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Vienna 2018 Delegate Registration Programme Exhibition Virtual Exhibition Satellites 2018 Survey


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Predictability of different strategies to consider total corneal astigmatism in cataract surgery with a toric intraocular lens

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Session Details

Session Title: Toric IOL Calculations & Alignment

Session Date/Time: Sunday 23/09/2018 | 08:00-10:00

Paper Time: 08:12

Venue: Room A5

First Author: : T.Ferreira PORTUGAL

Co Author(s): :    F. Ribeiro   P. Ribeiro   J. O'Neill              

Abstract Details


To assess the prediction error in cylindrical power calculation of a toric intraocular lens (IOL) (Precizon Toric, Ophtec BV) in cataract surgery using four different calculation strategies.


Hospital da Luz, Lisbon, Portugal.


Spherical IOL power was calculated using the Barrett Universal II formula. The cylindrical power was calculated in the online Ophtec calculator (group 1); Total Corneal Refractive Power (TCRP) of a Scheimpflug camera (Pentacam HR, OCULUS Optikgeräte GmbH) (group 2); Total Corneal Astigmatism of a color-LED topographer (Cassini, i-Optics) (group 3) or Barrett toric calculator (group 4). In each of the groups 2 to 4, 20 eyes were included in a prospective randomized fashion. Group 1 was a historical control group of 51 eyes. The mean absolute prediction error (MAE) in cylindrical power calculation was analyzed using Alpins method.


The MAE in predicted toric IOL cylindrical power was reduced from 0.56 D (0.26 – 1.09) in group 1 to 0.48 D (0.20 – 1.10) in group 2, 0.18 D (0.05 – 0.34) in group 3 and 0.14 D (0.04 – 0.21) in group 4. There were no statistically significant differences between groups 1 and 2 (p = 0.109) and between groups 3 and 4 (p = 0.099). The percentage of eyes within 0.50 D of MAE in predicted cylindrical power was 54% in group 1, 57% in group 2, 71% in group 3 and 74% in group 4.


Using color-LED topography TCA data or the Barrett toric calculator significantly reduces the absolute error in cylindrical power calculation when implanting a toric IOL, with both methods showing similar results. Using one of these calculation methods improves clinical results with toric IOLs.

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