Comparison of the maximum applicable stretch force after femtosecond laser–assisted and manual anterior capsulotomy

PurposeTo objectively measure the strength of the capsulotomy performed with a femtosecond laser-assisted technique or performed manually in a pig-eye laboratory study.SettingInternational Vision Correction Research Centre, Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany.DesignExperimental study.MethodsTen fresh pig eyes were randomly assigned to femtosecond laser–assisted capsulotomy or manual capsulotomy. The capsule was immersed in hyaluronic acid, and retractors were fixed in the capsule opening with a pull-force measuring device. The force necessary to break the capsulotomy was measured in millinewtons (mN); the maximum stretching ratio was also assessed.ResultsThe observed mean rupture force (ie, maximum amount of force measured immediately before tissue rupture) was 113 mN ± 12 (SD) in the laser-assisted procedure and 73 ± 22 mN in the manual procedure (P<.05). The stretching ratios were 1.60 ± 0.10 (femtosecond) and 1.35 ± 0.04 (manual) (P<.05).ConclusionIn this laboratory pig-eye study, femtosecond laser–assisted capsulotomy resulted in a significantly stronger anterior capsule opening than the standard manually performed capsulotomy.Financial DisclosureDrs. Auffarth, Reddy, and Holzer have received research and travel grants from Technolas Perfect Vision GmbH. Mr. Ritter is an employee of Technolas Perfect Vision GmbH, Munich, Germany.