Goldmann applanation tonometry - not as good as gold

• Autorzy: Śródka W.
• Języki publikacji: EN

Abstrakty

EN

A thesis that linear mechanics does not apply to the analysis of cornea load during Goldmann applanation tonometry measurement and that the concept of surface tension in the lacrimal fluid is an ineffective attempt at circumventing the associated problems is put forward. The fundamental problem emerging during numerically simulated measurement of pressure on the eyeball, whose dimensions are considered to be calibrated, stems from the fact that the flattening of the cornea at the nominal intraocular pressure leads to a critical state in which the shell loses stability. The consequences are far-reaching. The Goldmann tonometer performs well at low intraocular pressure, but above the nominal pressure its readings are always understated. The cause of the error is not the tonometer itself (its readings can be even very accurate). It is shell “solution” called Imbert–Fick law which is faulty.

Słowa kluczowe

EN

cornea; biomechanical model; material parameters; Goldmann applanation tonometry; IOP

PL

rogówka; model biomechaniczny; pomiar ciśnienia; ciśnienie wewnątrzgałkowe

• Wydawca: Oficyna Wydawnicza Politechniki Wrocławskiej
• Czasopismo: Acta of Bioengineering and Biomechanics
• Rocznik: 2010
• Tom: Vol. 12, no. 2
• Strony: 39--47
• Opis fizyczny: Bibliogr. 22 poz., il.

Twórcy

autor

Śródka W.

• Deformable Body Mechanics Faculty Unit, Wrocław University of Technology, Poland,

Bibliografia

• [1] GOLDMANN H., SCHMIDT T., Weiterer Beitrag zur Applanationstonometrie, Ophthalmologica, 1961, 141, 441-456.
• [2] EHLERS N.T., BRAMSEN T., SPERLING S., Applanation tonometry and central corneal thickness, Acta Ophthalmol. (Copenh.), 1975, 53, 34-43.
• [3] BIER, N., LOWTHER G.E., Contact Lens Correction, London, Butterworths, 1977.
• [4] VITO R.P., CARNELL P.H., Finite element based mechanical models of the cornea for pressure and indenter loading, J. Cataract Refract. Surg., 1992, 8, 146-151.
• [5] ORSSENGO G.J., PYE D.C., Determination of the true intraocular pressure and modulus of elasticity of the human cornea, Bull. Math. Biol., 1999, 61(3), 551-572.
• [6] Adler's Physiology of the Eye, 10th edn, Elsevier, Mosby Published, 2002, Editors: Paul Kaufman, Albert Alm, 2002.
• [7] ELSHEIKH A., WANG D., KOTECHA A., BROWN M., GARWAYHEATH G., Evaluation of Goldmann applanation tonometry using a nonlinear finite element ocular model, Ann. Biomed. Eng., 2006, 34(10), 1628-1640.
• [8] YOUNG W.C., Roark's formulas for stress and strain, 6th edn., International Editions, McGraw-Hill, 1989.
• [9] Le GRAND, Y., El HAGE S.G., Physiological Optics, Springer Series in Optical Sciences, 1980, Vol. 13, Springer-Verlag, Berlin, Heidelberg, New York.
• [10] ASEJCZYK-WIDLICKA M., ŚRÓDKA W., KASPRZAK H., ISKANDER D.R., Influence of intraocular pressure on geometrical properties of a linear model of the eyeball: Effect of optical self-adjustment, Optik - International Journal for Light and Electron Optics, 2004, 115(11), 517-524.
• [11] WOO S.L.-Y., KOBAYASHI A.S., SCHLEGEL W.A., LAWRENCE C., Nonlinear material properties of intact cornea and sclera, Exp. Eye Res., 1972, 14(1), 29-39.
• [12] FUNG Y.C., Biomechanics: Mechanical Properties of Living Tissues, NY, Springer-Verlag, 1993.
• [13] NASH L.S., GREENE P.R., FOSTER C.S., Comparison of mechanical properties of keratoconus and normal corneas, Exp. Eye Res., 1982, 35, 413-423.
• [14] ETHIER C.R., JOHNSON M., RUBERTI J., Ocular biomechanics and biotransport, Annu Rev. Biomed. Eng., 2004, 6, 249-73.
• [15] ŚRÓDKA W., Effect of kinematic boundary conditions on optical and biomechanical behaviour of eyeball model, Acta of Bioengineering and Biomechanics, 2006, 8(2), 69-77.
• [16] ŚRÓDKA W., PIERSCIONEK B.K., Effect of material properties of the eyeball coat on optical image stability, Journal of Biomedical Optics, 2008, 13(5), 054013.
• [17] LIU J., ROBERTS C.J., Influence of corneal biomechanical properties on intraocular pressure measurement, J. Cataract Refract. Surg., 2005, 31, 146-155.
• [18] ANDERSON K., EL-SHEIKH A., NEWSON T., Application of structural analysis to the mechanical behavior of the cornea, J. R. Soc. Lond. Interf., 2004, 1, 3-15.
• [19] HJORTDAL J.Ø., Regional elastic performance of the human cornea, Journal of Biomechanics, 1996, 29(7), 931-942.
• [20] SHIN T.J., VITO R.P., JOHNSON L.W., MCCAREY B.E., The distribution of strain in the human cornea, Journal of Biomechanics, 1997, 30(5), 497-503.
• [21] ANDREASSEN T.T., SIMONSEN A.J., OXLUND H., Biomechanical properties of keratoconus and normal corneas, Exp. Eye Res., 1980, 31, 435-441.
• [22] UCHIO E., OHNO S., KUDOH J., AOKI K., KISIELEWICZ L.T., Simulation model of an eyeball based on finite element analysis on a supercomputer, Brit. J. Ophthalmol., 1999, 83, 1106-1111.