title: The effect of anesthetic eye drop instillation on the distribution of corneal thickness.
abstract: OBJECTIVE
  To address the effect of topical instillation of oxybuprocaine on the relative distribution of corneal thickness (CT) in young healthy subjects.
  
  
  METHODS
  Prospective study involving 30 eyes of 30 emmetropic subjects (24 ± 3 years). Corneal thickness measurements were carried out before and 3 minutes after the instillation of oxybuprocaine 4% using slit-scanning corneal topography (Orbscan topography system II). No acoustic correction factor was applied. The mean of 5 consecutive Orbscan measurements was obtained at the center and 3 mm from the visual axis in the temporal, superior, nasal, and inferior hemimeridians.
  
  
  RESULTS
  No significant mean differences were found at any corneal location after anesthesia (P > 0.05). The difference between the baseline values obtained of the central, superior, inferior, nasal, and temporal cornea and those obtained after anesthesia ranged from -15 to 16 μm, from -19 to 32 μm, from -14 to 24 μm, from -20 to 33 μm, and from -31 to 18 μm, respectively. The maximum paracentral CT was never found at the temporal location before anesthesia, whereas it was never found at the inferior location after anesthesia. The minimum paracentral CT was never found in the superior location after anesthesia.
  
  
  CONCLUSIONS
  Topical anesthetic eye drops induce CT increases and decreases at each corneal location; however, the differences are not significant. Nevertheless, a change in the location of the minimum and maximum paracentral thickness occurs in some individuals after corneal anesthesia.
authors.affiliation: Department of Anatomy and Human Embryology, Ocular Anatomy Unit, Faculty of Medicine, University of Valencia, Valencia, Spain. juan.sanchis@uv.es
authors.forename: Juan A
authors.initials: JA
authors.lastname: Sanchis-Gimeno
authors.forename: José M
authors.initials: JM
authors.lastname: Palanca-Sanfrancisco
authors.forename: Santiago
authors.initials: S
authors.lastname: García-Lázaro
authors.forename: David
authors.initials: D
authors.lastname: Madrid-Costa
authors.forename: Alejandro
authors.initials: A
authors.lastname: Cerviño
mesh_terms: D000287:Administration, Topical; D000779:Anesthetics, Local / Q000008:administration & dosage*; D003315:Cornea / Q000187:drug effects* / Q000473:pathology*; D019781:Corneal Topography; D058453:Emmetropia; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects / Q000502:physiology; D008297:Male; D009883:Ophthalmic Solutions; D011343:Procaine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D011446:Prospective Studies; D014065:Tonometry, Ocular; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D009883:Ophthalmic Solutions; D011343:Procaine; C005298:benoxinate