title: Comparison of capsulorhexis resistance to tearing with and without trypan blue dye using a mechanized tensile strength model.
abstract: OBJECTIVE
  To evaluate the influence of trypan blue staining on capsulorhexis tear resistance using a model for mechanical measurement of the entire capsular bag of fresh human cadaver eyes.
  
  
  METHODS
  John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  After the cornea and iris were removed, a 5.0 to 5.5 mm anterior continuous curvilinear capsulorhexis (CCC) was created; the capsule in study eyes was stained with trypan blue. The nucleus was hydroexpressed and the capsular bag was evacuated by irrigation/aspiration. Two metal shoetree-shaped fixtures were implanted separately in the capsular bag and assembled using a screw nut. After zonulectomy, the fixture-capsular bag assembly was removed from the eye and loaded onto a mechanized tester. The fixtures were separated at a velocity of 7.0 mm/min in 0.15 μm intervals to stretch the capsulorhexis to its rupture point. A graph was generated for each eye.
  
  
  RESULTS
  Ten study eyes were compared with 23 control eyes. The groups were comparable in donor age, time from death, and CCC diameter. The mean rupture load was 0.40 Newton (N) ± 0.13 (SD) in the trypan blue group and 0.39 ± 0.16 N in the control group (P=.94). The mean extension was 5.70 ± 0.99 mm and 5.85 ± 1.17 mm, respectively (P=.74).
  
  
  CONCLUSIONS
  There was no difference in CCC strength between trypan blue-stained capsules and control capsules. Staining with trypan blue did not reduce CCC tear resistance.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah 84132, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Jaber
authors.forename: Liliana
authors.initials: L
authors.lastname: Werner
authors.forename: Stan
authors.initials: S
authors.lastname: Fuller
authors.forename: Shaheen C
authors.initials: SC
authors.lastname: Kavoussi
authors.forename: Steele
authors.initials: S
authors.lastname: McIntyre
authors.forename: Michael
authors.initials: M
authors.lastname: Burrow
authors.forename: Nick
authors.initials: N
authors.lastname: Mamalis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D019923:Capsulorhexis; D004396:Coloring Agents / Q000494:pharmacology*; D004548:Elasticity / Q000502:physiology*; D006801:Humans; D007903:Lens Capsule, Crystalline / Q000187:drug effects / Q000293:injuries / Q000502:physiology*; D008875:Middle Aged; D008954:Models, Biological; D012421:Rupture; D013194:Staining and Labeling / Q000379:methods; D013314:Stress, Mechanical; D013718:Tensile Strength / Q000502:physiology*; D014019:Tissue Donors; D014343:Trypan Blue / Q000494:pharmacology*
chemical_list: D004396:Coloring Agents; D014343:Trypan Blue