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Letters |

Exact Toric Intraocular Lens Calculations Using Currently Available Lens Constants

Jack T. Holladay, MD, MSEE
Arch Ophthalmol. 2012;130(7):946-947. doi:10.1001/archophthalmol.2011.1917.
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The article by Goggin et al1 does an excellent job explaining that the ratio of the IOL plane cylinder needed to neutralize the corneal plane cylinder in toric IOLs cannot be a constant but must vary according to the effective lens position (ELP) and meridional powers of the toric IOL. Failure to compensate for these variables when selecting a toric IOL is a significant source of error, especially in unusual eyes. However, there are 2 differences in their calculations from those using standard IOL formulas (Holladay 1, SRK/T, Haigis, Hoffer Q, and Holladay 2) that make the results unique to their methods and do not apply to other IOL formulas.2


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