Posters

Impact of increased PTA values on visual outcomes up to three years after refractive lenticule extraction (ReLEx) SMILE

Poster Details

First Author: D.Breyer GERMANY

Co Author(s):    H. Kaymak   K. Klabe   P. Hagen   F. Kretz   G. Auffarth        

Abstract Details

Purpose:

Former studies showed comparable visual recovery and aberrometric results for the ReLEx smile and Femto-LASIK. For LASIK, however, there is evidence that PTA (Percent Tissue Altered) values >40% can be seen as a contributing factor in the development of keratectasia. This retrospective analysis addresses the question whether this also holds for increased PTA values in case of ReLEx SMILE.

Setting:

All ReLEx SMILE (VisuMax, CZM) surgeries were performed at the Breyer-Kaymak-Klabe Eyesurgery in Duesseldorf, Germany, which is part of the International Vision Correcton Research Center (IVCRC.net).

Methods:

We analyzed the impact of high PTA-values by comparing the results of 2 ReLEx smile groups; 350 eyes with PTA<40% and 350 eyes with PTA>40%. Follow up was performed between 1 day and up to 36 month postoperatively. Results were evaluated in terms of visual acuity, manifest refraction and wave front analysis (KR-1W, Topcon). Development of Ectasia was assessed using difference maps of corneal reference surfaces from Scheimpflug tomography (Belin-Ambrosio Enhanced Ectasia Display, Pentacam, Topcon).

Results:

Overall PTA values ranged from 29% to 53%. We could not detect significant differences between the two PTA-groups (<40% and >40%) in terms of safety, predictability and visual recovery. All groups showed a mean monocular UDVA of <0.05 LogMAR one year after treatment. Furthermore, no significant differences in ectasia difference maps were found between the two PTA-groups and no eye showed postoperative values within the critical range.

Conclusions:

For ReLEx SMILE our results do not provide evidence for keratectasia development for PTA values above 40%. Further studies with longer follow-up time and larger number of patients will be needed to confirm these first findings.

Financial Disclosure:

receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented, travel has been funded, fully or partially, by a competing company, travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented, receives consulting fees, retainer, or contract payments from a competing company