Orbital Blood Flow Research Articles

ВЛИЯНИЕ ОБЩЕСОМАТИЧЕСКИХ ФАКТОРОВ В РАЗВИТИИ ОСЛОЖНЕНННОЙ КАТАРАКТЫ И ГЛАУКОМЫ НА ФОНЕ ПСЕВДОЭКСФОЛИАТИВНОГО СИНДРОМА (ОБЗОР ЛИТЕРАТУРЫ).

The variety of surgical methods, modified approaches, and modern advances make it possible to predict the outcome of the intraoperative course in cataract and glaucoma surgery with minimal risk of complications. Interest in pseudoexfoliation syndrome will not subside and research and observations will be carried out at a broad clinical level, as the trend towards increasing life expectancy in the middle and older population continues. Pseudoexfoliation syndrome is a complex multifactorial process that is associated with cataracts and glaucoma. The etiology of PES remains unclear, despite the modern approach, the centuries-long development of clinical ophthalmology, non-nophysiology, and molecular biology. However, later, scientists, having discovered deposited abnormal material in internal organs and tissues, came to the conclusion that this syndrome is a systemic disorder of connective tissue metabolism. According to some authors, factors contributing to the development of this syndrome may be bad habits (smoking for many years), chronic somatic pathologies, mainly cardiovascular diseases, endocrinological pathologies, hypertension, atherosclerotic deposits, vascular aneurysms. Other authors have studied the risk of developing glaucoma with comorbid pathologies, noting the high incidence of cardiac and cerebrovascular pathologies. Comorbid pathologies can often increase intraocular fluid, which in turn can provoke the development of transient hypertension. The authors, comparing pseudoexfoliation syndrome with primary open-angle glaucoma, noted the influence of somatic conditions on orbital blood flow, which can also disrupt the hydrodynamics of the eye in the long term. In glaucoma and cataract surgery, there are various surgical, drug and non-drug approaches to improve the condition of the visual organ. This review describes the developments of various technologies, modified approaches, and the development of surgical instruments to solve complex problems for the surgeon.

Prospects Using of Colour Doppler Imaging to Study Ocular Hemodynamics in Pregnant Women with Diabetic Retinopathy. Review

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.

Diagnostic and predictive value of resistive / pulsatility indices of ophthalmic artery and common carotid artery for the development of diabetic retinopathy.

Ophthalmic artery resistive index (OA RI) was a controversial parameter to show hemodynamic changes due to diabetic retinopathy (DRP). To investigate the diagnostic and predictive value of resistive and pulsatility index (RI and PI, respectively) of OA and common carotid artery (CCA) for the development of DRP. A total of 60 patients with diabetes mellitus (DM) type 2 (study group) and 30 healthy participants (control group) were evaluated between January and June 2021 by Doppler ultrasonography (DUS). RI and PI values were compared between groups with a Student's t-test. Cutoff value, sensitivity, and specificity were calculated for the significant variables with receiver operating characteristic (ROC) analysis. In total, there were 20 (22.2%) patients with DM without DRP (DMwoRP), 20 (22.2%) patients in the non-proliferative diabetic retinopathy group (NPDRP), and 20 (22.2%) patients in the proliferative diabetic retinopathy group (PDRP). The mean of CCA RI and OA RI in the PDRP group was significantly higher than in the other three groups (P < 0.001). The mean of CCA RI and OA RI was significantly higher in the PDRP group than in the NPDRP group, and in the NPDRP group compared to the DMwoRP group. CCA RI and OA RI showed a significantly high correlation (r = 0.849; P < 0.001). Sensitivity was 95% and specificity was 100% for the diagnosis of PDRP for the 0.82 cutoff value of OA RI (AUR = 0.999, 95% confidence interval for AUC = 0.997-0.1000; P < 0.001). The OA RI accurately reflects DRP-induced orbital blood flow changes and is a predictive index for DRP prognosis.

Role Of Colour Doppler Imaging In Early Diagnosis Of Diabetic Retinopathy

Diabetic retinopathy is the most common cause of vision loss among people with diabetes and a leading cause of blindness among working-age adults in India. It is a form of microangiopathy, and is the most common ocular complication seen in diabetic patients. Diabetic retinopathy progresses from non proliferative to proliferative retinopathy. The non proliferative retinopathy is the milder form and it is reversible. As the progression to proliferative retinopathy happens, the patients are symptomatic and become irreversible. Vascular changes and subsequent ocular hemodynamic changes are critical events in the pathogenesis of diabetic retinopathy. Colour doppler imaging is one of the most widely used and well-established techniques for assessing ocular blood flow velocities in the retro bulbar vessels. This is a non-invasive, painless imaging method with highly reproducibility. Estimation of orbital blood flow velocity from colour doppler imaging of the ophthalmic artery and central retinal artery is a technique offering great potential for the identification of early retinopathy in diabetic patients.

Usefulness of orbital colour Doppler ultrasound in vascular-related monocular vision loss.

Acute, painless, monocular vision loss (APMVL) usually has a vascular aetiology. We conducted a prospective observational study from 2011 to 2018 to analyse the added value of colour Doppler imaging to assess orbital vessel blood flow in the diagnosis of APMVL. The study included 67 patients (39 [58.2%] men; mean age, 65.9 years [SD 13.7]) with APMVL evaluated at the Neurosonology Laboratory within the first 5 days of symptom onset, who were classified as having either transient or persistent monocular blindness. The blood flow in the ophthalmic and central retinal arteries was assessed using colour Doppler ultrasound with a linear 7.5-MHz transducer. Thirty-three (49.3%) patients presented transient monocular blindness, with reduced blood flow in either the ophthalmic or central retinal artery. The group with persistent vision loss included 24 cases of central retinal artery occlusion (CRAO) and 10 cases of ischaemic optic neuropathy (35.8% and 14.9%, respectively, of the total sample). These patients were older and had a higher prevalence of hypertension and mild carotid atherosclerosis. Orbital colour Doppler ultrasound (OCDUS) clarified the mechanism/cause of the ischaemia in 11 (16.4%) patients and showed abnormal flow in 46 (68.7%) patients, confirming the vascular origin in 19 (57.6%) of the transient monocular blindness cases. Lower peak systolic velocity was observed in patients with CRAO (p < 0.001), and a velocity < 10 cm/s in the central retinal artery was independently associated with the diagnosis of CRAO. OCDUS can be helpful in confirming the vascular cause and identifying the aetiology of APMVL.

EGFR Mutated Lung Adenocarcinoma with Secondary Glaucoma as Early Manifestation: A Case Report

Background: Orbital metastases are rare in pulmonary adenocarcinoma and can be manifested as glaucoma.Case: A 64-year-old male patient complained of swelling, redness, painful and protruded left eye. Physical and radiological examination revealed mass in the right lung, retrobulbar intraconal mass of the left oculi, and metastases in the ribs, liver, brain, and vertebrae. Result of bronchial mucosal biopsy showed adenocarcinoma. Epidermal growth factor receptor (EGFR) mutation examinations detected exon 19 deletions, therefore Gefitinib was given. Left orbital exenteration was performed and obtained a biopsy result of adenocarcinoma metastases.Conclusion: Orbital metastasis occurs by hematogenous pathway due to direct access of systemic circulation to left orbital blood flow. Glaucoma as a symptom of orbital metastases can appear before primary tumor symptoms, because lung cancer often does not show specific symptoms until advanced stage. Definitive treatment consists of targeted therapy and surgical management for metastases.

Compound Coherent Plane-Wave Ultrasound Imaging of Vascular Malformations of the Orbit.

Prior color-flow Doppler ultrasound studies of the eye have been performed with systems that exceed US Food and Drug Administration permissible ophthalmic ultrasonic energy limits. The authors report a study of orbital vascular malformations using a novel, Food and Drug Administration compliant, ultrafast compound coherent plane-wave ultrasound device to produce power Doppler images. Using a Verasonics Vantage 128 ultrasound engine and a user-developed MATLAB program with a 5-MHz linear-array probe, compound coherent plane-wave ultrasound data were collected on patients with orbital vascular malformations. Real-time color-flow Doppler visualized orbital blood flow. Power Doppler images were produced by post-processing compound coherent plane-wave ultrasound data acquired continuously for 2 seconds. Compound coherent plane-wave ultrasound was performed on 3 orbital vascular malformations (1 venolymphatic malformation, 1 infantile hemangioma, and 1 arteriovenous malformation). Compound coherent plane-wave ultrasound produced a high-resolution depiction of orbital blood flow for orbital vascular malformations with high sensitivity to slow flow. Analysis of blood flow within orbital lesions informs treatment planning. Compound coherent plane-wave ultrasound is an emerging ultrasound modality that falls within the Food and Drug Administration guidelines for use in the orbit and provides information to characterize orbital vascular malformations.

Evaluation of Orbital Blood Flow in Age-Related Macular Degeneration by Color Doppler Ultrasonography

Evaluation of Orbital Blood Flow in Age-Related Macular Degeneration by Color Doppler Ultrasonography

Assessment of the optic nerve and its arterial supply by ultrasound imaging in multiple sclerosis patients

BackgroundTransorbital sonography (TOS) has emerged as a promising assessment tool of the optic nerve and orbital arterial supply in multiple sclerosis (MS) patients.ObjectiveTo evaluate optic nerve diameter (OND), optic nerve sheath diameter (ONSD), and orbital hemodynamics using TOS in MS patients.MethodsForty MS patients and 28 matched healthy controls were included. Thirty-three eyes with previous optic neuritis (ON) and 47 eyes without previous ON of MS patients were examined. All subjects were submitted to assessment of OND, ONSD, and parameters of orbital hemodynamics using orbital ultrasound.ResultsOND and ONSD were smaller in MS eyes with previous ON than in controls. MS eyes with and without previous ON had statistically significant higher peak systolic and mean velocity of posterior ciliary arteries than the control eyes. Orbital blood flow velocities were negatively correlated with the duration of disease and Expanded Disability Status Scale (EDSS). A statistically significant decrease in blood flow velocities of the central retinal artery was detected in secondary progressive MS (SPMS) patients than in relapsing-remitting MS patients (RRMS).ConclusionTOS can be used as a feasible tool to detect optic atrophy in MS patients. MS patients may have abnormal retrobulbar hemodynamics compared to healthy controls.

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

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

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

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

Flow Changes in Orbital Vessels Detected with Color Doppler Ultrasound in Patients with Early Dysthyroid Optic Neuropathy.

SUMMARY – Thyroid-associated orbitopathy (TAO) is a common manifestation of Graves’ disease. The aim of the study was to assess the six percent of patients with TAO that develop dysthyroid optic neuropathy (DON), which is the most serious complication of TAO. As DON can cause permanent damage, it is essential to detect DON early when visual loss is still reversible. Color Doppler ultrasound is a noninvasive diagnostic method, which may be useful in early detection of DON. Thirty-six patients with confirmed Graves’ disease and active TAO were included, 21 (58%) of them with early DON (eDON) and 15 (42%) free from any signs of eDON. All study patients underwent Doppler ultrasound examination to determine the blood flow rates in the internal carotid artery, ophthalmic artery, and central retinal artery. Study results showed color Doppler ultrasound examination to have a potential to detect orbital blood flow changes in patients with eDON. Early detection of DON may result in earlier treatment and prevention of permanent optic nerve damage.

Effects of Obstructive Carotid Artery Disease on Ocular Circulation and the Safety of Carotid Artery Stenting

The aims of this study were to examine the ophthalmic artery flow changes in patients with obstructive carotid artery disease, evaluate the orbital blood flow changes after carotid artery stenting and assess the safety of carotid stenting procedure by using transorbital colour and spectral Doppler sonography. Thirty-one consecutive patients scheduled for carotid stenting with severe internal carotid artery stenosis (>60%; the study group) and 30 control subjects were included. Ophthalmic artery (OA) Doppler sonography was performed in the control group and study group before and after stenting. Peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI), and resistive index (RI) and systolic/diastolic ratio (S/D) in the ophthalmic artery were recorded. Statistical comparisons were made between controls and study group before stenting and before and after stenting in the study group. Comparison between control and study group before stenting revealed a statistically significant decrease in OA PSV (51.5±14.5 vs. 39.7±19cm/sec, p= 0.008) and EDV (15.2±4.5 vs. 11.3±5.7cm/sec, p=0.004) in the study group. Differences in PI (1.3±0.14 vs. 1.36±0.4, p=0.47), RI (0.7±0.04 vs. 0.75±0.21, p=0.19), and S/D (3.5±0.6 vs. 3.6±1, p= 0.5) ratio were not statistically significant between groups. Peak systolic velocity (39.7±18.9 vs. 51.3±22.2cm/sec, p <0.001), RI (0.75±0.21 vs. 0.81±0.13, p=0.16) and S/D ratio (3.6±1 vs. 4.6±1.5, p= 0.001) were found to be significantly increased in the study group after stenting compared to baseline. There were no statistically significant differences in EDV and RI EDV(11.3±5.7 vs. 11.7±5.7cm/sec, p=0.66), PI (1.36±0.4 vs. 1.6±0.6, p =0.047) after stenting. Ophthalmic artery flow parameters were significantly lower in patients with severe carotid artery stenosis compared to control, indicating compromised ocular blood flow in severe carotid stenosis. Flow indicators significantly improved after stent implantation suggesting the importance of revascularisation in restoring ocular blood flow and safety of carotid stenting.

Assessment of orbital blood flow velocities in retinopathy of prematurity.

The purpose of this study is to evaluate whether the presence of any stage retinopathy of prematurity (ROP) alters central retinal artery (CRA) and ophthalmic artery (OA) blood flow parameters in premature infants. The patients were divided into two groups according to the development of ROP; those who have ROP were defined as group I, those without ROP were defined as group II. Ninety eyes of 45 patients in group I and 40 eyes of 20 patients in group II were investigated. The blood flows in the CRA and OA were measured using ultrasound color doppler imaging (CDI) that allows to evaluate the peak systolic velocity (PSV), end diastolic velocity (EDV), and resistivity index (RI). The results were compared between two groups of subjects. There were no significant differences in the PSV, EDV, and RI of CRA between two groups (P=0.09, P=0.20 and P=0.63, respectively). The mean PSV value of OA in group I was found to be significantly higher than the one in group II (P<0.05), but there were no significant differences in the mean EDV and RI values of OA between two groups (P=0.40, P=0.17 respectively). The subgroup analysis revealed that the ocular blood dynamics were not found to be significant between eyes with stage I ROP and eyes with stage II ROP (P>0.05), whereas the difference in the mean PSV values of OA were found to be significant among the eyes with stage 1 ROP, eyes with stage 2 ROP, and eyes without ROP (P=0.03). This study demonstrated significant alterations in systolic flow velocities in the OA predicted by CDI in infants with ROP.

Orbital decompression surgery and horse chestnut seed extract improved superior orbital vein blood flow in patients with thyroid-associated ophthalmopathy.

To evaluate the efficacy and safety of orbital decomposition (OD) surgery in combination with horse chestnut seed extract (HCSE), as compared to OD alone, in patients with thyroid-associated ophthalmopathy (TAO). Sixty-two orbits from 62 TAO patients were randomly assigned to OD or OD+HCSE at 1:1 ratio (31 received OD alone, 31 received OD+HCSE). Forty-two orbits from 21 healthy subjects were used as controls. Complete ophthalmic examination and color Doppler flow imaging (CDFI) were performed before surgery and 3mo post-surgery on all 62 orbits from the TAO patients. CDFI were also performed on the 42 control orbits. The effect of OD+HCSE and OD alone on TAO orbits was compared on several endpoints, including superior ophthalmic vein blood flow (SOVBF) parameters, subjective assessment, soft tissue involvement, lid retraction, diplopia, eye movement restriction, degree of exophthalmos, and intraocular pressure. The control orbits were used as reference for the SOVBF parameters. OD surgery with or without HCSE improved SOVBF, symptoms and soft tissue involvement, decreased degree of exophthalmos and intraocular pressure in orbits of TAO patients. The OD+HCSE combination led to significantly better improvement of SOVBF than OD alone. The differences between the reductions of SOVBF in the two groups are 1.26 cm/s in max-volecity and 0.52 cm/s in min-volecity (P<0.0001). SOVBF is significantly reduced in the orbits affected with TAO, indicating that congestion may be an important factor contributing to TAO pathogenesis. OD surgery improves the SOVBF, and combination of HCSE medication and OD surgery further improved venous return than OD surgery alone.

Color Doppler Imaging of the Orbital Vessels in Ankylosing Spondylitis

Purpose: To analyze the hemodynamic features of orbital blood flow velocities using Doppler ultrasonography in ankylosing spondiylitis (AS) patients, as well as to compare these results with those of healthy controls. Methods: 33 AS patients and 32 healthy controls were consecutively included in the study groups. The same radiologist performed ocular blood flow measurements. Peak systolic velocity (PSV), end diastolic velocity (EDV), and resistive index (RI) were measured in the central retinal artery (CRA), posterior ciliary arteries (PCAs), and ophthalmic artery (OA). Resistive index was used to assess arterial resistance; it was automatically calculated as RI [(PSV–EDV)/PSV]. Results: There were no significant differences in the PSV, EDV, and RI of the OA, CRA, and PCAs between AS patients and controls. Conclusion: This result suggests no possible contributory role of vascular structures in formation of uveitis in AS. We believe that our preliminary results need to be complemented with further studies, particularly including AS patients with uveitis and rheumatic diseases with other ocular involvement.

Role of Color Doppler Imaging in Early Diagnosis and Prediction of Progression in Glaucoma

This longitudinal and prospective study analyzes the ability of orbital blood flow measured by color Doppler imaging (CDI) to predict glaucoma progression in patients with glaucoma risk factors. Patients with normal perimetry but having glaucoma risk factors and patients in the initial phase of glaucoma were prospectively included in the study and divided, after a five-year follow-up, into two groups: “Progression” and “No Progression” based on the changes in the Moorfields regression analysis (MRA) classification of Heidelberg retina tomograph (HRT). An orbital CDI was performed in all patients and the parameters obtained were correlated with changes in HRT. A logistic discrimination function (LDF) was calculated for ophthalmic artery (OA) and central retinal artery (CRA) parameters. Receiver operating characteristics curves (ROC) were used to assess the usefulness of LDFs to predict glaucomatous progression. A total of 71 eyes were included. End-diastolic velocity, time-averaged velocity, and resistive index in the OA and CRA were significantly different (P < 0.05) between the Progression and No Progression groups. The area under the ROC curves calculated for both LDFs was of 0.695 (OA) and 0.624 (CRA). More studies are needed to evaluate the ability of CDI to perform early diagnosis and to predict progression in glaucoma in eyes.

Early Orbital Blood Flow Changes in Multiple Sclerosis Patients with Unilateral Acute Optic Neuritis

The aim of this study was to evaluate orbital blood flow by using colour Doppler imaging before corticosteroid administration in multiple sclerosis patients with unilateral acute optic neuritis. Thirty multiple sclerosis patients with unilateral acute optic neuritis and 30 healthy subjects were included as the study and the control groups. The diagnosis of multiple sclerosis optic neuritis was based on clinical presentation, visually evoked potential, and magnetic resonance imaging findings. Data obtained from affected and unaffected eyes were compared with each other and the control group. Ophthalmic artery peak systolic velocity, end-diastolic velocity, resistivity index, and pulsatile index were measured in all patients before administration of systemic corticosteroid treatment and in control subjects. All parameters of blood flow obtained from affected eyes of patients who developed acute optic neuritis were significantly higher than those of the clinically uninvolved eyes of the affected patients (p < 0.001) and those of control eyes (p < 0.001). In addition, statistically significant increases were found in ophthalmic artery peak systolic velocity, end-diastolic velocity, and resistivity index of the clinically uninvolved eye of the affected patients compared with the control group (p = 0.002, p = 0.012, p = 0.013, respectively). No significant differences were found in blood flow data between left and right eyes of the control group (p > 0.05).

Success of Intra-arterial Chemotherapy (Chemosurgery) for Retinoblastoma

To review results of orbital angiography performed during intra-arterial chemotherapy (chemosurgery) for treatment of retinoblastoma to assess the association of angiographic variability in orbitovascular anatomy with tumor response and outcomes. Medical records and 64 orbital angiograms were reviewed for 56 pediatric patients with retinoblastoma undergoing chemosurgery using a combination of melphalan hydrochloride, topotecan hydrochloride, or carboplatin. The major orbital arteries and capillary blush patterns were graded, and tumor response and recurrence were compared using the log-rank and Fisher exact tests. Statistically significant variables for tumor response were lacrimal artery prominence (P=.001), previous treatment (P=.003), and lacrimal blush (P=.004). The only statistically significant variable for vitreous seed response was ciliary body blush (P=.03). Statistically significant variables influencing time to recurrence and time to enucleation were choroidal blush absence (P=.01) and lacrimal artery presence (P=.03), respectively. The success of intra-arterial chemotherapy is dependent on delivery of drug to the target tumor within the eye via the ophthalmic artery. Because of the small volume of drug used (0.50-1.25 mL per treatment) and the selectivity of catheterization, variables affecting orbital blood flow greatly influence drug delivery and the success of chemosurgery.

Orbital Doppler Evaluation of Blood Flow Velocities in Optic Neuritis

PurposeTo evaluate orbital blood flow velocities and optic nerve diameter with Doppler and gray-scale sonography in patients with acute unilateral optic neuritis (ON).MethodsOrbital Doppler and gray-scale sonography was performed in 46 eyes of 23 patients aged 19- to 47-years with acute unilateral ON. ON was diagnosed by an ophthalmologist on the basis of clinical presentation, presence of decreased visual acuity and assessment of visual evoked potentials. The peak systolic velocity (PSV) and end-diastolic velocity (EDV), as well as the resistance index (RI) and pulsatile index (PI) of the ophthalmic artery (OA), central retinal artery (CRA), posterior ciliary arteries (PCAs) and optic nerve diameter were measured in both eyes. We compared results from affected and unaffected eyes using the paired t-test. The area under the receiver operating characteristic (ROC) curves was used to assess the diagnosis of ON based on measured blood flow parameters of the OA, CRA and PCAs and optic nerve diameter.ResultsThe mean (standard deviation) optic nerve diameter in eyes with ON was 4.1 (0.8) mm, which was significantly larger than the 3.0 (0.4) mm diameter measured in unaffected control eyes (p < 0.001). There were no differences in average PSV, EDV, RI, or PI of the OA and CRA between affected and unaffected eyes (p > 0.05). The mean RI in the PCAs was slightly lower in the eyes with ON than in the contralateral eyes (0.60 vs. 0.64, p < 0.05). The area under the ROC curves indicated that optic nerve diameter was the best parameter for the diagnosis of ON.ConclusionsOptic nerve diameter was related to ON, but orbital blood flow parameters were not.