Posters

Cross-linking with non-thermal laser therapy

Poster Details

First Author: S.Alageel SAUDI ARABIA

Co Author(s):                        

Abstract Details

Purpose:

To test if corneas treated with combined Verteporfin with non-thermal laser (NTL) increase corneal mechanical stiffness and increase resistance to enzymatic degradation.

Setting:

Thirty human corneas were fitted into Barron® artificial anterior chambers, de-epithelialized at the Cornea Service at Massachusetts Eye and Ear Infirmary, Boston, MA.

Methods:

Corneas treated with Verteporfin alone (V), irradiated with Non-thermal Laser Therapy (689 nm ) alone (NTL), and combined treatment of Verteporfin with Non-thermal Laser Therapy(VNTL) for one sequence (V+NTL1)and six sequences of 1 minute of non-thermal Laser Therapy(V+NTL6) . Other were pre-treated with 0.1% riboflavin/20% dextran every 3 to 5 minutes for 30 minutes then irradiated with ultraviolet light type A (λ=370nm, irradiance= 3mW/cm2) for 30 minutes using Dresden protocol. Biomechanical Testing The biomechanical properties of untreated corneas and corneas treated with R+UVA and V+NTL6 were measured using : 1.Compression Testing 2.Creep Testing 3.Tensile strength testing

Results:

On gross examination, corneas treated by topical verteporfin followed by six non-thermal laser irradiations (V+NTL6) and corneas treated by riboflavin and UVA light using the Dresden protocol (R+UVA) were observed to have a much more rigidity and more pronounced curvature than untreated corneas. The stress strain tests showed that V+NTL6 and UVA groups stiffer than control( p<0.005). Interestingly the V+NTL6 therapy group appears to be slightly stiffer than UVA group (although this difference is not statistically significant). Corneas treated by V+NTL6 were found to have a significantly lower absolute creep rate than untreated corneas (-1.87 vs. -3.46, p < 0.05) .

Conclusions:

Verteporfin-NTL increases corneal mechanical stiffness and resistance to enzymatic collagenase degradation. Although a clinical study of this methodology in human patients is still needed, our results suggest that verteporfin-NLT induces corneal crosslinking and corneal biomechanical changes that are similar to that induced by corneal collagen crosslinking using ultraviolet-A (UVA) irradiation combined with riboflavin.

Financial Disclosure:

NONE