Relevant bibliographies by topics / Tonometry

Academic literature on the topic 'Tonometry'

Author: Grafiati
Published: 4 June 2021
Last updated: 3 March 2023

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Journal articles on the topic "Tonometry"

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Marshall, Andrea P., and Sandra H. West. "Gastric Tonometry and Enteral Nutrition: a Possible Conflict in Critical Care Nursing Practice." American Journal of Critical Care 12, no. 4 (July 1, 2003): 349–56. http://dx.doi.org/10.4037/ajcc2003.12.4.349.

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• Background Gastric tonometry is used to assess gastrointestinal mucosal perfusion in critically ill patients. However, enteral feeding is withheld during monitoring with gastric tonometry because enteral feeding is thought to influence tonometric measurements.• Objectives To examine the effect of enteral feeding on the tonometric measurement of gastric mucosal carbon dioxide.• Methods Gastric tonometers were placed in 20 critically ill patients, and the Pco2 of the gastric mucosa was measured in both the full and the empty stomach during a 48-hour period.• Results The Pco2 measured by the tonometer increased after enteral feeding, and a significant difference in the Pco2 of the full versus the empty stomach was evident at 24 and 48 hours. Pco2 at 4, 24, and 48 hours differed significantly in the full stomach and in the empty stomach. However, the data did not reveal a significant difference in either the full stomach or the empty stomach between Pco2 at 24 hours and Pco2 at 48 hours.• Conclusion After 24 hours of feeding, the initial increase in Pco2 observed at 4 hours was not evident, suggesting stabilization of the intragastric environment. However, a higher Pco2 was evident in the empty stomach, indicating that the presence of the feeding solution may reduce the diffusion of carbon dioxide into the tonometer balloon. Consequently, measurements of intragastric Pco2 obtained after 24 hours of feeding may be reliable if the stomach is emptied by aspiration via the tonometer immediately before measurement.
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Cacho, Isabel, Juan Sanchez-Naves, Laura Batres, Jesús Pintor, and Gonzalo Carracedo. "Comparison of Intraocular Pressure before and after Laser In Situ Keratomileusis Refractive Surgery Measured with Perkins Tonometry, Noncontact Tonometry, and Transpalpebral Tonometry." Journal of Ophthalmology 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/683895.

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Purpose. To compare the intraocular pressure (IOP) before and after Laser In Situ Keratomileusis (LASIK), measured by Diaton, Perkins, and noncontact air pulse tonometers.Methods. Fifty-seven patients with a mean age of 34.88 were scheduled for myopia LASIK treatment. Spherical equivalent refraction (SER), corneal curvature (K), and central corneal thickness (CCT) and superior corneal thickness (SCT) were obtained before and after LASIK surgery. IOP values before and after surgery were measured using Diaton, Perkins, and noncontact air pulse tonometers.Results. The IOP values before and after LASIK surgery using Perkins tonometer and air tonometers were statistically significant (p<0.05). However, no significant differences were found (p>0.05) for IOP values measured with Diaton tonometer. CCT decreases significantly after surgery (p<0.05) but no statistical differences were found in SCT (p=0.08). Correlations between pre- and postsurgery were found for all tonometers used, withp=0.001andr=0.434for the air pulse tonometer,p=0.008andr=0.355for Perkins, andp<0.001andr=0.637for Diaton.Conclusion. Transpalpebral tonometry may be useful for measuring postsurgery IOP after myopic LASIK ablation because this technique is not influenced by the treatment.
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R. B., Bharathi, Gopalakrishna Prabhu, Ramesh S. Ve, Rakshath Poojary, and S. Meenatchi Sundaram. "Investigation of deformation of the cornea during tonometry using FEM." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 6 (December 1, 2020): 5631. http://dx.doi.org/10.11591/ijece.v10i6.pp5631-5641.

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A three dimensional finite element model of the human eye is developed to evaluate the force which will be applied over the surface of cornea during tonometry and gonioscopy tests. The standard tonometers and gonioscopy experiences deformation from 0.5mm to 3mm of the cornea is adopted during both point contact and boundary contact on the surface of the cornea. The results demonstrate the maximum force experienced by the tonometer with point contact at the center of the cornea for the maximum possible deformation of the cornea during tonometry. The study also analyzes for the force experienced by the tonometer or goniolens with boundary layer contact for the defined deformation of the cornea along the direction from cornea towards the retina.
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Andrade, Silvia Franco, Rodrigo de Jesus Palozzi, Rodrigo Duarte Rolim, José Ricardo Cecílio Junqueira, Heloisa Ferreira do Valle, Marcelo Kurak da Silva, Marcelo Augusto Maia, and Rodrigo Augusto Zampiere. "Intraocular pressure measurements with the Tono-Pen XL® and Perkins® applanation tonometers in horses and cattle." Ciência Rural 43, no. 5 (April 2, 2013): 865–70. http://dx.doi.org/10.1590/s0103-84782013005000030.

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The objective of this study was to compare the accuracy between two applanation tonometers, Tono-Pen XL® and Perkins®, in horses and cattle. The eyes of 20 horses and 20 cattle conscious and healthy were evaluated for the in vivo study and both eyes of 5 horses and 5 cattle were used as controls for the postmortem study. In conscious animals, the tonometry was performed with auriculopalpebral nerve block and then topical anesthesia for both tonometers and 1% fluorescein eye drops only for the Perkins tonometer. Readings of intraocular pressure (IOP) in the postmortem study were taken using manometry and tonometry by Tono-Pen XL® and Perkins®. The correlation coefficient (r²) between manometry and applanation tonometers Tono-Pen XL® and Perkins®, in horses, were 0.845 and 0.989, respectively, and in cattle, were 0.772 and 0.988, respectively. The mean IOP values in conscious horses with Tono-Pen XL® and Perkins® were 20.1±3.9mmHg and 20.9±3.2mmHg, respectively, and in conscious cattle, these values were 17.2±2.4mmHg and 17.9±1.4mmHg, respectively. There was a strong correlation between the IOP values obtained by direct ocular manometry and the Tono-Pen XL® and Perkins® tonometers in horses and cattle. There was no statistically significant difference between the mean IOPs obtained with both tonometers in conscious animals; however, there was a difference between the minimum values, which were on average 2-3 mmHg lower with the Tono-Pen XL® tonometer than with the Perkins® tonometer, which justifies a table of normal values differentiated for each tonometer.
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Dorofeev, D. A., A. A. Antonov, D. Yu Vasilenko, A. V. Gorobets, K. A. Efimova, E. V. Kanafin, E. V. Karlova, et al. "A method for measuring intraocular pressure using artificial intelligence technology and fixed-force applanation tonometry." Russian Ophthalmological Journal 15, no. 2 (Прил) (June 16, 2022): 49–56. http://dx.doi.org/10.21516/2072-0076-2022-15-2-supplement-49-56.

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Purpose. To estimate the accuracy of IOP measurement using artificial intelligence (AI) technologies and applanation tonometry with fixed strength. Material and methods. 290 patients (576 eyes) underwent applanation tonometry according to Maklakov with tonometer weights of 5, 10, and 15 g using a modified elastotonometry technique followed by an analysis of impression quality and diameter measurements by three independent ophthalmologist experts. The prints were then fed into a neural network to check the repeatability and reproducibility of the measurements. Results. The comparison of the diameters of the Maklakov tonometer prints determined by AI based on the neural network with the measurements data provided by three experts showed that neural network underestimates the measurement results by an average of 0.27 (-3.81; 4.35) mm Hg. At the same time, the intraclass correlation coefficient for all prints was 98.3%. The accuracy of diameter measurements of prints by neural network differs for tonometers of different weights, e.g. for a 5 g tonometer the difference was 0.06 (-3.38; 3.49) mm Hg, for 10 g and 15 g tonometers was 0.14 (-3.8; 3.51) and 0.95 (-3.84; 5.74) mm Hg, respectively. Conclusion. High accuracy and reproducibility of the measurements by the neural network, was shown to surpass the reproducibility of human-implemented measurements.
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Cvenkel, Barbara, Makedonka Atanasovska Velkovska, and Vesna Dimovska Jordanova. "Self-measurement with Icare HOME tonometer, patients’ feasibility and acceptability." European Journal of Ophthalmology 30, no. 2 (January 11, 2019): 258–63. http://dx.doi.org/10.1177/1120672118823124.

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Purpose: To evaluate and compare the accuracy of self-measurement of intraocular pressure using Icare Home rebound tonometer with Goldmann applanation tonometer and assess acceptability of self-tonometry in patients with glaucoma and ocular hypertension. Methods: In the study, 117 subjects were trained to use Icare Home for self-measurement. Icare Home tonometer readings were compared with Goldmann applanation tonometer, including one eye per patient. Agreement between the two methods of measurement was evaluated by Bland and Altmann analysis. Questionnaire was used to evaluate patients’ perception of self-tonometry. Results: One hundred and three out of 117 patients (88%) were able to measure their own intraocular pressure and 96 (82%) fulfilled the requirements for certification. The mean (SD) difference Goldmann applanation tonometer minus Icare Home was 1.2 (2.4) mmHg (95% limits of agreement, –3.4 to 5.9 mmHg). The magnitude of bias between the two methods depended on central corneal thickness, with greater bias at central corneal thickness <500 µm. In 65 out of 96 subjects (67.7%), Icare Home results were within 2 mmHg of the Goldmann applanation tonometer. Seventy-three out of 93 (78.5%) felt that self-tonometry was easy to use and 75 patients (80.6%) responded that they would use the device at home. Conclusion: Icare Home tonometry tends to slightly underestimate intraocular pressure compared to Goldmann applanation tonometer. Most patients were able to perform self-tonometry and found it acceptable for home use. Measurements using rebound self-tonometry could improve the quality of intraocular pressure data and optimize treatment regimen.
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Maheshwari, Rajat, Nikhil S. Choudhari, and Manav Deep Singh. "Tonometry and Care of Tonometers." Journal of Current Glaucoma Practice 6, no. 3 (2012): 124–30. http://dx.doi.org/10.5005/jp-journals-10008-1119.

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Tugeeva, Elina E., and Vladimir V. Brzheskiy. "Features of measurement of intraocular pressure in children." Ophthalmology journal 9, no. 3 (September 15, 2016): 23–31. http://dx.doi.org/10.17816/ov9323-31.

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This review discusses the results of various studies conducted in recent years on the comparison of modern methods of measuring intraocular pressure (IOP) in children: pneumotonometry, Maklakov applanation tonometry, and tonometry using Perkins tonometer, Goldmann tonometer, Icare tonometer, Ocular Response Analyzer, TonoPen handheld tonometer, transpalpebral tonometer TIOP01, or a dynamic contour Pascal tonometer. This study discusses the advantages and disadvantages of different methods of measurement of IOP in children, including the evaluation of patients with fibrous lens capsules that might affect the measurement of IOP and an analysis of the characteristics of evaluation of IOP in children with congenital glaucoma.
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Kolkman, J. J., A. B. J. Groeneveld, F. G. van der Berg, J. A. Rauwerda, and S. G. M. Meuwissen. "Increased gastric Pco 2 during exercise is indicative of gastric ischaemia: a tonometric study." Gut 44, no. 2 (February 1, 1999): 163–67. http://dx.doi.org/10.1136/gut.44.2.163.

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BackgroundDiagnosis of gastric ischaemia is difficult and angiography is an invasive procedure. Angiographic findings may not correlate with clinical importance.AimsTo investigate whether tonometric measurement of intragastric Pco2during exercise can be used to detect clinically important gastric ischaemia.MethodsFourteen patients with unexplained abdominal pain or weight loss were studied. Splanchnic angiography served as the gold standard. Three patients were studied again after a revascularisation procedure. Gastric Pco2 was measured from a nasogastric tonometer, with 10 minute dwell times, and after acid suppression. Gastric and capillary Pco2 were measured before, during, and after submaximal exercise of 10 minutes duration.ResultsSeven patients had normal angiograms; seven had more than 50% stenosis in the coeliac (n=7) or superior mesenteric artery (n=4). Normal subjects showed no changes in tonometry. In patients with stenoses, the median intragastric Pco2(Pico2) at rest was 5.2 kPa (range 4.8–11.2) and rose to 6.4 kPa (range 5.7–15.7) at peak exercise; the median intragastric blood Pco2 gradient increased from 0.0 kPa (range −0.8 to 5.9) to 1.7 kPa (range 0.9 to 10.3; p<0.01). Only two subjects had abnormal tonometry at rest; all had supernormal values at peak exercise. The Pco2 gradient correlated with clinical and gastroscopic severity; in patients reexamined after revascularisation (n=3), exercise tonometry returned to normal.ConclusionGastric tonometry during exercise is a promising non-invasive tool for diagnosing and grading gastrointestinal ischaemia and evaluating the results of revascularisation surgery for symptomatic gastric ischaemia.
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Ertel, Monica K., Jennifer L. Patnaik, and Malik Y. Kahook. "Comparison of intraocular pressure readings with Perkins, Tonopen, iCare 200, and iCare Home to manometry in cadaveric eyes." International Journal of Ophthalmology 15, no. 12 (December 18, 2022): 2022–27. http://dx.doi.org/10.18240/ijo.2022.12.19.

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AIM: To compare intraocular pressure (IOP) readings obtained with Perkins tonometry, iCare Home, iCare 200, and Tonopen to IOP readings obtained with the manometer of a perfusion system to assess the accuracy and reproducibility of each method of tonometry at set pressures. METHODS: The IOP of human cadaveric eyes (n=2) was measured using a manometer inserted into the eye through the optic nerve. IOP measurements were obtained using a Perkins tonometer, iCare Home, iCare 200, and Tonopen. These measurements were compared to set point IOP measurements of a manometer to determine accuracy and reproducibility of each device. RESULTS: Mean IOP readings obtained with the Perkins tonometer compared to manometer readings demonstrated a difference of -1.0±5.0 mm Hg (P=0.45), indicating a lower reading on average than manometery although not significant. Mean IOP difference between iCare 200 and manometer was 5.3±2.2 mm Hg (P<0.0001). Mean difference in IOP between iCare Home and manometer was 3.5±2.4 mm Hg (P=0.0004). Mean IOP difference compared to manometer was 4.6±4.0 mm Hg for the Tonopen (P<0.0001). IOP measurements obtained with the Perkins tonometer demonstrated a standard deviation of 5.0 mm Hg while the Tonopen measurements demonstrated a 4.0 mm Hg standard deviation. In comparison, iCare 200 and iCare Home demonstrated 2.2 and 2.4 mm Hg standard deviation, respectively. CONCLUSION: Applanation tonometry produces more accurate IOP readings than rebound tonometry or Tonopen, however it demonstrates greater variability than the other forms of tonometry. Rebound tonometry is more reproducible but tends to over-estimate IOP.
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Dissertations / Theses on the topic "Tonometry"

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Kniestedt, Christoph. "Tonometry through the ages = Tonometrie im Wandel der Zeit /." Zürich, 2007. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000253361.

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Silva, Marcelo Jordão Lopes da. "Influencia da idade, espessura central da cornea e do indice de qualidade na tonometria de contorno dinamico." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/309857.

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Orientador: Vital Paulino Costa
Tese (doutorado)- Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
Made available in DSpace on 2018-08-14T22:24:08Z (GMT). No. of bitstreams: 1 Silva_MarceloJordaoLopesda_D.pdf: 4720767 bytes, checksum: e65a7faa1b4b7b160cef41acf6f4b989 (MD5) Previous issue date: 2009
Resumo: Os objetivos deste trabalho são comparar a pressão intra-ocular (PIO), medida com tonometria de contorno dinâmica (TCD) e tonometria de aplanação de Goldmann (TAG), analisar a influência da espessura central da córnea (ECC) e idade, em ambas as medições, bem como a influência do índice de qualidade sobre as leituras da TCD. Foram avaliados 500 indivíduos saudáveis (1000 olhos), sem história prévia de glaucoma ou hipertensão ocular (idade: 7 a 86 anos) recrutados consecutivamente. TAG, TCD e ECC foram obtidos de ambos os olhos de cada indivíduo, nessa ordem, por três observadores. A média de cinco medidas da ECC foi utilizada para análise. As medições da TCD foram aceitas quando o escore de qualidade variou entre 1 (qualidade superior) e 3 (menor qualidade). A média das PIOs obtidas com TCD foram superiores em 3,2 mmHg às medições com TAG. A análise de Bland-Altmann revelou má concordância entre as leituras de TCD e TAG, com intervalos de confiança de 95% de ± 6,98 mmHg. Os valores da ECC variaram entre 449 e 653 µm. As PIOs medidas com TAG mostraram-se fortemente correlacionadas à ECC (r? = 0,28, p <0,001), enquanto as PIOs obtidas com TCD apresentaram fraca correlação com a ECC (r2 = 0,01, p = 0,017). Tanto as medidas de TCD (r2 <0,01, p = 0,044) quanto as obtidas com TAG (r2 = 0,01, p <0,001) apresentaram fraca correlação com a idade. Os escores de qualidade das medidas de TCD foram 1 (n = 369, 36,9%), 2 (n = 340, 34,0%) e 3 (n = 291, 29,1%). As leituras de medida com TCD com escore de qualidade 3 (18,8 ± 3,4 mmHg) foram significativamente maiores do que aquelas com escore 1 (16,7 ± 2,9 mmHg) e 2 (17,4 ± 2,9 mmHg) (p <0,001). Concluiu-se que a medida com TCD não é influenciada pela ECC, ao contrário daquela com TAG. As medidas de PIO tomadas com TCD e com TAG não são influenciados pela idade. Finalmente, medidas de TCD com qualidade inferior apresentam valores maiores que as de qualidade superior.
Abstract: The purposes of this study are to compare the IOP measurements obtained with dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT), and to analyze the influence of central corneal thickness (CCT) and age on both measurements, and the influence of the quality score on DCT readings. 500 healthy subjects with no previous history of glaucoma or ocular hypertension (ages: 7 to 86 years old) were consecutively recruited. GAT (Haag Streit R900, Switzerland), DCT (SMT Swiss Micro Technology, Switzerland), and CCT (Sonomed Micropach 200P+, USA) measurements were obtained from both eyes of each individual, in this order, by three observers. The mean of five CCT measurements was used for analysis. DCT measurements were accepted when quality scores varied between 1 (higher quality) and 3 (lower quality). In our series, the mean DCT measurements were 3.2 mmHg higher than GAT readings. CCT values varied between 449 and 653 µm. IOP measured by GAT correlated strongly with CCT (r2=0.28, p<0.001), whereas DCT readings correlated poorly with CCT (r2=0.01, p=0.017). Both DCT (r2<0.01, p=0.044) and GAT (r2=0.01, p<0.001) measurements correlated poorly with age. Bland-Altmann analysis revealed disagreement between DCT and GAT readings, with 95% confidence intervals of ± 6.98 mmHg. Quality scores for DCT measurements were 1 (n=369, 36.9%), 2 (n=340, 34.0%) and 3 (n=291, 29.1%). DCT readings with quality score of 3 (18.77±3.35 mmHg) were significantly higher than those with quality scores of 1 (16.61±2.91 mmHg) and 2 (17.44±2.93 mmHg) (p<0.001). In conclusion, DCT is not influenced by CCT, unlike GAT. Both DCT and GAT measurements are not influenced by age. DCT measurements with lower quality scores are associated with higher readings.
Doutorado
Doutor em Ciências Médicas
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Hallberg, Per. "Applanation Resonance Tonometry for Intraocular Pressure Measurement." Doctoral thesis, Umeå : Tillämpad fysik och elektronik, Umeå univ, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-784.

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Vandivier, Suzette D. (Suzette Denise) 1978. "An exploration of through-the-eyelid tonometry." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/86746.

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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.
Includes bibliographical references (leaves 44-45).
by Suzette D. Vandivier.
M.Eng.
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Hamilton, Kirsten School of Optometry &amp vVsion Science UNSW. "Corneal hydration and the accuracy of Goldmann tonometry." Awarded by:University of New South Wales. School of Optometry and vVsion Science, 2006. http://handle.unsw.edu.au/1959.4/30468.

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The purpose of this thesis was to investigate the effect of corneal swelling on the accuracy of Goldmann tonometry estimates of intraocular pressure (IOP). In the first experiment, central corneal thickness (CCT, ultrasonic pachymetry), IOP (Goldmann tonometry) and corneal curvature (keratometry) was measured in one eye of 25 subjects every two hours for 24 hours, except for 8 hours overnight (no measurements taken), and for the first two hours after awakening (measurement frequency 20 minutes). CCT (+20.1??10.9 pm) and IOP (+3.1??2.4 mmHg) peaked on eye opening, and then decreased at a similar rate (r=0.967, p<0.001) for the next two hours. Corneal swelling may have influenced the accuracy of Goldmann IOP measurements during this time. In the second and third studies, the CCT, IOP and corneal curvature were measured in both eyes of two groups of 25 subjects before and after the induction of corneal swelling, resulting from two hours of monocular closed eye contact lens wear. The increase in IOP was correlated to the increase in CCT at a rate of 0.33 to 0.48 mmHg per 10 pm, which signified an overestimation error in Goldmann IOP measurement. However, the change in IOP could not be accounted for solely by the change in CCT. In the fourth study, CCT, IOP and corneal curvature were used in conjunction with the Orssengo-Pye algorithm to determine the range of Young's modulus in the normal population, which was 0.29??0.06 MPa. Physiological variations in Young's modulus had a similar effect on Goldmann tonometry to CCT. In the fifth study, the data collected for studies 2 and 3 was used to calculate the Young's modulus changes associated with corneal swelling, again with the assistance of the Orssengo-Pye algorithm. No systematic change in Young's modulus was recorded after contact lens wear, but the model suggested that corneal biomechanical changes were responsible for the remainder of the change in IOP. All experimental results were combined to develop a model to calculate the diurnal variation of Goldmann IOP errors. The likely error in IOP due to overnight corneal swelling was 0.6 to 1.4 mmHg, which may explain as much as 45% (1.4 mmHg) of the 3.1 mmHg diurnal variation of IOP. In summary, small amounts of corneal swelling were shown to have a clinically significant impact on the accuracy of Goldmann tonometry. This may interfere with the measurement of the diurnal variation of IOP, particularly if measurements are taken prior to the resolution of overnight corneal swelling.
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McCafferty, Sean, Jason Levine, Jim Schwiegerling, and Eniko T. Enikov. "Goldmann and error correcting tonometry prisms compared to intracameral pressure." BIOMED CENTRAL LTD, 2018. http://hdl.handle.net/10150/626542.

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Background: Compare Goldmann applanation tonometer (GAT) prism and correcting applanation tonometry surface (CATS) prism to intracameral intraocular pressure (IOP), in vivo and in vitro. Methods: Pressure transducer intracameral IOP was measured on fifty-eight (58) eyes undergoing cataract surgery and the IOP was modulated manometrically to 10, 20, and 40 mmHg. Simultaneously, IOP was measured using a Perkins tonometer with a standard GAT prism and a CATS prism at each of the intracameral pressures. Statistical comparison was made between true intracameral pressures and the two prism measurements. Differences between the two prism measurements were correlated to central corneal thickness (CCT) and corneal resistance factor (CRF). Human cadaver eyes were used to assess measurement repeatability. Results: The CATS tonometer prism measured closer to true intracameral IOP than the GAT prism by 1.7+/-2.7 mmHg across all pressures and corneal properties. The difference in CATS and GAT measurements was greater in thin CCT corneas (2.7+/-1.9 mmHg) and low resistance (CRF) corneas (2.8+/-2.1 mmHg). The difference in prisms was negligible at high CCT and CRF values. No difference was seen in measurement repeatability between the two prisms. Conclusion: A CATS prism in Goldmann tonometer armatures significantly improve the accuracy of IOP measurement compared to true intracameral pressure across a physiologic range of IOP values. The CATS prism is significantly more accurate compared to the GAT prism in thin and less rigid corneas. The in vivo intracameral study validates mathematical models and clinical findings in IOP measurement between the GAT and CATS prisms.
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Wang, Defu. "Biomechanical simulation of the human cornea with applications in tonometry." Thesis, University of Dundee, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505612.

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Booysen, Dirk. "Tonometry and biomechanics of the cornea in contact lens wear." Thesis, Aston University, 2016. http://publications.aston.ac.uk/30151/.

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Aims: Research on use of contact lenses as drug delivery systems continues. Disposable lenses are often used to treat corneal injuries. Accurate intraocular pressure (IOP) measurements with lenses in situ will enhance patient care and save valuable chair time. Inter- and intraobserver reliability of rebound tonometer (RBT) and intraobserver reliability of ocular response analyser (ORA) with and without contact lenses of 50 (15 male, 35 female) healthy well adapted contact lens wearers between 18 – 55 years (M = 38.90, SD = 9.23) were examined. Clinical comparisons of IOP measurements with ORA and RBT were done. Accuracy of IOP measurements with four commonly prescribed disposable contact lenses (Acuvue Oasys, Frequency XC, Acuvue 1-Day Moist, and Pure Vision with powers -6.00 − +6.00 D) in situ was evaluated. Physiological and physical factors influencing IOP measurements with both instruments were determined. Findings: Intraobserver reliability of RBT without and with lenses was excellent (ICC > 0.88; > 0.92 respectively). Interobserver reliability of RBT was excellent without or with lenses (ICC 0.81; 0.88 respectively). Intraobserver reliability of ORA was good for all metrics measured except for corneal hysteresis (CH) (ICC: CH 0.63; corneal resistance factor (CRF) 0.79; corneal compensated IOP (IOPcc) 0.77; IOPg 0.87).RBT and ORA IOPg (Goldmann equivalent IOP) measurements were clinically and statistically comparable without or with lenses (differences < 0.6 mmHg). ORA IOPcc and RBT were less comparable (differences < 1.45 mmHg).Accurate RBT and ORA tonometry (within 2 mmHg) was possible with low minus power (range -0.50 to -6.00 D); moderate modulus of elasticity (< 0.75 MPa); thin silicone hydrogel (Acuvue Oasys) and hydrogel (Frequency XC; Acuvue 1-Day Moist) contact lenses in situ. Multiple regression analyses showed biomechanical metrics CRF and CH affected RBT and ORA (IOPcc and IOPg) measurements strongly (p < 0.0001). Therefore, cornea’s biomechanical properties had greater influence on accuracy of IOP measurements with these two instruments than other variables examined.
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Yamane, Iris de Souza. "Avaliação de parâmetros tomográficos de córnea e segmento anterior e de variáveis desencadeadas pela resposta ocular à tonometria de não contato." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/5/5149/tde-10102012-103707/.

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OBJETIVO: avaliar e correlacionar parâmetros tomográficos de segmento anterior e parâmetros biomecânicos de córnea entre si, com a idade e o gênero de pacientes com olhos normais. MÉTODOS: um estudo clínico de série de casos com intervenção diagnóstica foi realizado, envolvendo um olho selecionado aleatoriamente de 235 pacientes (235 olhos). Os pacientes foram submetidos a exame oftalmológico completo, incluindo avaliação tomográfica (Pentacam) e biomecânica (ORA). Parâmetros avaliados pelo Pentacam: K1, K2, K Front Max , Astig, ISV, IVA, KI, CKI, IHA, IHD, BAD D, BAD Df, BAD Db, BAD Dp, BAD Dt, BAD Dy, ART Max, ART Avg, ART Min, Enh BFS Front 8mm, Enh BFS Back 8mm, Ele F BFS 8mm Apex, Ele F BFS 8mm Thinnest, Ele F BFS 8mm Max 4mm zone, Ele B BFS 8mm Apex, Ele B BFS 8mm Thinnest, Ele B BFS 8mm Max 4mm zone, Ele F BFTE 8mm Apex, Ele F BFTE 8mm Thinnest, Ele F BFTE 8mm 4 mm zone, Ele B BFTE 8mm Apex, Ele B BFTE 8mm Thinnest, Ele B BFTE 8mm Max 4mm zone, RPI Max, RPI Avg, RPI Min, Diff RPI Max Compl, Diff RPI Min Compl, Pachy Min, Pachy Apex, Pachy Pupil, Rel Pachy Min, Asph Q Front 30º, Asph Q Back 30º, Q Asymmetr Frontal Hor 30º, Q Asymmetr Frontal Vert 30º, AC Depth, AC Volume, Ch Angle, Volume, PNS, Densid Avg %. Parâmetros avaliados pelo ORA: IOPg, IOPcc, CH, CRF, KC Score, KC Normal, KC Suspect, KC Mild, KC Moderate, KC Severe, WS, aindex, bindex, p1area, p2area, aspect1, aspect2, uslope1, uslope2, dslope1, dslope2, w1, w2, h1, h2, dive1, dive2 , path1, path2, mslew1, mslew2, slew1, slew2, aplhf, p1area1, p2area1, aspect11, aspect21, uslope11, uslope21, dslope11, dslope21, w11, w21, h11, h21, path11, path21. RESULTADOS: K1, K2, K Max Front, BAD Df, Ele B BFS 8mm Thinnest, Ele B BFTE 8mm Thinnest, CRF e CH apresentaram valores mais altos no sexo feminino, enquanto BAD Db, Enh BFS Front 8mm, AC Depth, AC Volume, Ch Angle, p1area, w2, h1, p1area1, w21 e h11 apresentam valores mais altos no sexo masculino. CKI, BAD Db, Ele F BFS 8mm Apex, Ele F BFS 8mm Thinnest, Ele F BFTE 8mm Apex, Ele F BFTE 8mm Thinnest, Asph Q Back 30º, AC Depth, Ch Angle mostraram forte correlação negativa com a idade. Ele B BFS 8mm Apex, Ele B BFS 8mm Thinnest, Ele B BFTE 8mm Apex, Ele B BFTE 8mm Thinnest mostraram forte correlação positiva com a idade. As correlações mais altas de CH e CRF ocorreram com BAD Dt, Pachy Min, Pachy Apex e Pachy Pupil, ou seja, CH e CRF apresentaram associação positiva com a espessura corneana central. As correlações mais altas da IOPg ocorreram com BAD Dt, ART Max, ART Avg, Pachy Min, Pachy Apex e Pachy Pupil mostrando ser afetada pela espessura corneana. A IOPcc mostrou correlações mais baixas do que as obtidas com a IOPg, sendo esta menos afetada pela espessura corneana. CONCLUSÃO: Os parâmetros tomográficos de segmento anterior (Pentacam) e biomecânicos (ORA) mostraram diversas associações estatisticamente significantes entre si com a idade e com o gênero de pacientes com olhos normais
PURPOSE: to evaluate and to correlate anterior segment tomography parameters and corneal biomechanical parameters between each other, age and gender in patients with healthy eyes. METHODS: a clinical study of case series design with diagnostic intervention was conducted, involving one eye randomly selected from 235 patients (235 eyes). Patients underwent complete ophthalmological examination, including tomographic (Pentacam) and biomechanical (ORA) evaluation. Pentacam parameters assesssed: K1, K2, K Front Max , Astig, ISV, IVA, KI, CKI, IHA, IHD, BAD D, BAD Df, BAD Db, BAD Dp, BAD Dt, BAD Dy, ART Max, ART Avg, ART Min, Enh BFS Front 8mm, Enh BFS Back 8mm, Ele F BFS 8mm Apex, Ele F BFS 8mm Thinnest, Ele F BFS 8mm Max 4mm zone, Ele B BFS 8mm Apex, Ele B BFS 8mm Thinnest, Ele B BFS 8mm Max 4mm zone, Ele F BFTE 8mm Apex, Ele F BFTE 8mm Thinnest, Ele F BFTE 8mm 4 mm zone, Ele B BFTE 8mm Apex, Ele B BFTE 8mm Thinnest, Ele B BFTE 8mm Max 4mm zone, RPI Max, RPI Avg, RPI Min, Diff RPI Max Compl, Diff RPI Min Compl, Pachy Min, Pachy Apex, Pachy Pupil, Rel Pachy Min, Asph Q Front 30º, Asph Q Back 30º, Q Asymmetr Frontal Hor 30º, Q Asymmetr Frontal Vert 30º, AC Depth, AC Volume, Ch Angle, Volume, PNS, Densid Avg %. ORA Parameters assessed: IOPg, IOPcc, CH, CRF, KC Score, KC Normal, KC Suspect, KC Mild, KC Moderate, KC Severe, WS, aindex, bindex, p1area, p2area, aspect1, aspect2, uslope1, uslope2, dslope1, dslope2, w1, w2, h1, h2, dive1, dive2 , path1, path2, mslew1, mslew 2, slew1, slew2, aplhf, p1area1, p2area1, aspect11, aspect21, uslope11, uslope21, dslope11, dslope21, w11, w21, h11, h21, path11, path21. RESULTS: K1, K2, K Max Front, BAD Df, Ele B BFS 8mm Thinnest, Ele B BFTE 8mm Thinnest, CRF and CH showed higher values in females and BAD Db, Enh BFS Front 8mm, AC Depth, AC Volume, Ch Angle, p1area, w2, h1, p1area1, w21 and h11 showed higher values in males. CKI, BAD Db, Ele F BFS 8mm Apex, Ele F BFS 8mm Thinnest, Ele F BFTE 8mm Apex, Ele F BFTE 8mm Thinnest, Asph Q Back 30º, AC Depth, Ch Angle showed strong negative correlation with age. Ele B BFS 8mm Apex, Ele B BFS 8mm Thinnest, Ele B BFTE 8mm Apex, Ele B BFTE 8mm Thinnest showed strong positive correlation with age. The highest correlations of CH and CRF occurred with BAD Dt, Pachy Min, Pachy Apex and Pachy Pupil, i.e. CH and CRF presented positive association with central corneal thickness. The highest correlations of IOPg occurred with BAD Dt, ART Max, ART Avg, Pachy Min, Pachy Apex and Pachy Pupil, showing that it is affected by the thickness of the cornea. IOPcc showed lower correlations than those obtained with IOPg, showing that it is less affected by the thickness of the cornea. CONCLUSION: Anterior segment tomographic parameters (Pentacam) and biomechanical parameters (ORA) showed several statistically significant associations between each other, age and gender in patients with healthy eyes
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Claros, Chacaltana Flor Diana Yokoay. "Avaliação da pressão intraocular em chinchilas (chinchilla Lanigera) de diferentes faixas etárias utilizando tonometria de rebote." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/76540.

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A aferição da pressão intraocular (PIO) é fundamental durante o exame oftálmico. Objetivou-se estabelecer os valores de referência da PIO de chinchilas de diferentes faixas etárias utilizando o tonômetro de rebote. A PIO foi aferida ao longo do dia às 7, 12 e 19 horas utilizando o tonômetro de rebote (Tonovet®). As chinchilas foram subdivididas em três grupos com 12 animais cada, considerando as idades, designados por GI (animais com idade entre dois a seis meses), GII (com idade entre 20 e 34 meses) e GIII (animais com idade entre 37 e 135 meses). Previamente, foram realizados teste da lágrima de Schirmer, prova da fluoresceína, biomicroscopia com lâmpada de fenda e oftalmoscopia indireta em todos os animais. O valor médio da pressão intraocular encontrado foi 2,49 ± 0,56 mmHg, os valores médios para o grupo I foi de 2,47±0,581 mmHg, no grupo II de 2,47±0,581 mmHg e no grupo III de 2,51±0,531 mmHg. Não foram encontradas diferenças significativas entre a idade e a PIO (P = 0,756). Não foram encontradas diferenças significativas entre as horas do dia e a PIO (P = 0,415). Não foram encontradas diferenças significativas entre os sexos (P = 0,857). Os valores da PIO em chinchilas não sofrem alterações decorrentes do sexo e da idade dos animais. Não ocorre influência do ritmo circadiano na PIO de chinchilas.
The assessment of intraocular pressure (IOP) is essential for the ocular examination. The purpose of this study was to establish reference values of intraocular pressure chinchillas (Chinchilla lanigera) of different age groups. Thirty-six Chinchillas were divided in three groups of 12 animals each, considering the ages designated by GI (animals aged two to six months), GII (aged between 20 and 34 months) and GIII (animals aged between 37 and 135 months). Intraocular pressure was measured at 7, 12 and 19 hours. Tear production was measured, fluorescein test, slit-lamp biomicroscopy and indirect ophthalmoscopy in all animals and IOP was measured using the rebound tonometer (Tono Vet®) set on the P (undefined species) setting, with measurements obtained from each eye. No abnormalities were found on ophthalmic examination. The mean (±SD) of IOP was 2.49 ± 0.56 mmHg, with a range of 2-4 mmHg. The mean (±SD) of IOP for group I, II and III were 2.47 ± 0.581 mmHg, 2.47 ± 0.581 mmHg and 2,51 ± 0.531 mmHg, respectively. No significant differences were found between age and IOP and no significant differences were found between the hours of day and IOP. No significant differences were found between the genders. The IOP in chinchillas is unchanged between genders and age of the animals. The circadian rhythm is not influenced by IOP in chinchillas.
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Books on the topic "Tonometry"

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Ophthalmology, American Academy of, ed. Basic skills for ophthalmic assistants: Testing visual acuity, performing lensometry, instilling eyedrops, performing tonometry. San Francisco, CA: American Academy of Ophthalmology, 1993.

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Bryniok, Laura. Vergleich der Messgenauigkeit des Corvis ST zur Goldmann- Applanationstonometrie und zur NonContact- Tonometrie bei verschiedenen Augeninnendruckniveaus. Freiburg: Universität, 2017.

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Collante Haad, Yohanna C. Destreza clínica I. Bogotá. Colombia: Universidad de La Salle. Ediciones Unisalle, 2012. http://dx.doi.org/10.19052/9789585136601.

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A partir de 1997 con la Ley 372, la optometría tiene nuevos campos de acción. La consulta se amplía al incorporar exámenes adicionales que antes eran de la competencia de otras especialidades. Es aquí donde el profesional en optometría debe poseer las destrezas clínicas fundamentales para el correcto manejo de estos test. Este documento tiene como propósito, de una manera sencilla y práctica, recordar y aclarar al estudiante de clínica, conceptos acerca de algunos test, sus técnicas y aplicaciones, entre ellos están la biomicroscopía, la tonometría, la evaluación de fondo de ojo y la gonioscopía. La biomicroscopía o examen con lámpara de hendidura debe incluir la exploración de los anexos oculares, la película lagrimal, la córnea, la superficie ocular, la cámara anterior, el iris, la pupila y el cristalino. Con la ayuda de lentes adicionales, el biomicroscopio también es de utilidad para valorar el polo posterior. La evaluación de la presión intraocular y la evaluación del seno camerular son factores determinantes en el diagnóstico y en el manejo del glaucoma. Asimismo, la valoración en detalle del fondo de ojo permitirá diagnosticar patologías oculares y en algunos casos sistémicos que detectadas a tiempo pueden tener un manejo oportuno.
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Leydhecker, W. Manual der Tonographie Für Die Praxis. Springer London, Limited, 2013.

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Huntbach, Julie, and Amar Alwitry. Glaucoma. Oxford University Press, 2012. http://dx.doi.org/10.1093/med/9780199237593.003.0007.

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The chapter begins by discussing optic nerve head anatomy and aqueous fluid dynamics, before covering the key clinical skills, namely optic nerve head assessment in glaucoma, tonometry and pachymetry , gonioscopy, and perimetry. It also covers the key areas of clinical knowledge, including ocular hypertension, primary open-angle glaucoma, acute angle closure, normal-tension glaucoma, steroid-induced glaucoma, traumatic glaucoma, inflammatory glaucomas, pseudoexfoliative and pigmentary glaucoma, neovascular glaucoma, malignant glaucoma, iridocorneal endothelial syndrome and iridocorneal dysgenesis, ocular hypotensive agents, laser therapy for glaucoma, and glaucoma surgery. The chapter concludes with three case-based discussions, on open-angle glaucoma, angle closure glaucoma, and steroid glaucoma.
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Tatham, Andrew, and Peng Tee Khaw. Glaucoma. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199672516.003.0008.

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This chapter explores glaucoma. It starts off with an outline of optic nerve head anatomy and then describes aqueous fluid dynamics and the pathogenesis of glaucoma. It then goes on to discuss the clinical skill areas of optic nerve head assessment in glaucoma, glaucoma imaging devices, tonometry and tachymetry, gonioscopy, and perimetry. The chapter also details ocular hypertension, primary open-angle glaucoma, primary angle closure, and secondary angle closure. In addition, it discusses normal tension glaucoma, steroid-induced glaucoma, traumatic glaucoma, inflammatory glaucomas, pseudoexfoliative glaucoma, pigmentary glaucoma, and neovascular glaucoma. It then covers aqueous misdirection, iridocorneal endothelial syndrome and iridocorneal dysgenesis, ocular hypotensive agents, laser therapy for glaucoma, and glaucoma surgery.
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Koprowski, Robert. Air Puff Tonometers: Challenges and insights. Iop Publishing Ltd, 2019.

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Kipnis, Eric, and Benoit Vallet. Tissue perfusion monitoring in the ICU. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0138.

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Resuscitation endpoints have shifted away from restoring normal values of routinely assessed haemodynamic parameters (central venous pressure, mean arterial pressure, cardiac output) towards optimizing parameters that reflect adequate tissue perfusion. Tissue perfusion-based endpoints have changed outcomes, particularly in sepsis. Tissue perfusion can be explored by monitoring the end result of perfusion, namely tissue oxygenation, metabolic markers, and tissue blood flow. Tissue oxygenation can be directly monitored locally through invasive electrodes or non-invasively using light absorbance (pulse oximetry (SpO2) or tissue (StO2)). Global oxygenation may be monitored in blood, either intermittently through blood gas analysis, or continuously with specialized catheters. Central venous saturation (ScvO2) indirectly assesses tissue oxygenation as the net balance between global O2 delivery and uptake, decreasing when delivery does not meet demand. Lactate, a by-product of anaerobic glycolysis, increases when oxygenation is inadequate, and can be measured either globally in blood, or locally in tissues by microdialysis. Likewise, CO2 (a by-product of cellular respiration) and PCO2 can be measured globally in blood or locally in accessible mucosal tissues (sublingual, gastric) by capnography or tonometry. Increasing PCO2 gradients, either tissue-to-arterial or venous-to-arterial, are due to inadequate perfusion. Metabolically, the oxidoreductive status of mitochondria can be assessed locally through NADH fluorescence, which increases in situations of inadequate oxygenation/perfusion. Finally, local tissue blood flow may be measured by laser-Doppler or visualized through intravital microscopic imaging. These perfusion/oxygenation resuscitation endpoints are increasingly used and studied in critical care.
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Book chapters on the topic "Tonometry"

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Shin, Jong-Hoon. "Tonometry." In Primary Eye Examination, 149–62. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-10-6940-6_11.

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Desai, Bobby K. "Tonometry." In Atlas of Emergency Medicine Procedures, 297–303. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-2507-0_51.

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Sampaolesi, Roberto, Juan Roberto Sampaolesi, and Jorge Zárate. "Pascal Tonometer: Dynamic Contour Tonometry." In The Glaucomas, 153–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-35500-4_12.

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Costello, William T. "Gastric Tonometry." In Monitoring Technologies in Acute Care Environments, 317–20. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-8557-5_38.

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Sampaolesi, Roberto, Juan Roberto Sampaolesi, and Jorge Zárate. "Applanation Tonometry." In The Glaucomas, 123–47. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-35500-4_10.

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Sampaolesi, Roberto, Juan Roberto Sampaolesi, and Jorge Zárate. "Indentation Tonometry." In The Glaucomas, 105–11. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-35500-4_8.

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Chapman, M. V., and M. G. Mythen. "Gastric Mucosal Tonometry." In Problems of the Gastrointestinal Tract in Anesthesia, the Perioperative Period, and Intensive Care, 143–57. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-60200-9_18.

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Zhou, Di, John McDermott, and Nisha Chadha. "Tonometry and Tonography." In Albert and Jakobiec's Principles and Practice of Ophthalmology, 1–16. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-319-90495-5_153-1.

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Zhou, Di, John McDermott, and Nisha Chadha. "Tonometry and Tonography." In Albert and Jakobiec's Principles and Practice of Ophthalmology, 1719–34. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-42634-7_153.

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Mythen, M. G., C. Hamilton-Davies, and A. R. Webb. "Peri-Operative Gastrointestinal Tonometry." In Yearbook of Intensive Care and Emergency Medicine, 227–40. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-80053-5_20.

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Conference papers on the topic "Tonometry"

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Enikov, Eniko T., Péter P. Polyvás, Gholam Peyman, and Sean Mccafferty. "Tactile Eye Pressure Measurement Through the Eyelid." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-50875.

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This article presents the early results from a 10-person human subject study evaluating the accuracy of a novel method of indirect estimation of intraocular pressure using tactile sensors. Manual digital palpation tonometery is an old method used to estimate the eye pressure through palpation with ones fingers. Based on this concept, we present an instrumented measurement method, where multiple tactile stiffness sensors are used to infer the intraocular pressure of the eye. The method is validated using experimental data gathered from human subjects with eye pressures from 15 to 22 mmHg and determined by Goldman applanation tonometry (GAT). Bland-Altman plots comparing the GAT measurements and the proposed through-the-eye-lid tonometry indicate a statistical error of 5.16 mmHg, within the 95% confidence interval, which compares favorably with the FDA-mandated error bound of 5 mmHg. Details on the unit operation and data filtering are also presented. Due to its indirect and non-invasive nature, the proposed new tactile tonometry method can be applied at home as a self-administered home tonometer for management of glaucoma.
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Enikov, Eniko T., Marcel Madarász, and Péter P. Polyvás. "Experimental and Numerical Analysis of Ocular Tactile Tonometry." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86972.

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This article describes the experimental and numerical analysis of a novel trans-scleral tonometer based on the use of an instrumented form of digital palpation tonometry. Similar to manual digital palpation tonometery (estimation of the eye pressure via tactile touch), the novel ocular tactile tonometer utilizes multiple force probes to gather force data from indentation experiments. The presented experimental and numerical analysis shows that force data obtained from these probes correlate with the intraocular pressure (IOP) of the eye. Enucleated porcine eyes were used to validate the approach. The observed hysteresis in the force data was analyzed using an analytical model that accounts for the outflow of the aqueous humor as well as experiments at different indentation rates. Experimental data from eye distention and indentation tests were then used to infer the conditions under which the novel tonometer would be expected to have an accuracy of 1 mmHg. Analysis of the data shows that visco-elastic behavior of the scleral tissue is the primary factor responsible for the observed hysteresis. Further analysis of the data shows that indentation rates should be kept below 0.5 mm/sec for a pressure range of 10–35 mmHg. A conceptual through-the-eye-lid ocular tactile tonometer based on four probes is also presented along with numerical validation of the measured response.
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Polyva´s, Pe´ter P., Eniko T. Enikov, Gholam Peyman, and Vasco Polyzoev. "Trans-Scleral Tonometry: Mechanical Palpation of the Eye." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64852.

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The development of new tonometers requires laboratory tests on enucleated eyes where the intraocular pressure (IOP) is usually controlled by the use of a fluid column (manometry). This article describes a novel eye pressure regulation system for IOP tests along with a new concept of mechanical palpation tonometry. Manometry is commonly regarded as an invasive technique that can measure precisely the pressure inside the eye. It is a common laboratory technique for evaluating changes in IOP over time, and for providing reference pressure by which all other tonometers can be evaluated. In general, the system consists of a fluid column (1% saline solution) connected via PVC tubing to a three way valve. The valve is able to connect the column branch to a syringe with a 21G needle inserted into the vitreous humor and to a pressure transducer. The syringe needle is inserted in the eye through the side, with the tip located approximately in the middle of the vitreous chamber [1]. However, this method is prone to errors due to the gelatinous and highly fibrous nature of the vitreous matter that could easily clog the syringe needle and prevent the accurate pressure control and measurement. To resolve this difficulty, we report an alternative control of the IOP through the anterior chamber of the eye. In addition to the clogging, severed blood vessels in enucleated eyes result in large rate of leakage of intraocular fluid. With these modifications in place, it was demonstrated that the pressure sensing is fast and accurate, allowing investigation of mechanical trans-scleral palpation and the development of a new concept of mechanical palpation tonometry device. The device is based on multiple probes for measuring contact forces. Experimental data from the performance of the device are presented.
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Kanngiesser, Hartmut E., and Yves C. Robert. "Dynamic observing tonometry (DOT)." In BiOS '99 International Biomedical Optics Symposium, edited by Pascal O. Rol, Karen M. Joos, Fabrice Manns, Bruce E. Stuck, and Michael Belkin. SPIE, 1999. http://dx.doi.org/10.1117/12.350570.

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Akinin, Abraham, Joshua Yang, Alexander Williams, Andrew Lee, Pedram Pourhoseini, Arnost Fronek, and Gert Cauwenberghs. "Continuous wave ultrasonic doppler tonometry." In 2014 IEEE Biomedical Circuits and Systems Conference (BioCAS). IEEE, 2014. http://dx.doi.org/10.1109/biocas.2014.6981729.

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Drescher, Joerg, Wilhelm Stork, Stefan Hey, Arnd Gundlach, Klaus-Dieter Mueller-Glaser, and Christine F. Kreiner. "Noncontact tonometry using laser interferometry." In BiOS Europe '98, edited by Gregory B. Altshuler, Stefan Andersson-Engels, Reginald Birngruber, Peter Bjerring, Adolf F. Fercher, Herbert J. Geschwind, Raimund Hibst, Herbert Hoenigsmann, Frederic Laffitte, and Hericus J. C. M. Sterenborg. SPIE, 1999. http://dx.doi.org/10.1117/12.339145.

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Leguy, Carole A. D., E. Marielle H. Bosboom, Hanneke Gelderblom, and Frans N. van de Vosse. "Estimation of the Arterial Mechanical Properties Based on a Patient Specific Wave Propagation Model Using a Stochastic Method." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206649.

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Arterial stiffness is an independent predictor of cardiovascular risk [1]. It is therefore crucial to accurately estimate the arterial mechanical properties. The mechanical properties are reflected in the pulse wave velocity (PWV), which can be estimated from the blood pressure (BP) waveforms measured at two locations (tonometry). However, accuracy of tonometry is limited by reflections in the BP waveforms and errors in distance estimation between the measurement sites.
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Kempf, Roland, Yuichi Kurita, Yoshichika Iida, Makoto Kaneko, Hiromu K. Mishima, Hidetoshi Tsukamoto, and Eiichiro Sugimoto. "Understanding eye deformation in non-contact tonometry." In Conference Proceedings. Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2006. http://dx.doi.org/10.1109/iembs.2006.259905.

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Ho, Tuan-Shu, Chien-Chung Tsai, Kuang-Yu Hsu, and Sheng-Lung Huang. "Optical-Low-Coherence-Reflectometry-Assisted Non-Contact Tonometry." In CLEO: Applications and Technology. Washington, D.C.: OSA, 2014. http://dx.doi.org/10.1364/cleo_at.2014.jtu4a.134.

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Krijger, Tim, and Makoto Kaneko. "Online measurement of cornea deformation during non-contact tonometry." In 2011 IEEE Sensors. IEEE, 2011. http://dx.doi.org/10.1109/icsens.2011.6127401.

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