title: Solid state ultraviolet laser (213 nm) ablation of the cornea and synthetic collagen lenticules.
abstract: We used a Q-switched Nd:YAG laser with non-linear optical crystals to produce the 5th (213 nm) and the 4th (266 nm) harmonic frequencies. Using these two wavelengths, we ablated fresh porcine corneas and type I collagen synthetic epikeratoplasty lenticules. For the 213-nm ablation, radiant exposure was 1.3 J/cm2. The ablation rate was 0.23 micron per pulse for the epikeratoplasty lenticules. We examined all tissues with light microscopy, transmission electron microscopy, and scanning electron microscopy. Histology for the 213-nm ablation showed a clean ablation crater with minimal collagen lamellae disruption and a damage zone less than 1 micron. In comparison, the 266 nm radiation showed more charring at the edges with a damage zone approximately 25 microns deep with disruption of the stromal lamella. Our results show that this solid state UV laser is a potential alternative to the excimer laser for cornea surgery.
authors.affiliation: Department of Ophthalmology, Emory University, Atlanta, Georgia.
authors.forename: R P
authors.initials: RP
authors.lastname: Gailitis
authors.forename: Q S
authors.initials: QS
authors.lastname: Ren
authors.forename: K P
authors.initials: KP
authors.lastname: Thompson
authors.forename: J T
authors.initials: JT
authors.lastname: Lin
authors.forename: G O
authors.initials: GO
authors.lastname: Waring
mesh_terms: D000538:Aluminum Silicates; D000818:Animals; D003094:Collagen / Q000737:chemistry*; D003315:Cornea / Q000601:surgery* / Q000648:ultrastructure; D016039:Corneal Transplantation / Q000379:methods; D004867:Equipment Design; D015603:Keratinocytes / Q000473:pathology / Q000648:ultrastructure; D007834:Lasers; D008028:Light Coagulation / Q000295:instrumentation / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D009354:Neodymium; D013552:Swine; D013997:Time Factors; D014466:Ultraviolet Rays; D015019:Yttrium
chemical_list: D000538:Aluminum Silicates; D009354:Neodymium; D015019:Yttrium; D003094:Collagen