Cornea - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group - Corneausing qPCR analysis.Results: After injury, macrophage accumulation was significantlyincreased in MMP12-/- mice compared with WT mice. Analysis ofthe expression levels of several CCL chemokines demonstratedsignificantly elevated RNA and protein levels of CCL2 in Mmp12-/-corneas compared with WT corneas. The trafficking of macrophagesinto the central cornea following injury was significantly reduced bysubconjunctival injections of CCL2 blocking antibodies. Theexpression of a macrophage M1 marker (TNF-α) was increased ininjured corneas of Mmp12-/- mice while expression of a macrophageM2 marker (CD23) was reduced.Conclusions: Excessive accumulation of macrophages followingcorneal injury and an M1 macrophage phenotype favor a fibroticresponse to corneal injury. MMP12 appears to protect against afibrotic response to injury by negatively regulating CCL2 expression,decreasing macrophage accumulation, and by promoting a tissuereparative M2 macrophage phenotype.Commercial Relationships: Matilda F. Chan, None; Jeffrey Lin,None; Neeraj Ramakrishnan, None; Zena Werb, NoneSupport: NIH Grant K08EY018858necessary to validate these results for in vivo human corneal tissue.Additionally, safety aspects at high intensities must be investigated.Stiffness increase of all treatment groups compared to control group.237 Corneal Cross-linking and BiomechanicsMonday, May 06, 2013 8:30 AM-10:15 AMExhibit Hall Poster SessionProgram #/Board # Range: 1611-1645/D0246-D0280Organizing Section: CorneaProgram Number: 1611 Poster Board Number: D0246Presentation Time: 8:30 AM - 10:15 AMThe efficacy of corneal cross-linking shows a sudden decreasewith very high intensity UV-light and short treatment timeJeremy Wernli 1, 3 , Silvia Schumacher 1, 3 , Eberhard Spoerl 2 , MichaelC. Mrochen 1, 3 . 1 IROC Science to Innovation AG, Zurich,Switzerland; 2 Ophthalmology, Carl Gustav Carus University HospitalDresden, Dresden, Germany; 3 IROC Innocross AG, Zurich,Switzerland.Purpose: Standard treatment in case of progressive keratectasia isUV-triggered corneal cross-linking. For irradiances larger than 10mW/cm 2 and treatment times below 10 min the scientific proof of abiomechanical strengthening effect is insufficient. The authorsinvestigated the biomechanical strengthening of ex-vivo cornealtissue treated with irradiances between 3 mW/cm 2 and 90 mW/cm 2and illumination times from 30 minutes to 1 minute, respectively.Methods: 100 porcine eyes received riboflavin+UV treatment(constant irradiation dose of 5.4 J/cm 2 ) with different intensities andillumination times and were randomly assigned into 10 groups. Acontrol group (80 eyes) was not irradiated but underwent the sametreatment otherwise. Young’s modulus at 10% strain was determinedfor each strip after uniaxial stress-strain measurement. A Kruskall-Wallis test was used for statistical analysis.Results: A statistically significant difference (α=0.01) was foundbetween the median value of Young’s modulus of the treatmentgroups up to 45 mW/cm 2 (illumination times from 30 min to 2 min)compared to the control group. There was no statistically significantdifference between the treatment groups from 50 mW/cm 2 up to 90mW/cm 2 (illumination times of less than 2 min) and the controlgroup.Conclusions: The ex vivo results of corneal cross-linking performedin porcine corneas show that the Bunsen-Roscoe reciprocity law isonly valid for illumination intensities up to 40 to 50 mW/cm 2 andillumination times of more than 2 min. Further experiments areYoung’s modulus at 10% strain of the control and different treatmentgroups.Commercial Relationships: Jeremy Wernli, IROC Innocross AG(C); Silvia Schumacher, IROC Innocross AG (C); EberhardSpoerl, None; Michael C. Mrochen, IROC Innocross AG (I)Program Number: 1612 Poster Board Number: D0247Presentation Time: 8:30 AM - 10:15 AMCorneal Biomechanical Properties after UV Cross-linking in theRabbitMichael D. Twa 1 , Jiasong Li 2 , Ravi Kiran Manapuram 2 , Floredes M.Menodiado 2 , Salavat Aglyamov 3 , Stanislav Emelianov 3 , Kirill Larin 2 .1 College of Optometry, University of Houston, Houston, TX;2 Biomedical Engineering, University of Houston, Houston, TX;3 Biomedical Engineering, University of Texas, Austin, TX.Purpose: Elasticity imaging has been applied in other areas ofmedicine and more recently used to characterize the structuralproperties of ocular tissues. An OCT-based elastography method wasdeveloped and measurements were performed in rabbit corneal tissuebefore and after UV-riboflavin corneal cross-linking (CXL).Methods: Corneal elastography measurements were performed usinga Phase Stabilized Swept Source Optical Coherence Elastography(PhS-SSOCE) with a sensitivity of ~10 nm along with air-pulse tissuestimulation. Surface wave propagation was measured over a 6x6mmarea before and after UV-riboflavin corneal cross-linking. Tissueproperties (Young's modulus, surface wave propagation speed andsurface wave amplitude) were measured.Results: Treatment resulted in a measurable increase cornealstiffness confirmed by mechanical extensiometry (before CXL:E=1.32±0.39MPa; after CXL: E=2.34±0.91MPa). Surface waveamplitude and velocity was greatest near the excitation position(Amplitude= 993nm and Velocity=0.8±0.09m/s) and decreased fromthis point to the apex. Following cross-linking surface waveamplitudes decreased (141nm) and wave velocity increased (8.2±5.6m/s).©2013, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permissionto reproduce any abstract, contact the ARVO Office at arvo@arvo.org.