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The values of the biomechanical human eyeball model parameters reported in the literature are still being disputed. The primary motivation behind this work was to predict the material parameters of the cornea through numerical simulations and to assess the applicability of the ubiquitously accepted law of applanation tonometry – the Imbert–Fick equation. Methods: Numerical simulations of a few states of eyeball loading were run to determine the stroma material parameters. In the computations, the elasticity moduli of the material were related to the stress sign, instead of the orientation in space. Results: Stroma elasticity secant modulus E was predicted to be close to 0.3 MPa. The numerically simulated applanation tonometer readings for the cornea with the calibration dimensions were found to be lower by 11 mmHg then IOP = 48 mmHg. Conclusions: This discrepancy is the result of a strictly mechanical phenomenon taking place in the tensioned and simultaneously flattened corneal shell and is not related to the tonometer measuring accuracy. The observed deviation has not been amenable to any GAT corrections, contradicting the Imbert–Fick law. This means a new approach to the calculation of corrections for GAT readings is needed.
Słowa kluczowe
Czasopismo
Rocznik
Tom
Strony
77--85
Opis fizyczny
Bibliogr. 36 poz., il.
Twórcy
autor
- Deformable Body Mechanics Faculty Unit, Wrocław University of Technology, Poland, wieslaw.srodka@pwr.wroc.pl
Bibliografia
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- [33] ŚRODKA W., Effect of kinematic boundary conditions on optical and biomechanical behaviour of eyeball model, Acta of Bioengineering and Biomechanics, 2006, 8(2), 69.77.
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- [36] ŚRODKA W., Goldmann applanation tonometry . not as good as gold, Acta of Bioengineering and Biomechanics, 2010, 12(2), 39.47.
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-article-BPBA-0012-0047