Changes in intraocular lens surface roughness during cataract surgery assessed by atomic force microscopy.

PURPOSE: To analyze the changes in optic surface roughness before and after injection of various intraocular lens (IOL) models using atomic force microscopy (AFM). SETTINGS: Departments of Ophthalmology, Medical University of Graz, General Hospital Linz and University Hospital Basel; Upper Austria University, School of Applied Health and Social Sciences, Linz, Austria. DESIGN: Experimental study. METHODS: The morphology and surface roughness of 3 hydrophobic acrylic IOLs from different manufacturers were analyzed by AFM in liquid using the tapping mode. First, AFM was performed on IOLs taken from the original package without further manipulation. In a second step, under sterile conditions, an experienced cataract surgeon loaded the IOLs into the appropriate injection system and pushed them through a system resembling an IOL implantation in cataract surgery; this was followed by AFM evaluation. Finally, 3 samples of a preloaded hydrophilic acrylic IOL taken from the original cartridge were compared with 3 samples that were pushed through the implantation system. RESULTS: Comparison of the arithmetic mean, standard deviation, root mean square, and surface skewness of the IOLs before and after injection showed a significant increase in surface roughness (P<.05). CONCLUSIONS: Standard application procedures of IOLs may alter the IOL surface. Increases in the surface roughness of IOLs may influence postoperative posterior capsule opacification. Further studies are necessary to evaluate the interfacial properties of IOLs.

High-frequency electromagnetic dynamics properties of THP1 cells using scanning microwave microscopy.

Microwave measurements combined with scanning probe microscopy is a novel tool to explore high-localized mechanical and electrical properties of biological species. Complex permittivities and permeabilities are detected through slight variations of an incident microwave signal. Here we report the high-frequency dependence of the electromagnetic dynamic characteristics in human monocytic leukemia cells (THP1) through local measurements by scanning microwave microscopy (SMM). The amplitude and phase images were shown to depend on the applied resonance frequency. While the amplitude yields information about the resistivity determined by the water and the ionic strength, the phase information reflects the dielectric losses arising from the fluid density.