Tomey MR-6000, Instruction Manual

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4. TECHNICAL INFORMATION
<Correction of intraocular pressure by corneal thickness>
It is said that measurement of intraocular pressure represented by the Goldman applanation
tonometer is strongly affected by the cornea. This influence can be adjusted with the corneal
center thickness (CCT) to some extent.
The reported correction formulae are as shown below.
1) corrected IOP = measured IOP - ( CCT - 554 ) x 0.045
Burvenich H, et al. Bull Soc belge Ophthalmol, 276, 15-18, 2000
2) corrected IOP = measured IOP - ( CCT - 550 ) x 0.05
Michelson G, Online J Ophthalmol, 1-2, 2001
All of these correction formulae are linear regressions of corneal thickness and intraocular
pressure. However, in reality, because other elements are involved including ethnic
differences, refractive degree and radius of corneal curvature, it cannot be determined
which formula is correct.
This instrument has a function to calculate the corrected intraocular pressure by entering
coefficients of these correction formulae and central corneal thickness (CCT) measured with
this instrument.