Posters

Toric IOL calculation: comparison between anterior and total keratometry

Poster Details

First Author: F.Teixeira PORTUGAL

Co Author(s):    P. Guerra   A. Barata   F. Caiado-Sousa   A. Goncalves   A. Quintas   W. Rodrigues     

Abstract Details

Purpose:

To evaluate the astigmatism and cylindrical power of Acrysoft Toric�Â� intra-ocular lens (IOL) calculated with anterior keratometry obtained with optical biometry and total keratometry obtained with corneal tomography.

Setting:

Ophthalmology Department of Hospital de Santa Maria, Centro Hospitalar Lisboa Norte �â�€�“ Lisbon, Portugal.

Methods:

Prospective non-comparative analysis of patients with senile cataract, with more than 55 years old, a regular astigmatism of more than 1,25 diopters (D), with no history of corneal pathology, advanced glaucoma, retinal disease or previous ocular surgery. All patients did optical biometry with Lenstar and corneal tomography with Pentacam HR. To calculate IOL cylindrical power with anterior keratometry the new Alcon online Barret Toric calculator was used, and for the calculation with the 3mm zone Total Cornea Refractive Power (TCRP) the Alcon online Acrysoft IQ Toric calculator was used.

Results:

A total of 52 eyes of 31 patients were analysed. Mean age was 72�Â�±6 years-old. Mean astigmatism measured with Lenstar (LS_A) was 2.3�Â�±0.9D, and mean TCRP astigmatism (TCRP_A) was 2.2�Â�±1.0D, there was no difference between measures (p>0,05). In most cases (51,9%), LS_A and TCRP_A was against-the-rule. The cylindrical power of IOL calculated with Lenstar�â�€�™s keratometry was T 5.3�Â�±1.6, and with TCRP keratometry was T 4.9�Â�±2.0. Bland-Altman analysis showed that in patients with against-the-rule astigmatism, the cylindrical power calculated with Lenstar were superior compared with the TCRP (p<0,05).

Conclusions:

Our study revealed that patients with against-the-rule astigmatism have higher IOL�â�€�™s cylindrical power calculated with optical biometry keratometry compared with TCRP keratometry. Due to the differences between the toric IOL power calculated with both keratometric methods, patients undergoing toric IOL implantation, should have an integrated decision based on both methods.

Financial Disclosure:

NONE