title: Interaction between infrared radiation and vitreous substitutes.
abstract: OBJECTIVE
  To characterize the interaction between midintrared radiation of cutting lasers used or proposed for vitreoretinal surgery and fluid vitreous substitutes commonly used in vitreoretinal surgery.
  
  
  METHODS
  Optical transmittance of vitreous substitutes was measured with a double-beam spectrophotometer. Measurements were performed in a wide spectral range of infrared radiation, including the 2120-nm wavelength of the holmium-YAG laser and the water absorption peaks at 1440, 1930, and 2940 nm.
  
  
  RESULTS
  The wavelengths considered have a penetration depth varying from 410 to 1 microns in Ringer's solution, balanced salt citrate-buffered solution, balanced salt bicarbonated-buffered solution, hyaluronate sodium, and hydroxypropyl methylcellulose ophthalmic solution, from 2000 to 13 mm in perfluorocarbon liquid, and from 52 to 2.5 mm in silicone and fluorosilicone oils.
  
  
  CONCLUSIONS
  Midinfrared optical radiation exhibits dramatic differences of penetration depth in different vitreous substitutes. High-absorbing liquids should be used mainly with contact laser procedures and could provide a shield for remote structures. Low-absorption vitreous substitutes allow noncontact laser surgical procedures, but they also may cause direct optical damage to remote tissues. The knowledge of wavelength transmittance of vitreous substitutes is necessary to evaluate and optimize the efficacy and safety of cutting laser sources.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Scientific Institute H S. Raffaele, University of Milan, Milan, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Azzolini
authors.forename: P G
authors.initials: PG
authors.lastname: Gobbi
authors.forename: R
authors.initials: R
authors.lastname: Brancato
authors.forename: L
authors.initials: L
authors.lastname: Bosi
authors.forename: D
authors.initials: D
authors.lastname: Gallo
authors.forename: M
authors.initials: M
authors.lastname: Zelada
authors.forename: F
authors.initials: F
authors.lastname: Patelli
mesh_terms: D005466:Fluorocarbons / Q000528:radiation effects*; D006801:Humans; D006820:Hyaluronic Acid / Q000528:radiation effects*; D065347:Hypromellose Derivatives; D007259:Infrared Rays; D007552:Isotonic Solutions / Q000528:radiation effects*; D053685:Laser Therapy / Q000379:methods; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000528:radiation effects; D008953:Models, Anatomic; D009883:Ophthalmic Solutions / Q000528:radiation effects; D000077331:Ringer's Solution; D012827:Silicone Oils / Q000528:radiation effects*; D013055:Spectrophotometry, Infrared; D014822:Vitreous Body / Q000166:cytology* / Q000528:radiation effects / Q000601:surgery
chemical_list: D005466:Fluorocarbons; D007552:Isotonic Solutions; D009883:Ophthalmic Solutions; D012827:Silicone Oils; D065347:Hypromellose Derivatives; C054077:fluorosilicone oil; D000077331:Ringer's Solution; D006820:Hyaluronic Acid; D008747:Methylcellulose