title: Thermal study of longitudinal and torsional ultrasound phacoemulsification: tracking the temperature of the corneal surface, incision, and handpiece.
abstract: OBJECTIVE
  To evaluate the change and difference in the corneal surface, incision, and handpiece temperatures during longitudinal and torsional ultrasound (US) phacoemulsification with standard incisions (2.75 mm) and microincisions (2.20 mm) and the thermal effect on wounds.
  
  
  METHODS
  Department of Ophthalmology, Duke University, Durham, North Carolina, USA.
  
  
  METHODS
  In this prospective study, human cadaver eyes had simulated phacoemulsification. Group 1 had a 2.75 mm incision with 100% longitudinal US; Group 2, a 2.20 mm incision with 100% longitudinal US; Group 3, a 2.75 mm incision with 100% torsional US; and Group 4, a 2.20 mm incision with 100% torsional US. During phacoemulsification, the corneal incision was evaluated by surgical microscopy and scanning electron microscopy (SEM) and images of the corneal surface, incision, and handpiece were captured with an infrared camera.
  
  
  RESULTS
  Twelve eyes (3 each group) were evaluated. The maximum incision temperature was higher in the longitudinal groups than in the torsional groups. With the same US modality, the maximum microincision temperature was higher than the maximum standard incision temperature. After application of full power for 40 seconds, wound burn was observed in all eyes in the longitudinal groups and no eyes in the torsional groups. On SEM, there was more extensive loss of Descemet membrane in the longitudinal groups than in the torsional groups.
  
  
  CONCLUSIONS
  Incision temperature was influenced by US modality and was significantly lower with torsional US than with longitudinal US. Using torsional US with smaller incisions may decrease the risk for wound burn in eyes with denser cataracts.
authors.affiliation: Duke University Eye Center, Durham, North Carolina 27710-3802, USA.
authors.forename: Bokkwan
authors.initials: B
authors.lastname: Jun
authors.forename: John P
authors.initials: JP
authors.lastname: Berdahl
authors.forename: Terry
authors.initials: T
authors.lastname: Kim
mesh_terms: D000368:Aged; D001831:Body Temperature / Q000502:physiology*; D003315:Cornea / Q000502:physiology* / Q000648:ultrastructure; D006358:Hot Temperature; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D018918:Phacoemulsification / Q000295:instrumentation / Q000379:methods*; D011446:Prospective Studies; D013817:Thermography; D014019:Tissue Donors; D014945:Wound Healing