PURPOSE To compare the accuracy of four different intraocular lens (IOL) power calculation formulas for eyes with mean keratometry values greater than 46 diopters (D). METHODS Forty five eyes from 45 patients who were candidates for senile cataract surgery with mean keratometry values greater than 46 D were included. Calculation of the IOL power was performed by the Lenstar. The implanted IOL...

PURPOSE To investigate the accuracy of a new optical biometer for intraocular lens (IOL) power calculation in eyes undergoing cataract surgery. METHODS Consecutive eyes of patients undergoing cataract surgery with the same IOL model were enrolled in a prospective cohort study. Axial length (AL) and corneal power were measured with an optical biometer based on optical low-coherence interferome...

Results of intraocular lens power calculation were lower than actual required power in eyes with previous corneal refractive surgery because the inaccurate readings of corneal power obtained from standard keratometry. This causes the unacceptable hyperopia after cataract surgery. With increasing of population undergone excimer laser refractive surgery, this problem will be an obvious problem in...

PURPOSE To determine the accuracy of intraocular lens (IOL) power calculations in eyes with high myopia and to suggest adjusted constants for these cases. SETTING Centre for Ophthalmology, Eberhard-Karls-University, Tuebingen, Germany. METHODS Patients with high myopia having phacoemulsification with implantation of an AcrySof MA60MA IOL (power range +5.00 to -5.00 diopters [D]) were evalua...

A total of 94 patients underwent extracapsular cataract extraction and insertion of Sinsky style two-loop posterior chamber intraocular lenses. Forty-six eyes received a standard power IOL and 48 eyes were given a preoperatively calculated IOL. A significant difference was found in the two groups with regard to the postoperative refractive error and uncorrected visual acuity.

The matrix calculation was applied to Gaussian optics. Matrices were defined for a single diopter, a lens, an association of two centered systems having the same axis when the origins are taken at the vertices of the first and last refracting surfaces. The matrix formula then was used to calculate the power of the emmetropizing lens implant, and its results compared with the ones obtained by fi...