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Experimental model for analyzing cutting resistance by various knives for cataract surgery


Dr Takeshi Ide, Bascom Palmer Eye Institute, 7101 Fairway Drive, Palm Beach Gardens, FL 33418, USA. Email:


Background:  The trend in current cataract surgery towards clear corneal incision and sutureless procedures makes us realize the importance of wound construction. For optimal surgical outcomes, we need good surgical instruments. In this study, we employed a resistance recording system to analyze the characteristics of seven commercially available disposable cataract knives and to find clues for the future development of ‘good’ cataract knives.

Methods:  The cutting resistance was recorded during perpendicular penetrations of porcine scleral tissues by cataract knives. This data was processed and analysed mathematically with MATLAB software (The MathWorks, Inc, Natick, MA, USA) to see the resistance wave shapes and their derivatives to show the products' differing characteristics.

Results:  The wave shapes demonstrated product-dependent characteristics. The average maximum penetration resistance varied from 86.4 to 233 mN. The first order time derivatives also showed distinctive wave shapes.

Conclusion:  We used an experimental model to analyze one aspect of a knife's character. This model can help give clues for future developments, although this is the initial step.