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Applanation Tonometry (applanation + tonometry)
Selected AbstractsComparison of in vivo effects of nitroglycerin and insulin on the aortic pressure waveformEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 1 2004J. Westerbacka Abstract Background, Individuals whose platelets are resistant to the antiaggregatory effects of insulin in vitro are also resistant to the antiaggregatory effects of nitroglycerin (GTN). We have previously shown that insulin acutely diminishes central wave reflection in large arteries and that this action of insulin is blunted in insulin-resistant subjects. However, as yet, no studies have compared the haemodynamic effects of insulin and GTN on large arterial function in the same group of subjects. The aim of this study was to determine whether resistance to the haemodynamic effects of insulin is a defect specific to insulin or whether individuals resistant to the vascular actions of insulin are also resistant to GTN. Design and results, Dose,response characteristics of insulin and GTN on the aortic waveform were determined using applanation tonometry and pulse wave analysis (PWA) in seven healthy men (age 26 ± 1 year, BMI 25 ± 2 kg m,2). Three doses of sublingual GTN (500 µg for 1, 3 or 5 min) and insulin (0·5, 1 or 2 mU kg,1 min,1 for 120 min) were administered on three separate occasions. Both agents dose-dependently decreased central pulse pressure and the augmentation index (AIx) without changing brachial artery blood pressure. We next compared responses to insulin (2 mU kg,1 min,1 for 120 min) and sublingual GTN (500 µg for 5 min) in 20 nondiabetic subjects (age 50 ± 2 year, BMI 21·0,36·3 kg m,2). Again, both agents significantly decreased AIx. Although the vascular effects of insulin and GTN vascular were positively correlated [Spearman's r = 0·92 (95% confidence interval 0·81,0·97), P < 0·0001], the time-course for the action GTN was faster than that of insulin. Brachial systolic blood pressure remained unchanged during the insulin infusion (122 ± 3 vs. 121 ± 3 mmHg, 0 vs. 120 min) but aortic systolic blood pressure decreased significantly by 30 min (111 ± 3 vs. 107 ± 3 mmHg, 0 vs. 30 min, P < 0·01). Similarly, GTN decreased aortic systolic blood pressure from 119 ± 4 to maximally 112 ± 3 mmHg (P < 0·001) without significantly decreasing systolic blood pressure in the brachial artery. Conclusions, The effects of insulin and GTN on large arterial haemodynamics are dose-dependent and significantly correlated. The exact mechanisms and sites of action of insulin and GTN in subjects with insulin resistance remain to be established. [source] Variations in carotid arterial compliance during the menstrual cycle in young womenEXPERIMENTAL PHYSIOLOGY, Issue 2 2006Koichiro Hayashi The effect of menstrual cycle phase on arterial elasticity is controversial. In 10 healthy women (20.6 ± 1.5 years old, mean ±s.d.), we investigated the variations in central and peripheral arterial elasticity, blood pressure (carotid and brachial), carotid intima,media thickness (IMT), and serum oestradiol and progesterone concentrations at five points in the menstrual cycle (menstrual, M; follicular, F; ovulatory, O; early luteal, EL; and late luteal, LL). Carotid arterial compliance (simultaneous ultrasound and applanation tonometry) varied cyclically, with significant increases from the values seen in M (0.164 ± 0.036 mm2 mmHg,1) and F (0.171 ± 0.029 mm2 mmHg,1) to that seen in the O phase (0.184 ± 0.029 mm2 mmHg,1). Sharp declines were observed in the EL (0.150 ± 0.033 mm2 mmHg,1) and LL phases (0.147 ± 0.026 mm2 mmHg,1; F= 8.51, P < 0.05). Pulse wave velocity in the leg (i.e. peripheral arterial stiffness) did not exhibit any significant changes. Fluctuations in carotid arterial elasticity correlated with the balance between oestradiol and progesterone concentrations. No significant changes were found in carotid and brachial blood pressures, carotid artery lumen diameter, or IMT throughout the menstrual cycle. These data provide evidence that the elastic properties of central, but not peripheral, arteries fluctuate significantly with the phases of the menstrual cycle. [source] Relationship of asymmetric dimethylarginine and homocysteine to vascular aging in systemic lupus erythematosus patientsARTHRITIS & RHEUMATISM, Issue 6 2010Michelle Perna Objective Systemic lupus erythematosus (SLE) is independently associated with accelerated atherosclerosis and premature arterial stiffening. Asymmetric dimethylarginine (ADMA) and homocysteine are mechanistically interrelated mediators of endothelial dysfunction and correlates of atherosclerosis in the general population. The aim of this study was to assess the relationship of ADMA and homocysteine to subclinical vascular disease in patients with SLE. Methods One hundred twenty-five patients with SLE who were participating in a study of cardiovascular disease underwent clinical and laboratory assessment, carotid artery ultrasonography to detect atherosclerosis, and radial artery applanation tonometry to measure arterial stiffness. Results Neither ADMA nor homocysteine correlated with the presence or extent of carotid atherosclerosis. In contrast, ADMA was significantly related to the arterial stiffness index. Independent correlates of arterial stiffening included the ADMA concentration, the presence of diabetes mellitus, older age at the time of diagnosis, longer disease duration, and the absence of anti-Sm or anti-RNP antibodies. A secondary multivariable analysis substituting homocysteine for ADMA demonstrated comparable relationships with arterial stiffness (r2 = 0.616 for homocysteine and r2 = 0.595 for ADMA). Conclusion ADMA and homocysteine are biomarkers for and may be mediators of premature arterial stiffening in patients with SLE. Because arterial stiffness has independent prognostic value for cardiovascular morbidity and mortality, its predictors may identify patients who are at increased risk of cardiovascular disease. [source] Central corneal thickness in children with growth hormone deficiencyACTA OPHTHALMOLOGICA, Issue 6 2010Fulvio Parentin Acta Ophthalmol. 2010: 88: 692,694 Abstract. Purpose:, To evaluate central corneal thickness (CCT), intraocular pressure (IOP) and eye refraction in patients with congenital growth hormone (GH) deficiency. Methods:, Retrospective case series. Forty-five patients with growth defect treated with recombinant GH and 45 healthy children underwent ophthalmological examination, including CCT measurements, applanation tonometry and cycloplaegic refraction. Results:, The average CCT in the GH deficiency group was 570.6 ,m [standard deviation (SD) 37.4]. In the control group, it was 546.0 (SD 24.9). The average IOP in the GH deficiency group was 18.2 mmHg (SD 3.4). In the control group, it was 14.6 (SD 2.0). The mean refractive error (spherical equivalent) in the GH deficiency group was 0.59 D (SD 1.9). In the control group, it was 0.11 (SD 2.1). Conclusion:, GH and insulin-like growth factor 1 are involved in ocular growth by influencing the synthesis of the extracellular matrix of the sclera. Children with congenital GH deficiency or insensitivity have a mean hyperopic defect related to a shorter axial length. A number of studies have demonstrated that CCT in newborns is significantly greater than in adults; a decrease in CCT is closely correlated with an increase in corneal diameter. This finding suggests that the growth of the eye, with possible remodelling and stretching of collagen fibres, may play an important role in the reduction of corneal thickness in the first years of life. Therefore, we conclude that a greater CCT can represent a sign of a delayed growth of the eye in patients with GH deficiency. Finally, our study confirms the influence of corneal thickness on IOP measures, and the prevalence of hyperopia among children with growth defect. [source] 2352: The influence of central corneal thickness and corneal biomechanics in glaucomaACTA OPHTHALMOLOGICA, Issue 2010FC LAM Purpose To look at the impact that central corneal thickness and corneal biomechanics can have on intraocular pressure (IOP) measurements and their effect on visual fields. Methods Written and informed consent from patients and guidance from the local research ethics committee was obtained. Ocular diagnoses and ocular medications were recorded. IOPs were recorded using Goldmann applanation tonometry (GAT)followed by dynamic contour tonometry with the Pascal tonometer. Central corneal thickness(CCT) was measured using ultrasound. Visual fields were recorded using Humphries perimetry. Bland-Altman plots were used to compare the 2 methods. Results 92 eyes of 46 patients were included. Median CCT 556µm(range:427µm-634µm). Despite a good correlation of the IOP measurements usin the two different techniques(r=0.7; p< 0.01), there was a significant difference in limits of agreement(LOA) of DCT to GAT on the Bland-Altman analysis. The LOA was 8.6mmHg to -4.8mmHg with a mean bias of 1.9mmHg. This persisted even after correction for CCT. Ocular hypertensives had a wider LOA than glaucoma patients. Conclusion DCT IOP measurements can be significantly different from GAT IOPs even after taking into account central corneal thickness. Compared to CCT, corneal hysteresis appears to have a greater impact on IOP measurements. This could have important prognostic implications. [source] 2353: The influence of corneal thickness and curvature on IOP measurement by IcareTM rebound tonometer and applanation tonometry in glaucoma patients and normal subjects.ACTA OPHTHALMOLOGICA, Issue 2010P KRZYZANOWSKA-BERKOWSKA Purpose To evaluate the influence of central corneal thickness (CCT) and radius of the corneal curvature (R) on IOP measurements obtained with the ICare rebound tonometer and the Goldmann applanation tonometer (GAT). Methods Eighty four eyes of 48 subjects (65 eyes of glaucoma patients and 19 eyes of healthy volunteers) were examined with ICare and Goldmann tonometers. Central corneal thickness was determined by ultrasound pachymetry. Corneal radius of curvature was determined using corneal topography. Results There was no significant difference between IOP readings with ICare and GAT. Intraocular pressure measurements were found to be higher with the ICare tonometer, both in glaucoma patients (15,3±4,0 mmHg) and normal subjects (14,4±3,0 mmHg). ICare-GAT mean difference was 1.1±3.6mmHg (95% CI, -6.1-8.3mmHg) for glaucoma patients and 1.8±3.2mmHg (95% CI, -4.6-8.2mmHg) for healthy volunteers. Using CCT patients were divided into 2 groups: 1) thinnest corneas - CCT<556 ,m (mean CCT 531±23 ,m), 39 eyes and 2) thickest corneas - CCT >556 ,m (mean CCT 578±17 ,m), 45 eyes. In the group of thinnest corneas there was no correlation between IOP, CCT and R. In thickest corneas there was significant correlation between IOP readings obtained by ICare and CCT (r=-0.4, p<0.01), and mean radius (R) (r=0.5, p<0.001). Conclusion Measurements of IOP using the ICare rebound tonometer are in good agreement with Goldmann applanation tonometer in glaucoma patients and normal subjects, although influenced by CCT. [source] Ocular blood flow and oxygen delivery to the retina in primary open-angle glaucoma patients: the addition of dorzolamide to timolol monotherapyACTA OPHTHALMOLOGICA, Issue 1 2010Brent Siesky Abstract Purpose:, To assess the effects of adding dorzolamide to timolol monotherapy on ocular haemodynamics and retinal oxygen saturation in patients with primary open-angle glaucoma (POAG). Methods:, Twenty-four patients (12 healthy, 12 with POAG) were treated with dorzolamide/timolol combination (DT) versus timolol maleate 0.5% twice daily in a randomized, crossover, double-blind study conducted over a period of 18 months. Patients received each treatment for 8 months then crossed over to the other treatment after a 1-month washout and second baseline. Goldmann applanation tonometry, Heidelberg retinal flowmetry (HRF), colour Doppler imaging (CDI) and retinal photographic oximetry were performed at each visit. Results:, DT significantly reduced intraocular pressure (IOP) in both glaucomatous [right eye (OD) ,13.15%, left eye (OS) ,14.43%; p < 0.036] and non-glaucomatous (OD ,12.4%, OS ,13.88%; p < 0.039) patients compared to timolol after 8 months of treatment. DT significantly reduced the number of zero blood flow pixels in the superior (,39.72%; p < 0.014) and inferior (,51.44%; p < 0.008) retina in the non-glaucomatous group and inferior retina in the glaucomatous group (,55.38%, p < 0.006). The continuation of timolol monotherapy from baseline did not change (p < 0.05) any measured parameter and neither treatment had a significant effect (p < 0.05) on retinal oximetry or CDI parameters. Conclusion:, The addition of dorzolamide to timolol monotherapy decreases IOP and increases retinal blood flow in the superficial retinal vasculature in both glaucomatous and healthy patients following 8 months of treatment. The combination of increased retinal blood flow with consistent oxygen saturation may potentially increase oxygen delivery to the retina. [source] Association between corneal hysteresis and central corneal thickness in glaucomatous and non-glaucomatous eyesACTA OPHTHALMOLOGICA, Issue 8 2009George Mangouritsas Abstract. Purpose:, We aimed to determine corneal hysteresis values (CH) using the ocular response analyser (ORA) in non-glaucomatous and glaucomatous eyes and their relationship with central corneal thickness (CCT). Methods:, Corneal hysteresis, intraocular pressure (IOP) as measured by Goldmann applanation tonometry (GAT) and CCT were prospectively evaluated in 74 non-glaucoma subjects with IOP < 21 mmHg and in 108 patients with treated primary open-angle glaucoma (POAG). One eye in each subject was randomly selected for inclusion in the analysis. Results:, Mean (± standard deviation [SD]) age was 59.2 ± 14.2 years in the non-glaucoma group and 62.4 ± 9.8 years in the glaucoma group. Mean (± SD) GAT IOP was 15.7 ± 2.65 mmHg and 16.38 ± 2.73 mmHg in the non-glaucoma and glaucoma groups, respectively. There was no statistically significant difference between the two groups in mean age (p = 0.396) or mean GAT IOP (p = 0.098). Mean (± SD) CH was 10.97 ± 1.59 mmHg in the non-glaucoma and 8.95 ± 1.27 mmHg in the glaucoma groups, respectively. The difference in mean CH between the two groups was statistically significant (p < 0.0001). There was a strong positive correlation between CH and CCT in the non-glaucoma group (r = 0.743) and a significantly (p = 0.001) weaker correlation (r = 0.426) in the glaucoma group. Conclusions:, Corneal hysteresis was significantly lower in eyes with treated POAG than in non-glaucomatous eyes. The corneal biomechanical response was strongly associated with CCT in non-glaucoma subjects, but only moderately so in glaucoma patients. It can be assumed that diverse structural factors, in addition to thickness, determine the differences in the corneal biomechanical profile between non-glaucomatous and glaucomatous eyes. Corneal hysteresis could be a useful tool in the diagnosis of glaucoma. [source] Ocular pulse amplitude under pressure: what happens to OPA in glaucoma before and after surgery?ACTA OPHTHALMOLOGICA, Issue 2009I STALMANS Purpose To investigate whether trabeculectomy, besides its intraocular pressure (IOP) - lowering effect, has an effect on the ocular pulse amplitude (OPA). To determine if OPA changes are influenced by IOP changes. Methods Forty-eight glaucoma patients (48 eyes) scheduled for unilateral first-time trabeculectomy were prospectively enrolled from October 2007 to April 2008. The eye undergoing trabeculectomy was considered as study eye, whereas the non-operated fellow eye was used as control eye. OPA, IOP, blood pressure and heart rate were measured prior to and 4 weeks following trabeculectomy by means of Pascal dynamic contour tonometry (DCT), Goldmann applanation tonometry (GAT) and sphygmomanometry. A regression model for repeated measures was used. Results Preoperative GAT, DCT and OPA were 20.92 ±8.55 mmHg, 21.33 ±7.06 mmHg and 3.23 ±1.58 mmHg, respectively. One month following trabeculectomy, GAT, DCT and OPA were 11.23 ±5.03 mmHg, 14.45 ±4.79 mmHg and 2.12 ±1.07 mmHg, respectively. There was a significant decrease in OPA after filtering surgery in the study eye compared to the control eye (P<0.0001). Changes in OPA were correlated with changes in IOP (Spearman rho = 0.49, P=0.0004). When the IOP change caused by filtering surgery was taken into account, no significant difference in effect on the OPA following trabeculectomy could be demonstrated in the study eye compared to the control eye (P=0.18). Conclusion OPA changes were strongly correlated with IOP changes. There was no evidence for an effect of filtering surgery on the OPA when the concomitant IOP decrease after trabeculectomy was taken into account. [source] Do patients with normal tension glaucoma have a thinner conjunctiva?ACTA OPHTHALMOLOGICA, Issue 2009R VAN GINDERDEUREN Purpose The central cornea is thinner in patients with normal tension glaucoma (NTG). We had developed the surgical impression of thinner conjunctivas in patients with NTG. The purpose of this study was to determine whether there is a difference between the conjunctival thickness of patients with NTG and those with high tension primary open-angle glaucoma (POAG). Methods In this prospective study, 40 patients scheduled for trabeculectomy were categorized into NTG and POAG based on maximum intraocular pressure (IOP) as measured by Goldmann applanation tonometry. Ten (10) patients with NTG (max. IOP,21mmHg) and 30 patients with high tension POAG (max IOP>21mmHg) were included in the study. Conjunctival biopsies taken from the inferior fornix one month prior to trabeculectomy were fixed in formalin and embedded in Historesin. The conjunctival thickness was measured on a standardised way and compared between the two groups. Non-paired Student T test for two-tailed groups with equal variance was used for statistical analysis. Results The difference in mean conjunctival thickness between patients with NTG (66.4,±21.1) and patients with high tension POAG (104.6,±44.3) was statistically significant (P=0.045). The mean CCT in NTG (537,6±19.6) was lower than in POAG (548.3±38.0), but did not reach significancy in this study. Conclusion Patients with NTG have a thinner conjunctiva than those with high tension POAG [source] Comparison of dynamic contour tonometry with Goldmann applanation tonometry in glaucoma practiceACTA OPHTHALMOLOGICA, Issue 3 2009Ioannis Halkiadakis Abstract. Purpose:, To compare intraocular pressure (IOP) readings taken using dynamic contour tonometry (DCT) with IOP readings taken with Goldmann applanation tonometry (GAT) in eyes with glaucoma or ocular hypertension. Methods:, The present study included 100 eyes in 100 patients with glaucoma or ocular hypertension. After pachymetry DCT and GAT were performed. Intraocular pressures as measured with DCT and GAT were compared with one another and with central corneal thickness (CCT). Results:, Mean DCT IOP measurements (20.1 ± 4.3 mmHg) were significantly (p < 0.001) higher than GAT IOP values (17.9 ± 4.7 mmHg). The mean difference between DCT and GAT measurements was 2.1 mmHg (range , 3.4 to 9.7 mmHg). The difference followed a normal distribution. Measurements made with DCT and GAT correlated significantly with one another (Spearman's rho = 0.761, p < 0.001). Neither GAT nor DCT measurements showed a significant correlation with CCT (537 ± 39 ,m, range 458,656 ,m). Multivariate regression analysis has shown that the difference between DCT and GAT is influenced significantly by ocular pulse amplitude (r = , 0.334, p = 0.001) and it is not influenced by CCT (r = , 0.106, p = 0.292). Conclusions:, In eyes with glaucoma or ocular hypertension, DCT facilitates suitable and reliable IOP measurements which are in good concordance with GAT readings. Variation in CCT cannot by itself explain the differences in measurements taken with DCT and GAT in a number of eyes. [source] Re-examination of organ-cultured, cryopreserved human corneal grafts after 27 yearsACTA OPHTHALMOLOGICA, Issue 2 2009Charlotte Corydon Abstract. Purpose:, To determine the long-term fate of cryopreserved corneas. Review of 17 organ-cultered cryopreserved corneas grafted in 1978,1979. Methods:, We measured visual acuity and refraction and performed biomicroscopy, applanation tonometry and optical pachometri (CCT). Endothelial photos were taken, cells were counted and morphology was studied. Results:, Four of 16 grafted corneas were still clear after 27 years. Mean CCT was 0.52 mm, endothelial cell density was 882 cells/mm2 and visual acuity was 0.25 or better with an average of 0.6 in the four patients. Cell morphology showed irregularity in shape and size. Conclusion:, This study shows that cryopreserved endothelium can function as well as non-frozen corneas and that a regular hexagonal pattern is not essential for corneal clarity. The four grafts showed long-term durability despite the irregularity in shape and size. [source] AER lecture: Some reflections on corneal thicknessACTA OPHTHALMOLOGICA, Issue 2007N EHLERS The corneal thickness as an object for studies was recognized in the renaissance. A value of 1 mm, representing the maximally swollen human cornea, was reported. Optical in vivo measurements were done by Blix in 1880 reporting a thickness of about 0.5 mm, the value that we today know is correct. Blix lived in "the golden age of physiologic optics". His interest was the contribution of the cornea to the optical refraction of the eye, and was thus the distance between the anterior and the posterior surface rather than the thickness of the cornea as such. A biomechanical interest in corneal thickness was initiated by the studies of tonometry, in particular Hans Goldmann's development of applanation tonometry. He predicted correctly that corneal thickness would influence the estimated pressure reading. Another physiological aspect of the cornea is its transparency. Earlier explanations by equal refractive index was revolutionized by the interference theory by David Maurice. Optical transparency required a regular fiber pattern, and thus a stabilized thickness and stromal hydration. This led to extensive interest in the permeability of the limiting layers, in particular the transport of fluid across the endothelium. The physiological concepts required a regulated or stabilized thickness. The thickness as such became interesting. The human cornea is thinner in the center than more peripherally and the central, presumably regulated central thickness (CCT) became a biometric and clinical study object. The exact individual value became of interest. Several optical and later ultrasonic principles were presented. Questions addressed were: Is CCT a life-long, age independent characteristics. Is CCT diagnostic for certain disease conditions (e.g. Macular dystrophy of Groenouw). Is CCT a useful clinical parameter to follow disease processes (e.g. progression in keratoconus or acute changes in graft rejections). Today refractive surgery has revived the interest in biomechanical and optical properties of the cornea. Modern computer technology allows for a description of the "thickness profile" of the entire cornea. This gives us access to an overwhelming amount of data, and reopen many issues of the past. We must realize, however, that what we see is the pendulum swinging back to the problems of the last century. The machinery is smarter but many of the basic questions remain to be solved. [source] Dynamic contour tonometry in corneal oedemaACTA OPHTHALMOLOGICA, Issue 2007CA RENNINGS Purpose: Tonometry in corneal oedema is a current problem. In clinical routine intraocular pressure (IOP) may be measured erroneously too low in edematous thickened cornea using Goldmann applanation tonometry. To compare Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT, Pascal, Technomed, Germany) in postsurgical corneal oedema. Methods: Fifty patients with cataract were included in a prospective study. IOP was measured by means of GAT and DCT before and one day after cataract surgery. Corneal thickness was determined using a Scheimpflug camera system (Pentacam, Oculus, Germany). Results: After surgery corneal thickness increased significantly (pre-surgery: 548 ,m, post-surgery: 677 ,m, p<0.0001). No significant difference of IOP values measured with DCT compared to GAT was detected before and after cataract surgery (pre-surgery: GAT: 17 ±5 mmHg, DCT: 17 ±6 mmHg; post-surgery: GAT 15 ± 7 mmHg, DCT: 15 ±7 mmHg). IOP measured with DCT and GAT were significantly correlated (pre-surgery: r=0.808, p<0.0001; post-surgery: r=0.767, p<0.0001). The difference between GAT and DCT pre-surgery compared to post-surgery was not significantly different. The IOP difference using GAT or DCT pre-surgery compared to post-surgery was not correlated to the change in corneal thickness. Conclusions: DCT does not give any additional information compared to GAT in patients with corneal oedema. However, a marked difference in IOP values using GAT or DCT is apparent in some subjects. [source] Influence of Ginkgo biloba on ocular blood flowACTA OPHTHALMOLOGICA, Issue 4 2007Barbara Wimpissinger Abstract. Purpose:, To investigate the effect of Ginkgo biloba extract (EGb761) on ocular blood flow. Methods:, This randomized, double-masked, placebo-controlled, two-way crossover study included 15 healthy male volunteers. Measurements were taken with laser Doppler flowmetry, laser Doppler velocimetry, a retinal vessel analyser, laser interferometry and applanation tonometry, before and up to 3 hours after oral intake of 240 mg EGb761. Results:, At baseline, no significant differences in ocular and systemic haemodynamic parameters were observed between the two study days. Ginkgo biloba significantly decreased retinal venous diameters (p < 0.05 versus baseline), but there was no significant difference between the two groups. Blood pressure, retinal arterial and venous diameters, choroidal blood flow, fundus pulsation amplitude, intraocular pressure and retinal blood flow remained unchanged in both groups and did not differ between groups. Optic nerve head blood flow significantly increased in response to Ginkgo biloba (p < 0.002 versus baseline), but this effect was not significant compared with that of placebo. Conclusions:, The results of this study indicate that a single administration of Ginkgo biloba does not influence ocular blood flow to a relevant degree. Whether the drug may influence ocular blood flow in patients with ocular vascular disease after longterm treatment remains to be investigated in a randomized, placebo-controlled clinical trial. [source] Comparisons between Pascal dynamic contour tonometry, the TonoPen, and Goldmann applanation tonometry in patients with glaucomaACTA OPHTHALMOLOGICA, Issue 3 2007Maria L. Salvetat Abstract. Purpose:, To compare intraocular pressure (IOP) measurements taken with Pascal dynamic contour tonometry (DCT), the TonoPen and the Goldmann applanation tonometry (GAT). The influence of central corneal thickness (CCT) on IOP measurements taken with Pascal DCT and the TonoPen was evaluated. Methods:, One eye in each of 101 consecutive patients with primary open-angle glaucoma (POAG) underwent ultrasonic CCT measurement and IOP evaluation with GAT, Pascal DCT and the TonoPen in random order. The agreement between results from Pascal DCT and the TonoPen and those of GAT was assessed using the Bland,Altman method. The deviation of Pascal DCT and TonoPen readings from GAT values, corrected for CCT, was calculated and correlated to CCT using a linear regression model. Results:, The mean of the differences in IOP measurements was 3.2 ± 2.4 mmHg for Pascal DCT minus GAT readings and 0.5 ± 4.5 mmHg for TonoPen minus GAT readings. The 95% confidence interval of differences in IOP measurements was higher between TonoPen and GAT readings (, 6 to 7 mmHg) than between Pascal and GAT readings (0.1,6.8 mmHg). Pascal DCT significantly overestimated IOP compared with GAT, especially for higher IOP readings. Bland,Altman scatterplots showed reasonable inter-method agreement between Pascal DCT and GAT measurements, and poor agreement between TonoPen and GAT measurements. The deviations of Pascal DCT and TonoPen readings from the corrected GAT values were both highly correlated with CCT values (linear regression analysis, p < 0.0001). The mean change in measured IOP for a 10-µm increase in CCT was 0.48 mmHg for Pascal DCT and 0.74 mmHg for the TonoPen. Conclusions:, Agreement with GAT measurements was higher for Pascal DCT than for TonoPen readings; however, Pascal DCT significantly overestimated IOP values compared with GAT. Measurements of IOP obtained with both Pascal DCT and the TonoPen appeared to be influenced by CCT, and this influence appeared to be greater for the latter. [source] Intraocular pressure measurement in patients with previous LASIK surgery using pressure phosphene tonometerCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 2 2005Arthur CK Cheng MRCS Abstract Purpose:,To compare intraocular pressure (IOP) assessment in post-LASIK patients using non-contact tonometry, pressure phosphene tonometry and applanation tonometry. Methods:,Sixty-two consecutive LASIK patients were analysed preoperatively and postoperatively with non-contact, pressure phosphene and applanation tonometry. Comparisons among these values were assessed with paired sample Student t -test, Pearson's correlation test and Bland,Altman plotting. Results:,There was no significant difference for preoperative IOP measurement between non-contact, pressure phosphene and applanation tonometry. The mean ±SD difference between the preoperative non-contact tonometry and postoperative pressure phosphene tonometry IOP measurements was 0.80 ± 2.77 mmHg (P < 0.01). Postoperative applanation tonometry significantly underestimated IOP measurement by 5.45 ± 2.96 mmHg (P < 0.001) and postoperative non-contact tonometry significantly underestimated IOP measurement by 9.96 ± 2.25 mmHg (P < 0.001). Conclusion:,Pressure phosphene tonometry may provide an alternative method for the assessment of IOP in post-LASIK patients. [source] | ||||||||||