title: Resistance force for intraocular lens insertion through lens cartridges and syringe-type injectors.
abstract: OBJECTIVE
  To measure and compare the resistance force for intraocular lens (IOL) insertion using 5 syringe-type injector systems.
  
  
  METHODS
  Tokyo Medical University and laboratory in Kowa Co., Tokyo, Japan.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  Intraocular lenses were inserted into the lens capsular bag of porcine eyes after phacoemulsification using 5 implantation systems (Groups A, B, C, D, and E). For each system, the resistance force for IOL insertion to the lens capsular bag of porcine eyes was measured using an automated force gauge system. For control, the resistance force for IOL delivery into a plastic dish was measured. Changes in the resistance force and its curve and maximum value were evaluated. The mean total area under the curve (AUC) was compared. Data were statistically analyzed.
  
  
  RESULTS
  For all groups, the mean resistance forces were 17.2, 6.3, 4.2, 20.7, and 2.3 newtons (N), respectively, in porcine eyes, and 14.4, 5.8, 4.5, 12.6, and 2.2 N in controls. The mean sizes of the total AUC were 43 371, 8465, 6771, 30 306, and 2334 pixels in porcine eyes and 40 940, 7080, 6876, 20 710, and 2215 pixels in controls; the correlation coefficients between the resistance forces and the sizes of the total area were 0.576, 0.113, 0.346, 0.726, and 0.933 in porcine eyes and 0.707, 0.557, 0.914, 0.951, and 0.893 in controls.
  
  
  CONCLUSIONS
  Resistance force and its curve were clarified in 5 IOL implantation systems. Appropriate IOL and injector selection may be achieved after clarifying resistance force and its waveform during IOL insertion.
  
  
  BACKGROUND
  Neither author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: From Tokyo Medical University (Usui) and the Eye Institute (Tanaka), Ebisu Clinic Ganka, Tokyo, Japan. Electronic address: gakucho@tokyo-med.ac.jp.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Usui
authors.affiliation: From Tokyo Medical University (Usui) and the Eye Institute (Tanaka), Ebisu Clinic Ganka, Tokyo, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D003187:Compliance / Q000502:physiology*; D055119:Elastic Modulus / Q000502:physiology*; D007903:Lens Capsule, Crystalline / Q000502:physiology / Q000601:surgery*; D019654:Lens Implantation, Intraocular / Q000295:instrumentation*; D007910:Lenses, Intraocular; D023421:Models, Animal; D018918:Phacoemulsification; D011312:Pressure; D013552:Swine; D014160:Transducers, Pressure