title: Effects produced by different types of laser in cornea of Guinea pigs: Identification of a laser capable of producing superficial lesions without leaving scars.
abstract: OBJECTIVE
  Climatic droplets keratopathy (CDK) is closely associated with superficial corneal erosions and lack of protective mechanisms against the harmful effects of ultraviolet radiation (UVR) during a prolonged period of time. One of the difficulties in studying the pathogenic mechanisms involved in this human disease is the lack of an experimental animal model. In this paper, a study is conducted on the effects of 4 types of lasers at various powers and time conditions on the normal guinea pig corneas in order to select only one laser condition that reversibly injures the epithelium and superficial stroma, without leaving scarring.
  
  
  METHODS
  Damage was induced in the cornea of Guinea pigs using different powers and exposure times of 4 types of laser: argon, CO2, diode and Nd-Yag, and any injuries were evaluated by biomicroscopy (BM) and optical microscopy. Corneas from other normal animals were exposed to argon laser (350 mW, 0.3s, 50 μm of diameter), and the induced alterations were studied at different times using BM, optical coherence tomography (OCT) and transmission electron microscopy (TEM).
  
  
  RESULTS
  Only argon laser at 350 mW, 0.3s, 50 μm of diameter produced epithelium and superficial stroma lesions. Some leukomas were observed by BM, and they disappeared by day 15. Corneal thickness measured by OCT decreased in the eyes treated with argon laser during the first week. Using TEM, different ultra structural alterations in corneal epithelium and stroma were observed during the early days, which disappeared by day 15.
  
  
  CONCLUSIONS
  It was possible to develop reproducible corneal epithelium and anterior stroma injuries using Argon laser at 350 mW, 0.3s, 50 μm of diameter. In vivo and in vitro studies showed that injured corneas with these laser conditions did not leave irreversible microscopic or ultra structural alterations. This protocol of corneal erosion combined with exposure to UVR and partial deficiency of ascorbate in the diets of the animals for an extended period of time has been used in order to try to develop an experimental model of CDK.
authors.affiliation: Facultad de Agronomía y Veterinaria, Universidad Nacional de Río Cuarto, Córdoba, Argentina.
authors.forename: A C
authors.initials: AC
authors.lastname: Suárez
authors.affiliation: Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
authors.forename: M F
authors.initials: MF
authors.lastname: Suárez
authors.affiliation: Servicio de Oftalmología, Clínica Universitaria Reina Fabiola, Universidad Católica de Córdoba, Córdoba, Argentina.
authors.forename: N
authors.initials: N
authors.lastname: Crim
authors.affiliation: Servicio de Oftalmología, Clínica Universitaria Reina Fabiola, Universidad Católica de Córdoba, Córdoba, Argentina.
authors.forename: R
authors.initials: R
authors.lastname: Monti
authors.affiliation: Servicio de Oftalmología, Clínica Universitaria Reina Fabiola, Universidad Católica de Córdoba, Córdoba, Argentina.
authors.forename: J A
authors.initials: JA
authors.lastname: Urrets-Zavalía
authors.affiliation: Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina. Electronic address: hserra@fcq.unc.edu.ar.
authors.forename: H M
authors.initials: HM
authors.lastname: Serra
mesh_terms: D000818:Animals; D001206:Ascorbic Acid Deficiency / Q000150:complications / Q000235:genetics; D003315:Cornea / Q000528:radiation effects / Q000648:ultrastructure; D065306:Corneal Injuries / Q000209:etiology*; D003318:Corneal Opacity / Q000150:complications / Q000209:etiology* / Q000276:immunology; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D004781:Environmental Exposure; D005260:Female; D006168:Guinea Pigs / Q000235:genetics; D006801:Humans; D007834:Lasers / Q000009:adverse effects*; D054020:Lasers, Gas / Q000009:adverse effects; D052638:Particulate Matter / Q000009:adverse effects; D015203:Reproducibility of Results; D066167:Slit Lamp; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D052638:Particulate Matter
keywords: Cicatrización; Cobayos; Cornea; Córnea; Guinea pig; Healing; Injury; Laser; Laser argon; Lesión; Láser; Láser de argón