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E. Chihara, M. Nishikawa, K. Okazaki, M. Tanito, M. Park; Theoretical Background to Correct Intraocular Pressure After LASIK . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2604.
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Purpose: To elucidate the reason why differences in corneal curvature can be ignored to correct intraocular pressure (IOP) after laser in situ keratomileusisL(ASIK) for myopia Methods: Equations were theoretically drawn to clarify relationships among parameters such as original corneal curvature R0, central deflection of corneal sphere (δ), corneal thickness t, and changes in the IOP (Δ IOP). Results: After the LASIK for myopia, anterior corneal surface and posterior corneal surface are not parallel, thus, Imbert-Fick law cannot be applied. An equation for central deflection: δ=A(µ)*R0 P/t2*√(1-ν2)/E was useful to know relationship between the R0, δ and Δ IOP. Where A(µ) is a function of the corneal radius and thickness, t; corneal thickness, ν; Poisson's ratio, E; Young modulus.As the cornea becomes flatter, the δ becomes smaller. In spite of this, theoretically calculated Δ IOP was nearly constant at different setting of the R0. Conclusions: An effect of differences in corneal curvature R0 on Δ IOP was theoretically drawn. Following the theory, effect of the differences in corneal curvature on the Δ IOP was minimal. On the otherhand, ablated thickness of the central cornea was an important parameter to correct post LASIK IOP. View OriginalDownload SlideView OriginalDownload Slide
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