title: The influence of viscoelastic substances on the corneal endothelial cell population during cataract surgery: a prospective study of cohesive and dispersive viscoelastics.
abstract: OBJECTIVE
  To compare the ability of cohesive and dispersive ophthalmic viscoelastic devices (OVDs) to protect the corneal endothelium following in-the-bag phacoemulsification with implantation of a foldable posterior chamber intraocular lens (IOL).
  
  
  METHODS
  In a prospective single-masked randomized study, 60 eyes of 60 cataract patients were assigned to three groups of 20 patients each, according to which OVD was used: Celoftal, Vitrax or Healon. The corneal response to surgery was evaluated by measuring the endothelial cell loss, the variation in mean cell area of the endothelial cells (CV), the frequency of hexagonal cells, and the central corneal thickness. Data were recorded preoperatively and 3 months postoperatively.
  
  
  RESULTS
  Preoperatively, no significant difference was observed in cell count, CV, hexagonal pattern or pachymetry among groups. Postoperatively, all three groups had a significant decrease in cell count, but the decrease was significantly less in the Vitrax group (6.97%) than in the Celoftal (18.03%) and Healon groups (18.46%). No changes in CV, hexagonality or corneal thickness were observed within any of the three groups or among the groups. There was an equal and significant increase in visual acuity.
  
  
  CONCLUSIONS
  Phacoemulsification with implantation of a posterior chamber lens is known to affect the density and morphology of corneal endothelial cells. Viscoelastics facilitate cataract surgery and protect the corneal endothelium during the procedure. Choosing a dispersive hyaluronate OVD during the phaco procedure may allow for protection of the endothelial cells while suppressing the formation of free radicals. This may be the reason for the superior protective effect on the corneal endothelial cells of Vitrax compared with Celoftal and Healon.
authors.affiliation: Department of Ophthalmology, Frederiksberg University Hospital, Frederiksberg, Denmark. allanstorr@dadlnet.dk
authors.forename: Allan
authors.initials: A
authors.lastname: Storr-Paulsen
authors.forename: Jens Christian
authors.initials: JC
authors.lastname: Nørregaard
authors.forename: Ghassan
authors.initials: G
authors.lastname: Farik
authors.forename: Jens
authors.initials: J
authors.lastname: Tårnhøj
mesh_terms: D000368:Aged; D002452:Cell Count; D004728:Endothelium, Corneal / Q000187:drug effects* / Q000473:pathology; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000627:therapeutic use*; D019654:Lens Implantation, Intraocular; D008297:Male; D008747:Methylcellulose / Q000627:therapeutic use*; D018918:Phacoemulsification; D011446:Prospective Studies; D016037:Single-Blind Method
chemical_list: D006820:Hyaluronic Acid; D008747:Methylcellulose