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The heart activity is one of the most important factors influencing the ocular pulsation. It is known that the high correlation between axial corneal displacements and cardiovascular system activity exists. However, phase relationships between those factors are still unknown. The main goal of the research was to measure noninvasively longitudinal corneal apex displacement (LCAD) of the left eye, applying an ultrasonic sensor. Synchronically, the electrical heart activity (ECG) was recorded in Einthoven's triangle. To find phase dependencies between these signals the coherence function was used. It is observed that coherence value, computed between the first five harmonics of both signals, is different for shifted signals along each other. Therefore, the time delay between the ECG and LCAD signals, for which particular harmonic achieves the maximum of coherence function, was examined. It can be noticed that for increasing number of the signals' harmonic, the time delay between considered signals decreases. This tendency is clear for both of examined subjects. To receive more information about this phenomenon more subjects should be measured and the statistical test should be introduced to calculate the time delay values. The presented noninvasive method might be helpful in the future for measuring the IOP pulse and estimating hemodynamic status of the eye.
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Tom
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17--25
Opis fizyczny
Bibliogr. 25 poz., rys., wykr.
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autor
autor
autor
- Institute of Physics, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370, Poland, monika.danielewska@pwr.wroc.pl
Bibliografia
- 1. Schmetterer L. F., Lexer F., Unfried C. J., Sattmann H., Fercher A. F.: Topical measurement of fundus pulsations. Opt. Eng. 1995, 34, 711-716.
- 2. Northrop R. B., Nilakhe S. S.: A non-touch ocular pulse measurement system for the diagnosis of carotid occlusions. IEEE Trans. Biomed. Eng. 1977, BME-24, 139-148.
- 3. Langham M. E., Farell R. A., O'Brien V., Silver D. M., Schilder P.: Blood flow in the human eye. Acta Ophthalmol. Suppl. 1989, 191, 9-13.
- 4. Trew D. R., James C. B.: Thomas S. H., Sutton R, Smith S. E.: Factors influencing the ocular pulse - the heart rate. Graefes Arch.Clin. Exp. Ophthalmol. 1991, 229, 553-556.
- 5. Bosley T. M., Cohen M. S., Gee W., Reed III J.: Amplitude of the Ocular Pneumoplethysmography wave form is correlated with cardiac output. Stroke 1993, 24, 6-9.
- 6. Langham M. E., To'Mey K. F.: A clinical procedure for the measurements of the ocular pulse-pressure relationship and the ophthalmic arterial pressure. Exp. Eye Res. 1978, 27(1), 17-25.
- 7. Astakhov Y. S., Irkaev S. M., Rzhanov B. I.: Gamma Resonance Velocimetry of the Eye. Vestn. Oftalmol. 1989, 105(3), 59-62.
- 8. LaCourse J. R., Sekel D. A.: A Contact Method of Ocular Pulse Detection for Studies of Carotid Occlusions. IEEE Trans. Biomed. Eng. 1977, 24, 139-148.
- 9. Zuckermann J. L., Grossman H. J. et al.: Method of measuring ocular pulse. US Patent 3948248, 1976.
- 10. Zuckerman J. L., Taylor K. D., Grossman H. J.: Noncontact detection of ocular pulse-correlation with carotid stenosis. Invest. Ophthalmol. Vis. Sci. 1977, 16(11), 1018-1024.
- 11. Campagna D. P., Drake A. D.: Interferometric measurement of the ocular pulse. Proc. 14th Ann. Northeast Bioengineering Conference, Durham, USA, 1988, 118-121.
- 12. Iskander D., Kasprzak H.: Dynamics in longitudinal eye movements and corneal shape. Ophthalmic Physiol. Opt. 2006, 26, 572-579.
- 13. Kowalska M. A., Kasprzak H., Iskander D. R.: Comparison of high-speed videokeratoscopy and ultrasound distance sensing for measuring the longitudinal corneal apex movements. Ophthal. Physiol. Opt. 2009, 29, 227-236.
- 14. Kowalska M., Kasprzak H., Iskander D. R.: Ultrasonic measurement of binocular longitudinal apex movements and their correlation to cardiopulmonary system. Biocybernetics and Biomedical Engineering, 2008, 28(3), 35-43.
- 15. Kasprzak H., Iskander D. R.: Spectral characteristics of longitudinal corneal apex velocities and their relation to the cardiopulmonary system. Eye 2007, 21, 1212-1219.
- 16. Evans D. W., Hosking S. L., Embleton S. J., Morgan A. J., Barlett J. D.: Spectral content of the intraocular pressure pulse wave: glaucoma patients versus normal subjects. Graefes Arch. Clin. Exp. Ophthalmol. 2002, 240(6), 475-480.
- 17. Eadie A. S., Pugh J. R., Winn B.: The use of coherence functions in the study of ocular mechanisms. Ophthalmic Physiol. Opt. 1995, 15(4), 311-317.
- 18. Eadie A. S., Winn B., Pugh J. R.: The influence of arterial pulse on miniature eye movements. Invest. Ophthalmol. Vis. Sci. 1994, 35(S4), 2037.
- 19. Collins M., Davis B., Wood J.: Microfluctuations of steady-state accommodation and the cardiopulmonary system. Vision Res. 1995, 35(17), 2491-2502.
- 20. Kobayashi M., Musha T.: 1/f fluctuation of heartbeat period. IEEE Trans. Biomed. Eng. 1982, BME-29, 456-457.
- 21. Sahakian A. V., Ropella K. M., Baerman J. M., Swiryn S.: Measuring the organization of cardiac rhythms using the magnitude-squared coherence function. IEEE Eng. Med. Biol. Mag. 1990, 9(1), 25-28.
- 22. Ropella K. M., Sahakian A. V., Baerman J. M., Swiryn S.: The coherence spectrum. A quantitative discriminator of fibrillatory and nonfibrillatory cardiac rhythms. Circulation 1989, 80(1), 112-119.
- 23. Sahakian A. V., Ropella K. M., Baerman J. M., Swiryn S.: Coherence measures of cardiac arrhythmias from intracardiac and epicardial leads. Proc IEEE Computers in Cardiology Conf. 1988, 329-332.
- 24. Kasprzak H. T., Iskander D. R: Ultrasonic measurement of fine head movements in a standard ophthalmic headrest. IEEE Trans. Instr. Meas., 2010, 59, 164-170.
- 25. Conover M. B.: Electrocardiography. Mosby's Pocket Guide Series, Mosby Inc: St. Louis 2004.
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Bibliografia
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bwmeta1.element.baztech-article-BPZ1-0069-0002