Transepithelial high-fluence cross-linking in femtosecond laser-assisted pocket: an ex-vivo biomechanical effect evaluation

Session Details

Session Title: Cornea
Session Date/Time: Sunday 28/02/2016 | 08:30-11:00
Paper Time: 09:24
Venue: MC2 Room
First Author: : A.Kanellopoulos GREECE
Co Author(s): :    G. Asimellis   S. Bourdou           

Abstract Details

Purpose:

To evaluate biomechanical changes induced by in-situ corneal cross-linking (CXL) with stromal pocket-delivered enhanced-concentration riboflavin and high-fluence, high-energy, UV-A irradiation.

Setting:

LaserVision.gr Clinical and Research Eye Institute, Athens, Greece

Methods:

Eight human donor corneas were subjected to intrastromal lamellar corneal tissue removal of anterior 140 μm, 80-μm thick× 5-mm diameter central stromal button, extracted through a 3.5-mm width tunnel, surfacing in the superior cornea periphery. Enhanced concentration riboflavin solution (0.25%) was instilled in the pocket. In the study group-A (CXL), superficial high-fluence UV-A irradiation was applied, while in the control group-B (no CXL), none. To comparatively assess changes in corneal rigidity the corneal specimens were subjected to transverse biaxial resistance measurements by application of unidirectional tangential shear force. Biomechanical differences were evaluated via stress and Young’s shear modulus.

Results:

Stress at the 10% strain was 305±24 kPa in the study group-A, versus 157±11 kPa in the control group-B (relative difference Δ=107%, p=0.021). Stress at the 20% strain was 1,284±34 kPa in the study group-A, versus 874±29 kPa in the control group-B (Δ=47%, p=0.043). Average shear modulus in the study group-A at the 10% strain was 6.98±1.12 MPa, versus 4.04±0.85 MPa in the control group-B (Δ=73%, p=0.036). Average shear modulus in the study group-A at the 20% strain was 11.46±0.75 MPa, versus 8.80±0.72 MPa in the group-B (Δ=30%, p=0.047).

Conclusions:

Adjunct CXL in this ex-vivo simulation refractive lens extraction procedure appears to provide significant increase in corneal rigidity, up to +107%. These findings also support our previous reported work on LASIK combined with CXL.

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