End-diastolic Velocity Of Ophthalmic Artery Research Articles

Orbital blood vessels changes on color duplex imaging in diabetics with and without diabetic retinopathy

To compare changes in ophthalmic artery (OA) and its branches in diabetics with and without diabetic retinopathy (DR) using color duplex imaging (CDI), and to correlate these changes with the disease variables. 60 eyes of 60 diabetic patients were enrolled, divided into 3 groups: without DR (Group A), with Non-Proliferative DR (Group B) and with Proliferative DR (PDR) (Group C). Laboratory testing including HbA1c was done. Patients underwent CDI, by which OA, Central Retinal Artery (CRA) and Ciliary Arteries were identified; for each of them we measured Peak systolic velocity (PSV), End Diastolic velocity (EDV) and Resistivity Index (RI). Results were compared to clinical, laboratory and fundus examination. OA EDV was significantly lower and OA RI was found to be significantly higher in Group C (p = 0.027 and 0.025 respectively). CRA PSV and EDV were significantly lower in Group C (p = 0.017 and 0.001 respectively). PCA RI was significantly higher in Group C (p = 0.008). HbA1c was negatively correlated with CRA PSV (p = 0.041), also it was negatively correlated with CRA EDV (p = 0.0001), as well as with PCA EDV (p = 0.002). There was direct significant correlation between HbA1c and PCA RI (p = 0.012). Duration since diagnosis was negatively correlated with CRA EDV (p = 0.004). Multivariate linear regression showed that DR is an independent predictor for low OA EDV, high OA RI, low CRA EDV and high PCA RI. DR is an independent risk factor for orbital and ocular vessels flow alteration, thus can be used as a prognostic tool in diabetic patients. CDI can be reliably used in diabetics to predict early changes or progression of DR.

OCTA and Doppler Ultrasound in Primary Open-Angle Glaucoma and Normal-Tension Glaucoma.

The aim of this study was to determine whether the values of vessel density (VD) and perfusion parameters in the ophthalmic artery (OA) and central retinal artery (CRA) of the same eye differ in patients with hypertensive glaucoma (HTG) from patients with normotensive glaucoma (NTG). The first group consisted of 20 HTG patients (40 eyes). Patients with HTG were verified to have primary open-angle glaucoma (POAG). The second group consisted of 20 HTG patients (40 eyes). VD was used to determine the Avanti RTVue XR from Optovue (USA). Peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistance index (RI) were measured in both the central retinal artery (CRA) and ophthalmic artery (OA) using Doppler sonography on the Affinity 70G from Philips (USA). The visual field (VF) was examined by a fast threshold glaucoma program using a Medmont M700 (Australia). We showed no differences in VF, VD, PSV-OA and EDV-CRA between the two groups. Statistically significant differences between the two groups were observed in PSV in CRA (p = 0.04), EDV in OA (p = 0.009) and in RI in both CRA and OA. Other values were without significant differences in both groups. In both HTG and NTG, we observed in PSV-CRA, EDV-OA, RI-CRA and RI-OA.

The impact of obesity on ocular hemodynamics and choroidal thickness.

Obesity affects microvascular structures. The effect of obesity on the ocular vascular system can be evaluated by changes in the choroidal thickness (CT) and retrobulbar blood flow (RBF). To evaluate the CT and RBF parameters in obese patients with various body mass index (BMI) values and compare these parameters with normal weight, healthy subjects. A prospective study. The study included 102 eyes of 102 female patients. Patients were divided into three groups according to BMI as group 1 with a BMI of 18.5-24.99 (n = 32), normal weight group; group 2 with a BMI of 30-34.99 (n = 35), as obese class I; and group 3 with a BMI of 35-39.99 (n = 35), as obese class II. The peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index, and pulsatility index values of the central retinal artery (CRA) and ophthalmic artery (OA) were evaluated with color Doppler ultrasonography. CT was measured at the subfoveal area and at 500-µm intervals nasal and temporal to the fovea up to a distance of 1500 µm by using the enhanced depth imaging technique of optical coherence tomography. Intraocular pressure (IOP) was measured with a Goldmann applanation tonometry. There was a significant difference in IOP values within the groups with the highest values in group 3 (17.6 ± 2.1 mmHg) and the lowest in group 1 (12.4 ± 1.7 mmHg). The CT in groups 2 and 3 was found to be statistically significantly lower than that in group 1 at all measurement points (p < 0.001). There was a statistically significant negative correlation between CT at all measurement points and BMI (p < 0.001). The mean CRA PSV, EDV, and OA EDV values were statistically significantly lower in each obese group than those values in group 1 (p < 0.001). The OA PSV values were significantly lower in group 3 (36.5 ± 5.9 cm/s) than those in group 2 (43.8 ± 4 cm/s) and group 1 (44.6 ± 5.2 cm/s) (p < 0.001). Also, significant associations were found between BMI and CRA PSV, CRA EDV, and OA PSV values (p < 0.001). Obesity may predispose to eye pathologies by changing the ocular vascular circulation.

Retrobulbar ocular blood flow and choroidal vascular changes in patients recovering from COVID-19 infection

BackgroundTo evaluate the effects of COVID-19 infection on the ocular vascular structure including choroidal thickness and retrobulbar blood flow values in comparison with healthy subjects. MethodsNinety eyes of 90 patients were included in this study. Participants were divided into Group 1 (n = 30) with mild COVID-19 infection, Group 2 (n = 31) with moderate disease, and Group 3 with age- and sex-matched healthy subjects (n = 29). Choroidal thickness was measured at the subfoveal area and at 500-µm intervals nasal and temporal to the fovea up to a distance of 1500 µm, using the enhanced depth imaging (EDI) technique of spectral coherence tomography (SD-OCT). The peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI), and pulsatility index (PI) values of the central retinal artery (CRA) and ophthalmic artery (OA) were evaluated with color Doppler ultrasonography (CDU). ResultsThe choroidal thickness was significantly thinner in Group 1 and Group 2 than in Group 3 at all measurement points (p <0.001). This difference was not present between Group 1 and Group 2 who had COVID-19 disease of different severity (p>0.05).Among the retrobulbar blood flow parameters, OA PSV value was significantly lower in Group 1 and Group 2 compared to Group 3 (p = 0.025, p = 0.016, respectively). However, the CRA PSV and EDV and OA EDV values, and the CRA and OA PI and RI values were not statistically different between the groups (p> 0.05). ConclusionCOVID-19 infection may predispose patients to ocular vascular pathologies by affecting both choroidal and retrobulbar blood flow.

Ocular blood flow and choroidal thickness in ocular hypertension.

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

Comparison of Color Doppler Imaging Criteria for the Ophthalmic Artery and Central Retinal Artery in Infants with Retinopathy of Prematurity with and Without Plus Disease

Background: Color Doppler imaging (CDI) is a non-aggressive and safe technique for the clinical management of retinal diseases. Recently, the number of infants with retinopathy of prematurity (ROP) has increased due to the incidence of premature births. Objectives: This study aimed to compare the CDI criteria for the ophthalmic artery (OA) and central retinal artery (CRA) in ROP infants with and without plus disease. Patients and Methods: In this case-control study, 42 premature infants (21 infants with plus disease and 21 infants without plus disease) underwent CDI. The arterial CDI parameters, including end-diastolic velocity (EDV), pulsatility index (PI), resistance index (RI), and peak systolic velocity (PSV), were measured in these patients. After collecting the data, t-test and chi-square tests were used for data analysis. P &lt; 0.05 was considered to be statistically significant. Results: The mean EDV of CRA in patients with and without plus disease was 4.35 ± 1.00 and 5.27 ± 1.02 cm/sec, respectively (P = 0.005). The mean PSV of CRA in patients with and without plus disease was 15.65 ± 3.35 and 18.39 ± 4.39 cm/sec, respectively (P = 0.029). However, no significant difference was found between the two groups in terms of PSV or EDV of OA (P &gt; 0.05). Also, no significant difference was observed between the two groups considering the RI and PI of CRA and OA (P &gt; 0.05). Conclusion: According to the findings of this study, CDI criteria, such as EDV and PSV of CRA, were significantly lower in infants with plus disease as compared to those without plus disease. Since detecting the early stages of plus disease is a challenge for ophthalmologists, assessment of these criteria can be helpful for differentiation of these two subgroups of patients. However, further studies with a larger sample size are needed to determine the cutoff value.

Abnormal retrobulbar blood flow variables in central serous chorioretinopathy.

To evaluate if the retrobulbar blood flow variables were deteriorated in central serous chorioretinopathy (CSC) patients. We included 25 CSC patients and 25 healthy subjects. We used color Doppler ultrasonography to assess the ophthalmic artery (OA), the central retinal artery (CRA), and the posterior ciliary arteries (PCA) for peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistance index (RI). Mean ages of the patients and controls were 42.3 ± 8.5 and 41.3 ± 9.4 years, respectively (P = .853). There were no significant differences between the two groups with regard to the values of PSV, EDV, and RI of CRA (P = .406, P = .627, P = .227) and PCA (P = .785, P = .403, P = .935, respectively). The PSV and EDV of OA were lower in the CSC patients (P = .005, P = .024, respectively). Whereas the RI of OA was not significantly different (P = .729). Submacular choroidal thickness (SCT) was greater in CSC patients (P < .001). There was a negative correlation between SCT and PSV of PCA (P = .022, r = -0.457) and between SCT and EDV of PCA (P = .004, r = -0.560) in CSC patients. Hemodynamic changes in OA and a negative correlation between PCA values and SCT suggest ocular circulatory dysfunction in patients with CSC.

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

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

Baseline retrobulbar blood flow is associated with both functional and structural glaucomatous progression after 4 years.

Previous studies suggest that vascular abnormalities are involved in the pathogenesis of open-angle glaucoma. This study aims to examine the relationship of baseline retrobulbar blood flow measurements with functional and structural glaucomatous progression in patients with open-angle glaucoma over 4 years. In this study, 112 patients with open-angle glaucoma were examined at baseline and 78 with retrobulbar blood flow assessments were followed to 4 years. Colour Doppler imaging was used to evaluate retrobulbar blood flow. Structural disease progression was examined with optical coherence tomography and Heidelberg Retinal Tomography III. Functional disease progression was monitored with automated perimetry using Humphrey visual fields. Mixed-model analysis of covariance was used to test for significance of changes from baseline to 4-year follow-up. Two-sample t tests and χ2 tests were used to test for baseline blood flow differences between patients who progressed and those who did not progress. Patients who progressed structurally had a statistically significant lower baseline mean ophthalmic artery peak systolic velocity (PSV) (p=0.024) and ophthalmic artery end diastolic velocity (EDV) (p=0.012) compared with those who did not progress. Similarly, a lower baseline mean ophthalmic artery PSV (p=0.031) and ophthalmic artery EDV (p=0.005) were associated with patients who progressed functionally compared with those who did not progress after 4 years. In this study population, lower baseline ophthalmic artery blood flow velocities were associated with simultaneous structural and functional glaucoma progression after 4 years.

Differences in Ocular Blood Flow in Glaucoma Between Patients of African and European Descent

To investigate differences in ocular blood flow in individuals of African descent (AD) and European descent (ED) with open angle glaucoma (OAG). A retrospective data analysis was performed on OAG patients of AD and ED who were previously examined for ocular blood flow within the Department of Ophthalmology at Indiana University School of Medicine. Data analysis included blood pressure, heart rate, visual fields, intraocular pressure, ocular perfusion pressure, and color Doppler imaging of retrobulbar vessels. Color Doppler imaging measurements were performed on ophthalmic, central retinal, and nasal and temporal short posterior ciliary arteries, with peak systolic (PSV) and end diastolic velocities (EDV) as well as the Pourcelot vascular resistive index calculated for each vessel. Two-sample t tests of unequal variance were performed with P values <0.05 considered statistically significant. OAG patients of AD had statistically significant lower retrobulbar blood flow values than patients of ED including lower ophthalmic artery PSV (P=0.0001), ophthalmic artery EDV (P=0.0008), central retinal artery PSV (P=0.01), temporal short posterior ciliary artery PSV (P=0.0037), and nasal short posterior ciliary artery PSV (P<0.0001). No significant differences were found in terms of intraocular pressure or visual field parameters. Significantly lower blood flow values were identified in all retrobulbar blood vessels in AD compared with ED OAG patients. These findings suggest that the contribution of ocular blood flow to the disease process may be different in AD compared with ED OAG patients.

Impact of intravitreal triamcinolone acetonide versus intravitreal bevacizumab on retrobulbar hemodynamic in patients with diabetic macular edema

Purpose: To evaluate and compare retrobulbar hemodynamic changes measured with color Doppler imaging (CDI) in diabetic patients receiving intravitreal triamcinolone acetonide (IVTA) versus bevacizumab.Methods: Patients with diffuse diabetic macular edema were assessed prospectively by CDI following intravitreal injection of triamcinolone acetonide (group I, 12 eyes) versus bevacizumab (group II, 14 eyes). CDI was used to measure the peak systolic velocity (PSV), end diastolic velocity (EDV) and the resistive index (RI) of the central retinal artery (CRA), ophthalmic artery (OA) and posterior ciliary arteries (PCA) one day preoperatively and one week postoperatively.Results: In group I, EDV of OA and CRA decreased significantly (p = 0.007 and 0.018, respectively). The PSV and RI of PCA decreased significantly (p = 0.035 and 0.002, respectively). In group II, both the PSV and EDV of the CRA decreased significantly (p = 0.000). Comparing the percentage of change in both groups, PSV of the CRA decreased significantly in group II (p = 0.034), while IVTA has more significant effect on the ophthalmic artery hemodynamic parameters as EDV decreased and RI increased significantly (p = 0.045 and 0.043, respectively)Conclusion: Intravitreal injections of triamcinolone acetonide and bevacizumab have a significant effect on the ocular hemodynamic. The effect of bevacizumab is statistically significant on the PSV of CRA compared to IVTA.

The effect of anisometropic amblyopia on retrobulbar blood flow parameters

To look for a correlation between or the effect of anisometropia amblyopia on retrobulbar blood flow parameters. Peak systolic velocity (PSV) and end-diastolic velocity (EDV) of the ophthalmic artery (OA), central retinal artery (CRA), and temporal posterior ciliary artery (tPCA) were measured with color Doppler imaging, and systolic/diastolic ratio, resistivity index (RI), and pulsatility index (PI) were computed in 42 patients with anisometropic amblyopia. The mean PSV of OA, CRA, and tPCA in amblyopic and fellow eyes were 62.69 ± 24.04, 62.64 ± 20.18; 9.28 ± 3.71, 10.27 ± 4.18; 10.81 ± 4.59, 11.28 ± 4.91, respectively. The mean EDV of OA, CRA, and tPCA in amblyopic and fellow eyes were 15.87 ± 11.31, 14.52 ± 6.54; 2.48 ± 1.17, 2.62 ± 2.06; 3.04 ± 2.34, 3.14 ± 2.18, respectively. The mean RI of OA, CRA, and tPCA in amblyopic and fellow eyes were 0.76 ± 0.08, 0.76 ± 0.08; 0.72 ± 0.08, 0.74 ± 0.95; 0.72 ± 0.09, 0.72 ± 0.08, respectively. The mean PI of OA, CRA, and tPCA in amblyopic and fellow eyes were 1.77 ± 0.42, 1.81 ± 0.46; 01.58 ± 0.42, 1.59 ± 0.43; 1.54 ± 0.43, 1.58 ± 0.49, respectively. There was no statistically significant difference in any of the measured parameters between the amblyopic and fellow eyes. Anisometropic amblyopia did not cause any change in retrobulbar blood flow in amblyopic eyes.

Diagnostic compatibility of structural and haemodynamic parameters in open‐angle glaucoma patients

Current evidence indicates that alteration in ocular blood flow may be relevant in open-angle glaucoma (OAG) patients independent of intraocular pressure (IOP). Presently, the lack of an adequate methodology capable of assessing all vascular beds limits the clinical role of blood flow parameters in glaucoma management. We aimed to compare differences in retinal nerve fibre layer (RNFL) thickness and retrobulbar haemodynamics between OAG patients and healthy age-matched control subjects. Sixty eyes of 30 OAG patients and 30 healthy age-matched controls were enrolled into the prospective, randomized study. Retinal nerve fibre layer thickness was analysed by scanning laser polarimetry (SLP). Standard SLP parameters were determined, including: average temporal, superior, nasal, inferior thickness (TSNIT); superior and inferior averages; TSNIT standard deviation (TSNIT-SD), and nerve fibre indicator (NFI). Retrobulbar haemodynamics were assessed using colour Doppler imaging (CDI). Peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI) and resistivity index (RI) in the ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary artery (SPCA) were evaluated. The RNFL in OAG patients was statistically significantly thinner compared with that in age-matched controls: the NFI was 24.9 +/- 10.24 in OAG patients and 16.13 +/- 7.95 in healthy controls (p < 0.05). Statistically significant differences were observed: CRA PSV was 20.54 +/- 7.84 cm/second in OAG subjects and 16.5 +/- 6.19 cm/second in healthy controls (p = 0.0038); OA EDV was 8.99 +/- 4.71 cm/second in OAG subjects and 5.93 +/- 3.23 cm/second in healthy controls (p = 0.0048). Correlation analysis of NFI was in positive association with CRA EDV (r = 0.395; p < 0.05) and CRA PI (r = 0.403; p < 0.05) in OAG subjects, but no statistically significant association was seen in healthy controls. Statistically significant thinning of the RNFL in association with reduced retrobulbar blood flow velocities was observed in OAG patients. Combining ocular structural alterations with ocular circulation assessment may increase our ability to elucidate potential IOP-independent glaucomatous risk factors.

Ocular perfusion pressure and retrobulbar haemodynamics in pseudoexfoliative glaucoma

Previous investigations have shown that vascular factors are involved in pseudoexfoliative glaucoma (XFG). The present study aims at comparing ocular perfusion pressure (OPP), diastolic ocular perfusion pressure (dOPP), and retrobulbar haemodynamics in pseudoexfoliative glaucoma and primary open-angle glaucoma (POAG). Forty-seven XFGs, 41 POAGs, and 38 healthy controls were evaluated. OPP and dOPP were calculated. Peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistivity index (RI) were recorded in ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary arteries (SPCAs) by color Doppler imaging (CDI). Correlations between OPP and CDI parameters and between dOPP and CDI parameters were determined. OPP and dOPP were significantly lower in XFGs than in POAGs and controls (p < 0.001). CDI investigation revealed decreased EDV of OA, SPCAs, and CRA (p < 0.001) and increased RI of all the three considered vessels in XFGs compared with POAGs and controls (p < 0.001). A negative correlation between OPP and RI of OA and between dOPP and RI of OA was found in XFGs (p = 0.022 and p = 0.015 respectively). Ocular perfusion pressure is decreased and retrobulbar haemodynamics are worse in pseudoexfoliative glaucoma patients than in primary open-angle glaucoma patients and healthy controls. An impaired ocular vascular regulation is suggested in pseudoexfoliative glaucoma.

Retrobulbar haemodynamic effects of the latanoprost/timolol and the dorzolamide/timolol fixed combinations in newly diagnosed glaucoma patients

The objective of this study was to compare the effect of the latanoprost/timolol fixed combination (LTFC) and the dorzolamide/timolol fixed combination (DTFC) on the retrobulbar haemodynamic and intraocular pressure (IOP) in patents with open-angle glaucoma (OAG). This was a prospective, examiner masked, randomised and crossover study. Participants were 32 consecutive subjects, who met the inclusion/exclusion criteria, with newly diagnosed OAG. Patients were randomised to either LTFC or DTFC for the first 1-month treatment phase after a 1-month washout period, without medical treatment, patients began with the opposite treatment for the second 1-month treatment period. Colour Doppler parameters in ophthalmic artery (OA) and posterior ciliary arteries (PCA), ocular perfusion pressure, IOP and systemic haemodynamics were assessed at each baseline and at the end of each treatment period. The main outcomes include peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistance index (RI) in OA and PCA. DTFC significantly increased EDV in OA from 7.55 (1.16) to 9.32 (1.22), p<0.0001, and in the PCA from 4.41 (0.70) to 5.36 (0.60), p<0.0001, and significantly decreased RI in OA from 0.775 (0.036) to 0.725 (0.032), p<0.0001, and in the PCA from 0.694 (0.045) to 0.634 (0.034). LTFC significantly decreased the EDV and significantly increased RI in PCA, p=0.0076 and p=0.0009, respectively. There were no statistical significant differences in the IOP lowering effect between both treatments. DTFC seems to have a beneficial vascular effect on retrobulbar vessels in OAG patients.

Effects of pars plana vitrectomy on retrobulbar haemodynamics in diabetic retinopathy

The purpose of the present study was to determine the effects of pars plana vitrectomy on retrobulbar haemodynamics in patients with proliferative diabetic retinopathy (PDR). Colour Doppler imaging was used for measurement of blood flow velocities and resistive index of the ophthalmic artery (OA), posterior ciliary arteries (PCA) and central retinal artery (CRA) in 14 eyes of 14 patients with PDR before pars plana vitrectomy and at the 1 and 6 months after operation. The patients were also treated by laser photocoagulation before or during surgery. Twenty age- and sex-matched healthy subjects were used as control group. Mean peak systolic velocity and the end diastolic velocity of the CRA in the patients with PDR were lower and the mean resistive index was higher than in those of the control group (P < 0.05). The mean end diastolic velocity of OA in the patients was lower and the mean resistive index was higher than in the control group (P < 0.05). The peak systolic velocity of the OA and the end diastolic velocity of the CRA were significantly increased (P = 0.043 and P = 0.018, respectively) and the mean resistive index of the CRA was significantly decreased after pars plana vitrectomy (P = 0.043). No significant changes were detected among preoperative and postoperative values of peak systolic velocity, end diastolic velocity, and resistive index of the PCA and the mean velocity of the central retinal vein (P > 0.05). The blood flow velocities of OA and CRA are decreased but the resistive index is increased significantly in patients with PDR. Pars plana vitrectomy in patients with PDR may decrease resistive index and improve blood flow in the CRA.

Graves' Ophthalmopathy: Comparison of the Doppler sonography parameters with the clinical activity score

Our aim was to compare the Doppler ultrasonography (US) parameters with clinical activity score (CAS) in patients with Graves' ophthalmopathy. Blood flow parameters in the ophthalmic artery (OA), superior ophthalmic vein (SOV), central retinal artery (CRA) and central retinal vein (CRV) were measured by Doppler US in 118 patients with Graves' disease in 3 groups (A, B, and C) and 20 control subjects. Group A included 25 patients with CAS value "0"; group B 55 patients with CAS value "1 or 2"; group C 38 patients with CAS value "3 or above." Peak systolic velocities (PSV) and end-diastolic velocities (EDV) in the OA, PSV, and in the CRA calculated for group C were significantly higher than for group A, group B, and the control group. Resistance index in the OA and maximal velocity (MV) in the SOV calculated for group C were significantly lower than those calculated for group A, group B, and the control group. Doppler parameters of MV in SOV, PSV and EDV in OA, and PSV in CRA seem to be helpful in the differentiation of active and inactive phases of Graves' ophthalmopathy.