title: Surface roughness of intraocular lenses with different dioptric powers assessed by atomic force microscopy.
abstract: OBJECTIVE
  To analyze the optic surface roughness and morphology of 2 types of hydrophobic acrylic intraocular lenses (IOLs) with various dioptric powers using atomic force microscopy (AFM).
  
  
  METHODS
  Technical University of Cluj-Napoca, Faculty of Mechanics, Cluj-Napoca, Romania.
  
  
  METHODS
  Atomic force microscopy was used to characterize the topography of 2 types of hydrophobic acrylic IOLs from a single manufacturer (SN60AT and SA30AL) with dioptric powers ranging from 10.0 diopters (D) to 30.0 D. The AFM analysis was performed in contact mode using a V-shaped silicon nitride cantilever with a pyramidal tip curvature of 15 nm and a nominal spring constant of 0.2 N/m. Detailed surface characterization of the IOL optic was obtained using 6 quantitative parameters provided by the AFM software.
  
  
  RESULTS
  Five of 6 roughness parameters indicated statistically significant differences (P<.05) between IOLs with different dioptric powers, with the 10.0 D IOL in both models providing the smoothest optic surface. Between models with the same dioptric power, the SN60AT model had lower values of each surface roughness parameter than the SA30AL model.
  
  
  CONCLUSIONS
  Atomic force microscopy was an accurate tool for assessing the surface properties of IOL optics. Manufacturing processes were responsible for introducing detectable differences in the topography of IOL biomaterials with identical copolymer constituents but different dioptric powers. Nanometric analysis may assist IOL manufacturers in developing IOLs with optimal surface characteristics.
authors.affiliation: GB Bietti Eye Foundation-IRCCS, Rome, Italy. mlombardo@visioeng.it
authors.forename: Marco
authors.initials: M
authors.lastname: Lombardo
authors.forename: Stefan
authors.initials: S
authors.lastname: Talu
authors.forename: Mihai
authors.initials: M
authors.lastname: Talu
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Serrao
authors.forename: Pietro
authors.initials: P
authors.lastname: Ducoli
mesh_terms: D000180:Acrylic Resins; D007910:Lenses, Intraocular; D018625:Microscopy, Atomic Force; D013499:Surface Properties
chemical_list: D000180:Acrylic Resins