Abstract
We have created a computer model of the eye that improves upon previous models with two assumptions: (1) the cornea is considered anisotropic, and (2) the strain tensor is non-linear for large displacements. Values used include those for Young's modulus, Poisson's ratio, and three coefficients of anisotropia. A finite element computer program was used to stimulate the behaviour of the eye. Four simulations were done:
(1) a full thickness arcuate limbal cataract incision,
(2) a partial thickness arcuate corneal relaxing incision,
(3) a partial thickness radial incision extending across the limbus,
(4) a partial thickness radial incision confined to the cornea.
A full thickness corneal arcuate incision for cataract induced more change in corneal shape than a limbal incision. However, the gaping is more important in the limbal incision. Partial thickness arcuate corneal relaxing incisions were found to be more effective with a clear zone 3-5 mm in diameter.
Radial incision simulation demonstrated little enhancement of the effect of the incisions when across the limbus.
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Hanna KD and Jouve FE : Preliminary computer simulation of the effects of radial keratotomy. Arch Ophthalmol. (In Press).
Hanna KD, Jouve FE, Bercovie JH, Waring GO : Computer simulation of lamellar keratectomy and myopic keratomileusis. J Refrac Surg. (In Press).
Maurice DM : The cornea and sclera. In Davson H ed. The Eye. Vol. 1, 3rd ed., London: Academic Press 1985; 1–158.
Maurice DM : Mechanics of the cornea. In Cavanagh HD ed. The Cornea: Transactions of the World Congress on the Cornea III, New York: Raven Press 1988: 187–193.
Lotmar W : Theoretical eye model with aspherics. J Optical Soc Am 1971; 61: 1522–9.
Duke-Elder S and Wybar KC : Anatomy of the visual system. In Duke-Elder S ed. System of Ophthalmology. Vol. II. St Louis: CV Mosby 1961; 92–120.
Battaglioli JL and Kamm RD : Measurements of the compressive properties of the scleral tissue. Invest Ophthalmol Vis Sci 1984; 25: 59–65.
Chuong CHJ and Fund YC : Compressibility and constitutive equation of arterial wall in radial compression experiments. J Biomechanics 1984; 17: 35–40.
Green AE and Zerna W : Theoretical elasticity. 2nd ed. London: Oxford Press 1968: 159.
Woo SL, Kobayashi AS, Schlegel WA : Non-linear material properties of intact cornea and sclera. Exp Eye Res 1982, 14: 29–39.
Woo SL : Structural analysis of a cornea-scleral shell. Seattle, Washington: Doctoral Thesis, University of Washington, 1971.
Ciarlet PG : The finite element method for elliptic problems. New York: North Holland Publishing 1978: 36–101.
Zienkiewicz OC : The finite element method. 3rd ed. New York: McGraw Hill 1977.
Gullstrand A : Helmholtz's treatise on physiological optics. Vol. I. 3rd ed. Southall JPC (trans). New York: Optical Society of America 1924.
Taber LA : Large deformation mechanics of the enucleated eyeball. ASME J Biomech Eng 1984; 16: 229–35.
Schachar RA, Black TD, Huang T : A physicist view of radial keratotomy with practiced surgical implications. In Schachar RA, Levy NA, Schachar L eds. Keratorefraction. Denison, TX: LAL Publishing 1980: 195–220.
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Hanna, K., Jouve, F., Waring III, G. et al. Computer simulation of arcuate and radial incisions involving the corneoscleral limbus. Eye 3, 227–239 (1989). https://doi.org/10.1038/eye.1989.32
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DOI: https://doi.org/10.1038/eye.1989.32
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