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Comparison of IOL power calculations in post-LASIK eyes undergoing cataract surgery using multiple formulae, optical coherence tomography (OCT) and intraoperative aberrometry
Session Title: Biometry
Session Date/Time: Tuesday 08/10/2013 | 08:00-10:30
Paper Time: 09:56
Venue: Elicium 2 (First Floor)
First Author: : S.Masket USA
Co Author(s): : N. Fram
Post-Lasik IOL power calculations continue to challenge cataract surgeons. This poses particular difficulty when prior laser vision correction history is unavailable. The purpose of this paper is to compare predicted outcomes in post-LASIK eyes undergoing cataract surgery using the Haigis-L formula, Fourier-domain OCT (Optovue, Inc., Freemont, CA) for "true" corneal power, ORA intraoperative aberrometry (WaveTec Vision, Aliso Viejo, CA), and Masket regression formula when prior history was available.
Patients with previous laser vision correction undergoing cataract surgery with IOL implantation were reviewed. Partial coherence interferometry IOLMaster 500 (Carl Zeiss Meditech, Germany) was used to measure axial length, corneal curvature and anterior chamber depth and supplied HaigisL post-Lasik formulae for both myopic and hyperopic ablations. Fourier-domain OCT (Optovue) IOL formula was used to measure corneal power and suggest IOL power. ORA wavefront aberrometry was used in all cases to determine IOL power in the aphakic state intra-operatively. Masket regression formula was used only when prior laser history was available. Two week post-operative refraction was chosen as the final BCVA and endpoint. The mean absolute error (MAE) of desire IOL power was compared for all formulae and methods.
Preliminary results with twenty-six eyes with previous laser vision correction undergoing cataract surgery were evaluated. The range of laser vision correction was (+4.21D to-7.25D). Nineteen eyes had previous myopic laser vision correction and seven had hyperopic laser vision correction. Eleven patients had prior laser vision correction history available. All eyes completed the two-week post-operative refraction and obtained BCVA spherical equivalent within selected aim +/-0.30. The MAE was 0.36 for the Haigis-L formula, 0.31 for the ORA wavefront aberrometer. The MAE was 0.53 for the OCT-based IOL formula and 0.22 for the Masket regression formula.
In this small preliminary investigation all formulae were within 0.53D of desired optical outcome (+/- 0.25 D). OCT-based IOL formula (Optovue) shows promising predictive results in patients without prior laser vision correction history available.
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