title: Effect of neodymium: YAG laser on sodium hyaluronate in vitro as a model for postcapsulotomy intraocular pressure change.
abstract: OBJECTIVE
  To define one possible etiology for the rise in intraocular pressure (IOP) after neodymium: YAG (Nd:YAG) laser capsulotomy and provide information for the continued investigation of this process.
  
  
  METHODS
  Laser Center, Eye and Ear Institute, Pittsburgh, Pennsylvania.
  
  
  METHODS
  Samples of 1% sodium hyaluronate or balanced salt solution (BSS) (control) were placed in a closed system and exposed to varying amounts of Nd:YAG energy delivered by a Coherent YAG laser. This system was hydrostatically coupled to a pressure monitor, and changes in pressure were recorded as a function of time.
  
  
  RESULTS
  Average pressure increase was 0.140 mm Hg/mJ of YAG energy in the sodium hyaluronate samples and 0.017 mm Hg/mJ in BSS (P < .01). The relationship between total energy delivered and maximum pressure recorded for both substances was nearly linear. Further analysis of treated sodium hyaluronate samples showed that Nd:YAG energy can produce structural alterations.
  
  
  CONCLUSIONS
  Neodymium:YAG laser energy has a pronounced effect on sodium hyaluronate that exceeds the thermal effect seen with BSS when the pressure is monitored in a closed system. These structural changes might contribute to the IOP rise seen clinically.
authors.affiliation: Department of Ophthalmology, University of Pittsburgh, Pennsylvania 15213, USA.
authors.forename: E A
authors.initials: EA
authors.lastname: Adams
authors.forename: T C
authors.initials: TC
authors.lastname: Verstraeten
authors.forename: T R
authors.initials: TR
authors.lastname: Friberg
authors.forename: P G
authors.initials: PG
authors.lastname: Rehkopf
authors.forename: M
authors.initials: M
authors.lastname: Stefanovic-Racic
mesh_terms: D002387:Cataract Extraction; D006801:Humans; D006820:Hyaluronic Acid; D007429:Intraocular Pressure; D007552:Isotonic Solutions; D053685:Laser Therapy / Q000009:adverse effects*; D007903:Lens Capsule, Crystalline / Q000601:surgery*; D008953:Models, Anatomic; D009798:Ocular Hypertension / Q000209:etiology*; D014160:Transducers, Pressure
chemical_list: D007552:Isotonic Solutions; D006820:Hyaluronic Acid