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R. W. Frey, E. V. Teuma, D. O’Suilleabhain, D. Elliot, G. R. Downes, Jr., G. R. Downes, III, J. Bielitzki; Evaluation of the Mechanical Properties of the Crystalline Lens Capsule Following Photodisruption Capsulotomy and Continuous Curvilinear Capsulorrhexis. Invest. Ophthalmol. Vis. Sci. 2009;50(13):1141.
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© ARVO (1962-2015); The Authors (2016-present)
The manual continuous curvilinear capsulorhexis (CCC) is currently the most frequently used technique for capsulorhexis in routine cataract surgery. Computer controlled photodissruption laser capsulotomy may be very accurate dimensionally, however, the mechanical properties of such a laser cut crystalline lens capsule are unknown. The purpose of this effort is to compare the differences in the biomechanical properties at the edges of the lens capsule following photodisruption laser capsulotomy to the manual CCC technique.
Capsulotomies were performed on 22 porcine lens specimens within 6 hours of slaughter by either photodisruption laser or manual continuous curvilinear capsulorhexis (11 per each method). Following capsulotomy the lens contents were removed by phacoemulsification. The intended CCC and laser capsulotomy diameter was 5 mm. The capsulotomy edges of the resulting capsular bag were placed on two arms of experimental setup with controlled stretching capability. One arm was connected to a load cell and the second attached to a computer-controlled stepping motor. As the stepper motor stretched the capsulotomy edge the load cell read the corresponding force applied. The test was completed when the capsulotomy edge ruptured. The magnitude of the applied force and the level of enlargement of the capsular edges before rupture, are an indication of the lens capsule’s ability to respond to surgical manipulations.
The capsulotomy edge generated by the photodisruption laser was significantly stronger compared to CCC. The mean force necessary to rupture the capsular edge was significantly greater at 177±53 mN with photodisruption laser versus 125±43 mN with CCC with a p<0.05. The mean capsular edge distention was significantly greater with laser at 7.45±0.47 mm than that following CCC at 4.68±1.01 mm with a p<0.001.
Photodisruption laser capsulotomy provides a favorable mechanical capsule and may produce a more expandable and stronger capsule edge compared to CCC and therefore may be preferable for next generation cataract surgery.
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