Mihai Talu

Surface roughness of intraocular lenses with different dioptric powers assessed by atomic force microscopy

PURPOSE: 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). SETTING: 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. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Multifractal analysis of human peripapillary atrophy

Multifractal characteristics of the retinal vascular networks in healthy patients and patients with peripapillary atrophy (PPA) are compared in the paper. Segmented and skeletonized fundus images from the DRIVE database were analyzed over the image region corresponding to the macular area and over the whole image. The regional and overall multifractal characteristics of fundi could serve as further clues in detecting human PPA and for quantifying the pathological stages of PPA cases.

An Overview on Mathematical Models of Human Crystalline Lens

To describe the human crystalline lens, mathematical models are required. Advanced mathematical models are applied for human vision studies and biomechanical behavior of the crystalline lens. The accurate modeling of the crystalline lens is important in the development of intraocular lenses. This paper presents an overview of researches for human crystalline lens modeling using mathematical models.

Mathematical Analysis of the Human Crystalline Lens in Giovanzana Parametric Model

The objective of this paper is to present a mathematical analysis of the human crystalline lens in Giovanzana parametric model. This model can serve to improve computational modeling, such as finite element modeling of the human crystalline lens.