Impact of increased PTA values on visual outcomes one year after refractive lenticule extraction (ReLEx) SMILE

Session Details

Session Title: Smile: Small Intrastromal Lenticule Extraction II

Session Date/Time: Tuesday 13/09/2016 | 16:00-17:30

Paper Time: 16:42

Venue: Hall C3

First Author: : E.Taylor GERMANY

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

Abstract Details

Purpose:

Former studies showed comparable visual recovery as well as aberrometric results for the ReLEx smile and the Femto-LASIK technique. For the latter treatment, however, there is evidence that a PTA (Percent Tissue Altered) value above 40% can be seen as a contributing factor in the development of keratectasia. This retrospective quality management investigation addresses the question whether this also holds for increased PTA (Percent Tissue Altered) 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.

Conclusions:

For ReLEx smile our results do not provide evidence for keratectasia development for cap thicknesses of 150µm and PTA values above 40%.

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