title: Endothelial cell damage after cataract surgery: divide-and-conquer versus phaco-chop technique.
abstract: OBJECTIVE
  To compare endothelial cell damage during cataract surgery performed using the divide-and-conquer or phaco-chop nuclear fracturing technique.
  
  
  METHODS
  Department of Ophthalmology, Frederiksberg University Hospital, Frederiksberg, Denmark.
  
  
  METHODS
  In a prospective study, 60 eyes of 60 patients were randomly assigned to 1 of 2 groups (30 eyes each group) based on the phacoemulsification technique used: phaco chop or divide and conquer. During surgery, phaco time, phaco power, irrigation volume, and grade of nuclear firmness were recorded. The endothelial cell density, variation in endothelial cell size, percentage of hexagonal cells, and central corneal thickness (CCT) were recorded at baseline and 3 and 12 months postoperatively. Sample size was based on a power calculation (power 0.90, P = .05, clinically important difference = 300 cells/mm2).
  
  
  RESULTS
  Significantly less phaco power was used during phaco-chop surgery than during divide-and-conquer surgery. Postoperatively, both groups had a significant but equal decrease in cell density. There were no statistically significant changes in variation in endothelial cell size, percentage of hexagonal cells, or CCT. Visual acuity increased significantly and equally in the 2 groups. Higher endothelial cell loss was significantly correlated with shorter axial length.
  
  
  CONCLUSIONS
  It has been suggested that the phaco-chop technique is less harmful to the corneal endothelium than the divide-and-conquer technique because it uses less phaco power. The findings did not support this hypothesis as similar and low cell loss was observed in the 2 groups.
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: Norregaard
authors.forename: Shakil
authors.initials: S
authors.lastname: Ahmed
authors.forename: Thomas
authors.initials: T
authors.lastname: Storr-Paulsen
authors.forename: Tina Hyldebrandt
authors.initials: TH
authors.lastname: Pedersen
mesh_terms: D000368:Aged; D002452:Cell Count; D003316:Corneal Diseases / Q000209:etiology; D004728:Endothelium, Corneal / Q000473:pathology*; D006801:Humans; D019654:Lens Implantation, Intraocular; D018918:Phacoemulsification / Q000009:adverse effects / Q000379:methods*; D011446:Prospective Studies; D014792:Visual Acuity