title: Osmolality of various viscoelastic substances: comparative study.
abstract: OBJECTIVE
  To determine the osmolality of various viscoelastic substances.
  
  
  METHODS
  Department of Ophthalmology, Johannes Gutenberg-University, Mainz, and Institute for Medical Device Testing, Memmingen, Germany.
  
  
  METHODS
  The analysis was carried out according to the European Pharmacopoeia by means of a calibrated osmometer using the freezing-point depression method. Each syringe was analyzed as a duplicate analysis.
  
  
  RESULTS
  Mean osmolalities (mOsmol/kg) of the sodium hyaluronate viscoelastic substances were Allervisc 299; Allervisc Plus 307; Amvisc Plus 335; AMO Vitrax 284; Biolon 279; Dispasan 311; Dispasan Plus 314; Healon 295; Healon GV 312; Healon5 322; HYA-Ophtal 376; Microvisc 313; Microvisc Plus 341; Provisc 307; Rayvisc 312; Viscoat 340; Visko 296; Visko Plus 319. Mean osmolarities of the hydroxypropyl methylcellulose viscoeslatic substances were Adatocel 278; HPMC Ophtal L 358; HPMC Ophtal H 360; La Gel 317; OcuCoat 309; Visco Shield 376.
  
  
  CONCLUSIONS
  There were significant differences in osmolality among viscoelastic substances, which may explain the differences in corneal thickness after cataract surgery. A viscoelastic substance with an osmolality of 305 mOsmol/kg or slightly higher is preferable, especially in patients with a compromised corneal endothelium.
authors.affiliation: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. bdick@mail.uni-mainz.de
authors.forename: H B
authors.initials: HB
authors.lastname: Dick
authors.forename: A J
authors.initials: AJ
authors.lastname: Augustin
authors.forename: N
authors.initials: N
authors.lastname: Pfeiffer
mesh_terms: D000867:Anterior Chamber; D002387:Cataract Extraction / Q000379:methods; D003315:Cornea / Q000166:cytology / Q000187:drug effects; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000737:chemistry*; D065347:Hypromellose Derivatives; D007267:Injections; D008747:Methylcellulose / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000737:chemistry*; D009994:Osmolar Concentration; D011480:Protease Inhibitors / Q000008:administration & dosage / Q000737:chemistry; D015203:Reproducibility of Results
chemical_list: D011480:Protease Inhibitors; D065347:Hypromellose Derivatives; D006820:Hyaluronic Acid; D008747:Methylcellulose