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Comparison of centration and functional optical zones between small incision lenticule extraction vs laser in-situ keratomileusis in a randomized trial

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Session Details

Session Title: LASIK Outcomes and Refinements

Session Date/Time: Monday 09/10/2017 | 14:30-15:50

Paper Time: 14:42

Venue: Room 4.4

First Author: : M.Ang SINGAPORE

Co Author(s): :    I. Pedersen   C. Roberts   A. Mahmoud   M. Farook   J. Mehta        

Abstract Details


To compare centration and functional optical zones between Small Incision Lenticule Extraction (SMILE) and laser in situ keratomileusis (LASIK).


Single tertiary center, parallel group, single-masked, paired-eye design, non-inferiority, randomized controlled trial.


Each participant was randomized to receive SMILE or LASIK using the VisuMax (Carl Zeiss Meditec, Germany) 500kHz femtosecond laser system; with LASIK excimer ablation using Wavelight Allegretto 400Hz laser system (Alcon Laboratories Inc., USA). We analyzed centration and functional optical zones between SMILE and LASIK eyes using corneal topography (Pentacam, Oculus, Germany) at 3 months follow-up. Functional optical zones were calculated using the refractive power map. Centration was estimated using the distance between the center of the functional optical zone and the pupil center.


We analyzed our results in 54 subjects (mean age 29 ±5 years, 40% female) who randomly underwent SMILE and LASIK in each eye (spherical equivalent, -5.41±1.72D vs. 5.35±2.07D, P=0.741 respectively) – of which, 49 valid scans were included in this analysis. We found that although the ablation area was greater in LASIK compared to SMILE (46.5±2.3 vs. 33.9±0.85, P<0.001), the functional optical zone: ablation area ratio was greater in SMILE versus LASIK (0.88±0.09 vs. 0.62±0.08, P<0.001). Centration was comparable between SMILE and LASIK (0.421±0.21mm vs. 0.415±0.20mm, P=0.867).


In our randomized contralateral eye study, we found that SMILE and LASIK had comparable centration, while SMILE may have a greater functional optical zone compared to LASIK, despite having a smaller ablation area.

Financial Disclosure:


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