Does Fundus Fluorescein Angiography Procedure Affect Ocular Pulse Amplitude?

Aim:To investigate whether, intraocular pressure (IOP) is affected when there is a second fetus in the uterus during pregnancy.Materials and Methods:Eighty eyes of 40 twin pregnancies (TwPs), 80 eyes of 40 singleton pregnancies (SiPs) and 80 eyes of 40 non-pregnant females (NoPs) were included in the study.Statistical Analysis:Repeated measurements analysis of variance with two factors, one-way analysis of variance (ANOVA) and theTukey's multiple comparison test were used.Results:The mean IOP (MIOP) values in TwPs were 14.29 ± 1.28, 11.48 ± 1.20, and 9.81 ± 1.36 mmHg and the MIOP values in SiPs were 14.42 ± 0.95, 13.12 ± 0.75, and 10.97 ± 0.89 mmHg in subsequent trimesters. The MIOP values in NoPs were 14.77 ± 1.18, 14.92 ± 1.33, and 15.08 ± 0.89 mmHg in subsequent 3-month measurements. The results show that the MIOP values for the TwPs group were significantly lower than the SiPs in all trimesters.Conclusions:During pregnancy, the number of fetuses in the uterus is an indirectly important factor that influences the decrease in IOP. We hypothesize that the increased ocular hypotensive effect of TwPs is most likely related to the presence of higher levels of hormones, particularly estrogen, progesterone and relaxin compared with SiPs.

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.

The purpose of this study was to develop a method of estimating pulsatile ocular blood volume (POBV) from measurements taken during an ophthalmic exam, including axial length and using a tonometer capable of measuring intraocular pressure (IOP) and ocular pulse amplitude (OPA). Unpublished OPA data from a previous invasive study was used in the derivation, along with central corneal thickness (CCT) and axial length (AL), as well as IOP from the PASCAL dynamic contour tonometer (DCT) and intracameral (ICM) measurements of IOP for 60 cataract patients. Intracameral mean pressure was set to 15, 20, and 35 mmHg (randomized sequence) in the supine position, using a fluid-filled manometer. IOP and OPA measurements were acquired at each manometric setpoint (DCT and ICM simultaneously). In the current study, ocular rigidity (OR) was estimated using a published significant relationship of OR to the natural log of AL in which OR was invasively measured through fluid injection. Friedenwald’s original pressure volume relationship was then used to derive the estimated POBV, delivered to the choroid with each heartbeat as a function of OR, systolic IOP (IOPsys), diastolic IOP (IOPdia), and OPA, according to the derived equation POBV = log (IOPsys/IOPdia) / OR. Linear regression analyses were performed comparing OPA to OR and calculated POBV at each of the three manometric setpoints. POBV was also compared to OPA/IOPdia with all data points combined. Significance threshold was p < 0.05. OR estimated from AL showed a significant positive relationship to OPA for both DCT (p < 0.011) and ICM (p < 0.006) at all three manometric pressure setpoints, with a greater slope for lower IOP. Calculated POBV also showed a significant positive relationship to OPA (p < 0.001) at all three setpoints with greater slope at lower IOP, and a significant negative relationship with IOPdia. In the combined analysis, POBV showed a significant positive relationship to OPA/ IOPdia (p < 0.001) in both ICM and DCT measurements with R2 = 0.9685, and R2 = 0.9589, respectively. POBV provides a straight-forward, clinically applicable method to estimate ocular blood supply noninvasively. Higher IOP in combination with lower OPA results in the lowest values of POBV. The simplified ratio, OPA/ IOPdia, may also provide a useful clinical tool for evaluating changes in ocular blood supply in diseases with a vascular component, such as diabetic retinopathy and normal tension glaucoma. Future studies are warranted.

AimsTo investigate the change that occurs in intraocular pressure (IOP) and ocular pulse amplitude (OPA) with accommodation in young adult myopes and emmetropes.MethodsFifteen progressing myopic and 17 emmetropic young adult...

Purpose The aim of this study was to compared the effect of cataract extraction by phacoemulsification and posterior chamber lens implantation on measured intraocular pressure (IOP) using the Goldmann applanation tonometer, the Pascal dynamic contour tonometer (DCT), the Goldmann applanation tonometer (GT) and pneumotonometer (PT)Methods 97 eyes were measured in the operated eye one day before and one day, one week and one month after cataract surgery with the three tonometers, the IOP, ocular pulse amplitude (OPA),and central corneal thickness (CCT)Results Corneal edema induced by phacoemulsification cataract surgery resulted in statistically significant increases in CCT (87,8 μm SD 56,8 ;p&lt; 0,001), Pascal DCT IOP (4,8 mmHg, SD 8,0; p&lt; 0,001),Goldmann IOP (1,4 mmHg, SD 5,1;p&lt;0,015) and OPA (0,9 mmHg, SD 3,5; p&lt; 0,025) but not in pneumotonometry IOP (1,1mmHg, SD 5,3; p=0,065). Changes in IOP measured by GT and PT were less than those measured by the Pascal DCT. The variation between the Pascal DCT (Rho 0,247; p=0,038), and Pneumotonometer (Rho 0,358; p=0,002) was strongly correlated to the change in CCTConclusion Corneal edema after phacoemulsification cataract surgery increased IOP readings in the three tonometer compared, this increment is bigger in Pascal DCT readings. Changes in CCT are statistically significant associated with increased Pascal DCT IOP readings. Change in corneal biomechanics may in part be responsible for increased in the measured of IOP with Pascal DCT and GT

The Pascal dynamic contour tonometer (DCT) allows measurement of intraocular pressure (IOP) independently of corneal properties. It records, simultaneously, haemodynamic IOP fluctuations and the difference between the systolic and the diastolic IOP corresponding to the ocular pulse amplitude (OPA). The OPA indirectly reflects choroidal perfusion and could be considered as an independent risk factor in glaucoma. We aimed to establish the physiological diurnal variability of the OPA and its correlations with other biophysical parameters because its characteristics remain partly unclear. Prospective study including 52 eyes of 28 normal subjects with Goldmann applanation tonometry (GAT) IOPs < 22 mmHg. Subjects treated with systemic medications that could interfere with blood pressure or heart rate were excluded. IOP was measured at 9:00 am, 1:00 pm, and 4:00 pm by GAT and DCT. Two consecutive GAT followed by three consecutive DCT measurements were performed in each session by the same clinician (SP). Only DCT measurements with quality 1 and 2 were taken into account. Blood pressure, pulse rate, and central corneal thickness (CCT) were recorded after the last IOP measurements. Spearman correlation coefficient was used for assessment of correlations. Mean age was 40 +/- 14 years. Mean DCT values were significantly higher than GAT readings (mean = 16.8 +/- 2.0 vs. 15.2 +/- 2.8 mmHg, P < 0.02). The mean OPA was 2.2 +/- 0.7 mmHg (range: 1-3.4 mmHg). The mean amplitude of diurnal OPA fluctuations was 0.4 mmHg. There was no significant difference in the mean OPA values at each time of the diurnal curve. The intraclass correlation (ICC) of only one OPA measurement in relation to part of total variance due to inter-measurement variation was 78%. Averaging over three independent readings of OPA improved ICC to 91%. The OPA was correlated with GAT (r = 0.31, P < 0.0001) and DCT IOP measurements (r = 0.49, P < 0.0001). It was correlated neither with blood pressure nor with age. OPA values of both eyes of the same individual were highly correlated (r = 0.89, P < 0.0001). In normal healthy eyes, the ocular pulse amplitude remains stable during normal outpatient office hours and was not correlated with blood pressure or age of patients.

Objective To investigate the effects of body mass index (BMI) on intraoeular pressure (IOP) and ocular pulse amplitude (OPA).Methods Totally 60 healthy individuals who came to our hospital for health examination without any systemic diseases were included in the study on June 3,2013.BMI (kg/m2) 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,Group 1,BMI＜25kg/m2; Group 2,25kg/m2≤BMI＜30kg/m2; Group 3,BMI≥30kg/m2.Mean values of IOP,OPA,systolic blood pressure (SBP) and diastolic blood pressure (DBP) were used in statistical analysis.Results There were no statistically significant difference between groups in terms of IOR SBP and DBP,while OPA values had statistically significant difference between groups,and there was significantly lower in group3.Conclusions Decreased OPA values in individuals with higher BMI may indicate that subjects with higher BMI have lower choroidal perfusion and lower ocular blood flow. Key words: Body mass index; Intraocular pressure; Ocular pulse amplitude; Obesity

Twenty-four-hour IOP measurements with a CLS showed that among IOP indicators studied, the range of IOP fluctuation was most important and significantly larger in NTG eyes compared with nonglaucoma eyes. We conducted the present study to determine (1) the best factor for distinguishing normal tension glaucoma (NTG) and nonglaucoma subjects based on the intraocular pressure (IOP) values measured by a CLS and (2) the optimal cutoff values of that factor. The eyes of 18 nonglaucoma subjects and 26 NTG patients were examined. We evaluated 5 indicators: maximum IOP value, SD, IOP fluctuation range, the cosine-fit curve amplitude, and the amplitude of dual-harmonic regression values. We determined the indicators' cutoff values to distinguish between nonglaucoma subjects and NTG patients with the area under the curve. The mean IOP values were 12.3±2.7mmHg in the nonglaucoma eyes and 12.5±3.1mmHg in the NTG eyes ( P =0.824). All 5 indicators were significantly higher in the NTG group. The best factor to distinguish the nonglaucoma subjects and NTG patients was the IOP fluctuation range ( P <0.0001, area under the curve=0.844); the cutoff level value was 436.5 millivolt equivalents. Twenty-four-hour IOP measurements with a CLS showed that among IOP indicators studied, the range of IOP fluctuation was most important and significantly larger in NTG eyes compared with nonglaucoma eyes.

To evaluate the influence of silicone hydrogel contact lenses on the intraocular pressure (IOP) measurement using Goldmann applanation tonometry (GAT), non-contact tonometry (NCT), and Pascal dynamic contour tonometry (DCT). We included in the study 40 eyes of 40 patients who did not have any ocular or systemic diseases or contraindications to contact lens use. We measured and recorded the IOP values of each patient using NCT without and with contact lenses (groups 1 and 2, respectively), using DCT without and with contact lenses (groups 3 and 4, respectively), and using GAT without contact lenses (group 5). The mean IOP value of group 1 was 14.55 ± 2.95 mm Hg and 13.92 ± 2.58 mm Hg in group 2. We detected no statistically significant difference between group 1 and group 2 (P=0.053). The mean IOP values for group 3 and group 4 were 16.26 ± 2.33 mm Hg and 15.19 ± 2.40 mm Hg, respectively. We detected a statistically significant difference between groups 3 and 4 (P=0.005). Group 5's mean IOP value was 12.97 ± 2.65 mm Hg. IOP values measured with DCT were statistically significantly higher compared with IOP values measured with NCT and GAT (P<0.0001 and P<0.0001, respectively). Additionally, IOP values measured with NCT were statistically significantly higher compared with IOP values measured with GAT (P<0.0001). According to the results of our study, silicone hydrogel soft contact lens use does not significantly affect IOP values measured with NCT, but it affects IOP values measured with DCT.

Objective: To assess the impact of microgravity exposure on ocular rigidity (OR), intraocular pressure (IOP), and ocular pulse amplitude (OPA) following long-term space missions. OR was evaluated using optical coherence tomography (OCT) and deep learning-based choroid segmentation. IOP and OPA were measured with the PASCAL Dynamic Contour Tonometer (DCT). Results: The study included 26 eyes from 13 crew members who spent 157 to 186 days on the International Space Station. Post-mission results showed a 25% decrease in OPA (p < 0.005), an 11% decrease in IOP from 16.0 mmHg to 14.2 mmHg (p = 0.04), and a 33% reduction in OR (p = 0.04). No significant differences were observed between novice and experienced astronauts. Conclusions: These findings reveal previously unknown effects of microgravity on the eye's mechanical properties, contributing to a deeper understanding of Spaceflight-Associated Neuro-ocular Syndrome (SANS). Long-term space missions significantly alter ocular biomechanics and have the potential to become biomarkers of disease progression.

To compare the short-term effectiveness and ocular side-effects of fixed combinations of dorzolamide/timolol (DTFC) and brimonidine/timolol (BTFC) in patients with primary open-angle glaucoma (POAG). Forty-two eyes of 42 patients newly diagnosed with primary open-angle glaucoma were assessed prospectively. One of the two eyes was chosen randomly and treated with DTFC (2×1) for 4weeks. The treatment was then stopped to allow a 4-week wash-out period. Following the wash-out period, the same eye was treated with BTFC (2×1) for 4weeks. Intraocular pressure (IOP) values were measured before and after each treatment at 0800, 1,200 and 1,600h. Tear function test results and ocular side-effects were also recorded. The mean baseline IOP values for DTFC and BTFC were 24.1±1.8 and 24.6±2.4mmHg, respectively. The mean IOP values after 4weeks of treatment with DTFC or BTFC were 17.1±2.9 and 16.9±2.5mmHg, respectively. Both medications reduced IOP values significantly (P=0.0000). The effectiveness of both medications was similar (P=0.7363). Both combinations significantly reduced the amount of tear secretion and tear break-up time (P=0.0000). Eye burning was more common with DTFC than with BTFC (P=0.0182). Other adverse effects were observed at similar rates for both combinations. This study demonstrated that the IOP-reducing effects of DTFC and BTFC in patients with POAG are similar. The side-effect profile of BTFC is similar to that of DTFC. Lower occurrence of a burning sensation may improve patient compliance in the BTFC group.

PurposeTo evaluate the effect of intravitreal (IVT) bevacizumab in neovascular age-related macular degeneration (AMD) on global choroidal hemodynamics, as measured by ocular pulse amplitude (OPA).MethodsThis was a two-center prospective study (Sheba Medical Center, Israel, and University Hospitals Leuven, Belgium). AMD patients who required IVT bevacizumab (1.25 mg/0.05 mL; first or repeated) were examined three times: at days 0 (prior to injection), 7 (±3), and 28 (±7) postinjection. At each visit, OPAs of both eyes were measured using the Pascal dynamic contour tonometer (DCT). A paired t-test between preoperative and postoperative OPA was conducted. Pearson correlation was used to evaluate the influence of various measured parameters on DCT–OPA.ResultsA total of 38 neovascular AMD patients were recruited, and 30 patients were included in the final analysis (18 females and 12 males; age 78.8 ± 5.82 years [mean ± standard deviation]). A good correlation was found throughout the study between the DCT–intraocular pressure (IOP) and Goldmann IOP and between DCT–IOP and DCT–OPA. No change in OPA of bevacizumab-treated eyes was found between the visits (2.24 ± 0.73, 2.2 ± 0.86, and 2.23 ± 0.73 mm Hg at visits 1, 2, and 3, respectively; paired t-test: P = 0.77 between visits 1 and 2, P = 0.98 between visits 1 and 3). No correlations were found between DCT–OPA and age, heart rate, systemic blood pressure, axial length, keratometry readings, and central corneal thickness.ConclusionsOPA, an indirect measure of global choroidal hemodynamics, remains unchanged following IVT off-label bevacizumab. This finding adds to the growing evidence regarding the safety profile of bevacizumab in AMD treatment.

Intraocular pressure (IOP) is known to be subject to daily fluctuations, the occurrence of which is a risk factor for progression of glaucoma. Control of IOP during the day by drugs is an important therapeutic target. We set out to compare the IOP control of travoprost and latanoprost taking into account the time since last instillation and the time of IOP measurement. This was a prospective, cross-sectional observational study with some retrospective data collection. Private ophthalmologists were selected to each recruit ten patients with primary open-angle glaucoma and/or ocular hypertension receiving either travoprost or latanoprost as monotherapy. Clinical endpoints included IOP measurements and percentage of patients attaining predefined target IOPs. Six patient subgroups were defined according to: (a) IOP measurement time: before 1200h, 1200h-1600h and after 1600h, and (b) time since last intake (<24 hours, >24 hours). Analyses comprised chi(2) and Wilcoxon tests, ANOVA, logistic regressions and adjustment by propensity score. In total, 2052 patients treated with travoprost (n = 1704) or latanoprost (n = 348) participated in the study. Treatment groups were comparable at baseline, except for a longer treatment duration in latanoprost-treated patients. When the interval between the last treatment instillation and IOP measurement (treatment/IOP interval) was <24 hours (n = 1241), 82% of travoprost-treated patients attained pre-defined target IOP versus 67% with latanoprost (p < 0.0001). This difference was greatest after 1600 h, when the mean IOP was 16.5 mm Hg for travoprost-treated patients and 17.7 mm Hg for latanoprost-treated patients (p = 0.0025). When the treatment/IOP interval was >24 hours (n = 461), travoprost was superior to latanoprost, i.e. more patients using travoprost attained the predefined target IOP (78.5% vs 68.3%; p = 0.0344), and the mean IOP value was lower in the travoprost group (16.8 vs 17.8 mm Hg; p = 0.0016). After adjustments for confounding factors, similar results were obtained. According to this observational survey, travoprost appears to reduce evening and mean diurnal IOP more effectively than latanoprost. Latanoprost IOP control appears to be more sensitive to time since the last dose.

The objective of this study was to compare the accuracy between two applanation tonometers, Tono-Pen XL® and Perkins®, in horses and cattle. The eyes of 20 horses and 20 cattle conscious and healthy were evaluated for the in vivo study and both eyes of 5 horses and 5 cattle were used as controls for the postmortem study. In conscious animals, the tonometry was performed with auriculopalpebral nerve block and then topical anesthesia for both tonometers and 1% fluorescein eye drops only for the Perkins tonometer. Readings of intraocular pressure (IOP) in the postmortem study were taken using manometry and tonometry by Tono-Pen XL® and Perkins®. The correlation coefficient (r²) between manometry and applanation tonometers Tono-Pen XL® and Perkins®, in horses, were 0.845 and 0.989, respectively, and in cattle, were 0.772 and 0.988, respectively. The mean IOP values in conscious horses with Tono-Pen XL® and Perkins® were 20.1±3.9mmHg and 20.9±3.2mmHg, respectively, and in conscious cattle, these values were 17.2±2.4mmHg and 17.9±1.4mmHg, respectively. There was a strong correlation between the IOP values obtained by direct ocular manometry and the Tono-Pen XL® and Perkins® tonometers in horses and cattle. There was no statistically significant difference between the mean IOPs obtained with both tonometers in conscious animals; however, there was a difference between the minimum values, which were on average 2-3 mmHg lower with the Tono-Pen XL® tonometer than with the Perkins® tonometer, which justifies a table of normal values differentiated for each tonometer.

Pediatric celiac disease (CeD) and type 1 diabetes mellitus (T1DM) have well established effects on eye health but comorbid effect is not known. To evaluate the eye health of children with T1DM and CeD to predict microvascular retinal pathologies by diagnosis of probable intraocular pressure increase which is an important glaucoma trigger. In this case-controlled study, 28 eyes of 14 children both T1DM and CeD, with a mean age of 12.6 ± 3.9 years, and 28 eyes of gender-matched 14 healthy children as a control group were included. In both groups, detailed ocular examinations and measurement of intraocular pressure (IOP), ocular pulse amplitude (OPA), thicknesses of ganglion cell layer (GCL), inner plexiform layer (IPL), retinal nerve fiber layer (RNFL), and choroid thicknesses (CT) were done. All the patients with T1DM and CeD were newly diagnosed. The evaluations of IOP and OPA were made using a Pascal dynamic tonometer and thicknesses measured by optical coherence tomography. The IOP and OPA values of the patient group were found to be statistically significantly higher than those of the control group (17.1 and 1.86 vs 14.78 and 1.57 mmHg, P <.0001, P <.001, respectively). IOP values of all patients were higher than IOP cut off levels for diagnosis of hypertension. CT was significantly thinner in the patient group than in the control group (385.4 μm vs 331.71 μm, respectively, P < 0.03). No significant difference was found between the groups in respect of GCL, IPL, and RNFL values. The higher IOP and OPA values of the children with T1DM and CeD were considered to be the result of the microvascular pathologies in T1DM and increased inflammation associated with CeD. High IOP and OPA values can lead to damage in the eye as intraocular blood flow and choroidal perfusion are affected. In order to prevent these eye problems, measurement of IOP and OPA should be done in children with diagnosis of T1DM and CeD and also follow up studies needed.