiological course of pregnancy. In patients with diabetic retinopathy (DR) in the third trimester of pregnancy, PSV and EDV in the CRA and SPCAs were significantly lower, and the pulsatility index (PI) and RI were significantly higher compared to pregnant women with DM without DR. In pregnant women with DR during gestation, there was a decrease in PSV and EDV against the background of an increase in RI and PI in the CRA and in the SPCAs. In pregnant women with DM and absence of DR during gestation, there was an increase in PSV, EDV and PI in the CRA and SPCAs from the first to the third trimesters. The revealed features of the state of hemodynamics in the CRA and SPCAs in pregnant women with DM with presence or absence of DR can become the basis for creating criteria for manifestation and progression of DR.

Color Doppler imaging became widespread for study hemodynamics in patients with vascular eyes pathologies. A number of studies have shown changes in ocular blood flow velocity and Doppler indices in patients with diabetes mellitus in both the absence and presence of diabetic retinopathy. With the progression of diabetic retinopathy, an increase in parameters’ changes was revealed, variations in ocular blood flow were studied after conservative treatment, retinal laser photocoagulation, against the background of anti-VEGF therapy. Due to its non-invasiveness, color Doppler imaging is used to assess orbital blood flow in pregnant patients at any gestational age. The works of this direction concern the assessment the changes in orbital blood flow during the physiological course of pregnancy and preeclampsia. However, there is still no information on the state of ocular blood flow in pregnant women with diabetes mellitus, which can serve as a basis for further research.

Glaucoma is a leading cause of irreversible blindness worldwide. To date, intraocular pressure (IOP) is the only modifiable risk factor in glaucoma treatment, but even in treated patients, the disease can progress. Cannabinoids, which have been known to lower IOP since the 1970s, have been shown to have beneficial effects in glaucoma patients beyond their IOP-lowering properties. In addition to the classical cannabinoid receptors CB1 and CB2, knowledge of non-classical cannabinoid receptors and the endocannabinoid system has increased in recent years. In particular, the CB2 receptor has been shown to mediate anti-inflammatory, anti-apoptotic, and neuroprotective properties, which may represent a promising therapeutic target for neuroprotection in glaucoma patients. Due to their vasodilatory effects, cannabinoids improve blood flow to the optic nerve head, which may suggest a vasoprotective potential and counteract the altered blood flow observed in glaucoma patients. The aim of this review was to assess the available evidence on the effects and therapeutic potential of cannabinoids in glaucoma patients. The pharmacological mechanisms underlying the effects of cannabinoids on IOP, neuroprotection, and ocular hemodynamics have been discussed. [ABSTRACT FROM AUTHOR]

Objective: Hypertensive and diabetic patients are at higher risk of developing ocular complications. Color and spectral Doppler, as a noninvasive technique, can be used to monitor and access the ophthalmic artery (OA) and its hemodynamic characteristics. The aim of this study was to investigate the hemodynamics of OA in diabetes and hypertension. Materials and Methods: This cross-sectional study was conducted at the University of Lahore sonography clinic. The patients were investigated using Toshiba Xario with 5 to 7.5 MHz linear transducer and the scanning was completed with closed eyelids. Those included in the study were hypertensive and diabetic patients. Exclusions were made based on a patient's history of eye surgeries, trauma, inflammation, glaucoma, cataract, and pregnancy. Results: There were 200 patients recruited and of which, 41 were hypertensive and diabetic, whereas 159 were normal subjects. In this cohort, 41 patients (20%) were positive for hypertension and diabetes. There were 159 patients (79%) were negative for diabetes and hypertension. The resistive index (RI) of right OA was 0.783 ± 0.114 with 0.029. When considering the OA hemodynamics recorded, the pulsatility index (PI), the systolic/diastolic (S/D) ratio, RI, and end diastolic velocity (EDV) were significantly correlated among those with hypertension and diabetes. In the normal subjects, all hemodynamic measurements were seen as normal, when compared to those with hypertension and diabetic. Conclusion: This cohort study may suggest that there is a pathological increase in vascular resistance, PI, S/D ratio, and decreased blood flow velocities, in ophthalmic artery, for those hypertensive and diabetic patients. [ABSTRACT FROM AUTHOR]

Imaging of the ocular vasculature can provide new insights into the pathophysiology of ocular diseases. This study proposes a novel high-frequency super-resolution ultrasound localization microscopy (SRULM) technique and evaluates its ability to measure in vivo perfusion changes in the rat eye at elevated intraocular pressure (IOP). A 38.4 MHz center frequency linear array transducer on a VisualSonics Vevo F2 imaging platform was used to collect high frame rate (1 kHz) radiofrequency data of the posterior rat eye following systemic microbubble contrast injection. Following clutter and spatiotemporal non-local means filtering, individual microbubbles were localized and tracked. The microbubble tracks were accumulated over 10,000 frames to generate vascular images quantifying perfusion velocity and direction. Experiments were performed using physiologic relevant controlled flow states for algorithm validation and subsequently performed in vivo on the rat eye at 10 mm Hg IOP increments from 10 to 60 mm Hg. The posterior vasculature of the rat eye, including the ophthalmic artery, long posterior ciliary arteries and their branches, central retinal artery and retinal arterioles and venules were successfully visualized, and velocities quantified at each IOP level. Significant reductions in arterial flow were measured as IOP was elevated. High-frequency SRULM can be used to visualize and quantify the perfusion velocity of the rat eye in both the retrobulbar and intraocular vasculature simultaneously. The ability to detect ocular perfusion changes throughout the depth of the eye may help elucidate the role ischemia has in the pathophysiology of ocular diseases such as glaucoma. [ABSTRACT FROM AUTHOR]

Our understanding of ocular hemodynamics and its role in ophthalmic disease progression remains unclear due to the shortcomings of precise and on-demand biomedical sensing technologies. Here, we report high-resolution in vivo assessment of ocular hemodynamics using a Fabry-Pérot cavity-based micro-optical sensor and a portable optical detector. The designed optical system is capable of measuring both static intraocular pressure and dynamic ocular pulsation profiles in parallel. Through a dynamic intensity variation analysis method which improves sensing resolution by 3-4 folds, our system is able to extract systolic/diastolic phases from a single ocular pulsation profile. Using a portable detector, we performed in vivo studies on rabbits and verified that ophthalmic parameters obtained from our optical system closely match with traditional techniques such as tonometry, electrocardiography, and photo-plethysmography.

Background: In spite of recent advances in ophthalmology, the diagnosis and treatment of uveitis is still a challenge. Purpose: To assess ocular hemodynamics in patients with primary and recurrent posterior uveitis (focal and disseminated chorioretinitis) using ophthalmic rheography. Material and Methods: One hundred and eighteen patients (mean age ± standard deviation, 37.2 ± 1.5 years) with posterior uveitis were included in the study. The median duration of recurrent posterior uveitis was 2920 days (range, 1080 to 5110 days). The etiology of chorioretinitis was not established in all patients of the study. The age-matched control group was composed of 16 healthy volunteers (32 eyes). Patients and controls underwent ophthalmic rheography (ORG) with Reocom, the computerized rheography apparatus (Kharkiv, Ukraine). ORG included measurements of ocular pulse blood filling (expressed as RQ, ‰ rheographic coefficient) and vascular tone (expressed as alpha/T percentage index), and volumetric pulse blood filling rate (expressed as Ohm/s). Results: In primary focal and disseminated chorioretinitis, inflammation was characterized by increased ocular circulation, which was manifested by (a) 20% increased ocular pulse blood filling (both for unilateral and bilateral inflammation); (b) 1.4-times and twice, respectively, increased volumetric pulse blood filling rate and (c) 12.5% and 33.3%, respectively, increased vascular tone in large-caliber vessels and small-caliber vessels. Ocular hemodynamics was increased in patients with unilateral recurrent focal, bilateral recurrent focal and bilateral recurrent disseminated chorioretinitis in the period of recurrence; particularly, ocular pulse blood filling was 17% increased, and volumetric pulse blood filling rate, 1.6 times increased. In addition, vascular tone in large-caliber vessels was increased. The period of remission in patients with focal chorioretinitis was characterized by normal ocular pulse blood filling, whereas in those with recurrent disseminated chorioretinitis, by 20% decreased ocular pulse blood filling compared to the norm. Volumetric pulse blood filling rate in the period or remission was 1.4-1.5-times increased in patients with focal chorioretinitis, but not in those with disseminated chorioretinitis. Conclusion: Ocular pulse blood filling, volumetric pulse blood filling rate, and vascular tone in large-caliber and small-caliber vessels were increased in patients with primary posterior uveitis and those with recurrent posterior uveitis in the period of recurrence, both for unilateral and bilateral inflammation. In patients with recurrent posterior uveitis, the period of remission was characterized by a wide range of changes, from normal values to mild deficits, in ocular pulse blood filling, as well as increased vascular tone in vessels, which requires adequate anti-ischemic treatment in the period between recurrences.

Hui-Ping Duan,1 Rong Liu2 1Department of Ophthalmology, Shanxi Province Fenyang Hospital, Fenyang, 032200, Shanxi Province, People’s Republic of China; 2Department of Ophthalmology, Shanxi Datong University, Datong, 037000, Shanxi Province, People’s Republic of ChinaCorrespondence: Hui-Ping Duan, Department of Ophthalmology, Shanxi Province Fenyang Hospital, Fenyang, 032200, Shanxi Province, People’s Republic of China, Tel +86-13037099450, Email duanhuiping2002@163.comBackground: Open-angle glaucoma is a common ophthalmic disease, which has a great impact on the vision of middle-aged and elderly people. Medication plays an important role in the treatment of glaucoma, so finding effective drug treatment is of great significance to improve the quality of life of glaucoma patients.Objective: To explore the curative effect of nimodipine combined with latanoprost in the treatment of open-angle glaucoma and its effect on ocular hemodynamics and visual field defects.Methods: This study retrospectively analyzed the clinical data of 87 patients with open-angle glaucoma who came to the Shanxi Province Fenyang Hospital and The First Affiliated Hospital of Shanxi Datong University for treatment from January 2019 to January 2021. According to different treatment plans, the patients were divided into two groups: an observation group (n = 46) treated with nimodipine combined with latanoprost, and a control group (n = 41) treated by latanoprost monotherapy. Treatment efficacy, hemodynamics, visual field defects, 24-hour peak intraocular pressure, binocular optic disc parameters, adverse reactions and quality of life were recorded and compared between two groups of patients.Results: The overall therapeutic effect of the observation group was significantly better than that in the control group. After treatment, ocular hemodynamics, visual field defects, 24-hour peak intraocular pressure, binocular optic disc parameters and life quality of both groups were obviously improved compared to those before treatment, with more significant improvements in the observation group. In addition, there was no significant difference in the incidence of adverse reactions between the two groups.Conclusion: Nimodipine combined with latanoprost eye drops is effective in the treatment of primary open-angle glaucoma, which could effectively improve the ocular hemodynamics and visual field defects of patients with fewer adverse reactions and higher safety. Therefore, it can be further promoted and used in clinical practice.Keywords: nimodipine, latanoprost, open-angle glaucoma, ocular hemodynamics, degree of visual field defects

An algorithm for the calculation of steady-state flowing under uncertain conditions is introduced in this work in order to obtain a probabilistic distribution of uncertain problem parameters. This is particularly important for problems with increased uncertainty, as typical deterministic methods are not able to fully describe all possible flow states of the problem. Standard methods, such as polynomial expansions and Monte Carlo simulations, are used for the formation of the generalized problem described by the incompressible Navier-Stokes equations. Since every realization of the uncertainty parameter space is coupled with non-linear terms, an incremental iterative procedure was adopted for the calculation. This algorithm adopts a Jacobi-like iteration methodology to decouple the equations and solve them one by one until there is overall convergence. The algorithm was tested in a typical artery geometry, including a bifurcation with an aneurysm, which consists of a well-documented biological flow test case. Additionally, its dependence on the uncertainty parameter space, i.e., the inlet velocity distribution, the Reynolds number variation, and parameters of the procedure, i.e., the number of polynomial expansions, was studied. Symmetry exists in probabilistic theories, similar to the one adopted by the present work. The results of the simulations conducted with the present algorithm are compared against the same but unsteady flow with a time-dependent inlet velocity profile, which represents a typical cardiac cycle. It was found that the present algorithm is able to correctly describe the flow field, as well as capture the upper and lower limits of the velocity field, which was made periodic. The comparison between the present algorithm and the typical unsteady one presented a maximum error of ≈2% in the common carotid area, while the error increased significantly inside the bifurcation area. Moreover, "sensitive" areas of the geometry with increased parameter uncertainty were identified, a result that is not possible to be obtained while using deterministic algorithms. Finally, the ability of the algorithm to tune the parameter limits was successfully tested. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The aim of the current study was to describe the alternation pattern of cerebral and ocular blood flow velocities (BFVs) in symptomatic patients with unilateral carotid stenosis after carotid endarterectomy. PATIENTS AND METHODS: 20 symptomatic patients underwent carotid endarterectomy for = 50% unilateral carotid stenosis. Cerebral and ocular hemodynamics were evaluated by Transcranial Doppler (TCD) and Color Doppler imaging (CDI), respectively, first preoperatively, then during the following several days after carotid endarterectomy before discharge, and finally two to sixteen months later. RESULTS: Statistically significant improvements in the BFVs were recorded in the ipsilateral anterior cerebral artery (ACA), middle cerebral artery (MCV) and short posterior ciliary artery (SPCA) during the following several days after carotid endarterectomy. Preoperative retrograde flows of the ipsilateral ophthalmic artery (OA) in two patients returned to anterograde direction immediately following carotid endarterectomy. At the follow-up of two to sixteen months, the BFVs of the ipsilateral ACA, MCA and SPCA tended to decline and were no longer statistically significant from the preoperative values. CONCLUSIONS: Carotid endarterectomy significantly increased the flow velocities of ipsilateral cerebral anterior circulation and OA branching artery in patients with unilateral carotid stenosis early after surgery. At the longterm follow-up, the flow velocities in the ipsilateral hemisphere had the tendency to reduce and approach the preoperative level. [ABSTRACT FROM AUTHOR]

Purpose: Determine whether NCX 470, a nitric oxide (NO)-donating bimatoprost with clinically demonstrated intraocular pressure (IOP)-lowering effects, improves ocular hemodynamics and retinal physiology. Methods: Endothelin-1 (ET-1)-induced ischemia/reperfusion model in New Zealand white rabbits was used. ET-1 was injected next to the optic nerve twice/week (Monday and Thursday) for 6 weeks. Starting on week 3, animals received NCX 470 (0.1% bid, 6 days/week Monday-Saturday) or vehicle until the end of ET-1 treatment. IOP, ophthalmic artery resistive index (OA-RI) and retina physiology (electroretinogram, ERG) were determined before dosing and at different times post-dosing. All measurements were taken on Mondays before the AM daily dosing (36 h treatment-free). Finally, oxidative stress markers were determined in dissected retina and iris/ciliary body of treated eyes. Results: Injection of ET-1 progressively increased IOP (20.7 ± 0.6, 24.9 ± 1.2, and 27.0 ± 0.6 mmHg at baseline, week 2 and 6, respectively) and OA-RI (0.30 ± 0.02, 0.39 ± 0.02, and 0.42 ± 0.03 at baseline, week 2 and 6, respectively) and reduced rods and/or cones response as indicated by changes in ERG amplitudes under different stimulating conditions. NCX 470 re-established baseline IOP (21.8 ± 1.0 mmHg), OA-RI (0.33 ± 0.02), and ERG amplitude by week 6 (mostly rod response, 0.01Dark_AVeh_6week = 32.2 ± 3.0 μV and 0.01Dark_ANCX470_6week 44.3 ± 4.5 μV; mostly cone response, 3.0Dark_AVeh_6week = 87.6 ± 10.1 μV and 3.0Dark_ANCX470_6week = 122.8 ± 11.4 μV; combined rod/cone response, 3.0Light_AVeh_6week = 49.8 ± 6.5 μV and 3.0Light_ANCX470_6week = 64.2 ± 6.8 μV). NCX 470 also reversed ET-1-induced changes in glutathione and manganese superoxide dismutase (oxidative stress markers) in retina and iris/ciliary body. Conclusions: Repeated ocular topical dosing with NCX 470 reverses ET-1-induced changes in IOP, OA-RI, and ERG suggesting improved ocular hemodynamics and retinal physiology likely independently from its demonstrated IOP-lowering effect. [ABSTRACT FROM AUTHOR]

Imaging of the ocular vasculature can provide new insights into the pathophysiology of ocular diseases. This study proposes a novel high-frequency super-resolution ultrasound localization microscopy (SRULM) technique and evaluates its ability to measure in vivo perfusion changes in the rat eye at elevated intraocular pressure (IOP). A 38.4 MHz center frequency linear array transducer on a VisualSonics Vevo F2 imaging platform was used to collect high frame rate (1 kHz) radiofrequency data of the posterior rat eye following systemic microbubble contrast injection. Following clutter and spatiotemporal non-local means filtering, individual microbubbles were localized and tracked. The microbubble tracks were accumulated over 10,000 frames to generate vascular images quantifying perfusion velocity and direction. Experiments were performed using physiologic relevant controlled flow states for algorithm validation and subsequently performed in vivo on the rat eye at 10 mm Hg IOP increments from 10 to 60 mm Hg. The posterior vasculature of the rat eye, including the ophthalmic artery, long posterior ciliary arteries and their branches, central retinal artery and retinal arterioles and venules were successfully visualized, and velocities quantified at each IOP level. Significant reductions in arterial flow were measured as IOP was elevated. High-frequency SRULM can be used to visualize and quantify the perfusion velocity of the rat eye in both the retrobulbar and intraocular vasculature simultaneously. The ability to detect ocular perfusion changes throughout the depth of the eye may help elucidate the role ischemia has in the pathophysiology of ocular diseases such as glaucoma.

AIM: To observe the improvement of ocular hemodynamics before and after intraocular pressure(IOP)intervention in patients with non-arteritic anterior ischemic optic neuropathy(NAION).METHODS: Retrospective case series. Totally 92 patients(92 eyes)with NAION were admitted to the Department of Ophthalmology, Xi'an Fourth Hospital from July 2012 to September 2018. Forty-six patients received only basic treatment without IOP lowering treatment as the conventional treatment group. The other 46 patients were treated with brinzolamide eye drops combined with brimonidine eye drops to lower IOP on the basis of conventional treatment, as the IOP intervention group. Before and after treatment, the blood flow rate of the ophthalmic artery and central retinal artery were measured by color Doppler ultrasound. The IOP, best corrected visual acuity(BCVA), mean visual field defect(MD), retinal nerve fiber layer thickness(RNFLT), ophthalmic artery and central retinal artery peak systolic blood velocity(PSV), end-diastolic blood velocity(EDV), pulse index(PI)and resistance index(RI)were compared.RESULTS: Before treatment, there were no significant differences in IOP, BCVA(LogMAR), MD, RNFLT, PSV, EDV, PI and RI between the two groups(P>0.05). After 14d of treatment, IOP, BCVA(LogMAR), MD and RNFLT of the two groups were significantly improved compared with those before treatment(P

Purpose. To assess increasing the functional effectiveness of the results of endovitreal surgery in patients with rhegmatogenous retinal detachment (RRD) by using modern pharmacotherapy drug in the postoperative rehabilitation.Material and methods. 108 people (108 eyes) with RRD. All patients underwent standard three-port vitrectomy, after which tamponade of the vitreous cavity with silicone oil with its removal 3 months after operation was performed. Patients were divided into 2 groups: the first – 60 people who received Cytoflavin on the background of standard therapy, and the second – 48 people with postoperative treatment only with standard therapy. Depending on the visual prognosis calculated before the operation, both groups were represented patients with satisfactory (A subgroup) and low (B subgroup) visual prognosis. Laser Doppler fluometry (LDF) was used to study chorioretinal microcirculation: microcirculation index and microcirculation efficiency index were recorded. Using OCT angiography (OCT-A), signs of macular ischemia were investigated: choroidal thickness, area nonperfusion of foveal avascular zone, density in the superficial capillary plexuses and density in the deep capillary plexuses in the macular area.Results. The inclusion of Cytoflavin in the postoperative rehabilitation of patients with RRD increases the possibility of a favorable functional outcome of the operation, affects the positive dynamics in the state of the capillary plexus in the macula. In the aggregate of patients of the 1st group, the increase in visual acuity was 2 times higher than in patients of the 2nd group 6 months after surgery. Also, in patients of the 1st group there was a more significant activation of chorioretinal blood flow according to LDF and OCT-A.Conclusion. The prescription of Cytoflavin in the postoperative treatment of patients underwent endovitreal surgery of RRD, regardless of the visual prognosis, increases the functional outcome of the operation. Improvement in visual functions in patients receiving Cytoflavin therapy is directly related to improved intraocular blood flow and macular perfusion.

Objective: To investigate the effects of Fuming tablets combined with travoprost eye drops on ocular hemodynamics,aqueous erythropoietin（EPO） and soluble CD44（s CD44） in patients with primary open-angle glaucoma（POAG）. Methods: 112 cases（193 eyes） of POAG who were treated in our hospital from April 2017 to November 2020 were selected, according to the random number table method, they were divided into control group（n=56, 96 eyes） and study group（n=56, 97 eyes）. Patients in the control group were treated with travoprost eye drops, and patients in the study group were treated with Fuming tablets combined with travoprost eye drops.The efficacy, ocular hemodynamics, aqueous EPO, s CD44, visual acuity, visual field and intraocular pressure of the two groups were compared, and the occurrence of adverse reactions during the treatment period were observed. Results: The total clinical effective rate of the study group was higher than that of the control group（P<0.05）. 12 weeks after treatment, mean light sensitivity（MS） and visual acuity of the study group were higher than those of the control group, and the 24h mean intraocular pressure was lower than that of the control group（P<0.05）. 12 weeks after treatment, the end diastolic velocity（EDV） and peak systolic velocity（PSV） of the study group were higher than those of the control group, and the blood flow resistance coefficient（RI） was lower than that of the control group（P<0.05）. 12weeks after treatment, EPO and s CD44 of the study group were lower than those of the control group（P<0.05）. There was no significant difference in the incidence of adverse reactions between the two groups（P>0.05）. Conclusion: Fuming tablets combined with travoprost eye drops can improve the visual acuity, visual field and intraocular pressure of patients with POAG, which may be related to the regulation of ocular hemodynamics and the levels of EPO and s CD44 in aqueous humor. [ABSTRACT FROM AUTHOR]

Background: In spite of recent advances in ophthalmology, the diagnosis and treatment of uveitis is still a challenge. Purpose: To assess ocular hemodynamics in patients with primary and recurrent posterior uveitis (focal and disseminated chorioretinitis) using ophthalmic rheography. Material and Methods: One hundred and eighteen patients (mean age ± standard deviation, 37.2 ± 1.5 years) with posterior uveitis were included in the study. The median duration of recurrent posterior uveitis was 2920 days (range, 1080 to 5110 days). The etiology of chorioretinitis was not established in all patients of the study. The age-matched control group was composed of 16 healthy volunteers (32 eyes). Patients and controls underwent ophthalmic rheography (ORG) with Reocom, the computerized rheography apparatus (Kharkiv, Ukraine). ORG included measurements of ocular pulse blood filling (expressed as RQ, ‰ rheographic coefficient) and vascular tone (expressed as alpha/T percentage index), and volumetric pulse blood filling rate (expressed as Ohm/s). Results: In primary focal and disseminated chorioretinitis, inflammation was characterized by increased ocular circulation, which was manifested by (a) 20% increased ocular pulse blood filling (both for unilateral and bilateral inflammation); (b) 1.4-times and twice, respectively, increased volumetric pulse blood filling rate and (c) 12.5% and 33.3%, respectively, increased vascular tone in large-caliber vessels and small-caliber vessels. Ocular hemodynamics was increased in patients with unilateral recurrent focal, bilateral recurrent focal and bilateral recurrent disseminated chorioretinitis in the period of recurrence; particularly, ocular pulse blood filling was 17% increased, and volumetric pulse blood filling rate, 1.6 times increased. In addition, vascular tone in large-caliber vessels was increased. The period of remission in patients with focal chorioretinitis was characterized by normal ocular pulse blood filling, whereas in those with recurrent disseminated chorioretinitis, by 20% decreased ocular pulse blood filling compared to the norm. Volumetric pulse blood filling rate in the period or remission was 1.4-1.5-times increased in patients with focal chorioretinitis, but not in those with disseminated chorioretinitis. Conclusion: Ocular pulse blood filling, volumetric pulse blood filling rate, and vascular tone in large-caliber and small-caliber vessels were increased in patients with primary posterior uveitis and those with recurrent posterior uveitis in the period of recurrence, both for unilateral and bilateral inflammation. In patients with recurrent posterior uveitis, the period of remission was characterized by a wide range of changes, from normal values to mild deficits, in ocular pulse blood filling, as well as increased vascular tone in vessels, which requires adequate anti-ischemic treatment in the period between recurrences. [ABSTRACT FROM AUTHOR]

An algorithm for the calculation of steady-state flowing under uncertain conditions is introduced in this work in order to obtain a probabilistic distribution of uncertain problem parameters. This is particularly important for problems with increased uncertainty, as typical deterministic methods are not able to fully describe all possible flow states of the problem. Standard methods, such as polynomial expansions and Monte Carlo simulations, are used for the formation of the generalized problem described by the incompressible Navier-Stokes equations. Since every realization of the uncertainty parameter space is coupled with non-linear terms, an incremental iterative procedure was adopted for the calculation. This algorithm adopts a Jacobi-like iteration methodology to decouple the equations and solve them one by one until there is overall convergence. The algorithm was tested in a typical artery geometry, including a bifurcation with an aneurysm, which consists of a well-documented biological flow test case. Additionally, its dependence on the uncertainty parameter space, i.e., the inlet velocity distribution, the Reynolds number variation, and parameters of the procedure, i.e., the number of polynomial expansions, was studied. Symmetry exists in probabilistic theories, similar to the one adopted by the present work. The results of the simulations conducted with the present algorithm are compared against the same but unsteady flow with a time-dependent inlet velocity profile, which represents a typical cardiac cycle. It was found that the present algorithm is able to correctly describe the flow field, as well as capture the upper and lower limits of the velocity field, which was made periodic. The comparison between the present algorithm and the typical unsteady one presented a maximum error of ≈2% in the common carotid area, while the error increased significantly inside the bifurcation area. Moreover, “sensitive” areas of the geometry with increased parameter uncertainty were identified, a result that is not possible to be obtained while using deterministic algorithms. Finally, the ability of the algorithm to tune the parameter limits was successfully tested.

AIM: To investigate the ocular hemodynamic effects of applying a hot compress to the eye. METHODS: The right eyes of five New Zealand white rabbits, both male and female, were hot-compressed for 18min. An independently designed novel ocular contact-type temperature measuring device was used to measure the ocular surface temperature before and after the heating. Relevant retrobulbar hemodynamic parameters such as peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI) of each of the central retinal artery (CRA), long posterior ciliary artery (LPCA), and ophthalmic artery (OA), as well as the mean velocity (Vm) of the central retinal vein (CRV), were measured using a color Doppler flow imaging (CDFI) technique and expressed as mean values with standard deviation (mean±SD). A statistical analysis was conducted based on a paired t-test and the Wilcoxon signed-rank test. RESULTS: The employed real-time temperature measuring device was able to accurately measure ocular surface temperature during the hot-compress process. The temperature increased after the hot compress was applied. Analysis showed that the PSV and EDV values of the CRA and LPCA significantly increased after the application of the hot compress, as did the Vm of the CRV. There were no significant changes in the EDV of the OA nor the RI of each artery. CONCLUSION: This experiment, which is the first of its kind, confirms that the retrobulbar blood flow velocities can increase upon heating the ocular surface. This simple method may be useful in the future.

Background. Keratoconus is a progressive dystrophic condition of the cornea. Dystrophic changes in keratoconus are observed in the connective tissues of the sclera, drainage area, and iris. The role of a vascular factor in the development of such diseases as glaucoma, uveitis, and cataract is well-known. In this respect, studying the ocular blood supply in keratoconus appears to be reasonable. Material and Methods. Rheography was performed in 90 patients (125 eyes), aged 16-39, with keratoconus of stages I-V and the volume pulse blood flow in the eye was determined according to rheographic coefficient (RQ (‰)). In 21 eyes, stage IV-V keratoconus was accompanied by ocular hypertension and non-penetrating deep sclerotomy was performed. Depending on volume pulse blood flow rates and a vascular tone in the eye, 14 patients (28 eyes) with stage I-V keratoconus were treated using anti-ischemic and antioxidant drugs. Results. The decreased blood flow rates were noted in the eyes in each group as compared to norm. Volume blood flow was decreased by 26.7% in the eyes of the patients with stage II, III, and IV and by 44.8% in stage V keratoconus as compared to healthy patients of the same age. Volume blood flow RQ was 2.36±0.40 ‰ in stage IV-V keratoconus, complicated by ocular hypertension above 27 mmHg, i.e. by 43.8% lower than the age norm. Volume blood flow in the patients with stage IV keratoconus and intraocular hypertension was by 22.3% lower as compared with the uncomplicated course of stage IV keratoconus. Non-penetrating deep sclerotomy (NPDS) for ocular hypertension in the patients with stage IV-V keratoconus facilitated an increase in volume blood flow by 72.5%; RQ increased from 2.36±0.4 ‰ to 4.07±0.7 ‰), р

Purpose: To study ocular blood flow velocity in the ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery in patients with Type 2 diabetes. Materials and Methods: The retrobulbar circulation in 46 eyes of Type 2 diabetic patients was compared with age-matched 21 nondiabetic eyes. The diabetic subjects were further divided into diabetics with no-clinical retinopathy (n = 24) and with either preproliferative or proliferative retinopathy (n = 22). Philips HD11XE machine was used for performing Color Doppler imaging. Results: The end-diastolic velocity (EDV) in OA was 3.21 cm/s in the preproliferative/proliferative group as compared to 6.0 and 8.5 cm/s in no-retinopathy and control group, respectively. The peak systemic velocities and EDVs of CRA in the diabetic group were significantly lower than those of normal subjects regardless of the retinopathy. The resistivity index (RI) of CRA was 0.81 in diabetic group and 0.70 in control group, which was statistically significant. Conclusion: The study showed reduced blood flow velocity and increased RI in Type 2 diabetic patients as compared to normal healthy individuals. There are significant changes noted in retrobulbar flow in patients with diabetic retinopathy as compared to patients without retinopathy.

Assessment of ocular hemodynamics is an important element in diagnosis of all forms of glaucoma. Existing methods, unlike the transpalpebral rheoophthalmography (TP-ROG), evaluate only the posterior eye segment. This study evaluates the opportunities of new TP-ROG technology to assess the effectiveness of the glaucoma treatment. The proposed TP-ROG method is characterized by ease of use and the lack of direct contact between the surface of the eyeball and the electrodes; this method is highly informative and quite accurate, which allows us to objectively assess the state of ocular hemodynamics in patients with primary open-angle glaucoma.

Background: Given the complex pathogenetic mechanism of the development of uveitis, it is important to investigate the features of the interaction between the immune, vascular and nervous systems, the level of their activity, and the potential for preventing the development of irreversible morphological changes. Purpose: To investigate the hemodynamic state of the eye and activity of autonomic nervous system in anterior uveitis at different stages of the inflammatory process. Materials and Methods: The study involved 66 anterior uveitis patients. They underwent general clinical examination and ophthalmic rheography involving measurement of pulsatile ocular blood flow (POBF, indicated by RQ, ‰ index), maximum blood flow velocity in the eye (? index, Om/s), and vascular tone (alpha/T percentage index) with Reocom, the computerized rheography apparatus. Results and Discussion: The level of POBF was found to depend on the level of activity of the process, with the Spearman correlation rank rho= 0.26 (P < 0.05). The lowest RQ index values, RQ = (2.54 ± 0.6)‰, were found in steady remission of chronic uveitis, and were statistically significantly lower by 32% (P < 0.05) than those in exacerbation of the disease. Ocular blood flow velocity changes were similar to those of pulsatile ocular blood flow. A direct relationship was revealed between index RQ (‰) and erythrocyte sedimentation rate (ESR, mm/h), an indicator of inflammatory activity (rho = 0.45, P < 0.05). In patients with anterior uveitis complicated by macular edema, the RQ levels and the tone of major ocular vessels during exacerbation episodes were found to be by 54% (P = 0.02) and by 35.5% (P = 0.001), respectively, higher than those in patients with uncomplicated anterior uveitis. In anterior uveitis patients with macular edema, the LF index was by 46% higher (P = 0.02) than in those with uncomplicated anterior uveitis, that is, excessive sympathicotonia was accompanied by retinal damage. Conclusion: We found the ocular hemodynamics features of anterior uveitis depending on the stage of inflammatory process, and the mechanisms of influence of different subsystems of the autonomic nervous system on the hemodynamic state of the eye and complicated course of uveitis.

AIM: To observe and analyze the change situation of hemorheology, Aβ, β-EP, Hcy and ocular hemodynamics indexes of patients with glaucoma.METHODS: Sixty patients with glaucoma in our hospital from November 2011 to October 2013 were the observation group, 60 healthy people were the control group, then the hemorheology, Aβ, β-EP, Hcy and ocular hemodynamics indexes of two groups were detected and compared, then the detection levels of patients with different Richardson stages were compared.RESULTS: The hemorheology, Aβ, β-EP, Hcy and RI of observation group were all significantly higher than those of control group, and the PSV and EDV were obviously lower than those of control group, the fluctuation of patients with higher Richardson stages were all bigger than those of patients with lower Richardson stages,all PCONCLUSION: The change of hemorheology, Aβ, β-EP, Hcy and ocular hemodynamics indexes of patients with glaucoma are great, and the blood supply of patients with higher stages are worse, and the serum related indexes were higher.

The aim of this study was to evaluate selected lipid-related and vascular factors and their effect on retrobulbar hemodynamics in glaucoma. Fifty-six patients with primary open angle glaucoma (POAG) [POAG group; mean age 68.32 years (SD±0.21)] and 54 patients in control group [CG, mean age 68.1 years (SD±5.34)] were examined. Peak systolic velocity, end-diastolic velocity, mean velocity, pulsatility index, and resistive index of the ophthalmic artery, the central retinal artery and the posterior ciliary arteries were measured by Color Doppler Imaging. Selected lipid-related, systemic and local vascular parameters were evaluated. Statistical methods included Shapiro-Wilk, Student-t and Mann-Whitney U tests, and Spearman rank correlations. In POAG group systolic arterial blood pressure, diastolic arterial blood pressure, total cholesterol, low density lipoprotein cholesterol (LDL-ch), and intraocular pressure were significantly higher; while ocular perfusion pressure, high density lipoprotein cholesterol (HDL-ch) and diastolic ocular perfusion pressure were significantly lower (p≤0.05). Color Doppler Imaging confirmed blood flow abnormalities in all investigated arteries. In addition, significant correlations of HDL-ch, LDL-ch and triglycerides (TG) with peak systolic velocity, end-diastolic velocity and mean velocity were found in individual arteries (p≤0.05). Also, significant associations of systolic arterial blood pressure, ocular perfusion pressure, systolic oclular perfusion pressure and diastolic ocular perfusion pressure with peak systolic velocity, end-diastolic velocity, mean velocity and resistive index were revealed in the posterior ciliary arteries (p≤0.05). Dysregulation of lipid-related and vascular factors, as well as statistical correlation between the above and retrobulbar blood flow indices, might imply their role in vasoconstrictive processes during glaucomatous endotheliopathy.

Study Objective: To determine the effects of the McGrath Series 5 video laryngoscope on intraocular pressure (IOP) during laryngoscopy.Design: Prospective, randomized, double blind.Setting: Operating room.Patients: Eighty adult patients of American Society of Anesthesiologist physical status 1 scheduled for nonophthalmic elective surgery under general anesthesia.Interventions: The endotracheal intubation was provided using McGrath series 5 video laryngoscope in MG group (n=40) or Macintosh laryngoscope in M group (n=40).Measurements: The IOP of the right and left eyes was measured before and after the laryngoscopic process.Main Results: The mean arterial blood pressure values just before laryngoscopy and intubation and after intubation were 77.38±6.18 and 97.38±12.77 in the McGrath video laryngoscope group and 75.85±7.88 and 99.12±14.30 in the Macintosh laryngoscope group, respectively. The IOP values of the left eye after intubation and at the 5th and the 10th minutes in the Macintosh laryngoscope group were found to be significantly higher than those in the McGrath video laryngoscope group (P=.019, P=.019, and P=.007, respectively). In addition, the IOP values of the right eye were found to be higher after intubation and at the 5th and the 10th minutes in the Macintosh laryngoscope group, compared to the McGrath video laryngoscope group (P=.009, P=.021, and P=.011, respectively). The mean IOP values for the left eye just before laryngoscopy and intubation and after intubation were 10.65±2.52 and 15.57±3.62 in the McGrath video laryngoscope group, and for the right eye, they were 10.60±1.64 and 17.17±2.38 in the Macintosh laryngoscope group, respectively.Conclusion: The McGrath Series 5 video laryngoscope may provide a lower IOP level compared to the Macintosh laryngoscope in an otherwise healthy, young patient population. [ABSTRACT FROM AUTHOR]

The aims of this study are to investigate (1) the ocular thermographic profiles in eyes affected by Age related Macular Degeneration (AMD) and age-matched controls to detect possible hemodynamic abnormalities that could be involved in the pathogenesis of the disease, (2) whether any risk factors associated with the disease could affect the development of a form of AMD rather than another. Thirty-four eyes with Age-Related Maculopathy (ARM), 41 eyes with dry AMD, 60 eyes affected by wet AMD, and 74 eyes with fibrotic AMD were included in the study. The control group consisted of 48 healthy eyes. Exclusion criteria were represented by any other ocular diseases other than AMD, tear film abnormalities, systemic cardiovascular abnormalities, systemic diseases and a body temperature higher than 37.5 °C. A total of 210 eyes without pupil dilation were investigated by infrared thermography (FLIR A320). The Ocular Surface Temperature (OST) of five ocular areas was calculated by means of an image processing technique from the infrared images. Two-sample t -test, one-way ANOVA test and multivariate analysis were used for statistical analyses. ANOVA analyses showed no significant differences among AMD groups ( P -value > 0.05), however, OST in AMD patients was significantly lower than in controls ( P -value < 0.0001). Smokers showed higher possibility ( P -value = 0.012) of developing wet AMD instead of dry AMD. Infrared thermography may be a helpful, non-invasive and not time-consuming method to be used in the management of patients with this common degenerative maculopathy. [ABSTRACT FROM AUTHOR]

Purpose: To explore changes in retrobulbar ocular blood flow dynamics in patients with nonexudative age- related macular degeneration (ARMD). Materials and Methods: 52 patients (M=28, F=24) with ARMD and 45 age-matched healthy controls (M=23, F=22) were included in our evaluation. Full ophthalmic examination and orbital color Doppler imaging was performed in both eyes. Peak systolic and end-diastolic velocities, resistive and pulsatility indices were considered as Doppler blood flow parameters in our evaluation. Central retinal, ophthalmic, temporal posterior ciliary and nasal posterior ciliary arteries measurements were taken. Results: The mean age was 65.90 ± 2.05 (55-81) in ARMD and 60.95 ± 1.34 (55-70) in the control group. Pulsatility and resistive indices in ophthalmic arteries of ARMD patients were significantly higher than the control group. The peak systolic and end-diastolic velocities in nasal and temporal posterior ciliary arteries were significantly lower whereas pulsatility and resistive indices were significantly higher in ARMD compared to the control group. Peak systolic and end-diastolic velocities and resistive indices were significantly higher in ARMD cases, especially in posterior ciliary arteries supplying the choroid. Conclusion: Perfusion defects of the retrobulbar vasculatures were significantly higher in ARMD compared to the healthy controls. [ABSTRACT FROM AUTHOR]

To investigate ocular blood flow changes in healthy myopic patients following laser in situ keratomileusis (LASIK) using color Doppler imaging. Sixteen eyes of 16 myopic patients were studied. LASIK was performed and intraocular pressure was raised to levels ≥65 mmHg. Color Doppler images were obtained to study the ophthalmic and central retinal arteries preoperatively and postoperatively at 1 day, 1 week, and 1 month. There was no significant correlation between patient age and preoperative ocular blood flow parameters. A significant positive correlation between the degree of myopia and the peak systolic volume of the ophthalmic artery ( r = 0.6, P = 0.01) was found. A highly significant decrease in the peak systolic volume and end-diastolic volume with an increase in the resistive index of both arteries ( P < 0.005) was seen at 1 day and 1 week postoperatively. There was no significant difference between the preoperative and postoperative data 1 month after the procedure. The findings of this study show temporary alterations in ocular blood flow parameters after LASIK. LASIK is an increasingly common lifestyle procedure and further studies on larger groups are still recommended. [ABSTRACT FROM AUTHOR]

Objectives – The aim of this study is to examine the relationship of ocular blood flow velocities and pulsatility to intracranial pressure (ICP). Methods – We measured arterial and venous flow velocities using color Doppler imaging (CDI) and calculated resistance indices for the central retinal (CRA) and the ophthalmic (OA) arteries from 16 patients (32 eyes) with chronic intracranial hypertension (ICH) and varying degrees of ICP and papilledema. The results were compared with normal data from 16 age-matched, healthy subjects. Results – Arterial flow velocities were significantly decreased for the aggregate subject group compared with controls. A corresponding rise in arterial resistance with increasing ICP in the mild-moderate range was noted. Unexpectedly, with more severe elevations of ICP these trends reversed. Conclusions – In mild-moderate increased cerebrospinal fluid (CSF) pressure, a reduction of flow velocities may result because of increased vascular resistance. Paradoxically, in more severe chronic ICH, we hypothesize that local autoregulatory vascular changes and/or diversion of cerebral blood flow into the ophthalmic circulation may normalize these parameters. This phenomenon may partially underlie the relative sparing of visual function early in the course of pseudotumor cerebri (PTC), regardless of actual ICP levels. [ABSTRACT FROM AUTHOR]

Copyright of Der Ophthalmologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aim: To investigate the ocular hemodynamic effects of applying a hot compress to the eye., Methods: The right eyes of five New Zealand white rabbits, both male and female, were hot-compressed for 18min. An independently designed novel ocular contact-type temperature measuring device was used to measure the ocular surface temperature before and after the heating. Relevant retrobulbar hemodynamic parameters such as peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI) of each of the central retinal artery (CRA), long posterior ciliary artery (LPCA), and ophthalmic artery (OA), as well as the mean velocity (V m ) of the central retinal vein (CRV), were measured using a color Doppler flow imaging (CDFI) technique and expressed as mean values with standard deviation (mean±SD). A statistical analysis was conducted based on a paired t -test and the Wilcoxon signed-rank test., Results: The employed real-time temperature measuring device was able to accurately measure ocular surface temperature during the hot-compress process. The temperature increased after the hot compress was applied. Analysis showed that the PSV and EDV values of the CRA and LPCA significantly increased after the application of the hot compress, as did the V m of the CRV. There were no significant changes in the EDV of the OA nor the RI of each artery., Conclusion: This experiment, which is the first of its kind, confirms that the retrobulbar blood flow velocities can increase upon heating the ocular surface. This simple method may be useful in the future.

Open angle glaucoma (OAG) is a severe ocular disease characterized by progressive and irreversible vision loss. While elevated intraocular pressure (IOP) is a well-established risk factor for OAG, the progression of OAG in many cases, despite IOP treatment, suggests that other risk factors must play significant roles in the development of the disease. For example, various structural properties of the eye, ocular blood flow properties, and systemic conditions have been identified as risk factors for OAG. Ethnicity has also been indicated as a relevant factor that affects the incidence and prevalence of OAG; in fact, OAG is the leading cause of blindness among people of African descent. Numerous clinical studies have been designed to examine the possible correlation and causation between OAG and these factors; however, these studies are met with the challenge of isolating the individual role of multiple interconnected factors. Over the last decade, various mathematical modeling approaches have been implemented in combination with clinical studies in order to provide a mechanical and hemodynamical description of the eye in relation to the entire human body and to assess the contribution of single risk factors to the development of OAG. This review provides a summary of the clinical evidence of ocular structural differences, ocular vascular differences and systemic vascular differences among people of African and European descent, describes the mathematical approaches that have been proposed to study ocular mechanics and hemodynamics while discussing how they could be used to investigate the relevance to OAG of racial disparities, and outlines possible new directions of research.