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Purpose: A meta-analysis found that including atmospheric pressure as altitude in generalized linear models reveals higher differences between Goldmann tonometry and Pascal dynamic contour tonometry at higher altitudes, with the difference increasing in thinner corneas. To examine the difference in intraocular pressure (IOP) measurements by using Goldman applanation tonometry (GAT) and dynamic contour tonometer (DCT) tonometry in published literature and determine the influence of central corneal thickness (CCT), age, and altitude on that difference. Methods: Articles that compare GAT and DCT were selected for an extensive literature review, and the location and altitude of the research centers were found online. CCT and age were analyzed as covariates, when available. Results: A total of 157 studies including 24,211 eyes of 20,214 patients were included in the study. The results showed that the difference between DCT and GAT was higher at higher altitudes above sea level and increased with thinner corneas. However, the results were different in eyes with corneal transplants, where altitude and CCT had less influence, and in those post-refractive surgery where age was found to influence the difference. Theoretical correction formulas using altitude, CCT, and age were derived from this meta-analysis, but their accuracy and usefulness in clinical practice need validation. Conclusion: The findings suggest that there is a higher risk of underestimating IOP when the Goldmann tonometer is used at a higher altitude, particularly in eyes with glaucoma, thinner corneas, or corneal refractive surgery. Further research is needed to validate the accuracy of the correction formulas derived from this meta-analysis in clinical practice. [ABSTRACT FROM AUTHOR]

Purpose: A meta-analysis found that including atmospheric pressure as altitude in generalized linear models reveals higher differences between Goldmann tonometry and Pascal dynamic contour tonometry at higher altitudes, with the difference increasing in thinner corneas. To examine the difference in intraocular pressure (IOP) measurements by using Goldman applanation tonometry (GAT) and dynamic contour tonometer (DCT) tonometry in published literature and determine the influence of central corneal thickness (CCT), age, and altitude on that difference. Methods: Articles that compare GAT and DCT were selected for an extensive literature review, and the location and altitude of the research centers were found online. CCT and age were analyzed as covariates, when available. Results: A total of 157 studies including 24,211 eyes of 20,214 patients were included in the study. The results showed that the difference between DCT and GAT was higher at higher altitudes above sea level and increased with thinner corneas. However, the results were different in eyes with corneal transplants, where altitude and CCT had less influence, and in those post-refractive surgery where age was found to influence the difference. Theoretical correction formulas using altitude, CCT, and age were derived from this meta-analysis, but their accuracy and usefulness in clinical practice need validation. Conclusion: The findings suggest that there is a higher risk of underestimating IOP when the Goldmann tonometer is used at a higher altitude, particularly in eyes with glaucoma, thinner corneas, or corneal refractive surgery. Further research is needed to validate the accuracy of the correction formulas derived from this meta-analysis in clinical practice.

BACKGROUND: The aim of this study is to analyze and compare the intraocular pressure (IOP) values measured in three different kinds of participants such as healthy subjects (HS), keratoconus patients (KP), and those who underwent myopic photorefractive keratectomy (MPRK). The devices used in this study are the Goldmann Applanation Tonometry (GAT), the dynamic contour tonometry (DCT), the ocular response analyzer (ORA), and the Corvis ST (CST). SUBJECTS AND METHODS: This research included 92 eyes of 92 h, 63 eyes of 63 KP, and 58 eyes of 58 MPRKM. Each participant underwent a complete ophthalmic evaluation and IOP measurement with GAT, DCT, ORA, and CST. A statistical analysis was conducted to detect possible differences and correlations. RESULTS: First, according to the observed data, HS eyes displayed mean IOP values measured with GAT, DCT, ORA, and CST, respectively, 15.82 ± 2.74 mmHg, 17.63 ± 2.28 mmHg, 16.24 ± 3.14 mmHg, and 17.31 ± 3.21 mmHg. Then, KP eyes showed mean IOP values measured with GAT, DCT, ORA, and CST of, respectively, 14.89 ± 1.64 mmHg, 16.97 ± 2.08 mmHg, 13.09 ± 3.12 mmHg, and 13.78 ± 2.11 mmHg. Finally, MPRK eyes showed mean IOP values measured with GAT, DCT, ORA, and CST of, respectively, 13.92 ± 1.34 mmHg, 15.39 ± 2.86 mmHg, 16.63 ± 2.51 mmHg, and 15.06 ± 1.56 mmHg. CONCLUSION: According to the observed data, ORA and GAT might be used interchangeably in HS, whereas GAT, ORA, and CST in KP eyes. Moreover, it has been noticed that in those eyes that previously undergone a myopic PRK, GAT provided lower values of IOP in comparison with other devices.

BACKGROUND: The aim of this study is to analyze and compare the intraocular pressure (IOP) values measured in three different kinds of participants such as healthy subjects (HS), keratoconus patients (KP), and those who underwent myopic photorefractive keratectomy (MPRK). The devices used in this study are the Goldmann Applanation Tonometry (GAT), the dynamic contour tonometry (DCT), the ocular response analyzer (ORA), and the Corvis ST (CST). SUBJECTS AND METHODS: This research included 92 eyes of 92 h, 63 eyes of 63 KP, and 58 eyes of 58 MPRKM. Each participant underwent a complete ophthalmic evaluation and IOP measurement with GAT, DCT, ORA, and CST. A statistical analysis was conducted to detect possible differences and correlations. RESULTS: First, according to the observed data, HS eyes displayed mean IOP values measured with GAT, DCT, ORA, and CST, respectively, 15.82 ± 2.74 mmHg, 17.63 ± 2.28 mmHg, 16.24 ± 3.14 mmHg, and 17.31 ± 3.21 mmHg. Then, KP eyes showed mean IOP values measured with GAT, DCT, ORA, and CST of, respectively, 14.89 ± 1.64 mmHg, 16.97 ± 2.08 mmHg, 13.09 ± 3.12 mmHg, and 13.78 ± 2.11 mmHg. Finally, MPRK eyes showed mean IOP values measured with GAT, DCT, ORA, and CST of, respectively, 13.92 ± 1.34 mmHg, 15.39 ± 2.86 mmHg, 16.63 ± 2.51 mmHg, and 15.06 ± 1.56 mmHg. CONCLUSION: According to the observed data, ORA and GAT might be used interchangeably in HS, whereas GAT, ORA, and CST in KP eyes. Moreover, it has been noticed that in those eyes that previously undergone a myopic PRK, GAT provided lower values of IOP in comparison with other devices. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Introduction Dynamic contour tonometry (DCT) is a contact, non-applanation method for measuring intraocular pressure (IOP). Objektive The study aimed at evaluating the impact of central corneal thickness (CCT) on values of IOP measured using two methods: Goldmann applanation tonometry (GAT) and DCT. Methods The study included 150 patients (300 eyes) with the diagnosis of open-angle glaucoma (54 males) and mean age of 59.39± 13.12 years. IOP was measured using two methods: GAT and DCT. CCT was measured (ultrasound pachymetry). DCT introduced a new value - the ocular pulse amplitude (OPA). Results The IOP measured with the GAT was lower compared to the IOP measured with DCT (17.71±3.35mmHg vs 19.80± 3.67mmHg). There was a significant positive correlation between IOP measured with GAT and IOP measured with DCT (r= 0.867, p< 0.01). In all patients, there was a significant positive correlation between CCT and IOP measured with GAT (r=0.198, p< 0.01), as well as between CCT and IOP measured with DCT (r=0.180, p< 0.05). With every 10mm of change in CCT, the change of IOP measured with GAT was 0.3mmHg, while the average change of IOP measured with DCT was 0.4 mmHg. There was a significant positive correlation between CCT and OPA (r=0.204, p< 0.01). There was also a significant positive correlation between OPA and IOP measured with GAT (r= 0.393, p< 0.01) and between OPA and IOP measured with DCT (r= 0.452, p< 0.01). Conclusion IOP measured with GAT was lower than IOP measured with DCT. CCT had impact on both methods: GAT and DCT. The impact of CCT on IOP (DCT) was lower compared to the impact of CCT on IOP(GAT).

INTRODUCTION[|]This study aimed to investigate whether trabeculectomy and its intraocular pressure (IOP)-lowering effect have an effect on ocular pulse amplitude (OPA) in glaucoma patients.[¤]METHODS[|]Thirty-five consecutive patients with glaucoma (70 eyes) who had undergone unilateral first-time trabeculectomy between April and November 2012 were enrolled in this retrospective study. Patients with intraoperative or postoperative complications were excluded from this study. The eye that underwent trabeculectomy was considered the study eye; the fellow eye was used as the control eye. OPA and IOP were measured by Pascal dynamic contour tonometry (DCT), IOP was measured by Goldmann applanation tonometry (GAT), and systolic and diastolic blood pressure and heart rate were measured before and one month after trabeculectomy. The change in the pre- and postoperative values was compared between the two eyes.[¤]RESULTS[|]The study sample included 17 male and 18 female patients with a mean age of 60.83+-13.46 years. The mean preoperative GAT, DCT and OPA values in the study eyes were 24.97+-8.26, 31.23+-10.55 and 4.22+-1.77 mmHg, respectively. One month after trabeculectomy, the GAT, DCT and OPA values were 12.83+-4.35, 20.28+-7.34 and 2.96+-1.66 mmHg, respectively. There was a significant decrease in OPA after filtration surgery in the study eyes (p0.05). Changes in OPA were positively correlated with changes in IOP (p

Background: To evaluate ocular pulse amplitude (OPA) in patients with carotid artery stenosis (CAS) using the Pascal dynamic contour tonometer (DCT).Methods: Consecutive 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).Results: A 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).Conclusion: OPA decreases in patients with moderate to severe CAS. OPA measurement with Pascal DCT can be used as a screening test for CAS. [ABSTRACT FROM AUTHOR]

AIM: To determine the effects of peripheral corneal thickness (PCT) on dynamic contour tonometry(DCT) and Goldmann applanation tonometry (GAT). METHODS: A cross-sectional study. We created a software which calculates the corneal contour (CC) as a function of the radius from the corneal apex to each pixel of the contour. The software generates a central circumference with a radius of 1 mm and the remainder of the cornea is segmented in 5 rings concentric with corneal apex being its diameter not constant around the corneal circumference as a consequence of the irregular CC but keeping constant the diameter of each ring in each direction of the contour. PCT was determined as the mean thickness of the most eccentric ring. Locally weighted scatterplot smoothing (LOWESS) regression was used to determine the pattern of the relationship between PCT and both DCT and GAT respectively. Thereafter, two multivariable linear regression models were constructed. In each of them, the dependant variable was intraocular pressure (IOP) as determined using GAT and DCT respectively. In both of the models the predictive variable was PCT though LOWESS regression pattern was used to model the relationship between the dependant variables and the predictor one. Age and sex were also introduced control variables along with their first-degree interactions with PCT. Main outcome measures include amount of IOP variation explained through regression models (R2) and regression coefficients (B). RESULTS: Subjects included 109 eyes of 109 healthy individuals. LOWESS regression suggested that a 2nd-degree polynomial would be suitable to model the relationship between both DCT and GAT with PCT. Hence PCT was introduced in both models as a linear and quadratic term. Neither age nor sex nor interactions were statistically significant in both models. For GAT model, R2 was 17.14% (F=9.02; P=0.0002), PCT linear term B was -1.163 (95% CI: -1.163, -0.617). PCT quadratic term B was 0.00081 (95% CI: 0.00043, 0.00118). For DCT model R2 was 14.28% (F=9.29; P=0.0002), PCT linear term B was -0.712 (95% CI: -1.052, -0.372), PCT quadratic term was B=0.0005 (95% CI: 0.0003, 0.0007). CONCLUSION: DCT and GAT measurements are conditioned by PCT though this effect, rather than linear, follows a 2nd-degree polynomial pattern.

Abstract Background To evaluate the ocular pulse amplitude (OPA) in patients with chronic non-arteritic anterior ischaemic optic neuropathy (NAION). Methods This 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. Results No 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). Conclusion No significant difference was determined in the OPA levels of eyes with NAION at the chronic stage and eyes in the control group.

Purpose: 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. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to investigate whether trabeculectomy and its intraocular pressure (IOP)-lowering effect have an effect on ocular pulse amplitude (OPA) in glaucoma patients. Methods: Thirty-five consecutive patients with glaucoma (70 eyes) who had undergone unilateral first-time trabeculectomy between April and November 2012 were enrolled in this retrospective study. Patients with intraoperative or postoperative complications were excluded from this study. The eye that underwent trabeculectomy was considered the study eye; the fellow eye was used as the control eye. OPA and IOP were measured by Pascal dynamic contour tonometry (DCT), IOP was measured by Goldmann applanation tonometry (GAT), and systolic and diastolic blood pressure and heart rate were measured before and one month after trabeculectomy. The change in the pre- and postoperative values was compared between the two eyes. Results: The study sample included 17 male and 18 female patients with a mean age of 60.83±13.46 years. The mean preoperative GAT, DCT and OPA values in the study eyes were 24.97±8.26, 31.23±10.55 and 4.22±1.77 mmHg, respectively. One month after trabeculectomy, the GAT, DCT and OPA values were 12.83±4.35, 20.28±7.34 and 2.96±1.66 mmHg, respectively. There was a significant decrease in OPA after filtration surgery in the study eyes (p<0.001), but not in the control eyes (p>0.05). Changes in OPA were positively correlated with changes in IOP (p<0.05), and a significant association was found between OPA and IOP, and as measured by DCT (Regression coefficient = 0.093 [0.041-0.145]) and GAT (Regression coefficient = 0.093 [0.013-0.173]). Conclusion: There was a significant decrease in OPA in the eyes that underwent trabeculectomy, and the change in OPA after surgery was significantly different in the study eyes in comparison to the change in OPA in the control eyes. The OPA changes were strongly correlated with the IOP changes in the study eyes. [ABSTRACT FROM AUTHOR]

Copyright of Arquivos Brasileiros de Oftalmologia is the property of Arquivos Brasileiros de Oftalmologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: Our purpose was to assess the effect of LASEK surgery on ocular rigidity and to compare its effect on intraocular pressure (IOP) readings with Goldmann applanation tonometry (GAT), Schiøtz indentation tonometry (ST) and dynamic contour tonometry (DCT). Methods: Prospective, observational, single-masked cohort study. One eye per patient from 31 consecutive subjects who underwent LASEK refractive surgery to correct myopia, as well as from 108 non-operated myopic patients, were included. IOP was measured using GAT, DCT, and ST. The coefficient of ocular rigidity (K) was obtained from the regression line of the three readings obtained with each weight of the ST. Linear multiple regression analysis was performed with dummy variables to assess the effect of age, central corneal thickness (CCT), and previous refractive surgery on IOP values. Results: Age, CCT, and LASEK surgery explained 23% of the IOP readings with GAT, 11% with DCT, and had no significant influence on ST readings. The IOP readings obtained with GAT and DCT, but not with ST, were significantly different between LASEK and control groups. Significant differences in K were observed between LASEK (0.014 mmHg/μL ±0.007) and control groups (0.021 mmHg/μL ±0.013) ( P = 0.001). K values were not related with age or CCT, in either LASEK or control groups. Conclusions: ST readings seems to be less affected by LASEK surgery than the other tonometers evaluated. There is a difference in the ocular rigidity between the control and the LASEK eyes that it is not correlated with CCT, so it seems that ST can detect changes in the biomechanical behavior of the LASEK operated corneas. [ABSTRACT FROM AUTHOR]

The aim of the present study was to compare the ocular pulse amplitude (OPA) in patients with different types of glaucoma using dynamic contour tonometry (DCT), to evaluate ocular and systemic factors associated with the OPA and to verify whether OPA measured by DCT is an independent predictor for glaucoma diagnosis. A total of 217 eyes of 217 participants in the following five groups were included in this cross.sectional study: Chronic angle closure glaucoma (CACG), primary open angle glaucoma, normal tension glaucoma (NTG), suspected open angle glaucoma (SOAG) and normal control (NC). The following tests were simultaneously performed during a single visit: Intra.ocular pressure (IOP), OPA, cup.to.disk (C/D) ratio, mean damage (MD) and loss variance (LV). OPAs were compared in each group. The association between OPA and IOP, age, C/D ratio, MD and LV was detected. OPA analysis prior to and after trabeculectomy was also performed to assess its prognostic value. Among the 217 individuals, the OPA was consistent with the IOP, both measured by DCT, along with the MD and LV. Patients with CACG and SOAG had higher OPA values than those with NTG and normal controls. Compared with patients aged >30 years, the OPA was significantly lower in younger patients, while they may not have been affected by different C/D ratios. After trabeculectomy, the OPA had significantly decreased compared with the values prior to surgery. In conclusion, the present study showed that the OPA is correlated with the IOP determined by DCT. CACG and SOAG patients had higher OPA values than patients with other types of glaucoma. OPA measured by DCT may be a predictor for glaucoma diagnosis and prognosis. [ABSTRACT FROM AUTHOR]

Copyright of Der Ophthalmologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: To evaluate the agreement of intraocular pressure (IOP) measurements using dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) in eyes after vitrectomy with silicone oil endotamponade and controls. Methods: In this prospective comparative study, IOP was measured with GAT and DCT in 30 eyes with oil endotamponade 1–3 days after vitrectomy and 40 untreated controls. In addition, ocular pulse amplitude (OPA), corneal pachymetry (CCT), and axial length (AL) were measured. Results: GAT values in the oil group were significantly higher compared to control eyes (mean GAT oil 13.6 ± 5.1 mmHg; mean GAT control 10.8 ± 2.1 mmHg;p =0.003). There was no significant difference in DCT measurements (mean DCT oil 12.0 ± 4.1 mmHg; mean DCT control 11.9 ± 2.9 mmHg;p =0.9). This led to a significant difference of GAT-DCT between the oil and control group (mean difference of GAT-DCT oil 1.6 ± 4.7 mmHg; mean difference of GAT-DCT control −1.1 ± 2.6 mmHg;p =0.004). The difference between GAT and DCT was negatively correlated with the mean IOP measured by both methods (r =−0.36,p =0.02) and positively correlated with CCT only in the control group (r =0.36,p =0.02), as well as to AL only in the oil group (r =0.46,p =0.01). The OPA did not differ significantly between groups. Conclusion: GAT and DCT showed a good agreement in control eyes. The difference of GAT and DCT is significantly changed in eyes after vitrectomy with silicone oil endotamponade. Our findings suggest that GAT overestimates IOP in this situation. [ABSTRACT FROM AUTHOR]

Background: To evaluate the ocular pulse amplitude (OPA) in patients with chronic non-arteritic anterior ischaemic optic neuropathy (NAION).Methods: This 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.Results: No 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).Conclusion: No significant difference was determined in the OPA levels of eyes with NAION at the chronic stage and eyes in the control group. [ABSTRACT FROM AUTHOR]

OBJETIVOS: Determinar la asociación entre la amplitud del pulso ocular y la tensión ocular en los pacientes con glaucoma primario de ángulo abierto según grupos de tratamiento. Evaluar la amplitud del pulso ocular como medio para medir la efectividad de la terapia antihipertensiva ocular. Definir correlación entre espesor corneal central/tensión ocular y entre espesor corneal/amplitud del pulso usando el tonómetro de contorno dinámico. MÉTODOS: Se estudiaron 90 pacientes mayores de 15 años con diagnóstico reciente de glaucoma primario de ángulo abierto que aún no habían recibido tratamiento alguno; con ellos se conformaron tres grupos de estudio de forma aleatoria y según el medicamento indicado: Grupo l: Timolol 0,5 %, Grupo II: Travoprost (Travatán) 0,2 % y Grupo III: Dorzolamida (Trusopt) 2 %. A estos pacientes se les tomó la medida del espesor corneal central por paquimetría previa al tratamiento, a la semana, al mes y a los 3 meses en el servicio de glaucoma del Hospital "Ramón Pando Ferrer" (diciembre-2006 a mayo-2007). Se midieron además las variables presión intraocular y amplitud del pulso ocular. RESULTADOS: Se encontró menor amplitud del pulso a medida que disminuía la presión intraocular, existió mayor descenso de la presión y de la amplitud del pulso en el grupo tratado con Travoprost, hubo para este grupo de tratamiento una mejor correlación entre ambas variables. No se encontró correlación entre el espesor corneal central y presión intraocular, ni entre espesor corneal y amplitud del pulso. CONCLUSIONES: Monitorear la presión y la amplitud del pulso puede ser eficaz para conocer el efecto de la terapéutica hipotensora ocular.OBJECTIVES: To determine the association of the ocular pulse amplitude and the ocular pressure in patients with primary open angle glaucoma by groups under treatment; to evaluate the ocular pulse amplitude as a means to assess the effectiveness of anti-hypertensive ocular therapy and to define correlation between central corneal thickness/ocular pressure, and corneal thickness and pulse amplitude using the dynamic contour tonometer. METHODS: Ninety patients aged over 15 years, recently diagnosed with primary open angle glaucoma and still untreated, were studied. They were randomly included in three study groups according to the indicated drug, that is, Group I- 0,5 % Timolol, Group II- 0,2 % Travoprost (Travatan) and Group III- 2 % Dorzolamide (Trusopt). Their central corneal thickness was measured by pachymetry prior to the treatment, and one week, one month and 3 months later at the the glaucoma service at "Ramón Pando Ferrer" Cuban Institute of Ophthalmology (December 2006-May 2007). Also the variables intraocular pressure and ocular pulse amplitude were taken. RESULTS: It was found that pulse amplitude decreases as the intraocular pressure goes down; higher decline in pressure and pulse amplitude existed in group under Travoprost treatment where the correlation of both variables was better. No correlation was observed between central corneal thickness and intraocular pressure; similarly the corneal thickness and the pulse amplitude did not correlate. CONCLUSIONS: Monitoring the pressure and the pulse amplitude may be effective to find out the effect of the ocular hypertensive therapy.

Introduction The Pascal Dynamic Contour Tonometer (DCT) is an ophthalmic investigational device which directly calculates the dynamic pulsatile fluctuations in intraocular pressure (IOP) using a piezoelectric pressure sensor embedded in the devices tip. Objective The aim of this study was to compare IOP results obtained with Goldmann applanation tonometer (GAT), and their correlation with central corneal thickness (CCT) in patients of various age groups. Methods We studied 37 patients (17 male and 20 female), divided into three age groups: younger than 40 years; 40-60 years old, and older than 60 years. In the first and second group there were patients rarely and in the third mostly diagnosed and medicamentously compensated glaucoma. In topical anesthesia, first we measured CCT, with ultrasound pachimeter, then IOP with DCT and GAT. Results Statistically significant difference between measurements of IOP with the DCT and GAT appeared in all groups: I mean diff. -1.71}1.27 mm; p

The purpose of this study is to evaluate the concordance between intraocular pressure (IOP) values obtained with a dynamic contour tonometer (DCT) and a non-contact tonometer (NCT) in healthy patients and to investigate the effect of central corneal thickness (CCT) on IOP readings for each of the two measuring systems. The mean IOP yielded by DCT, NCT and corrected non-contact tonometer (CNCT) was 17.1 mmHg, 15.5 mmHg and 12.2 mmHg, respectively. The average CCT was 563.6 μm and the ocular pulse amplitude (OPA) was 2.8 mmHg. There was a moderate correlation between CCT and CNCT ( r = 0.34, p = 0.001), a weak correlation between CCT and DCT ( r = 0.03, p = 0.788) and a weak-to-moderate correlation between CCT and NCT ( r = 0.27, p = 0.11). The intra-class correlation coefficient (ICC) was 0.59 for the DCT-vs.-NCT comparison and 0.56 for DCT-vs.-CNCT. The mean difference between the two instruments (DCT/NCT) ranged from 1.62 to 4.47 mmHg. We have shown that non-contact tonometer is significantly more affected by the central corneal thickness than the dynamic contour tonometer and therefore these methods are not interchangeable. [ABSTRACT FROM AUTHOR]

Purpose: To analyze and compare intraocular pressure (IOP) values measured in healthy subjects (HS), keratoconus (KC) patients and patients that underwent myopic photorefractive keratectomy (REF), using Goldmann applanation tonometry (GAT), dynamic contour tonometry (DCT), ocular response analyzer (ORA) and Corvis ST (CST).Methods: The study included 76 eyes of 76HS, 15 eyes of 15 KC patients and 18 eyes of 18 subjects that underwent REF. Each participant underwent a complete ophthalmic evaluation, IOP measurement with GAT, DCT, ORA and CST.Results: HS showed a mean GAT value of 15.62±2.33 mm Hg, a mean DCT value of 17.44±2.51 mm Hg, a mean ORA value of 15.99±3.58 mm Hg and a mean CST value of 17.24±3.44 mm Hg. KC showed a mean GAT value of 15.07±1.83 mm Hg, a mean DCT value of 17.01±1.96 mm Hg, a mean ORA value of 13.58±2.99 mm Hg and a mean CST value of 14.37±1.89 mm Hg. REF showed a mean GAT value of 14.06±1.51 mm Hg, a mean DCT value of 15.12±2.34 mm Hg, a mean ORA value of 16.85±2.4 mm Hg and a mean CST value of 15.57±1.77 mm Hg.Conclusion: Our data suggest that ORA and GAT could be used interchangeably in HS; GAT, ORA and CST could be used interchangeably in KC patients and that GAT provides lower IOP values compared to the other devices in eyes previously submitted to myopic PRK. [ABSTRACT FROM AUTHOR]

PURPOSE: The dynamic contour tonometer is a nonapplanation contact tonometer designed to be largely independent of the structural properties of the cornea. Theoretically, it may measure intraocular pressure most accurately in abnormally thinner corneas. This study compares intraocular pressure measurements by dynamic contour tonometry with Goldman applanation tonometry in eyes with normal corneas and eyes with advanced keratoconus. METHODS: A comparative case series. Subjects underwent intraocular pressure measurements by dynamic contour tonometry, Goldman applanation tonometry, ultrasonic pachymetry, and slit scanning topography. Exclusion criteria: any ocular pathology other than keratoconus, previous corneal or refractive surgery, stromal scarring due to acute hydrops, or any other corneal opacities. RESULTS: Ten patients with keratoconus were included in Group A, and 12 normal patients composed Group B according to the pre-established criteria. The mean Goldman tonometry measurement in group A was 10.3 ± 1.8 mm Hg and group B was 14.3 ± 0.75 mm Hg. (P = 0.024). In group A, the mean measurement with the dynamic contour tonometer was 14.6 ± 2.09 mm Hg, and in group B, it was 17.4 ± 3.1 mm Hg (P = 0.026). The difference between both methods of measurement in group A was statistically significant (P < 0.0002). CONCLUSION: Intraocular pressure readings with dynamic contour tonometry in the keratoconus group were significantly higher than Goldman measurements and lower when compared to the control group. As there are no published manometric studies in eyes with keratoconus, these lower intra-ocular readings with the dynamic contour tonometry could be related to the discrepancy between the radius of corneal curvature and its tip, the significant thinning of the cornea, or other corneal biomechanical abnormalities related to advanced keratoconus.OBJETIVO: O tonômetro de contorno dinâmico é um aparelho de contato e não-aplanação projetado para ser independente das propriedades estruturais da córnea. Teoricamente, ele mede de forma mais precisa a pressão intra-ocular em córneas muito finas. Este estudo compara as medidas de pressão intra-ocular pelo tonômetro de contorno dinâmico com a tonometria de aplanação de Goldman em olhos normais e em olhos com ceratocone avançado. MÉTODOS: uma série comparativa de casos. Pacientes foram submetidos às medidas de pressão intra-ocular por ambos os métodos mencionados, paquimetria ultrassônica e topografia corneana de varredura. Critérios de exclusão: qualquer patologia ocular exceto ceratocone, cirurgia ceratorrefrativa prévia, opacidade estromal resultante de hidropsia aguda ou qualquer outra opacidade corneana. RESULTADOS: Dez pacientes com ceratocone foram incluídos no grupo A e 12 pacientes com córneas normais no grupo B conforme os critérios pré-estabelecidos. A média das medidas da tonometria de Goldman no grupo A foi de 10.3±1.8 mmHg e no grupo B de 14.3±0.75 mmHg. (p = 0,024). No grupo A, a média das medidas com o tonômetro de contorno dinâmico foi de 14.6±2,09 mmHg e, no grupo B,17,4±3,1 mmHg (p = 0,026). A diferença entre as medidas dos tonômetros no grupo A foi estatisticamente significante (p < 0.0002). CONCLUSÃO: As medidas da pressão intra-ocular com o tonômetro de contorno dinâmico nos pacientes com ceratocone foram significativamente maiores que as medidas do Goldman e menores quando comparadas com o grupo controle. Na ausência de estudos manométricos em olhos com ceratocone, estas baixas medidas com a tonometria de contorno dinâmico podem estar relacionadas com a discrepância entre o raio de curvatura da córnea e a ponta do tonômetro, os baixos valores paquimétricos, ou outras anormalidades da biomecânica corneana relacionadas com o ceratocone avançado.

Purpose: To investigate the effect of aging on ocular parameters, including intraocular pressure (IOP), measured with different tonometry methods in healthy young (HY) and healthy elderly (HE) subjects and to study the effect of corneal parameters on tonometry methods. Methods: In this prospective, cross-sectional study, fifty eyes of 50 HY subjects (28 females, 22-31 years of age) and 43 eyes of 43 HE subjects (22 females, 64-79) were included. IOP was measured with four tonometry methods in a standardized order: ocular response analyser (ORA), dynamic contour tonometry (DCT), applanation resonance tonometry (ART) and Goldmann applanation tonometry (GAT). Other measurements included axial length (AL), central corneal thickness (CCT), corneal curvature (CC), anterior chamber volume (ACV), corneal hysteresis (CH) and corneal resistance factor (CRF). Results: The mean IOP (HY/HE; mmHg ± standard deviation (SD)) was 12.2 ± 2.2/14.1 ± 3.5 with GAT. IOP was significantly higher (difference ± standard error) in HE compared to HY measured with an ORA (+3.1 mmHg ± 0.6), GAT (+1.9 ± 0.6) and DCT (+1.6 ± 0.6). No significant difference was found in IOP measured with ART. CH and ACV were significantly lower in HE compared to HY. There was no difference between the groups in CCT, CC, AL or CRF. No tonometry method was dependant on CCT or CC. Conclusions: IOP measured with an ORA and via DCT and GAT was higher in HE compared to HY Swedish subjects, while IOP measured with ART did not differ between the groups. In these homogeneous groups, tonometry methods were independent of CCT and CC. [ABSTRACT FROM AUTHOR]

Objective: To evaluate factors affecting measurement quality of dynamic contour tonometry (DCT).Material and Methods: Three hundred patients took part in this prospective clinical study. For each patient, measurements for one eye were included in the study. Of the participants, 116 had ocular hypertension, 114 had glaucoma, and 70 had normal eyes. We used automatic refractokeratometry, ultrasonic pachimetry, Goldmann applanation tonometry, and DCT measurements to investigate the effects of age, corneal astigmatism, refractive error, central corneal thickness (CCT), intraocular pressures (IOP), and ocular pulse amplitude (OPA) on DCT measurement quality (Q). Logistic regression analysis was used for statistical analysis.Results: For 159 patients, the DCT Q score was 1 (group 1). For the remaining 141 patients, the Q score was 2–3 (group 2). The following values were determined for the two groups, respectively: mean age 58.9±9.9 and 61.4±10.6; mean corneal astigmatisms −0.78±0.67 and −0.92±0.77 diopter; mean spherical equivalents 0.33±1.87 and −0.01±2.02 diopter; mean CCT 547.0±35.2 and 549±38.7 µm. Measurements with DCT provided mean IOPs of 18.5±3.70 and 21.27±6.19 mm Hg and mean OPA 3.5±1.4 and 3.2±1.2 mm Hg. By logistic regression analysis, we determined that the parameters affecting measurement quality were age, DCT measurement level, and OPA (p=0.015, p=0.000, and p=0.000, respectively).Conclusion: High IOP values, advanced age, and low OPA values can lead to decreased DCT measurement quality.

Introduction: The choroid is involved in the pathogenesis of various retinal diseases, including age-related macular degeneration (AMD). The ocular pulse amplitude (OPA) gives 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 and choroidal thickness (CT) in the eyes of healthy individuals and of individuals with non-exudative early stage AMD. Materials and Method: Fourty-four eyes of 44 non-exudative AMD patients and 41 age-matched eyes of 41 healthy individuals were included in the study. All eyes underwent a detailed ophthalmic evaluation, including axial length (AL) and ocular pulse amplitude (OPA) measurements. The CT was measured using optical coherence tomography. Parameters were compared between the two groups and correlation between OPA and CT was assessed. Results: The mean subfoveal, foveal,and parafoveal CT were 245.82±24.29μm, 230.66±23.44μm, 219.55±25.39μm in AMD group, respectively. The corresponding values were 278.44± 34.18μm, 263.76±32.45μm, and 253.79±34.81μm in control group, respectively. The mean ages of groups were 69.6±8.97 years, and 65.0±5.89 years, respectively. The mean OPA was 3.43±1.14mmHg and 3.49±1.12mmHg , respectively. The average CT in AMD patients were significantly lower than the control group in all three regions (subfoveal- foveal-parafoveal) (all p<0,001). In controls, there was a moderate positive correlation between the OPA and CT in the three segments (p=0.002, 0.009, and 0.003; respectively). However only the foveal CT showed significant positive correlation with the OPA in AMD group (p=0.047). Conclusion: Our results showed a considerable correlation between ocular pulse amplitude and choroidal thickness in healthy subject. In non-exudative AMD group, there was a weak correlation between them. It can be hypothesized that; in patients with AMD, degeneration and/or thinning of choroidal pattern is a reason for this result. [ABSTRACT FROM AUTHOR]

We demonstrate the close relationship between a conspicuous ocular pulse amplitude and severe underlying cardiovascular disease. Two otherwise symptom-free glaucoma patients without any previously diagnosed underlying cardiovascular pathology but with a conspicuous ocular pulse amplitude and who underwent routine examinations in our glaucoma department were referred to the appropriate specialty for further diagnostic procedures. In both patients, the diagnosis of a tachyarrhythmia was made as suspected on dynamic contour tonometry measurements. In addition to medical treatment, one patient underwent electric cardioversion and the second patient was scheduled for pacemaker implantation. A third patient with an unexpected high ocular pulse amplitude despite severe cardiovascular pathology underwent major surgery due to an aortic aneurysm. Carotid stenosis was diagnosed due to side differences in ocular pulse amplitude as well. Ocular pulse amplitude might be a noninvasive and affordable screening tool and could be used to detect severe cardiovascular disease. A prospective study including a larger number of patients is needed to prove this hypothesis. [ABSTRACT FROM AUTHOR]

Background: To evaluate the clinical utility of spectral analysis of intraocular pressure pulse wave in healthy eyes of a control group (CG), patients having glaucomatous optic disc appearance or ocular hypertension, and patients with primary open angle glaucoma or primary angle closure glaucoma. Methods: This is a prospective study that enrolled 296 patients from a single glaucoma clinic. Age matched CG consisted of 62 individuals. Subjects underwent comprehensive clinical diagnostic procedures including intraocular pressure (IOP) measurement with dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT). DCT time series were analyzed with custom written software that included signal preprocessing, filtering and spectral analysis. An amplitude and energy content analysis, which takes into account non-stationarity of signals but also provides methodology that is independent of IOP and ocular pulse amplitude (OPA) levels, was applied. Spectral content up to the 6th harmonic of the pressure pulse wave was considered. Statistical analyses included descriptive statistics, normality test, and a multicomparison of medians for independent groups using Kruskal-Wallis test. Results: GAT IOP showed statistical significance (Kruskal-Willis test p < 0.05) for three out of 10 considered multiple comparisons, DCT IOP and OPA showed statistically significant results in five and seven cases, respectively. Changes in heart rate and central corneal thickness between the groups were statistically significant in two cases. None of the above parameters showed statistically significant differences between CG and the suspects with glaucomatous optic disc appearance (GODA). On the other hand, spectral analysis showed statistically significant differences for that case. Conclusions: Spectral analysis of the DCT signals was the only method showing statistically significant differences between healthy eyes and those of GODA suspects. [ABSTRACT FROM AUTHOR]

Purpose: To compare the intraocular pressure (IOP) measured by dynamic contour tonometry (DCT), Goldmann applanation tonometry (GAT), non-contact tonometry (NCT) and Tono-Pen and also to assess whether ocular parameters such as corneal thickness, keratometry and axial length affect the measurements by the tonometers. Materials and Methods: One hundred healthy subjects prospectively underwent IOP measurement with DCT, GAT, NCT and Tono-Pen. The correlation between the tonometer readings as well as the effect of keratometry, central corneal thickness (CCT), axial length and anterior chamber depth on IOP measurements were assessed. Results: DCT readings were higher than NCT (ΔIOP=2.0±3.2 mmHg, p<0.001) and GAT (ΔIOP=1.3±2.1 mmHg, p=0.003) but not Tono-Pen (ΔIOP=0.1±2.7 mmHg, p=0.981). DCT, GAT and NCT correlated positively with CCT (p=0.039, p=0.020 and p=0.001). GAT and NCT readings were significantly higher in eyes with thick cornea (>568 μm) compared to eyes with thin cornea (<535 μm) (p=0.021 and p=0.003). Ocular parameters other than CCT did not have a significant effect on the readings of tonometers. Conclusion: Despite significant correlation; DCT readings were higher than GAT and NCT but not Tono-Pen. DCT, NCT and GAT readings significantly correlated with CCT. GAT and NCT readings were significantly higher in eyes with thick cornea compared to eyes with thin cornea. [ABSTRACT FROM AUTHOR]

. Purpose: To characterize five models of corneal thickness circular zoning in a sample of healthy controls and a sample of patients with primary open-angle glaucoma (POAG) and to determine their effect on Goldmann (GAT), dynamic contour (DCT) and rebound tonometers (RT). Methods: The study participants were 122 controls and 129 cases. Five corneal thickness zoning models (A, B, C, D and E) were constructed. The partitioning pattern consisted of a circle centred at the corneal apex and several concentric rings, until the limbus; the contours of each ring followed the geometry of the corneal contour of each participant. In Model A, the central circle was 1 mm in diameter and five concentric rings were established. Mean was obtained for each zone for both samples and compared between them using a t-test. The effect on the tonometers of central cornel thickness (CCT) and mean thickness of the zones generated was determined through several linear regression models (one per tonometer and per sample). Results: According to a t-test, cases and controls differ in zones I [mean difference (MD): 17.93 μm], V (MD: 25.52 μm) and VI (MD: 31.78 μm) of model A (higher values in the cases sample). RT was affected by CCT (controls: B = 0.089; cases: B = 0.081). DCT was affected by zone IV of model A (controls: B = −0.029; cases: B = −0.012). GAT was affected by CCT (controls: B = 0.043; cases: B = 0.025) and zone III of model A (controls: B = −0.045; cases: B = −0.033). Conclusion: Our results highlight the importance of the thickness of other regions of the cornea different from its main centre in discriminating between healthy controls and patients with POAG and in IOP measurements made using DCT, GAT and RT. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to investigate the correlation between ocular perfusion pressure and ocular pulse amplitude in glaucoma, ocular hypertension, and normal eyes. Methods: Ninety 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. Results: Mean 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). Conclusion: There 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. [ABSTRACT FROM AUTHOR]

Ocular pulse amplitude (OPA), which is defined as the difference between systolic and diastolic intraocular pressure (IOP), is accepted as an indirect indicator of choroidal perfusion. OPA has become subject to investigations in many diseases in which choroidal perfusion changes might occur, particulary in glaucoma, either as a prognostic or diagnostic parameter. Dynamic contour tonometry records 100 IOP measurements per second by transcorneal method and determine OPA by providing dynamic IOP measurement. This article reviews OPA measured by dynamic contour tonometry in different clinical settings and the relevant factors. [ABSTRACT FROM AUTHOR]

To compare intraocular pressure (IOP) measurements obtained with Goldmann applanation (GAT) and dynamic contour tonometry (DCT) in a Mexican population. 40 glaucoma patients were included in this cross-sectional observational cohort study. IOP measurements were performed in the following order: DCT, ultrasonic pachymetry and GAT, with a 5-minute difference between each measurement, between 8 am and 2 pm. Only DCT measurements of good quality (Q ≤ 3) were accepted. GAT measurements were made three times with the same Goldmann tonometer, previously checked for calibration errors, and the mean was used for statistical purposes. The IOP (mean [standard deviation], 95 % confidence interval [CI]) measured with the Goldmann tonometer (13.2 [2.4], 12.4-14.0 mmHg) was significantly lower than that obtained with the DCT (18.4 [3.3], 17.0-19.2 mmHg), p < 0.0001. Pearson's correlation coefficients between CCT and IOP measured with GAT and DCT were ( r = 0.24, 95 % CI = 0.07-0.52, p = 0.133) and ( r = 0.13, 95 % CI = -0.19 to 0.43, p = 0.412), respectively. The concordance correlation coefficient between GAT and DCT was r = 0.3, 95 % CI = 0.17-0.41). DCT seems to overestimate the IOP as compared to GAT. Additionally, although there was a good correlation between the IOP measurements assessed with either GAT or DCT, the agreement was poor. [ABSTRACT FROM AUTHOR]

Introduction: Intraocular pressure (IOP) determination using dynamic contour tonometry (DCT) has been considered to be independent of central corneal thickness (CCT), while Goldmann applanation tonometry (GAT) is known to be influenced by various corneal properties. In this study, IOP was measured before and 1 day after cataract surgery using GAT and DCT to investigate the possible effects of corneal edema on IOP measurements. Methods: Thirty patients with advanced cataracts were included in a pilot study. IOP was measured using GAT and DCT before and 1 day after phacoemulsification. CCT was determined before and after surgery to quantify postsurgical corneal edema. Results: CCT increased significantly (by 89.7 ± 107.4 μm, P < 0.0001) 1 day after surgery. No significant difference was found for IOP measurements using GAT and DCT before surgery (mean IOP GAT: 17.5 ± 5.7 mmHg; mean IOP DCT: 17.9 ± 6.4 mmHg; P = 0.67) and 1 day after surgery (mean IOP GAT: 16.1 ± 6.6 mmHg; mean IOP DCT: 16.8 ± 8.3 mmHg; P = 0.69). IOP values using GAT and DCT were significantly correlated before as well as 1 day after surgery (before surgery: r = 0.82, P # 0.0001; after surgery r = 0.83, P < 0.0001). Bland-Altman plots showed a high variability in the difference in IOP measurements between methods before and 1 day after surgery. Conclusion: GAT and DCT seem to be equally valuable in IOP determination in postsurgical central corneal edema, although large differences between both methods are present in individual patients. IOP evaluation in corneal edema remains a difficult clinical challenge. [ABSTRACT FROM AUTHOR]

Purpose: To compare the intraocular pressures (IOP) and ocular pulse amplitudes (OPAs) in patients with primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PXG), and to evaluate ocular and systemic factors associated with the OPA. Materials and Methods: In this prospective study, on 28 POAG and 30 PXG patients, IOP was measured with the Goldmann applanation tonometry (GAT) and the Pascal dynamic contour tonometry (DCT). Other measurements included central corneal thickness (CCT), vertical cup-to-disc ratio (CDR), and systolic and diastolic blood pressure. Statistical significance was defined as P < 0.05. Results: In each of the POAG and PXG groups, GAT IOP was correlated with CCT (r = 0.40, P = 0.03 and r = 0.35, P = 0.05, respectively), whereas DCT IOP and CCT were not correlated. In all patients and in the POAG group, OPA was positively correlated with DCT IOP (r = 0.39, P = 0.002). OPA was not correlated with CCT in the POAG (P = 0.80), nor in the PXG (P = 0.20) group, after adjusting for DCT IOP. When corrected for DCT IOP and CCT, there was a significant negative correlation between OPA and vertical CDR in all patients (r = -0.41, P = 0.002). There was no significant difference in OPA between groups (P = 0.55), even when OPA was adjusted for IOP and systolic and diastolic pressure (P = 0.40), in a linear regression model. Conclusion: DCT IOP and OPA are not correlated with CCT. There is no significant difference between the OPA of PXG and POAG eyes. OPA is correlated with DCT IOP, and is lower in eyes with more advanced glaucomatous cupping. [ABSTRACT FROM AUTHOR]

Background: The intraocular pressure (IOP) could be measured by both Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT). Although these two methods have been discussed widely after laser-assisted sub-epithelial keratectomy (LASIK), there is little data in the cases undergoing photorefractive keratectomy (PRK). We aimed to compare the changes of IOP measurements obtained by GAT and DCT after PRK for myopia/myopic astigmatism. Methods: This prospective study enrolled 77 candidates (154 eyes) for PRK to correct myopia or myopic astigmatism and 30 matched patients (30 eyes) with myopia or myopic astigmatism who served as controls. Changes of the IOP measurements (ΔIOP) obtained by GAT and DCT before and at 6 months after PRK in the operated eyes, and at baseline and 6 months later in the controls, were documented. Changes of the central corneal thickness (ΔCCT) were determined in the same fashion. Results: The mean IOP readings obtained by DCT were comparable before and at 6 months after procedure (18.34 ± 3.03 mmHg and 17.87 ± 2.61 mmHg respectively, p = 0.41); whereas the mean IOP reading obtained by GAT decreased significantly 6 months postoperatively (17.92 ± 3.63 mmHg and 16.25 ± 2.66 mmHg, p < 0.001). A significant correlation was present between the ΔIOP obtained by GAT and ΔCCT ( r = 0.61, p < 0.001). Similar correlation was not significant between the DCT-obtained ΔIOP and the ΔCCT ( r = 0.07, p = 0.44). The mean ΔIOP obtained by GAT was significantly higher in the operated eyes than in the controls (−1.54 ± 1.45 vs 0.07 ± 0.44 mmHg, p = 0.02). The mean DCT-obtained ΔIOP was just marginally insignificant between the operated and nonoperated eyes (−0.63 ± 0.59 vs 0.02 ± 0.38 mmHg respectively; p = 0.09). Conclusions: The authors recommend DCT after PRK in the cases with myopia or myopic astigmatism [ABSTRACT FROM AUTHOR]

Background: To compare intraocular pressure (IOP) measurements obtained with dynamic contour tonometer (DCT) and Goldmann applanation tonometer (GAT), and to investigate their relationship to central corneal thickness (CCT) in primary congenital glaucoma (PCG) eyes. Methods: Thirty-one eyes of 31 PCG patients (25.7 ± 7.2 years old) were examined. PCG was defined as elevated IOP, enlarged corneal diameter (buphthalmos), Haab's striae and abnormal findings at gonioscopy. The mean of three measurements of GAT, DCT (quality scores 1 and 2), and CCT were obtained and assessed for agreement by means of Bland-Altman plot and for Spearman correlation test. Results: Mean CCT was 534 ± 72.3 μm (range: 430 to 610 μm). Mean IOP measurements were 15.1 ± 4.2 mmHg (range: 5.5 to 22.7 mmHg) for DCT and 14.5 ± 5.6 mmHg (range: 7.0 to 34.0 mmHg) for GAT ( P = 0.244). Spearman correlation tests showed that IOP difference (DCT − GAT) was not correlated with CCT ( r = 0.023, P = 0.417). IOP measurements by DCT were weakly but statistically correlated with those obtained with GAT (r = 0.213, P = 0.0089). Bland-Altman analysis revealed poor agreement between DCT and GAT readings, considering the 95 % confidence intervals of ±10.45 mmHg. Conclusions: The differences between DCT and GAT readings were not influenced by CCT in this series of patients. Considering the weak correlation and the poor agreement observed between GAT and DCT measurements and that they both may be affected by corneal biomechanical changes, these methods should not be used interchangeably, and may possibly give no meaningful IOP values in PCG patients. [ABSTRACT FROM AUTHOR]

Purpose: To compare choroidal thickness (CT) and ocular pulse amplitude (OPA) in childhood obesity with insulin resistance (IR) and without IR., Methods: 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., Results: 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)., Conclusions: 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.

Background and methods: Myopic photorefractive surgery induces a reduction in central corneal thickness, which may lead to underestimation of intraocular pressure. This retrospective clinical study compared intraocular pressure measurements obtained by Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT-Pascal) in eyes undergoing myopic intralaser-assisted in situ keratomileusis (IntraLASIK) or laser-assisted subepithelial keratomileusis (LASEK). Results: Of a total of 51 eyes, 21 underwent LASEK and 30 underwent IntraLASIK. By GAT, mean preoperative intraocular pressure was 16.2 ± 1.99 mmHg and postoperatively was 10.84 ± 1.45 mmHg. By DCT, mean preoperative intraocular pressure was 15.9 ± 2.08 mmHg and postoperatively was 16.1 ± 2.3 mmHg. Both preoperative and postoperative differences between measurements made by GAT and DCT were found to be statistically significant (P < 0.04 and P < 0.01, respectively). GAT and DCT readings were unaffected by type of surgery (P = 0.74 and P = 0.46, respectively). Conclusion: Postoperative GAT measurements were lower than those obtained by DCT. The difference between preoperative and postoperative DCT measurements was minimal, so DCT may be preferable for the measurement of intraocular pressure in eyes undergoing myopic IntraLASIK or LASEK. [ABSTRACT FROM AUTHOR]

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Purpose: To compare the correlate of intraocular pressure (IOP) measurements obtained using Goldmann applanation tonometer (GAT), Pascal Dynamic Contour Tonometer (DCT) and Tono-pen (TP) and to evaluate the influence of central corneal thickness (CCT) on IOP measurements in eyes with high intraocular pressure. Material and Methods: Thirty eight right eyes of 38 patients with high IOP were recruited in the study. After central corneal thickness (CCT) was measured in all eyes with ultrasonic pachymetry, IOP was measured with GAT, DCT and TP. Corrected GAT (CGAT) value was calculate according to the formula upon suggestion of Doughty and Zaman. Correlations between IOP measurements from these tonometers and CCT values were statistically analyzed. Results: Mean IOP was 34.6±10.9, 33.5±10.4, 31.8±11.7 and 28.7±6.8 mmHg for CGAT, GAT, TP and DCT respectively. There was a strong correlation between GAT and TP in eyes with high IOP, while DCT wasn't consistency. A significant association between measured IOP and CCT was found with each instrument in eyes with thin corneas. No correlation was found with each instrument in eyes with thick corneas. As CCT decreased, correlation was high of all IOP instruments. Conclusion: GAT and TP measurements were correlated in all groups. IOP measurement by all four methods is affected by CCT. IOP values obtained with GAT and TP were higher than with DCT. In conclusion, our study showed fair inter-method agreement between GAT and TP results, and poor agreement between GAT and DCT results in cases with high IOP. [ABSTRACT FROM AUTHOR]

Background: To compare the influence of central corneal thickness (CCT) during active anterior uveitis and after resolution on intraocular pressure (IOP) measurements by Goldmann applanation tonometry (GAT) and by dynamic contour tonometry (DCT). Design: Prospective, single-center study including 30 consecutive patients with active unilateral uveitis. Main Outcome Measure: CCT influence on GAT and DCT in active uveitis. Results: Average age of included patients (total n = 30; 16 women) was 46.5 years (range: 22.3-75.4). During activity, the cornea was thicker than on the unaffected side (645 vs. 585 μm, p = 0.0001). At the follow-up visit (inactive time point), the corneal thickness of the affected eye fell to a CCT of 581 μm (p < 0.0001). IOP measured by DCT was always higher than that measured by GAT. IOP was significantly lower during the active phase (GAT = 14.3 ± 5.8 mm Hg, DCT = 16.3 ± 5.9 mm Hg) than when disease was inactive (GAT = 17 ± 6.2 mm Hg, p = 0.016; DCT = 19.6 ± 6.9 mm Hg, p = 0.0006). The two techniques showed a high concordance, with a correlation coefficient of 0.76 (p < 0.001) in the affected eye at the active time point and when inactive 0.95 (p < 0.001). In addition, no systematic difference between these two techniques was observed according to the Bland-Altman method of comparison. No correlation between ΔIOP (GAT - DCT) and CCT could be detected at either time point. Conclusions: CCT increases during active phases of anterior uveitis. The edematous corneas lead to an additional decrease in IOP measurements by GAT and DCT. Both techniques were in good concordance in the patients, and the difference between GAT and DCT IOP readings was not influenced by CCT. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Purpose: To investigate the impact of cataract surgery on the association of the ocular pulse amplitude (OPA) and intraocular pressure (IOP) with respect to the interpretation of OPA as an estimate of ocular blood flow. Methods: Twenty-four patients with cataract were included in a clinical study. OPA was measured using dynamic contour tonometry (DCT, Pascal®, SMT Swiss Microtechnology AG, Switzerland). IOP was measured by means of Goldmann applanation tonometry (IOP GAT) and DCT (IOP DCT). All measurements were performed before and one day after cataract surgery. Results: At baseline, OPA was correlated to IOP GAT ( r == 0.67, P == 0.0002) and IOP DCT ( r == 0.82, P < 0.0001), but not to age or axial length. Postoperative OPA was correlated to IOP GAT ( r == 0.67, P == 0.0002) and IOP DCT ( r == 0.65, P == 0.0004). In 17 patients, IOP GAT decreased after surgery (IOP DCT n == 14), whereas an increase was apparent in seven patients (IOP DCT n == 10). The mean absolute deviation of IOP GAT pre- to post-surgery was 4.54 mmHg ± 2.47 (range 1-10 mmHg) and 5.4 mmHg ± 3.2 (range 1.1-13.1 mmHg) for IOP DCT. The changes of OPA were significantly correlated to changes in IOP GAT ( r == 0.48, P == 0.017) and IOP DCT ( r == 0.60, P == 0.001). IOP GAT and IOP DCT changes were not correlated to changes in corneal thickness. Conclusions: The OPA measured with the Pascal® device seems to be dependent on IOP changes. Particular caution should be taken in the interpretation of OPA in estimating pulsatile ocular blood flow. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to determine any difference in dynamic contour tonometry and ocular pulse amplitude in asymmetric glaucoma patients with the same applanation intraocular pressure. Methods: This is a prospective, observational study of 30 glaucoma patients and 11 controls from June 2007 to February 2008. Most of the glaucoma patients were on prostaglandin analog treatment. Results: Mean applanation intraocular pressure in the control group was 14.28 mmHg for the right eye and 14.10 mmHg for the left eye (P > 0.05). Corneal thickness was 519.10 μm for the right eye and 511.07 μm for the left eye (P > 0.05). Mean dynamic contour tonometry intraocular pressure was 17.28 mmHg for the right eye and 17.25 mmHg for the left eye (P > 0.05). Mean ocular pulse amplitude was 2.80 mmHg for the right eye and 2.92 mmHg for the left eye (P > 0.05). Conclusion: No differences in ocular pulse amplitude were found between the two groups and between the worst and the best eye. In spite of there being no difference in ocular pulse amplitude, dynamic contour tonometry intraocular pressure was 2.44 mmHg higher in the worst eye than in the best eye in the glaucoma patients, even with the same applanation intraocular pressure. Further studies are needed to confirm if this difference is related to glaucoma progression or a worst prognosis and whether it can be considered to be a new risk factor. [ABSTRACT FROM AUTHOR]

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This study aimed to investigate intraocular pressure (IOP) measurements taken using the dynamic contour tonometer (DCT) and the non-contact tonometer (NCT) in subjects with keratoconus. Intraocular pressure was measured in 20 keratoconus subjects and 20 age-matched control subjects using the DCT and NCT instruments. Central and off-centre measures were taken with the DCT in order to highlight any systematic errors associated with corneal biomechanical factors. Measures of anterior and posterior corneal topography and thickness were also taken in each subject. No significant difference was found between the central and off-centre DCT IOP readings for the keratoconus subjects and age-matched controls (p > 0.05). The average DCT IOP was 14.2 ± 1.4 mmHg in the keratoconus subjects and 14.2 ± 1.6 mmHg in the controls. However, the average NCT readings differed significantly (p < 0.001) between the keratoconus subjects (9.2 ± 1.5 mmHg) and the controls (12.9 ± 2.4 mmHg). Intraocular pressure measurements taken with the DCT showed no significant (p > 0.05) correlation with the severity of keratoconus as determined through measures of corneal topography and thickness. Equivalent IOP measurements taken with the NCT correlated significantly with certain measures of corneal curvature and thickness in the keratoconus population. The difference between DCT and NCT IOP was strongly correlated with measures of corneal topography and thickness, with differences increasing in more advanced keratoconus. The measurements obtained with the DCT do not appear to be dependent upon corneal factors, unlike those taken with the NCT. The presence or severity of keratoconus was not correlated with DCT IOP values. [ABSTRACT FROM AUTHOR]