title: NIR laser tissue welding of in vitro porcine cornea and sclera tissue.
abstract: OBJECTIVE
  The objective of this study was to test the hypothesis that an near infrared (NIR) laser system (1,455 nm) in combination with a motorized translational stage to control the position and speed of the laser beam and a shutter to control the laser exposure to the tissue being welded could be used to successfully weld ocular tissues.
  
  
  METHODS
  Seventy-five porcine corneas and 23 porcine scleral tissues were welded in vitro in this study. The welded tissues were examined using histopathology and tensile strength analysis. Eight different welding conditions were analyzed for porcine cornea and one for sclera tissues. The tensile strength of the welded groups was compared to a sutured cornea control group.
  
  
  RESULTS
  The NIR laser welding system provides strong, full thickness welds and does not require the use of extrinsic dyes, chromophores, or solders. Mean weld strengths of 0.15-0.45 kg/cm(2) were obtained for the cornea and 1.01 kg/cm(2) for sclera welds. The native H(2)O in the ocular tissue serves as an absorber of the 1,455 nm radiation and helps to induce the welds.
  
  
  CONCLUSIONS
  We conclude that an NIR laser system using an optimal laser radiation wavelength of 1,455 nm can effectively weld cornea and sclera tissue and that this laser tissue welding (LTW) methodology typically causes minimal disruption of tissue, and thus, avoids opacities and irregularities in the tissue which may result in decreased visual acuity. The optimization of a laser welding system that leads to a strong full thickness tissue bond without tissue destruction, an instant seal that promotes wound healing, and the absence of a continued presence of a foreign substance like a suture, is of considerable importance to the ophthalmology medical community. This need is especially apparent with respect to corneal transplantation and fixing the position of corneal flaps in Laser-Assisted In Situ Keratomileusis (LASIK), a laser procedure used to permanently change the shape of the cornea.
authors.affiliation: Department of Pathology, New York Eye and Ear Infirmary, 2nd Avenue & 14th Street, New York, NY 10003, USA. hsavage@nyee.edu
authors.forename: Howard E
authors.initials: HE
authors.lastname: Savage
authors.forename: Rabindra K
authors.initials: RK
authors.lastname: Halder
authors.forename: Uladzimir
authors.initials: U
authors.lastname: Kartazayeu
authors.forename: Richard B
authors.initials: RB
authors.lastname: Rosen
authors.forename: Tapan
authors.initials: T
authors.lastname: Gayen
authors.forename: Steven A
authors.initials: SA
authors.lastname: McCormick
authors.forename: Neil S
authors.initials: NS
authors.lastname: Patel
authors.forename: Alvin
authors.initials: A
authors.lastname: Katz
authors.forename: Henry D
authors.initials: HD
authors.lastname: Perry
authors.forename: Misu
authors.initials: M
authors.lastname: Paul
authors.forename: R R
authors.initials: RR
authors.lastname: Alfano
mesh_terms: D000818:Animals; D003315:Cornea / Q000601:surgery*; D066298:In Vitro Techniques; D053685:Laser Therapy; D012590:Sclera / Q000601:surgery*; D013552:Swine