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Updated: Jun 7, 2026
A Novel Capsulorhexis Technique Using Shearing Forces with Cystotome
Published on: May 15, 2010
Mechanized model to assess capsulorhexis resistance to tearing
Liliana Werner1, Guangyao Jia, Glenn Sussman
1University of Utah, Salt Lake City, Utah, USA. liliana.werner@hsc.utah.edu
Purpose:
To evaluate a model of mechanically measuring resistance to tearing of a continuous curvilinear capsulorhexis (CCC) using the entire capsular bag of fresh human cadaver eyes isolated from the eyes after complete evacuation.
Setting:
John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.
Design:
Experimental study.
Methods:
After the cornea and iris were removed, a 5.0 to 5.5 mm anterior CCC was created. The nucleus was hydroexpressed and the capsular bag evacuated by irrigation/aspiration. A pair of metal shoetree-shaped fixtures, designed based on human lens geometric dimensions, were implanted separately in the capsular bag and assembled together with a screw nut. After complete zonulectomy, the fixture-capsular bag assembly was removed from the eye and loaded onto a mechanical tester. The fixtures were separated at a velocity of 7.0 mm/min in 0.15 μm intervals to stretch the CCC to its rupture point. Rupture load (N) and extension were measured and graphed.
Results:
Testing of 23 donor eyes a mean of 69.04 hours ± 22.72 (SD) after death showed the following mean values: CCC diameter, 5.3 ± 0.12 mm; load, 0.39 ± 0.16 N; extension at CCC tearing, 5.85 ± 1.17 mm. There was a moderately strong negative correlation between donor age and load (P = .0018).
Conclusions:
Previous mechanized methods of assessing CCC strength used excised anterior capsules or partially phacoemulsified crystalline lenses, yielding lower tension strength values. This force-displacement method may facilitate assessment of small differences between anterior capsulotomy techniques.
