title: Early effects of pars plana vitrectomy combined with intravitreal gas tamponade on corneal biomechanics.
abstract: OBJECTIVE
  To detect the early effects of pars plana vitrectomy (PPV) combined with intravitreal gas tamponade on corneal biomechanics and compare these effects of sulfur hexafluoride (SF6) and perfluropropane (C3F8).
  
  
  METHODS
  19 eyes underwent PPV with C3F8, 14 eyes underwent PPV with SF6 tamponade and 16 eyes underwent PPV without tamponade. Corneal biomechanical parameters were measured preoperatively and at the first postoperative week by an ocular response analyzer.
  
  
  RESULTS
  There were no significant differences of corneal hysteresis (CH), corneal resistance factor (CRF), corneal compensated intraocular pressure (IOPcc) and Goldmann-correlated intraocular pressure (IOPg) between the groups preoperatively. The mean CRF, IOPcc and IOPg significantly increased at the first postoperative week in the C3F8 group. In the SF6 group, CRF increased significantly but the increases in IOPcc and IOPg were not significant. In the PPV group, the increases in CRF, IOPcc and IOPg were not significant. The mean CH decreased in the C3F8, SF6 and PPV groups postoperatively but these results were not significant. No statistically significant differences were found between the changes of preoperative and postoperative CH, CRF and IOPg between the groups, but the increase in IOPcc was statistically significantly higher in the C3F8 group than the others.
  
  
  CONCLUSIONS
  SF6 and C3F8 gas tamponade may affect corneal biomechanical parameters at the early postoperative period which should be related with surgery, gas tamponade or intraocular pressure changes.
authors.affiliation: Ulucanlar Eye Research Hospital Ankara, Ankara, Turkey.
authors.forename: Mehmet Y
authors.initials: MY
authors.lastname: Teke
authors.forename: Ufuk
authors.initials: U
authors.lastname: Elgin
authors.forename: Emine
authors.initials: E
authors.lastname: Sen
authors.forename: Pinar
authors.initials: P
authors.lastname: Ozdal
authors.forename: Faruk
authors.initials: F
authors.lastname: Ozturk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena / Q000502:physiology*; D003315:Cornea / Q000502:physiology*; D058450:Endotamponade; D005260:Female; D005466:Fluorocarbons / Q000008:administration & dosage*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012164:Retinal Diseases / Q000601:surgery; D013459:Sulfur Hexafluoride / Q000008:administration & dosage*; D014065:Tonometry, Ocular; D014821:Vitrectomy; D055815:Young Adult
chemical_list: D005466:Fluorocarbons; C042852:perflutren; D013459:Sulfur Hexafluoride