Correction of refractive errors with femtosecond laser corneal cross-linking in absence of photosensitizers

Session Details

Session Title: Corneal Refractive Surgery

Session Date/Time: Tuesday 17/09/2019 | 14:00-16:00

Paper Time: 14:12

Venue: Free Paper Forum: Podium 3

First Author: : S.Vukelic USA

Co Author(s): :    C. Wang   J. Fan   M. Fomovsky   M. Mencattelli   S. Vukelic                 

Abstract Details

Purpose:

This study aims to apply novel interaction modality between femtosecond laser and collagenous tissues towards correction of refractive errors. Our group has recently reported that a femtosecond laser-induced low-density-plasma can be produced in the interior of cornea when applied laser intensity is well below the optical breakdown threshold. Low-density-plasma ionizes water in the vicinity of the focal volume resulting in formation of reactive optical species that crosslink the surrounding tissue. Careful tailoring of the crosslink density in corneal stroma allows for adjustment of overall corneal curvature, which can be used for vision correction.

Setting:

All experiments and subsequent characterization has been performed in laboratory setting at Columbia University Medical Center. Novel, In-house built femtosecond laser-based crosslinking system capable of treating an eye within clinically relevant timeframe, without sacrificing accuracy and efficiency, was utilized for the treatment.

Methods:

Porcine and rabbit eyes ex vivo as well as rabbit eyes in vivo were utilized in the study. Presence of laser induced crosslinks has previously been confirmed with differential scanning calorimetry and two-photon imaging. The corneal topography has been utilized to assess the post-treatment changes in eye refractive power. Cellular structure and density in corneal stroma and endothelium has been assessed with confocal laser scanning microscopy. Change in mechanical properties of treated eyes and corresponding controls has been characterized with inflation tests.

Results:

Induced changes in eye refractive power changes have remained stable one year after the treatment. Evaluation of the haematoxylin and eosin (H&E) stained corneal sections showed no difference between control and treated corneas. No wound or wound healing effects was observed confirming photochemical nature of the laser-tissue interaction. The treatment stiffened corneas, as expected. Both, treated and control eyes have similar density of keratocytes and endothelial cells. Initial data has shown that we can adjust refractive power of the eye with approximately 0.75 diopter resolution. Varying lasing and/or other parameters is likely to further increase the resolution.

Conclusions:

Femtosecond laser-based corneal crosslinking has been induced without epithelial debriding, and in absence of photosensitizers. The treatment can be applied volumetrically, with crosslinking efficacy remaining constant throughout the entire depth of corneal stroma. Furthermore, the nature of the production of the reactive oxygen species is such that it enables micron-scale resolution. As such, the treatment modality is able to adjust the corneal curvature of an eye, and thus can be used for noninvasive vision correction. True potential of the treatment likely goes well beyond reported results, which primarily serve as a pre-clinical proof of principle of this novel technology.

Financial Disclosure:

has significant investment interest in a competing company, receives consulting fees, retainer, or contract payments from a competing company