The influence of dual Scheimpflug corneal tomographic parameters on intraocular lens power calculation accuracy

Session Details

Session Title: Cataract Surgery Outcomes. IOL Power Calculations

Session Date/Time: Monday 07/09/2015 | 16:30-18:30

Paper Time: 17:22

Venue: Room 1

First Author: : G.Reggiani Mello BRAZIL

Co Author(s): :    C. Serpe   M. Santhiago   D. Smadja              

Abstract Details

Purpose:

Identify dual Scheimpflug tomographic corneal factors that are able to affect the accuracy of intraocular lens power calculation in microincision phacoemulsification.

Setting:

A total of 71 eyes of 48 patients with cataract and without any other ophthalmic disorder were prospectively enrolled at the Federal University of Paraná,Brazil.

Methods:

The eyes were examined at two moments: preoperatively, several corneal and anterior segment variables were obtained by a dual Scheimpflug analyzer and a biometric evaluation was made by optical interferometry (Lenstar LS900 - Haag-Streit Koeniz, Switzerland) for intraocular lens power calculation. The corneal variables were: maximum elevation relative to a best-fit toric aspheric surface (BFTA); asphericity asymmetry index (AAI); corneal coma and spherical aberration, Kappa distance and the presence of a keratoconus suspect cornea. Two months after phacoemulsification, the refractive outcome was compared to the expected result and statistically associated to preoperative corneal variables.

Results:

Corneal power asymmetry represented by coma increased the mean absolute error (MAE) (P = 0.022), impairing the precision of the intraocular lens power calculation. There was a weak negative correlation between these results by the Pearson linear correlation test (P = 0.008) (IC 95: -0.510 to -0.087), showing a myopic error tendency for these patients. There was no statistical significance when analyzing the other corneal variables studied.

Conclusions:

The coma, a corneal power asymmetry index, is an important corneal factor in the precision of the intraocular lens power calculation. Increased values were correlated to a higher predictive biometric error.

Financial Interest:

NONE