title: Corneal endothelial cell loss during phacoemulsification: bevel-up versus bevel-down phaco tip.
abstract: OBJECTIVE
  To compare corneal endothelial cell loss during cataract extraction by phacoemulsification with 2 different phaco-tip positions.
  
  
  METHODS
  Ophthalmic Research Center and Department of Ophthalmology, Labbafinejad Medical Center, Shahid Beheshti Medical University, Tehran, Iran.
  
  
  METHODS
  Randomized clinical trial.
  
  
  METHODS
  Eyes scheduled for cataract extraction were randomly assigned stop-and-chop phacoemulsification with the phaco tip in the conventional bevel-up position or with the phaco tip in the bevel-down position. During surgery, the effective phacoemulsification time (EPT) was recorded. Preoperative endothelial cell parameters were compared with measurements taken 3 months postoperatively.
  
  
  RESULTS
  Each group comprised 30 eyes (30 patients). There were no statistically significant differences in age, sex, anterior chamber depth, axial length, or EPT between the 2 groups. The mean preoperative endothelial cell density (ECD) was 2544 cells/mm(2) ± 64 (SD) in the bevel-up group and 2471 ± 59 cells/mm(2) in the bevel-down group (P=.610). Postoperatively, both groups had a significant decrease in ECD. The mean endothelial cell loss was 5.9% in the bevel-up group and 13.6% in the bevel-down group (P=.012). The percentage of hexagonal cells and coefficient of variation in cell size were not different between the 2 groups preoperatively or postoperatively; however, after surgery, there was a significant decrease in the percentage of hexagonal cells in both groups.
  
  
  CONCLUSIONS
  Corneal endothelial cell loss during phacoemulsification was significantly higher when the phaco tip was in the bevel-down position than in the conventional bevel-up position.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: Ophthalmic Research Center and Department of Ophthalmology, Labbafinejad Medical Center, Shahid Beheshti Medical University, Tehran, Iran. amirfaramarzy@yahoo.com
authors.forename: Amir
authors.initials: A
authors.lastname: Faramarzi
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Javadi
authors.forename: Farid
authors.initials: F
authors.lastname: Karimian
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Jafarinasab
authors.forename: Alireza
authors.initials: A
authors.lastname: Baradaran-Rafii
authors.forename: Fariba
authors.initials: F
authors.lastname: Jafari
authors.forename: Mehdi
authors.initials: M
authors.lastname: Yaseri
mesh_terms: D000368:Aged; D002452:Cell Count; D055954:Corneal Endothelial Cell Loss / Q000209:etiology* / Q000473:pathology; D004728:Endothelium, Corneal / Q000473:pathology; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D019654:Lens Implantation, Intraocular; D008297:Male; D018918:Phacoemulsification / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods*; D011183:Postoperative Complications; D011446:Prospective Studies; D014065:Tonometry, Ocular; D014792:Visual Acuity / Q000502:physiology