Copenhagen 2016 Registration Programme Exhibitor Information Virtual Exhibition Satellite Meetings Glaucoma Day 2016 Hotel Star Alliance

10 - 14 Sept. 2016, Bella Center, Copenhagen, Denmark

This Meeting has been awarded 27 CME credits


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Detection of biomechanical changes with the ocular response analyzer keratoconus match index software: a comparison of eyes treated with ReLEx FLEX and ReLEx SMILE for moderate to high myopia

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Session Details

Session Title: Presented Poster Session: Corneal Biomechanics

Session Date/Time: Saturday 10/09/2016 | 15:00-16:30

Paper Time: 16:20

Venue: Poster Village: Pod 4

First Author: : A.Vestergaard DENMARK

Co Author(s): :    J. Grauslund   A. Ivarsen   J. Hjortdal        

Abstract Details


ReLEx flex (FLEX) and ReLEx smile (SMILE) are two relatively new corneal refractive procedures, where a stromal lenticule is cut by a femtosecond laser and manually extracted. FLEX is flap-based while SMILE is an intrastromal flap-free refractive technique, which in theory should preserve corneal integrity better than flap-based techniques. However, both proceudres induce corneal weakening due to the removal of corneal tissue. The purpose of this study was to compare if the ORA Keratoconus (KC) score could differentiate between the two techniques.


The Department of Ophthalmology, Aarhus University Hospital.


A prospective study of 34 patients treated with FLEX in one eye, and SMILE in the other eye. Preoperative spherical equivalent refraction averaged -7.50 D with astigmatism up to -1.75 D. A VisuMax® femtosecond laser (Carl Zeiss Meditec, Jena, Germany) was used. Lenticule diameters were the same in both eyes. An ocular response analyzer (ORA version 2.04: Reichert Ophthalmic Instruments) was used to assess information about corneal biomechanical properties during corneal deformation. ORA software for waveform-based keratoconus detection was used to measure “KC score” before and 6 months after surgery in an attempt to quantify changes in corneal biomechanical properties.


There were no significant differences in KC scores neither at baseline nor after 6 months between the FLEX and the SMILE group. Pre operative mean KC score in the FLEX group was 1.29 ± 0.39, and 1.19 ± 0.41 in the SMILE group (p=0.284). After 6 months, mean KC score in the FLEX group was 0.62 ± 0.28 as compared to 0.56 ± 0.37 in the SMILE group (p=0.491). Also, no difference was found when the change in KC score in both groups from pre to 6 months was compared (p=0.657). However, a significant difference was found (p<0.001) in both the FLEX group and the SMILE group, when comparing pre operative and 6 months KC scores.


The ORA waveform derived KC score was not able to differentiate between the flap-based FLEX procedure and the cap-based SMILE procedure. However, the KC score was significangly reduced after either procedure, indicating a weakening of corneal strength as previously demonstrated by other biomechanical parameters

Financial Disclosure:

One or more of the authors travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented

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