Ocular Arteries Research Articles

Spontaneous brain activity in patients with central retinal artery occlusion: a resting-state functional MRI study using machine learning.

Central retinal artery occlusion (CRAO) is a serious eye condition that poses a risk to vision, resulting from the blockage of the central retinal artery. Because of the anatomical connection between the ocular artery, which derives from the internal carotid artery, and the anterior middle cerebral artery, hemodynamic alterations and sudden vision loss associated with CRAO may impact brain functionality. This study aimed to examine alterations in spontaneous neural activity among patients with CRAO by resting-state functional MRI. In addition, we selected the amplitude of low-frequency fluctuation (ALFF) and fractional amplitude of low-frequency fluctuation (fALFF) values as classification features for distinguishing CRAO from healthy controls (HCs) using a support vector machine classifier. A total of 18 patients diagnosed with CRAO and 18 HCs participated in the study. Resting-state brain function images and structural images were acquired from both groups. Aberrant changes in spontaneous brain functional activity among CRAO patients were investigated utilizing ALFF and fALFF analysis methods. Group differences in ALFF/fALFF values were assessed through a two-sample t-test. Subsequently, a machine learning classifier was developed to evaluate the clinical diagnostic potential of ALFF and fALFF values. In comparison to HCs, individuals with CRAO exhibited significantly higher ALFF values in the left cerebellum_6, vermis_7, left superior frontal gyrus, and left inferior frontal gyrus, triangular part. Conversely, the CRAO group displayed notably lower ALFF values in the left precuneus and left median cingulum gyri. Furthermore, higher fALFF values were observed in the left inferior frontal gyrus, triangular part, whereas lower fALFF values were noted in the right cerebellum_Crus2, left precuneus, right angular gyrus, left angular gyrus, right supramarginal gyrus, right superior parietal gyrus, and left precuneus. Utilizing the ALFF/fALFF values, the receiver operating characteristic curves (area under the curve) yielded 0.99 and 0.94 through machine learning analysis techniques. CRAO patients exhibit atypical neural activity in the brain, characterized by ALFF and fALFF values predominantly localized in the frontal, parietal, and cerebellar regions, which are closely linked to visual cognition and motor control impairments. Furthermore, ALFF and fALFF could serve as potential neuroimaging markers beyond the orbit among CRAO.

Isolated ocular sarcoidosis

A rare clinical case of a patient with isolated sarcoidosis of the eyes is presented. Sarcoidosis is a polyethological disease, the morphological feature of which is the formation of epithelioid cell granulomas in various organs and tissues, which is accompanied by a violation of their structure and function. Both congenital and adaptive immune systems are involved in the pathogenesis of sarcoidosis, with damage to lymph nodes, lungs, skin, organ of vision, etc. Risk factors for the development of sarcoidosis have not been definitively established. Environmental factors and genetic predisposition play a crucial role in the development of the disease. The above clinical observation demonstrates the polymorphism of the clinical picture of isolated ocular sarcoidosis. In addition to standard ophthalmic examination methods, the genetic method of reverse transcription and quantitative polymerase chain reaction (RT-PCR, English qRT-PCR) was also used to determine the expression profile of signature microRNAs as potential diagnostic markers of sarcoidosis of the organ of vision.An increase in the expression level of hsa-miR-455-3p, hsa-miR-4663, hsamiR68063p, hsa-miR-450b-5p, hsa-miR-6716-3p, hsa-miR-5000-5p, hsa-miR150-5p can be considered as potential diagnostic biomarkers of sarcoid lesion of eye structures. With sarcoidosis, the involvement of the lacrimal gland is possible. In the presented clinical observation, this was indicated by the results of a functional examination, sonographic signs: revealed multiple linear tubular hyperechoic structures and a decrease in blood flow velocity in the ocular and lacrimal arteries, as well as an increase in the expression activity of hsa-miR150-5p (p < 0.05). In order to prevent possible damage to the ocular surface due to the development of lacrimal gland dysfunction, it is advisable to prescribe local tear replacement therapy with hyaluronic acid preparations. Such effective drugs include tear substitutes of the Optinol® line: “Optinol® Express Moisture” and “Optinol® Deep Moisture”.

Early and late chorioretinal complications of preeclampsia

Preeclampsia remains a serious problem of obstetric practice, the growth of severe forms of this complication of pregnancy is predicted in the future, which determines the scientific interest of specialists in the search for new markers of preeclampsia to prevent the progression of preeclampsia and maternal mortality. The ocular fundus is an area where vessels can be observed in real time, in addition, the structure of the retina predisposes to the development of edema, up to retinal detachment in severe preeclampsia. In the last decade, new diagnostic equipment has become available to study chorioretinal changes at the stage of preclinical manifestations. In order to study early and late complications of pre-eclampsia from the retina and vasculature, we analyzed domestic and foreign scientific sources published in the last five years. According to a number of authors, changes in the visual organ of varying degrees of severity in preeclampsia occur in 100% of cases. It is established that the key role in the pathogenesis of vascular disorders in preeclampsia belongs to endothelial dysfunction. Preeclampsia may be accompanied by hemorrhagic and ischemic retinal infarcts, retinal pigment epithelium detachment, corkscrew-shaped tortuosity of arterioles in the periphery of the retina, retinal detachment, optic disc edema, less frequently vitreous hemorrhages, lesions of the optic nerve, conjunctiva and cerebral cortex in the area of visual centers, which may resolve against the background of therapy when the patient's general condition improves. However, in some women endothelial dysfunction may persist for many years, the most frequent late complications of preeclampsia are retinal detachment and diabetic retinopathy. Along with traditional methods of ophthalmoscopy of the eye fundus for diagnostics of chorioretinal complications OCT for determination of serous retinal detachment, subretinal deposits and other pathologies of the vasculature, USDG of the central retinal artery, posterior short ciliary arteries, ocular artery for diagnostics of ophthalmologic complications of preeclampsia can be used. As a result of the analysis of scientific data, conclusions are drawn about the association of preeclampsia with the development of certain early and distant chorioretinal complications. The search for new, earlier changes on the ocular fundus may serve for early diagnosis of preeclampsia, prevention of severe complications of pregnancy.

Clinical cases of successful treatment of life-threatening complications of selective intraarterial chemotherapy in children with retinoblastoma

Introduction. Retinoblastoma (RB), a malignant neoplasm, is the most common pediatric intraocular tumor worldwide. With the advent of intra-arterial chemotherapy, interventional surgeons have assumed a central role in the treatment of this pediatric disease. Intra-arterial chemotherapy is a new treatment modality for RB in which chemotherapeutic agents are precisely delivered into the ocular artery, minimizing systemic toxicity. This procedure has shown impressive results and has significantly reduced the rate of enucleation in advanced and refractory RB. However, the procedure entails potentially serious acute respiratory and hemodynamic disturbances.Purpose of the study – present our experience with and features of anesthesia management in the development of life-threatening conditions during superselective intraarterial chemotherapy (SIAC) in two patients with RB.Materials and methods. We present clinical cases in 2 2-year-old patients with RB who received three courses of SIAC for RB with development of severe trigeminocardial reaction.Conclusion. SIAC is one of the new promising treatments for RB. Prominent cardiorespiratory complications are frequently observed during general anesthesia for repeated sessions of SIAC and can be potentially life-threatening. Presumably, these complications represent an autonomic reflex response to ocular catheterization. Therefore, all patients with RB who are scheduled for SIAC should be included in the high-risk group. The timing of occurrence of the trigeminocardiac reflex is predictable and temporary, but the anesthesiologist must be prepared to treat the developed complication with the help of emergency drugs (adrenaline).

The structure of the rostral epidural rete mirabile and caudal epidural rete mirabile of the domestic pig.

The rostral epidural rete mirabile in the domestic pig has been studied by many scientists; however, the caudal epidural rete mirabile has been poorly understood and is rarely mentioned in the literature in domestic pig species. Based on the role of the rostral epidural rete mirabile in retrograde transfer of neurotransmitters and its localisation and structure, we hypothesize that the caudal rete may also play an important role in this process. The study was conducted on 80 domestic pigs (Sus scrofa domestica) of the Suidae family, including 60 piglets aged 0-20 days and 20 adult animals aged 5-9 months. The rostral epidural rete mirabile is an even well-developed structure consisting of dozens of anastomosing arterioles embedded in the cavernous sinus, formed by the maxillary and external ocular artery branches, which are extensions of the external carotid artery, and a thick branch to the rostral epidural rete mirabile. However, the caudal epidural rete mirabile is a structure made up of several interlacing arterioles consisting of the vertebral, condylar and occipital arteries on the caudal side, while on the rostral side it is made up of the middle meningeal artery branching off the inner surface of the temporal bone. The whole caudal epidural rete mirabile is embedded in the basilar and occipital sinuses, which led us to hypothesise that in these sinuses a retrograde transfer of neurotransmitters may take place analogous to the rostral epidural rete mirabile.

The state of ocular arterial blood flow in active retinopathy of prematurity

Purpose: to study the state of blood flow in the ocular arteries of patients with various forms, stages and course types of active retinopathy of prematurity (ROP). Material and methods. Colour duplex scanning was performed by colour Doppler mapping and pulsed Doppler sonography for 55 premature babies (55 eyes) with active ROP and 8 premature babies (8 eyes) without ROP signs. The children’s gestation age was 25 to 32 weeks, and the body weight at birth was 680 to1760 g. Blood flow was examined in the ophthalmic artery (OA), the central retinal artery (CRA) and the medial and lateral posterior short ciliary arteries (PSCA). Results. The ophthalmic artery revealed no significant differences between the children with ROP and without ROP, except for a significant increase in the peak systolic velocity (Vsyst) in an unfavorable course of stage III of ROP. The development of aggressive posterior ROP is accompanied by a statistically insignificant decrease in blood flow velocity of OA. Hemodynamic parameters of CRA indicate an increase in peripheral vascular resistance in children with an unfavorable course of ROP. A significant increase of Vsyst in the posterior short ciliary arteries was revealed in children with an unfavorable course of stages I–III of ROP and Vsyst, and Vdiast (diastolic blood flow velocity) in children with aggressive posterior ROP as compared with children without ROP. A pronounced impact of the ROP course (favorable or unfavorable) on the Vsyst, Vdiast, and PI indicators in the posterior short ciliary arteries was revealed. The most informative hemodynamic parameters in predicting the course of active ROP are Vsyst and Vdiast values in the ophthalmic artery and Vsyst in the posterior short ciliary arteries. The least informative were the hemodynamic parameters of the central retinal artery. Conclusion. The assessment of hemodynamic changes in eye arteries may be used as an additional diagnostic criterion in the early diagnosis of ROP.

Retinal Vessel Segmentation, a Review of Classic and Deep Methods.

Retinal illnesses such as diabetic retinopathy (DR) are the main causes of vision loss. In the early recognition of eye diseases, the segmentation of blood vessels in retina images plays an important role. Different symptoms of ocular diseases can be identified by the geometric features of ocular arteries. However, due to the complex construction of the blood vessels and their different thicknesses, segmenting the retina image is a challenging task. There are a number of algorithms that helped the detection of retinal diseases. This paper presents an overview of papers from 2016 to 2022 that discuss machine learning and deep learning methods for automatic vessel segmentation. The methods are divided into two groups: Deep learning-based, and classic methods. Algorithms, classifiers, pre-processing and specific techniques of each group is described, comprehensively. The performances of recent works are compared based on their achieved accuracy in different datasets in inclusive tables. A survey of most popular datasets like DRIVE, STARE, HRF and CHASE_DB1 is also given in this paper. Finally, a list of findings from this review is presented in the conclusion section.

The Possibilities of Color Duplex Scanning in the Assessment of Hemodynamic Eye Disorders in Children with Uveitis

Purpose: to study the hemodynamic parameters in the eye’s vessels in children with endogenous uveitis, depending on the localization and degree and activity of the inflammatory process.Patients and methods: 67 children aged 6 to 18 years were examined. Of these, 19 people (35 eyes) were diagnosed with anterior uveitis, 20 (38) — peripheral, 8 (14) — posterior, 10 (20) — panuveitis. There were subgroups according to the degree of inflammation activity in each group. There were 10 healthy children (20 eyes) in the control group. The maximum systolic (Vsyst), final diastolic (Vdiast) blood flow rate and resistance index (RI) in the ocular artery (GA), central retinal artery (CAC), posterior short ciliary arteries (ZCCA), central retinal vein (CVS) and superior ocular vein (VGV) were detected with the method of the Color Duplex Scanning (CDR).Results. The maximum systolic and final diastolic blood flow rates in GA decrease, and in panuveitis, on the contrary, increase in anterior uveitis on the location of active inflamation. In panuveitis, the blood flow rate in the HBV also increases. In peripheral uveitis, there is a decrease in systolic and diastolic blood flow rates and an increase in the resistance index in CAC and WCC. With posterior uveitis, the blood flow in the HBV slows down and the RI in the CAC and WCC increases.Conclusion. In children with active uveitis, according to the CDR, hemodynamic changes in the vessels of the eye are observed, it depends on the localization of the inflammatory process. They have multidirectional nature. In most cases, a decrease in blood flow rate and an increase in RI are detected. The study of the eye’s hemodynamics can be an additional criterion for assessing the activity of inflammation and the effectiveness of therapy, as well as differential diagnosis of various localization of the uveitis.

Giant Cell Arteritis Presenting With Ocular Symptoms: Clinical Characteristics and Multimodal Imaging in a Chinese Case Series.

PurposeTo evaluate demographic and clinical characteristics of a Chinese population with giant cell arteritis using multimodal imaging focusing on ophthalmic examinations.DesignRetrospective observational case series.Materials and MethodsIn the neuro-ophthalmology division of the Eye, Ear, Nose, and Throat Hospital, Shanghai, we evaluated the demographic and clinical characteristics of patients diagnosed with giant cell arteritis between January 2016 and June 2021. Results of routine ophthalmic examinations including fundus examination, optical coherence tomography, color duplex ultrasonography of ocular and superficial temporal arteries, orbital magnetic resonance imaging, and superficial temporal artery biopsy were evaluated.ResultsA total of 15 patients (22 eyes; ten male and five female) were evaluated with a mean age of 77.0 ± 8.5 years. Among them, seven had bilateral involvement that occurred simultaneously or sequentially. Twelve patients presented with arteritic anterior ischemic optic neuropathy, two with arteritic anterior ischemic optic neuropathy combined with cilioretinal artery occlusion, and one with cotton-wool spots. In acute stages of optic neuropathy and retinopathy, optical coherence tomography revealed optic disc edema, thickening of the inner retinal nerve fiber layer and ganglion cell layer, and loss of layer structure. In late stages, optical coherence tomography revealed diffuse atrophy of the inner retina. The “halo” sign was observed in 12 patients in the superficial temporal artery ultrasound, and seven out of eight patients who underwent biopsy demonstrated classic giant cell arteritis pathological changes. Most patients having poor visual acuity but ability to perceive light; 10/22 eyes had permanent vision loss.ConclusionAlthough rare in Asians, giant cell arteritis may be underdiagnosed among elderly Chinese patients presenting with anterior ischemic optic neuropathy. Non-invasive superficial temporal artery ultrasound detecting inflammatory thickening of the intima as the “halo” sign combined with routine elevated erythrocyte sedimentation rate and C-reactive protein may be helpful in diagnosing patients with a high probability of having giant cell arteritis.

Первая доклиническая ангиоспастическая фаза ретинопатии недоношенных

Purpose. To evaluate the role of the first preclinical phase in the pathogenesis of retinopathy of prematurity (ROP). Material and methods. 642 premature babies were examined. The gestational age at the time of birth was up to 30 weeks and the weight was up to 1500 g. Ophthalmological monitoring was carried out from 28–30 weeks of postconceptional gestational age. Indirect ophthalmoscopy, digital calibration of retinal vessels, and studies on a wide-field retinal pediatric camera were performed. Dopplerography data of the blood flow in the brain vessels and in the ocular artery were analyzed in 28 children (56 eyes). The partial pressure of oxygen (pO2) and carbon dioxide (pCO2) in capillary blood was studied using Radiometer ABL800 FLEX gas analyzer (normal levels of pO2 are 40–60 mmHg, pCO2 is 35–45 mmHg). Results. It was revealed that the lower the degree of maturity of the child’s body was, the more often retinal arteriospasm was detected. In children with a postconceptional age of 25–27 weeks, arteriospasm was detected in 82% of cases, at 28 – 29 weeks – in 67%, 30 – 32 weeks – in 54% of cases. The degree of angiospasm correlates with a high index of blood flow resistance in the brain vessels and the ocular artery. The predominance of a high index of blood flow resistance in more premature infants with low body weight was revealed.The index of resistance of brain vessels 0.8 and higher, according to dopplerography, is a critical indicator of the threat of ROP development in a premature baby. Conclusion. During retinopathy of prematurity, it is important to detect the first preclinical, antispasmodic phase of ROP development, which lasts about one month and until now practically does not attract the attention of ophthalmologists. In this phase, the pathogenesis of pathological angiogenesis is formed. Further study of the preclinical phase will radically revise the strategy and tactics of diagnosis and treatment of RP. Key words: retinopathy of prematurity, first preclinical angiospastic ROP phase, active ROP phase, scarring ROP phase, autoregulation of retinal vessels, hypoxic and hypercapnic drives.

Transitory and Vestigial Structures of the Developing Human Nervous System

As with many body organs, the human central nervous system contains many structures and cavities that may have had functions in embryonic and fetal life but are vestigial or atrophic at maturity. Examples are the septum pellucidum, remnants of the lamina terminalis, Cajal-Retzius neurons, induseum griseum, habenula, and accessory olfactory bulb. Other structures are transitory in fetal or early postnatal life, disappearing from the mature brain. Examples are the neural crest, subpial granular glial layer of Brun over cerebral cortex, radial glial cells, and subplate zone of cerebral cortex. At times persistent fetal structures that do not regress may cause neurological problems or indicate a pathologic condition, such as Blake pouch cyst. Transitory structures thus can become vestigial. Examples are an excessively wide cavum septi pellucidi, suprapineal recess of the third ventricle, trigeminal artery of the posterior fossa circulation, and hyaloid ocular artery. Arrested maturation might be considered another aspect of vestigial structure. An example is the persistent microcolumnar cortical architecture in focal cortical dysplasia type Ia, in cortical zones of chronic fetal ischemia, and in some metabolic/genetic congenital encephalopathies. Some transitory structures in human brain are normal adult structures in lower vertebrates. Recognition of transitory and vestigial structures by fetal or postnatal neuroimaging and neuropathologically enables better understanding of cerebral ontogenesis and avoids misinterpretations.

Three-Dimensional Computed Tomography Scanning of Temporal Vessels to Assess the Safety of Filler Injections.

Temple filler injection is one of the most common minimally invasive cosmetic procedures involving the face; however, vascular complications are not uncommon. This study aimed to investigate the anatomy of the temporal vessels and provide a more accurate protocol for temple filler injection. Computed tomography (CT) scans of 56 cadaveric heads injected with lead oxide were obtained. We then used Mimics software to construct 3-dimensional (3D) images of the temporal vessels described by a coordinate system based on the bilateral tragus and right lateral canthus. In the XOY plane, the superficial temporal artery (STA), middle temporal artery (MTA), zygomatico-orbital artery (ZOA), posterior branch of the deep temporal artery (PDTA), and lateral margin of the orbital rim divide the temple into 4 parts (A, B, C, and D). The probabilities of the STA, MTA, ZOA, and PDTA appearing in parts A, B, C, and D were 30.73%, 37.06%, 39.48%, and 77.18%, respectively. In 3D images, these vessels together compose an arterial network that is anastomosed with other vessels, such as the external carotid, facial, and ocular arteries. 3D CT images can digitally elucidate the exact positions of temporal vessels in a coordinate system, improving the safety of temple filler injections in a clinical setting.

Diagnosis and clinical course of ocular ischemic syndrome with retinal vascular abnormalities due to unilateral ocular artery and internal carotid artery stenosis in a child with neurofibromatosis type 1: a case report

BackgroundNeurofibromatosis type 1 (NF1) is a hereditary disease that causes neurofibromas generally, but it has been reported to sometimes be associated with various forms of blood vessel stenosis, occlusion and vascular abnormalities of unknown mechanism. However, a symptomatic case with simultaneous ophthalmic artery stenosis and internal carotid artery stenosis is an extremely rare pathogenesis in a child with NF1. In this report, we performed the diagnosis and observation using various imaging modalities for this rare pediatric case.Case presentationA 6-year-old girl diagnosed with NF1 presented with gradual visual loss in the right eye. Best corrected visual acuity (BCVA) was 20/40 OD and the intraocular pressure (IOP) was normal in both eyes. Retinal vascular abnormalities with tortuous vessels and optic disc pallor were observed in the right fundus. Widefield fluorescein angiography revealed multiple sites of neovascularization and a large non-perfusion area in the peripheral retina. Optical coherence tomography angiography showed retinal vascular abnormalities in the right eye and revealed differences in inner retinal thickness and blood flow signal between the left and right eyes. Laser speckle flowgraphy showed that chorioretinal blood flow was significantly decreased in the right eye. Cerebral angiography revealed the right ophthalmic artery was significantly narrowed throughout. In addition, Magnetic resonance angiography revealed that the right internal carotid artery was significantly narrowed in the ophthalmic segment. We diagnosed ophthalmic artery and internal carotid artery stenosis with retinal vascular abnormalities and ocular ischemic syndrome in NF1. Because IOP increased to 35 mmHg, due to neovascular glaucoma in addition to mild vitreous hemorrhage occurred, panretinal photocoagulation was performed after intravitreal bevacizumab injection. After treatments, IOP normalized, but BCVA decreased to 20/100 OD. Arterial spin labeling showed normal cerebral blood flow. The patient is currently being carefully monitored.ConclusionsWe have described the diagnosis and treatment of ocular ischemic syndrome due to multiple arteries stenosis in a child with NF 1. Utilization of various imaging modalities was helpful in diagnosing the complicated pathogenesis. However, since direct intervention by neurosurgery is not possible in this case, it is expected that treatment will be extremely difficult in the future.

Clinical efficacy of osteopathic correction in the complex treatment of patients with unoperated open-angle glaucoma

Introduction.Glaucoma is one of the most significant eye diseases. It is often diagnosed, not always amenable to therapy, and can lead to a complete loss of visual functions. In recent years, the method of osteopathic correction has become widespread as one of the effective methods of treatment and rehabilitation of patients with pathologies of various body systems. In the pathogenesis of glaucoma, it is customary to distinguish a dystrophic concept, which considers primary open-angle glaucoma as a result of dystrophic changes in the connective tissue, as well as in the endothelial lining of the trabeculae and Schlemm′s canal, especially destructive changes in mitochondria and the alteration of their functional activity. A vascular concept is also distinguished. According to this concept, the central link in the pathogenesis of glaucoma is circulatory disorder in the ciliary vessels, ocular artery, and major vessels of the head and neck, it can be assumed that osteopathic correction in the treatment of patients with open-angle glaucoma will be pathogenetically substantiated and will have a positive effect on intraocular pressure and trophicity of the optic nerve. The goal of research — to study the influence of in osteopathic correction on the nature of unoperated glaucoma (stage IIA) and to substantiate the possibility of using osteopathic correction in the complex treatment of patients with this pathology.Materials and methods.A prospective controlled randomized study was conducted at 52 city polyclinics, branch 3, Moscow, from January 2018 to January 2019. 40 patients (70 eyes) aged 50 to 75 years with primary open-angle glaucoma IIA stage were examined. At this stage of the disease, patients most often seek medical care and the issue of conservative management is primarily considered. All patients were divided into two groups of 20 people: the main group and the control group. The treatment in the main group included hypotensive drug therapy and osteopathic correction. Patients of the control group received only drug therapy. All patients underwent ophthalmic (visometry, tonometry, perimetry) and osteopathic examination twice: before the treatment and after 3 months.Results.For patients with primary open-angle IIA non-operated glaucoma, regional (most often regions of the head, neck, dura mater) and local (abdominal diaphragm, iliac bones, hip and knee joints) somatic dysfunctions were the most typical. In the main group a statistically significant decrease in the frequency and severity of dysfunctions at all levels was stated. Also, in patients receiving osteopathic correction, a significant decrease in the level of intraocular pressure and perimetric indices was noted. In patients of the control group, no reliable changes in these indicators were obtained.Conclusion.The results obtained indicate that osteopathic correction is clinically effective in the complex treatment of patients with primary open-angle II A glaucoma.

Usefulness of color Doppler imaging of orbital arteries in young hypertensive patients

Color Doppler imaging (CDI) is an established method for investigating ocular blood flow characteristics, and several blood flow parameters can be obtained from the velocity wave. This study evaluated CDI parameters in hypertensive subjects by measuring flow velocities, resistive index, and the pulsatility index of ocular arteries. One hundred young hypertensive patients and 50 age- and gender-matched healthy controls were recruited for the study. CDI parameters of the ophthalmic artery, central retinal artery, and posterior ciliary artery were measured in all subjects. Doppler index cutoff points were calculated using area under the curve with 95% confidence intervals. Results showed that Doppler parameters were significantly higher in subjects diagnosed with hypertension in the young compared to controls.

Remodeled structure and reduced contractile responsiveness of ocular ciliary artery in spontaneously hypertensive rats.

To investigate the alterations in both structure and contractile responsiveness of ocular ciliary artery (OCA) in spontaneously hypertensive rat (SHR). In this experiment, 20-week-old male SHR and Wistar Kyoto rat (WKY) were studied. The heart rate (HR), the blood pressure (BP; the systolic BP and the diastolic BP) of rats with an electronic sphygmomanometer were measured. Vascular morphometry and isometric tension measurement were used to investigate the alterations in structure and contractility of OCA. A general narrowing of OCAs was observed in SHR compared to the control WYK. In SHR, the media of OCAs were thicker, the luminal diameters were smaller, and the media-to-lumen ratios were higher when compared with WKY (P<0.05). The contractions of OCAs evoked by norepinephrine were smaller in SHR compared to control (P<0.05). Then, OCAs were pretreated with iberiotoxin, L-NAME, or indomethacin 30min before norepinephrine-induced contraction. Iberiotoxin (0.1 µmol/L) has not changed the norepinephrine-induced contractions in OCAs from both groups. However, L-NAME (100 µmol/L) increased the vasoconstrictions, the increased extents were similar in SHR and WKY (P>0.05). Indomethacin (10 µmol/L) decreased the contractions induced by norepinephrine in OCAs from WKY (P<0.05), but did not change those contractions in vessels from SHR (P>0.05). Our results demonstrate that the structure and function of OCAs are altered in hypertension. OCAs from SHR are remodeled with decreased lumen diameter and increased media-to-lumen ratio. Moreover, the contractile responsiveness of OCAs from SHR is diminished due to the disruption of vasoconstrictive effect of prostaglandins.

The influence of collateral circulation recruitment on various cognitive functions after severe unilateral stenosis or unilateral occlusion of the internal carotid artery

Objective To investigate the influence of collateral circulation recruitment on cognitive functions in patients with severe unilateral stenosis or unilateral occlusion of the internal carotid artery by using TCD. Methods A total of 176 patients with severe unilateral stenosis or unilateral occlusion of the internal carotid artery were enrolled and were divided into a single vessel collateral group(n=80, 45.5%), a multiple vessel collateral group(n=74, 42.1%)and a no collateral group(n=22, 12.5%). In order to study the influence of single vessel collateral circulation on cognitive functions, the single vessel collateral group was further divided into an anterior communicating subgroup(AcoA), a posterior communicating subgroup(PcoA), an ocular artery subgroup(OA), and a normal control subgroup.All patients and 34 normal controls(NC)received MoCA, and scores for the overall assessment and individual domains were analyzed. Results Compared with the control group(26.3±1.1, 4.7±0.5, 2.0±0.0, 3.6±1.0), the multiple vessel collateral group, the single vessel collateral group and the no collateral group had lower overall scores(24.2±1.7, 21.9±2.3, 19.0±2.4), lower executive/visuospatial function(3.9±0.7, 3.2±0.8, 2.4±0.6), lower abstraction(1.7±0.5, 1.6±0.5, 1.3±0.5), and lower delayed recall(2.9±0.8, 1.9±0.8, 1.6±0.5)(F=80.52, 63.21, 12, 48.99, all P<0.05); both collateral groups had lower scores in subtraction and attention(4.6±0.6 vs. 5.2±0.7, 4.3±0.7 vs. 5.2±0.7); the no collateral group had lower scores in orientation(4.7±0.7 vs. 5.7±0.5)(P<0.05). Compared with the multiple vessel collateral group, both the single vessel collateral group and the no collateral group had lower overall scores(21.9±2.3 vs. 24.2±1.7, 19.0±2.4 vs. 24.2±1.7), executive/visuospatial function(3.2±0.8 vs. 3.9±0.7, 2.4±0.6 vs. 3.9±0.7), subtraction and attention(4.6±0.6 vs. 5.1±0.5, 4.3±0.7 vs. 5.1±0.5)(all P<0.05); the no collateral group had lower scores in abstraction(1.3±0.5 vs. 1.7±0.5), delayed recall(1.6±0.5 vs. 2.9±0.8)and orientation(4.7±0.7 vs. 5.7±0.5)(all P<0.05). Compared with the single vessel collateral group, the no collateral group had lower overall scores(19.0±2.4 vs. 21.9±2.3), executive/visuospatial function(2.4±0.6 vs. 3.2±0.8)and orientation(4.7±0.7 vs. 5.7±0.6)(all P<0.05). In single vessel collateral patients, the AcoA subgroup had higher MoCA scores than the PcoA subgroup(22.9±1.7 vs. 21.2±2.7)(P<0.05), and the AcoA subgroup had higher scores in delayed recall than the OA subgroup(2.2±0.8 vs. 1.7±0.6)(P<0.05). Conclusions Severe unilateral stenosis or unilateral occlusion in the internal carotid artery can result in cognitive impairment, especially in executive/visuospatial function, abstraction, delayed recall, subtraction and attention.However, collateral circulation can protect cognitive function in patients with unilateral internal carotid artery stenosis or occlusion and multiple vessel collateral circulation is more effective than single vessel collateral circulation, and AcoA is more effective than either PcoA or OA, but the difference between PcoA and OA is not significant. Key words: Transcranial Doppler; Internal carotid artery; Severe stenosis or occlusion; Collateral circulation; Cognitive function

Role of Circulatory Hypoxia in the Development of Retinopathy of Prematurity

Purpose: to study the pathogenesis of retinopathy of prematurity.Patients and methods.642 preterm infants born before 30 weeks gestation with the weight less 1500 grams were examined. The study included: indirect ophthalmoscopy; digital retinoscopy; calibrometry of retinal vessels; dopplerography; analysis of partial pressure of oxygen and carbon dioxide in the capillary blood. Results. The first phase of retinopathy of prematurity (ROP) occurred due to the immaturity of the mechanisms of autoregulation of the blood flow and the inadequate reaction of immature retinal vessels to oxygen. It was established: the less gestational age of a child, so there are less mechanisms of autoregulation of hemodynamics. The perverse reaction of autoregulation leads to pronounced arteriospasm, increasing the zone of hypoxia, and triggering pathological angiogenesis. In morphologically immature children, arteriospasm of retina vessels is more often detected, and narrowing degree of vessels is higher. Arteriospasm is defined in 82 % of children born at the age of gestation from 25 to 27 weeks, in 67 % — at a period from 28 to 29 weeks, in 54 % — from 30 to 32 weeks. In children with ROP in the preclinical period of the disease, retinal angiospasm is noted at values of pO2 in capillary blood less then 40 mm Hg or exceeding the upper limit of the norm values of pCO2 (the norm values of pO2 are 40–60 mmHg, pCO2 are 35–45 mm Hg). Autoregulation of blood flow is immature and inadequate. In the group before 30 weeks of post-conceptual gestational age without development of ROP, a spastic reaction of retinal arteries was revealed at the background of subnormal pO2 values in capillary blood. Biochemical autoregulation of blood flow is still immature. But from the 30 week of post-conceptual gestational age arteriospasm of retina is formed at values of pO2 of 45 mm Hg or higher (p &lt; 0.05). The normal caliber of retinal arteries in children without development of ROP is revealed at the background of mean values of pO2 below 45 mm Hg and values of pCO2 below 42 mm Hg before 30 weeks of post-conceptual gestational age, and above 45 mm Hg from the 30th week of post-conceptual gestational age. In children without ROP from 30 weeks of gestational age biochemical autoregulation of blood flow functions. It is important the degree of an angiospasm for the development of ROP. Dopplerographic critical index of blood flow disturbance in the ophthalmic and anterior cerebral arteries has been established — the index of resistance (IR) exceeding 0.8. It is a precursor of the development of ROP and pathological angiogenesis. In the group of children with ROP, the IR of the anterior cerebral artery is 0.84 ± 0.02 (in av.). The IR of the ocular artery was 0.83 ± 0.03. In higher index (up to 0.9–1), the process in the eye was more active.

Increased endothelin-1-mediated vasoconstriction after organ culture in rat and pig ocular arteries can be suppressed with MEK/ERK1/2 inhibitors.

Even though retinal vascular changes following ischaemia have been poorly understood, the upregulation of vasoconstrictive endothelin-1 (ET-1) receptors (ETA /ETB ) following global cerebral ischaemia has been described. The aim of this study was to investigate whether or not the MEK/ERK1/2 pathway is involved in the observed upregulation and whether specific MEK/ERK1/2 inhibitors U0126 and trametinib can prevent it. The aim was also to localize ETA and ETB receptors using immunohistochemistry in both fresh rat ophthalmic arteries and after 24-hr organ culture and study the receptors functionally using myography. Pig retinal arteries also underwent 24-hr organ culture to validate similar responses across species and the retinal vasculature. Results showed that following organ culture there is a significant increase in ET-1-mediated vasoconstriction, in particular via the ETB receptor. Furthermore, immunohistochemistry revealed a clear increase in pERK in the smooth muscle cells of rat ophthalmic artery. U0126 and trametinib were successful in attenuating the functional vasoconstriction in both rat and pig, as well as restoring immunofluorescence of pERK to fresh levels and counteracting ETB expression in the smooth muscle cells of the rat ophthalmic artery. This is the first study to show that the MEK/ERK1/2 pathway in responsible for the increase in functional vasoconstriction via ET-1 receptor in rat ophthalmic and pig retinal arteries. Furthermore, this study is the first to suggest a way of inhibiting and preventing such an increase. With these results, we suggest a novel approach in retinal ischaemia therapy.

Correlation of Ocular Pulse Amplitude, Choroidal Thickness, and Internal Carotid Artery Doppler Ultrasound Findings in Normal Eyes

ABSTRACTIntroduction: The choroid receives about 65–85% of ocular blood flow, which comes from the ophthalmic artery (OA), the first branch of the internal carotid artery (ICA). In the foveal avascular zone, there is no retinal vascular supply; therefore, choroidal blood supply plays a significant role in this subfoveal region. The ocular pulse amplitude (OPA) provides useful information about intraocular blood flow and is an indirect indicator of choroidal perfusion. In this study, we aimed to assess the correlation between the OPA, subfoveal choroidal thickness (CT), and ICA Doppler ultrasound findings in healthy eyes. Methods: In total, 48 eyes of 48 healthy volunteers were included in this study. All eyes underwent detailed ophthalmic evaluation, including slit-lamp biomicroscopy, fundus examination, axial length, OPA measurements, and optical coherence tomography (OCT) with enhanced depth imaging mode. Carotid Doppler ultrasound examination was performed by the radiologist. The correlation between the OPA, subfoveal CT, and ICA Doppler findings [peak systolic velocity (PSV) and end-diastolic velocity (EDV)] were evaluated, considering gender and age. Results: The mean OPA was 3.06 ± 1.34 mmHg. The mean subfoveal CT was 305.85 ± 33.98 µm. The mean PSV and EDV of ICA were 73.25 ± 23.63 cm/s and 26.93 ± 13.42 cm/s, respectively. A moderate positive correlation was found between OPA and subfoveal CT (p = 0.001; rho = 0.481). This relationship was present in both men and women. While a positive correlation was found between the OPA and subfoveal CT in subjects under the age of 50 years, there was no correlation in those over the age of 50 years. Conclusions: A fair correlation was found between the OPA and subfoveal CT in healthy subjects under the age of 50.