Stromal bed smoothness after excimer laser surface ablation as a key element for the expression of inflammatory genes

Session Details

Session Title: Moderated Poster Session: Refractive Surgery: Can Results Improve Even Further?

Venue: Poster Village: Pod 2

First Author: : E.Torres-Netto SWITZERLAND

Co Author(s): :    S. Kling   A. Hammer   S. Arba Mosquera   T. Magnago   N. Hafezi   F. Hafezi        

Abstract Details

Purpose:

Excessive haze formation represents a major clinical challenge in excimer laser surface ablation procedures. Haze formation depends on ablation depth, but may also be related to corneal ablation algorithms and excimer laser energy parameters. The purpose of this experimental in vivo study was to determine whether algorithms and energy optimizations of ablation profiles differed in gene expression, especially those concerning the inflammatory response.

Setting:

Ocular Cell Biology Group, University of Geneva (Geneva, Switzerland) and Center for Applied Biotechnology and Molecular Medicine at the University of Zurich (Zurich, Switzerland).

Methods:

Sixty-six eyes from 33 rabbits were included in this study. The first round included 12 eyes subjected to photorefractive keratectomy (PRK) divided into 4 groups with extreme parameters acceptable for clinical use: standard, high-fluence without optimization of corneal smoothness (OCS), low-fluence with OCS, and controls.   In rounds two and three, 24 and 30 eyes were used, respectively, to isolate the effect of each of the variables tested previously. For each round, rabbits were euthanized at 48 hours after treatment. Corneas were excised, homogenized, and prepared for gene expression analysis.

Results:

In the first round, a microarray analysis followed by reverse transcriptase qualitative PCR revealed 22 genes of interest related to inflammation and significant differences between treated groups. However, during rounds two and three, coding transcriptome analysis with TruSeq Stranded mRNA showed only significant differences between control and treated eyes, but not between different treatment groups. By using a three-dimensional fullerene algorithm to optimize corneal smoothness, the excimer ablation’s inflammatory response was similar even in groups with high-fluence irradiances.

Conclusions:

The optimization of different algorithms or energy settings allows for reduction of the inflammatory response after refractive laser surgery. Moreover, postoperative corneal smoothness appears to be the key factor in inflammatory regulation. Controlling stromal bed smootheness and thus, haze, may allow for deeper ablations, but also for the development of future ablation profiles.

Financial Disclosure:

... is employed by a competing company, ... research is funded, fully or partially, by a competing company