Analysis of intraocular lens surface properties with atomic force microscopy
Marco Lombardo1, Maria P De Santo, Giuseppe Lombardo
1Department of Experimental and Clinical Medicine, University Magna Graecia, Catanzaro and Vision Engineering, Reggio, Calabria, Italy. mflombardo@libero.it
Purpose:
To analyze the surface optics of 4 currently available intraocular lenses (IOLs) with atomic force microscopy.
Setting:
Licryl Laboratory, University of Calabria, Rende, Italy.
Methods:
The surface roughness and topography of poly(methyl methacrylate) (PMMA), silicone, hydrophobic, and hydrophilic acrylic IOLs were evaluated with atomic force microscopy in contact mode. The analysis was performed in a liquid environment using cantilevers with a 0.01 Newtonw/meter nominal elastic constant. Measurements were made over areas of 10 microm2 on different locations of the posterior optic surface of the IOL.
Results:
Atomic force microscopy permitted high-resolution imaging of IOL optic surface characteristics. Surface topography showed different features with respect to the lens biomaterial. The root-mean-square roughness of the IOL optic surface was significantly different between lenses of various materials (P < .001). The hydrophobic acrylic and silicone IOLs had the lowest mean surface roughness, 3.8 nm +/- 0.2 (SD) and 4.0 +/- 0.5 nm, respectively, and the 2 PMMA IOLs had the highest mean surface roughness, 6.6 +/- 0.3 nm and 7.0 +/- 0.6 nm.
Conclusions:
Atomic force microscopy was effective and accurate in analyzing IOL optics. The surface topography of IOLs may vary with different manufacturing processes.
