title: Superior Rim Stability of the Lens Capsule Following Manual Over Femtosecond Laser Capsulotomy.
abstract: Cataract surgery requires the removal of a circular segment of the anterior lens capsule (LC) by manual or femtosecond laser (FL) capsulotomy. Tears in the remaining anterior LC may compromise surgical outcome. We investigated whether biophysical differences in the rim properties of the LC remaining in the patient after manual or FL capsulotomy (FLC) lead to different risks with regard to anterior tear formation.
  
  
  
  Lens capsule samples obtained by either continuous curvilinear capsulorhexis (CCC) or FLC were investigated by light microscopy, laser scanning confocal microscopy, and scanning electron microscopy; atomic force microscopy (AFM) was used to test the biomechanical properties of the LC. The mechanical stability of the LC following either of the two capsulotomy techniques was simulated by using finite-element modeling.
  
  
  
  Continuous curvilinear capsulorhexis produced wedge-shaped, uniform rims, while FLC resulted in nearly perpendicular, frayed rims with numerous notches. The LC is composed of two sublayers: a stiff epithelial layer that is abundant with laminin and a softer anterior chamber layer that is predominantly made from collagen IV. Computer models show that stress is uniformly distributed over the entire rim after CCC, while focal high stress concentrations are observed in the frayed profiles of LC after FLC, making the latter procedure more prone to anterior tear formation.
  
  
  
  Finite-element modeling based on three-dimensional AFM maps indicated that CCC leads to a capsulotomy rim with higher stress resistance, leading to a lower propensity for anterior radial tears than FLC.
authors.affiliation: Department of Ophthalmology, University of Basel, Basel, Switzerland.
authors.forename: Magaly
authors.initials: M
authors.lastname: Reyes Lua
authors.affiliation: Biozentrum and the Swiss Nanoscience Institute, Basel, Switzerland.
authors.forename: Philipp
authors.initials: P
authors.lastname: Oertle
authors.affiliation: Zivildienst Basel-Stadt, Basel, Switzerland.
authors.forename: Leon
authors.initials: L
authors.lastname: Camenzind
authors.affiliation: Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Goz
authors.affiliation: Pallas Klinik, Aarau, Switzerland.
authors.forename: Carsten H
authors.initials: CH
authors.lastname: Meyer
authors.affiliation: Department of Ophthalmology, University of Basel, Basel, Switzerland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Konieczka
authors.affiliation: Biozentrum and the Swiss Nanoscience Institute, Basel, Switzerland.
authors.forename: Marko
authors.initials: M
authors.lastname: Loparic
authors.affiliation: Department of Ophthalmology, University of Basel, Basel, Switzerland.
authors.forename: Willi
authors.initials: W
authors.lastname: Halfter
authors.affiliation: Department of Ophthalmology, University of Basel, Basel, Switzerland 6Winterthur Cantonal Hospital, Winterthur, Switzerland 7Centro Ticinese di Chirurgia Ambulatoriale Avanti, Lugano, Switzerland.
authors.forename: Paul Bernhard
authors.initials: PB
authors.lastname: Henrich
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D057866:Anterior Capsule of the Lens / Q000503:physiopathology / Q000601:surgery / Q000648:ultrastructure*; D001696:Biomechanical Phenomena; D019923:Capsulorhexis / Q000379:methods*; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D008297:Male; D018625:Microscopy, Atomic Force; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D055815:Young Adult