title: Ultrasound energy and endothelial cell loss with stop-and-chop and nuclear preslice phacoemulsification.
abstract: OBJECTIVE
  To evaluate ultrasound (US) energy and endothelial cell loss in cataract surgery using the stop-and-chop and nuclear preslice techniques.
  
  
  METHODS
  Vision Institute, Federal University of São Paulo, São Paulo, Brazil.
  
  
  METHODS
  This prospective clinical trial comprised 43 patients (50 eyes) with senile nuclear cataract who were randomly assigned to 1 of 2 groups: stop-and-chop (n=26) or nuclear preslice (n=24). The groups were divided according to nuclear density (NO(3) NC(3) and NO(4) NC(4)) using the Lens Opacity Classification System III. A full ophthalmic examination including biometry, specular microscopy, and pachymetry was performed preoperatively and postoperatively. The following parameters were evaluated: age, anterior chamber depth, lens thickness, axial length, phaco time and power, effective phaco time (EPT), infusion volume, ocular inflammation, endothelial cell loss, and best corrected visual acuity (BCVA).
  
  
  RESULTS
  Phacoemulsification time, power, and EPT were significantly higher in the stop-and-chop group. Infusion volumes did not vary significantly between the groups. A significant decrease in endothelial cell density occurred postoperatively and was similar with both techniques (stop-and-chop, 8.70%; nuclear preslice, 8.72%). The BCVA improved significantly in both groups. No significant correlations were found between endothelial cell loss and either technique.
  
  
  CONCLUSIONS
  Ultrasound energy consumption was lower with the nuclear preslice technique. Both techniques had similar results including endothelial cell loss.
authors.affiliation: Vision Institute, Federal University of São Paulo, São Paulo, Brazil. pereiraa@terra.com.br
authors.forename: Ana Cláudia A
authors.initials: AC
authors.lastname: Pereira
authors.forename: Francisco
authors.initials: F
authors.lastname: Porfírio
authors.forename: Lincoln Lemes
authors.initials: LL
authors.lastname: Freitas
authors.forename: Rubens
authors.initials: R
authors.lastname: Belfort
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002452:Cell Count; D003316:Corneal Diseases / Q000209:etiology*; D004728:Endothelium, Corneal / Q000473:pathology*; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D008297:Male; D008875:Middle Aged; D018918:Phacoemulsification / Q000379:methods*; D011183:Postoperative Complications; D011446:Prospective Studies; D013010:Sonication / Q000009:adverse effects*; D013997:Time Factors; D014792:Visual Acuity