Mean Ocular Pulse Amplitude Research Articles

Relationship between Intraocular Pressure Fluctuation and Visual Field Progression Rates in the United Kingdom Glaucoma Treatment Study

To investigate whether intraocular pressure (IOP) fluctuation is associated independently with the rate of visual field (VF) progression in the United Kingdom Glaucoma Treatment Study. Randomized, double-masked, placebo-controlled multicenter trial. Participants with ≥5 VFs (213 placebo, 217 treatment). Associations between IOP metrics and VF progression rates (mean deviation [MD] and five fastest locations) were assessed with linear mixed models. Fluctuation variables were mean Pascal ocular pulse amplitude (OPA), standard deviation (SD) of diurnal Goldmann IOP (diurnal fluctuation), and SD of Goldmann IOP at all visits (long-term fluctuation). Fluctuation values were normalized for mean IOP to make them independent from the mean IOP. Correlated nonfluctuation IOP metrics (baseline, peak, mean, supine, and peak phasing IOP) were combined with principal component analysis, and principal component 1 (PC1) was included as a covariate. Interactions between covariates and time from baseline modeled the effect of the variables on VF rates. Analyses were conducted separately in the two treatment arms. Associations between IOP fluctuation metrics and rates of MD and the five fastest test locations. In the placebo arm, only PC1 was associated significantly with the MD rate (estimate, -0.19 dB/year [standard error (SE), 0.04 dB/year]; P < 0.001), whereas normalized IOP fluctuation metrics were not. No variable was associated significantly with MD rates in the treatment arm. For the fastest five locations in the placebo group, PC1 (estimate, -0.58 dB/year [SE, 0.16 dB/year]; P < 0.001), central corneal thickness (estimate, 0.26 dB/year [SE, 0.10 dB/year] for 10 μm thicker; P= 0.01) and normalized OPA (estimate, -3.50 dB/year [SE, 1.04 dB/year]; P= 0.001) were associated with rates of progression; normalized diurnal and long-term IOP fluctuations were not. In the treatment group, only PC1 (estimate, -0.27 dB/year [SE, 0.12 dB/year]; P= 0.028) was associated with the rates of progression. No evidence supports that either diurnal or long-term IOP fluctuation, as measured in clinical practice, are independent factors for glaucoma progression; other aspects of IOP, including mean IOP and peak IOP, may be more informative. Ocular pulse amplitude may be an independent factor for faster glaucoma progression. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Changes in ocular pulse amplitude and posterior ocular structure parameters in type 1 diabetic children without diabetic retinopathy.

Background:It is important to determine changes in posterior ocular structures in the early period before retinopathy develops in pediatric patients with type 1 diabetes mellitus (DM).Objective:To evaluate inner plexiform layer (IPL), ganglion cell layer (GCL), and retinal nerve fiber layer (RNFL) thicknesses, as well as the relationship between choroidal thickness (CT) and ocular pulse amplitude (OPA) in type 1 diabetic children without diabetic retinopathy (DR).Design:A prospective observational study.Methods:Group 1 (n = 44) consisted of pediatric patients with type 1 DM without DR, and Group 2 (n = 65) of pediatric control subjects. Both intraocular pressure (IOP) and OPA were measured using a dynamic contour tonometer. CT, IPL, GCL, and RNFL were all measured using spectral domain optical coherence tomography (OCT).Results:The mean IOP and OPA values were 16.67 ± 2.34 and 1.85 ± 0.34, respectively, in group 1, and 15.14 ± 2.17 and 1.65 ± 0.25 in Group 2 (p = 0.001 for both). The mean subfoveal CT value was 294.30 ± 67.61 μm in group 1 and 394.42 ± 69.65 μm in Group 2 (p < 0.001). The mean GCL and RNFL values were 1.09 ± 0.11 and 96.46 ± 11.69, respectively, in group 1, and 1.14 ± 0.09 and 101.73 ± 9.33 in Group 2 (p = 0.005 and p = 0.008, respectively).Conclusions:IOP and OPA values were higher, and CT, GCL, and RNFL values were lower in children with type 1 DM during the early stages than in the healthy control group. These findings suggest that CT may be a marker of retinal involvement in children with type 1 DM without DR.

Changes in intra-ocular pressure, ocular pulse amplitude and choroidal thickness after trabeculectomy

ABSTRACT Clinical relevance Glaucoma is one of the most common causes of blindness. Although high intra-ocular pressure (IOP) is the most important risk factor, ocular blood flow also has an effect on prognosis. Background The aim of this study was to investigate the IOP, ocular pulse amplitude (OPA) and choroidal thickness (CT) changes after trabeculectomy and to determine whether trabeculectomy has an effect on ocular blood flow. Methods This retrospective, comparative case series was conducted with 33 eyes of 33 patients who underwent trabeculectomy due to uncontrolled glaucoma. The fellow eyes of 20 patients who were followed up with medical therapy were included as a control group. IOP and OPA were evaluated using a dynamic contour tonometer. Subfoveal choroidal thickness (SFCT) was obtained with enhanced depth imaging (EDI) mode of Spectralis-OCT. Results The mean IOP was 21.6 ± 6.3 mmHg at baseline and 13.8 ± 0.9 mmHg after trabeculectomy (p ˂ 0.001), and the mean OPA was 4.1 ± 1.5 at baseline and 2.6 ± 1.6 mmHg after trabeculectomy (p ˂ 0.001). The mean SFCT was 292.2 ± 63.2 µm at baseline and 303.8 ± 70.4 µm after trabeculectomy (p = 0.024). The change in OPA was strongly positively correlated with the change in IOP (r = 0.597, p ˂ 0.001) and SFCT change was positively correlated with OPA change (r = 0.34, p = 0.05). There was no difference between the two groups in terms of IOP, OPA and SFCT values measured after trabeculectomy (respectively, p = 0.264, p = 0.627 and p = 0.949). Conclusion The large IOP decrease following trabeculectomy causes a decrease in OPA and choroidal thickening. On the other hand, trabeculectomy has no effect on OPA change.

Changes in ocular pulse amplitude and choroidal thickness in childhood obesity patients with and without insulin resistance.

To compare choroidal thickness (CT) and ocular pulse amplitude (OPA) in childhood obesity with insulin resistance (IR) and without IR. Seventy-three childhood obesity and 62 healthy children, who were both age-matched and gender-matched, comprised the study population in this prospective study. Obesity was determined as having a body mass index (BMI) - standard deviation (SD) score that was > 2 SD.Intraocular pressure (IOP) and OPA were measured using a dynamic contour tonometer. The CT measurements were performed using enhanced depth imaging optical coherence tomography at three locations, comprising at the fovea, at a position 500 µm nasal, and also at a position 500 µm temporal to the fovea. Mean BMI value was 28.72 ± 4.85 in the patients with childhood obesity and 21.47 ± 1.14 in the control group. The mean IOP and OPA values were determined 15.90 ± 2.30 and 14.10 ± 2.16 mm Hg, 1.50 ± 0.28 and 1.74 ± 0.32 mm Hg in the patients with childhood obesity and the control group, respectively (p < 0.001, p < 0.001). The mean subfoveal CT value was 350.50 ± 81.51 μm in the eyes with childhood obesity and 390.02 ± 71.50 μm in those of the control group (p = 0.003). When the patient groups with and without IR were compared, no significant difference was found between CT, OPA and IOP values (p > 0.005). Our results showed that both OPA and CT values were significantly decreased in childhood obesity patients. We suggest further studies to verify longitudinal changes in OPA and CT, as also the evaluation of these parameters in other populations.

Multimodal ocular evaluation in hemodialysis patients.

To evaluate choroidal thickness, intraocular pressure (IOP), axial length, central corneal thickness (CCT), lens thickness, anterior chamber depth, and ocular pulse amplitude (OPA) in hemodialysis patients. The patients with end-stage renal disease and undergoing hemodialysis were included in the study. Immediately before and 1 hour after hemodialysis, all patients underwent measurement of choroidal thickness with spectral domain optical coherence tomography (SD-OC, Cirrus HD-OCT; Carl Zeiss Meditec Inc., Dublin, CA), IOP and OPA with Pascal dynamic contour tonometry (Ziemer Ophthalmic Systems AG, Port, Switzerland), and anterior chamber depth, lens thickness, and axial length with optical biometry (LenStar LS900; Haag-Streit AG, Koeniz, Switzerland). Data from the patients' right eyes were included in the statistical analysis. The patient group included 8 (36.4%) males and 14 (63.6%) females with a mean age of 56, 14 ± 9, 96 (40-70) years. The mean subfoveal choroidal thickness before and after hemodialysis was 255.21 ± 6.15 (245-263) µm and 234.95 ± 7.89 (220-247) µm, respectively (p < 0.001). Mean choroidal thickness at 1500µm and 3000µm nasal and temporal of the fovea also decreased significantly after hemodialysis (p < 0.001). Mean OPA values before and after hemodialysis were 2.14 ± 1.07 (0.6-4) mmHg and 1.6 ± 0.86 (0.5-3.2) mmHg, respectively (p < 0.001). There was a statistically significant correlation between OPA and choroidal thickness measurements (p < 0.001, R = 0.923). IOP increased from 15.11 ± 2.58 (11-20) to 15.99 ± 2.21 (13-20) mmHg, but the change did not reach statistical significance (p = 0.05). There was no statistically significant change in mean axial length, anterior chamber depth, lens thickness, or CCT after hemodialysis (p > 0.05 for all). Although choroidal thickness and OPA may be decreased immediately after hemodialysis, there may be no significant changes in IOP or avascular ocular structures such as the lens and cornea.

Evaluation of ocular pulse amplitude in patients with carotid artery stenosis using the Pascal dynamic contour tonometer

BackgroundTo evaluate ocular pulse amplitude (OPA) in patients with carotid artery stenosis (CAS) using the Pascal dynamic contour tonometer (DCT).MethodsConsecutive patients who underwent ultrasound Doppler examination of the carotid artery for the suspicion of CAS were prospectively enrolled in the study. Each patient underwent a complete ocular examination. OPA was measured using Pascal DCT. The participants were divided into four groups according to the degree of CAS: Group 1 (no occlusion, control group), Group 2 (mild occlusion: < 50 per cent), Group 3 (moderate occlusion: 50–69 per cent), and Group 4 (severe occlusion: ≥ 70 per cent).ResultsA total of 161 eyes of 81 patients were included in the study. Of the 81 patients, 50 (61.7 per cent) were male, and 31 (38.3 per cent) were female. The mean age was 66.6 ± 12.3-years (range, 20–91-years). Mean OPA values were found to be 2.68 ± 0.97-mmHg in Group 1 (n = 64 eyes), 2.62 ± 0.83-mmHg in Group 2 (n = 49 eyes), 2.30 ± 0.97-mmHg in Group 3 (n = 27 eyes) and 1.66 ± 0.59-mmHg in Group 4 (n = 21 eyes). There was no statistically significant difference in mean OPA levels between Group 1 and Group 2 (p = 0.73). However, statistically significant differences were found between the other groups when they were compared with each other (Groups 1 and 3, p = 0.02; Groups 1 and 4, p < 0.001; Groups 2 and 3, p = 0.02; Groups 2 and 4, p < 0.001; Groups 3 and 4, p = 0.002).ConclusionOPA decreases in patients with moderate to severe CAS. OPA measurement with Pascal DCT can be used as a screening test for CAS.

Ocular Pulse Amplitude in Non-Diabetic Patients with End Stage Renal Disease and Normal Individuals Using Dynamic Contour Tonometry.

Ocular Pulse Amplitude (OPA) is the fluctuation of IOP with the cardiac cycle which is equal to the difference between systolic and diastolic IOP. These variations in IOP are thought to be caused by the blood volume that is pumped into the eye, mainly the choroidal bed during each cardiac cycle. In patients with end stage renal disease (ESRD), Choroidal perfusion has been found to be reduced as determined by Indocyanine Green Angiography (ICG) which is an invasive procedure. OPA is recorded by Dynamic Contour Tonometer (DCT) which represents a potential new technology for measuring choroidal blood flow indirectly & non-invasively especially in patients with suspected compromise in perfusion as in ESRD. In this study we postulate that measurement of OPA can be used to assess the choroidal perfusion inpatients with ESRD. To measure OPA in non-diabetic patients with ESRD on hemodialysis and to compare it with that of OPA in age matched normal individuals. It was a prospective Cross-sectional study and was done in a clinical set up during the period of January 2013 to October 2013. OPA among 44exposed and 44 non exposed individuals were measured using Dynamic Contour Tonometry (DCT) and analysis done. The mean OPA in non diabetic patients with ESRD was 1.945mm Hg (CI:1.847 - 2.043) and the mean OPA in age matched normals was 2.16mm Hg (CI: 2.08- 2.24). OPA in non diabetic ESRD patients was statistically significantly lower than that of age matched normals (p=0.03). There was no correlation between OPA and other parameters like age, gender, intraocular pressure, blood pressure or serumcreatinine levels.

Do ocular pulse amplitude and choroidal thickness change in patients with thyroid eye disease?

ABSTRACTPurpose: The aim of this study was to evaluate whether orbital changes induced by thyroid eye disease affect the ocular pulse amplitude and choroidal perfusion.Materials and Methods: A total of 38 eyes of 38 patients with thyroid eye disease (Group 1) and 38 eyes of 38 control individuals (Group 2) with normal intraocular pressure were enrolled in this study. Thyroid eye disease activity was defined using clinical activity score. Intraocular pressure measurement with Goldmann applanation tonometer, axial length, central corneal thickness, Hertel exophthalmometry and systolic and diastolic blood pressure measurements were taken from each patient. Ocular pulse amplitude and intraocular pressure were measured using dynamic contour tonometry. Choroidal thickness was measured by enhanced depth imaging-optical coherence tomography at subfoveal, nasal and temporal 1000 μm area.Results: Intraocular pressures measured with Goldmann applanation tonometer and dynamic contour tonometry and mean ocular pulse amplitude were not statistically different between groups. However mean choroidal thicknesses were significantly lower when compared to control group. Ocular pulse amplitude and intraocular pressure measurement with dynamic contour tonometry did not change significantly with the increase in clinical activity score. There was not statistically significant correlation between ocular pulse amplitude and choroidal thicknesses in patients with thyroid eye disease.Conclusion: Ocular pulse amplitude and choroidal perfusion were not found to change with orbital involvement in thyroid eye disease and with disease activity, especially in patients with normal intraocular pressure. Although choroidal thickness was thinner than control group, choroidal perfusion did not change as a compensatory mechanism for maintaining ocular homeostasis.

Evaluation of the effects on choroidal thickness of bimatoprost 0.03% versus a brinzolamide 1.0%/timolol maleate 0.5% fixed combination

Objective: To investigate the effects of two different medical treatment options on choroidal thickness (CT) in cases of open-angle glaucoma (OAG).Methods: Sixty-seven eyes newly diagnosed with OAG and 52 healthy eyes constituting the control group were included in the study. Glaucomatous eyes were randomly divided into two subgroups; Group I was started on bimatoprost 0.03% and Group II on a brinzolamide 1.0%/timolol maleate 0.5% fixed combination (BTFC). Intraocular pressure (IOP), ocular pulse amplitude (OPA) and subfoveal CT measurements were performed in all eyes in the study before treatment and on weeks 2, 4 and 8 after treatment.Results: Mean initial IOP values in groups I and II and the control group were 25.5 ± 4.7, 25.1 ± 5.2 and 16.1 ± 2.9 mmHg, mean OPA values were 3.7 ± 1, 3.6 ± 1.4 and 2.4 ± 0.6 mmHg and mean CT values were 269.4 ± 83, 264.5 ± 84.4 and 320.1 ± 56.6 μm, respectively. Eight weeks after treatment, mean IOP values in Groups I and II and the control group were 18.3 ± 2.6, 18.1 ± 3.4 and 15.7 ± 2.9 mmHg, mean OPA values were 2.9 ± 1.2, 2.8 ± 1.5 and 2.3 ± 0.8 mmHg and mean CT values were 290.2 ± 87.3, 271.8 ± 82.5 and 319.3 ± 56.8 μm, respectively. No significant difference was determined in terms of the decrease in IOP and OPA obtained after treatment in Group I and Group II. However, a significant difference was observed between the two groups in terms of choroidal thickening after treatment.Conclusion: The use of topical ocular hypotensive medication in eyes with OAG results in an increase in CT. This increase is relatively greater with bimatoprost 0.03% therapy compared to BTFC.

Evaluation of ocular pulse amplitude in non-arteritic anterior ischaemic optic neuropathy

BackgroundTo evaluate the ocular pulse amplitude (OPA) in patients with chronic non-arteritic anterior ischaemic optic neuropathy (NAION).MethodsThis cross-sectional study comprised a study group of 30 eyes from 30 patients with NAION and a control group of 31 eyes from 31 age and gender-matched healthy subjects. Bilateral OPA was measured with dynamic contour tonometry (DCT) and was compared between the study and control groups.ResultsNo statistically significant difference was found between the study and control groups in terms of hypertension, diabetes mellitus, ischaemic heart disease and hyperlipidemia. The mean intraocular pressure (IOP) measured with Goldmann Applanation Tonometry and DCT in the study and control groups was not statistically different (p1 = 0.094, p2 = 0.240). The mean OPA in the study group and the control group were 2.01 ± 0.69 mmHg and 1.97 ± 0.68 mmHg (p = 0.839).ConclusionNo significant difference was determined in the OPA levels of eyes with NAION at the chronic stage and eyes in the control group.

Effects of Swimming Goggles Wearing on Intraocular Pressure, Ocular Perfusion Pressure, and Ocular Pulse Amplitude.

To evaluate changes in the ocular pulse amplitude (OPA) and ocular perfusion pressure (OPP), and investigate factors associated with intraocular pressure (IOP) elevation due to periorbital compression during swimming goggles (SG) use. This cross-sectional study evaluated 35 eyes of 35 healthy volunteers during the wearing of a drilled SG. OPP calculation, Goldman applanation tonometry, and OPA measurements (using Pascal dynamic contour tonometer) were performed before, during, and after SG use. Scleral rigidity (calculated with Schiotz tonometry readings), orbital rim area, exophthalmometry, spherical equivalent, axial length, corneal thickness, and the goggles' rubber elastic force were considered in the multivariable analysis as potentially related to IOP changes. SG significantly increased IOP after 2 minutes of use (13.34±2.67 vs. 23.46±7.20 mm Hg, P<0.0001). After removal, IOP decreased significantly (10.20±5.85 mm Hg, P<0.0001). A inverse correlation between IOP and OPP differences was observed with the SG wearing (r=-0.57; P=0.0003). Mean OPA was significantly higher during compared with before SG wear (2.57±1.34 vs. 1.82±0.55 mm Hg for the timepoints 2 and 1, respectively; P=0.0064). Only orbital rim area (P=0.0052) and elastic force (P=0.0019) were significantly associated with IOP elevation. SG provoked acute IOP elevation and disturbance in the ocular hemodynamics, which was associated with larger orbital rim area and greater SG elastic force. These findings could have implications for subjects at high risk for glaucoma onset or progression.

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.

Ocular Pulse Amplitude and Retinal Vessel Caliber Changes after Intravitreal Dexamethasone Implant.

Purpose:The purpose of this study is to evaluate possible changes in ocular pulse amplitude (OPA), retinal arteriole caliber (RAC), and retinal venule caliber (RVC), following the intravitreal injection of dexamethasone implants (DIs).Methods:Thirty-four eyes of 34 patients with macular edema were included. All participants received a full ophthalmologic examination at baseline. RAC and RVC were measured via optical coherence tomography; OPA and intraocular pressure (IOP) were measured via dynamic contour tonometry at baseline, month 1, and month 3. Statistical analysis was performed for before-after comparison of OPA, IOP, RAC, and RVC measurements.Results:The mean OPA (in order to baseline, month 1, month 3) was 2.8 ± 0.8, 2.9 ± 1.0, 2.9 ± 0.9. The mean IOP was 16.8 ± 2.9, 17.3 ± 2.7, 18.4 ± 2.9 mmHg. The mean RAC was 97.8 ± 9.2, 97.2 ± 9.0, 97.6 ± 9.4. The mean RVC was 124.4 ± 8.2, 124.8 ± 8.8, 123.8 ± 8.2. There were no statistically significant changes in RAC (P = 0.688), RVC (P = 0.714), OPA (P = 0.348), and IOP (P = 0.115). There was also no correlation between RAC and OPA (r = 0.12, P = 0.62) or RVC and OPA (r = 0.16, P = 0.68) at the last visit.Conclusion:The intravitreal injection of DI does not significantly affect RAC, RVC, or OPA, which indicates that the treatment does not alter overall retinal-choroidal vasculature or hemodynamics.

Evaluation of ocular pulse amplitude and choroidal thickness in diabetic macular edema.

The aim of this study is to evaluate the ocular pulse amplitude (OPA) and choroidal thickness (CT) measurements in patients with diabetic macular edema (DME) and healthy subjects. A total of 34 patients (12 male and 22 female) who had type 2 diabetes mellitus with DME and 34 sex-matched healthy subjects (13 male and 21 female) were included in this prospective study. The intraocular pressure (IOP) and OPA were measured with Dynamic contour tonometer (Pascal DCT, Switzerland). The subfoveal CT was measured using the Cirrus HD-OCT (Carl Zeiss Meditec). The CT at 1500 μm and 3000 μm nasal and temporal to the central fovea was also measured. The mean IOP values were 18.4±3.5 and 17.1±2.1 mm Hg in DME patients and healthy controls, respectively (P= 0.091). The mean OPA values in patients with DME (2.58±0.96) and controls (3.52±1.03) were statistically different (P<0.001). The mean subfoveal CT value was 273.5±30.2 μm in the eyes with DME and 321.4±36.5 μm in the control group (P< 0.001). In both groups, linear regression analysis showed no significant association between OPA and CT measurements. The IOP showed a significantly positive correlation with OPA in both DME (P=0.002, r=0.526) and controls (P=0.004, r=0.483). The current study suggests that both pulsatile choroidal blood flow and CT are decreased in patients with DME.

The Effect of Non-Depolarising Muscle Relaxants on Ocular Pulse Amplitude and Intraocular Pressure

In general anaesthesia (GA) for ocular surgery the chosen non-depolarising muscle relaxant has a high influence on the fluctuations of intraocular pressure (IOP) and ocular pulse amplitude (OPA). In 229 patients, who needed GA for their ophthalmic surgery, OPA and IOP were measured with the dynamic contour tonometer (DCT) before and 5 minutes after intubation. For GA, three groups of non-depolarising muscle relaxants, namely, mivacurium (n = 71), atracurium (n = 91) and rocuronium (n = 67) were used. The IOP decreased by about 4.0 ± 2.3 mmHg using mivacurium in GA, by about 6.1 ± 2.2 mmHg using atracurium and by about 7.4 ± 1.7 mmHg using rocuronium (p < 0.001). The relative decrease of the IOP was 20% for mivacurium, 31% for atracurium and 37% for rocuronium. For mivacurium the OPA decreased from 3.4 ± 1.5 mmHg to 2.2 ± 1.1 mmHg (p < 0.001) in contrast to atracurium (decrease from 3.6 ± 1.5 mmHg to 1.8 ± 0.8 mmHg; p < 0.001) and rocuronium (decrease from 3.1 ± 1.6 mmHg to 1.7 ± 0.9 mmHg; p < 0.001). Mean OPA reduction was lowest with mivacurium (1.3 mmHg) and the highest with atracurium (1.7 mmHg). The mean relative decrease of the OPA was 34% with mivacurium, 46% with atracurium and 43% with rocuronium (p < 0.001). There was no linear correlation between the relative OPA decrease and the relative IOP decrease. Risks for ophthalmic surgery may be minimised by avoiding mivacurium in general anaesthesia. Due to its negative effects on IOP and OPA mivacurium does not seem to be suitable for operations with a large opening in the eye such as penetrating keratoplasty and block excision. Rocuronium can be used because it induces a favourised intraoperative decrease of the IOP.

Ocular pulse amplitude measurement using pascal dynamic contour tonometer in glaucoma patients.

This study aims to measure and compare the ocular pulse amplitude using Pascal dynamic contour tonometry in normal persons and in glaucoma patients. 20 patients (40 eyes) with primary open angle glaucoma (Group A), 8 patients (16 eyes) with normal tension glaucoma (Group B), and 12 patients (24 eyes) with ocular hypertension (Group C) were included in the study. Control group (Group D) comprised 25 normal volunteers (50 eyes). Intraocular pressure was measured using both Goldmann applanation tonometry in the slit-lamp and Pascal dynamic contour tonometry. Ocular pulse amplitude was evaluated with Pascal dynamic contour tonometry. Statistical evaluation of the differences in ocular pulse amplitude and intraocular pressure among the different groups was performed using Student's t-test. Mean ocular pulse amplitude values expressed in mmHg were 3.66 ± 1.00, 2.46 ± 0.60, 4.04 ± 1.47, and 2.52 ± 0.52, for Groups A, B, C, and D, respectively. The ocular pulse amplitude was significantly higher in Group A (primary open angle glaucoma) and Group C (ocular hypertension) when compared with Group D (control group) and Group B (normal tension glaucoma). No statistically significant difference was detected between Group D (control group) and Group B (normal tension glaucoma). Although we can measure the intraocular pressure with Goldmann applanation tonometry, no information can be derived regarding the ocular pulse amplitude. The use of Pascal dynamic contour tonometry in intraocular pressure estimation provides useful clinical information also about the magnitude of the ocular pulse amplitude in different types of glaucoma. Pascal dynamic contour tonometry discloses an elevation of ocular pulse amplitude in primary open angle glaucoma and ocular hypertension patients. On the contrary, the ocular pulse amplitude is within normal limits in normal tension glaucoma patients.

Ocular Pulse Amplitude in Patients With Descemet Stripping Endothelial Keratoplasty

To study the relationship of ocular pulse amplitude (OPA) and intraocular pressure (IOP) in eyes that have undergone successful Descemet stripping endothelial keratoplasty (DSEK). Fifty eyes of 38 patients with successful DSEK at a single tertiary referral center were followed up for at least 3 months. At the time of the study all patients were carefully examined to rule out any clinically detectable corneal edema. IOP was measured by Goldmann applanation tonometry (GAT), pneumotonometry (PT), and dynamic contour tonometry (DCT). IOP, OPA, and quality measurements were recorded. Central corneal thickness (CCT) was measured by ultrasonic pachymetry. Mean IOP was 15.9±4.9 mm Hg by GAT, 20.3±4.6 mm Hg by PT, and 19.8±4.4 mm Hg by DCT. Mean OPA was 2.53±1.24 mm Hg. OPA was correlated with GAT (r=0.357, P=0.011) and PT (r=0.316, P=0.026). The correlation of OPA and DCT approached significance (r=0.270, P=0.058). Mean CCT was 701±65 µm (range, 529 to 928 µm). OPA was not associated with CCT (r=0.238, P=0.096). In eyes with DSEK, our results showed that OPA was similar to that reported in normal eyes. Comparable with results in normal eyes, OPA was not associated with CCT but was associated with increasing IOP in DSEK eyes.

Effects of phacoemulsification surgery on ocular hemodynamics.

To evaluate the possible effects of phacoemulsification cataract surgery on ocular hemodynamics. In this prospective study, intraocular pressure (IOP), pulsatile ocular blood flow (POBF), and ocular pulse amplitude (OPA) were measured pre-operatively (baseline) and at 1 week and 3 weeks postoperation in 52 eyes of 26 patients (mean age 63.15±10.25 years) scheduled for unilateral phacoemulsification cataract surgery with intraocular lens implantation. In all of the eyes, a blood flow analyzer (Paradigm DICON; Paradigm Medical Industries Inc.; USA) was used to obtain measurements of IOP, POBF, and OPA. The data obtained from operated eyes were compared statistically to untreated fellow phakic eyes of the patients. For operated eyes, the mean baseline IOP, POBF, and OPA values were 15.9±4.64mmHg, 17.41±4.84µL/s, and 2.91±1.12mmHg, respectively. The IOP, POBF, and OPA values were 17.19±4.34mmHg, 17.56±6.46µL/s, and 3.12±1.1mmHg, respectively, in the nonoperated control eyes. Statistically significant differences from baseline measurements were not observed 1 week and 3 weeks postoperation for the operated or nonoperated eyes. There were also no statistically significant differences in any measurements between the operated and nonoperated eyes in all the examination periods (P>0.05 for all). Uncomplicated phacoemulsification surgery does not affect ocular hemodynamics in normotensive eyes with cataracts.

Correlation between ocular perfusion pressure and ocular pulse amplitude in glaucoma, ocular hypertension, and normal eyes

BackgroundThe purpose of this study was to investigate the correlation between ocular perfusion pressure and ocular pulse amplitude in glaucoma, ocular hypertension, and normal eyes.MethodsNinety eyes from 90 patients were included. Thirty patients had been recently diagnosed with glaucoma and had no previous history of treatment for ocular hypotension, 30 had elevated intraocular pressure (IOP) without evidence of glaucoma, and 30 had normal IOP (<21 mmHg) with no detectable glaucomatous damage. Goldmann applanation tonometry (GAT), dynamic contour tonometry (DCT), blood pressure measurement, pachymetry, Humphrey visual field, and routine ophthalmic examination was performed in each patient. Ocular perfusion pressure was calculated as the difference between mean arterial pressure and IOP. The ocular pulse amplitude was given by DCT. The Pearson correlation coefficient was used to compare the glaucomatous and ocular hypertensive groups, and comparisons with the normal IOP group were done using the Spearman’s rank correlation coefficient.ResultsMean IOP by DCT was 22.7 ± 4.3 mmHg in the glaucoma group, 22.3 ± 2.8 mmHg in the ocular hypertension group, and 14.3 ± 1.6 mmHg in the control group. Mean IOP by GAT was 19.0 ± 5.1 mmHg for glaucoma, 22.4 ± 2.1 mmHg for ocular hypertension, and 12.9 ± 2.2 mmHg for controls. Mean ocular pulse amplitude was 3.4 ± 1.2 mmHg in the glaucoma group, 3.5 ± 1.2 mmHg in the ocular hypertension group, and 2.6 ± 0.9 mmHg in the control group. Mean ocular perfusion pressure was 46.3 ± 7.9 mmHg in the glaucoma group, 46.3 ± 7.9 mmHg in the ocular hypertension group, and 50.2 ± 7.0 mmHg in controls. No significant correlation between ocular perfusion pressure and ocular pulse amplitude was found in any of the groups (P = 0.865 and r = −0.032, P = 0.403 and r = −0.156, P = 0.082 and ρ = −0.307 for glaucoma, ocular hypertension, and normal eyes, respectively).ConclusionThere is no significant correlation between ocular perfusion pressure and ocular pulse amplitude values in glaucoma, ocular hypertension, or normal eyes. IOP values measured by GAT correlate with those measured by DCT.

Effects of body mass index on intraocular pressure and ocular pulse amplitude.

To investigate the effects of body mass index (BMI) on intraocular pressure (IOP) and ocular pulse amplitude (OPA). Totally 140 healthy individuals without any systemic diseases were included in the study. BMI (kg/m(2)) was calculated for every individual. IOP and OPA were measured with Pascal Dynamic contour tonometer (DCT). Blood pressure was also measured along with the DCT. The patients were divided into three groups according to BMI as: Group1, BMI<25; Group2, 25≤BMI<30; Group3, BMI≥30. Mean values of IOP, OPA, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were used in statistical analysis. In Group1, the means of IOP, OPA, were 16.8±2.3mmHg, 2.7±0.7mmHg respectively; and SBP, DBP were 120.0±6.1mmHg, and 77.4±5.6mmHg respectively. In group2, the mean IOP, OPA, SBP, and DBP were found to be 16.6±2.1mmHg, 2.4±0.7mmHg, 121.7±5.3mmHg, and 79.5±4.9mmHg respectively. In group3, the mean IOP, OPA, SBP, and DBP were found to be 17.3±1.7mmHg, 2.1±0.7mmHg, 122.4±5.7mmHg, and 79.7±5.2mmHg respectively. There were no statistically significant difference between groups in terms of IOP, SBP and DBP, while OPA values were significantly lower in group3 (P=0.001). Decreased OPA values in individuals with higher BMI may indicate that subjects with higher BMI have lower choroidal perfusion and lower ocular blood flow.