AFM Study for Morphological Characteristics and Biomechanical Properties of Human Cataract Anterior Lens Capsules

Choi, Samjin; Lee, Hui-Jae; Cheong, Youjin; Shin, Jae-Ho; Jin, Kyung Hyun; Park, Hun-Kuk; Park, Young-Guk

doi:10.1002/sca.21001

Cited by 20 publications

(11 citation statements)

References 51 publications

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“…Capsular tears in FS laser assisted cataract surgery have been mainly reported to occur with hydrodissection and during lens manipulations [ 12 ], suggesting that reduced capsular distensibility may represent an additional factor to increased risk of capsular tears during FS laser assisted cataract surgery. On the other hand, there is still no evidence supporting this hypothesis [ 17 – 19 , 23 – 25 , 33 – 36 ].…”

Section: Discussionmentioning

confidence: 99%

Analysis of Femtosecond Laser Assisted Capsulotomy Cutting Edges and Manual Capsulorhexis Using Environmental Scanning Electron Microscopy

Serrao

Lombardo

Desiderio

et al. 2014

Journal of Ophthalmology

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Purpose. To investigate the structure and irregularity of the capsulotomy cutting edges created by two femtosecond (FS) laser platforms in comparison with manual continuous circular capsulorhexis (CCC) using environmental scanning electron microscopy (eSEM). Methods. Ten anterior capsulotomies were obtained using two different FS laser cataract platforms (LenSx, n = 5, and Victus, n = 5). In addition, five manual CCC (n = 5) were obtained using a rhexis forceps. The specimens were imaged by eSEM (FEI Quanta 400, OR, USA). Objective metrics, which included the arithmetic mean deviation of the surface (Sa) and the root-mean-square deviation of the surface (Sq), were used to evaluate the irregularity of both the FS laser capsulotomies and the manual CCC cutting edges. Results. Several microirregularities were shown across the FS laser capsulotomy cutting edges. The edges of manually torn capsules were shown, by comparison of Sa and Sq values, to be smoother (P < 0.05) than the FS laser capsulotomy edges. Conclusions. Work is needed to understand whether the FS laser capsulotomy edge microirregularities, not seen in manual CCC, may act as focal points for the concentration of stress that would increase the risk of capsular tear during phacoemulsification as recently reported in the literature.

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Section: Discussionmentioning

confidence: 99%

Analysis of Femtosecond Laser Assisted Capsulotomy Cutting Edges and Manual Capsulorhexis Using Environmental Scanning Electron Microscopy

Serrao

Lombardo

Desiderio

et al. 2014

Journal of Ophthalmology

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“…According to the Oliver‐Pharr method the contact stiffness can be calculated from the unloading part of the load‐indentation curve (Oliver and Pharr, ). It has been reported that the initial data of the unloading curve is almost linear for some materials, and as a result a linear fit is the most obvious solution regarding the upper portion of the curve (Fischer‐Cripps, ; Choi et al, ).…”

Section: Methodsmentioning

confidence: 99%

The effects of UV irradiation on collagen D-band revealed by atomic force microscopy

et al. 2014

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The objective of this paper was to investigate the influence of UV irradiation on collagen D-band periodicity by using the AFM imaging and nanoindentation methods. It is well known than UV irradiation is one of the main factors inducing destabilization of collagen molecules. Due to the human's skin chronic exposure to sun light, the research concerning the influence of UV radiation on collagen is of great interest. The impact of UV irradiation on collagen can be studied in nanoscale using Atomic Force Microscopy (AFM). AFM is a powerful tool as far as surface characterization is concerned, due to its ability to relate high resolution imaging with mechanical properties. Hence, high resolution images of individual collagen fibrils and load-displacement curves on the overlapping and gap regions, under various time intervals of UV exposure, were obtained. The results demonstrated that the UV rays affect the height level differences between the overlapping and gap regions. Under various time intervals of UV exposure, the height difference between overlaps and gaps reduced from ~3.7 nm to ~0.8 nm and the fibril diameters showed an average of 8-10% reduction. In addition, the irradiation influenced the mechanical properties of collagen fibrils. The Young's modulus values were reduced per 66% (overlaps) and 61% (gaps) compared to their initial values. The observed alterations on the structural and the mechanical properties of collagen fibrils are probably a consequence of the polypeptide chain scission due to the impact of the UV irradiation.

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“…Because of this, AFM is gaining popularity in ophthalmology and has been used to image other basement membranes in the eye. 1,8,9,13,24,25,46 The images obtained in the current study are similar to those acquired of other basement membranes in the eye: a dense interwoven fibrous structure separated by openings on the order of a micron.…”

Section: Discussionmentioning

confidence: 76%

Fractal Analysis of AFM Images of the Surface of Bowman’s Membrane of the Human Cornea

et al. 2014

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The objective of this study is to further investigate the ultrastructural details of the surface of Bowman's membrane of the human cornea, using atomic force microscopy (AFM) images. One representative image acquired of Bowman's membrane of a human cornea was investigated. The three-dimensional (3-D) surface of the sample was imaged using AFM in contact mode, while the sample was completely submerged in optisol solution. Height and deflection images were acquired at multiple scan lengths using the MFP-3D AFM system software (Asylum Research, Santa Barbara, CA), based in IGOR Pro (WaveMetrics, Lake Oswego, OR). A novel approach, based on computational algorithms for fractal analysis of surfaces applied for AFM data, was utilized to analyze the surface structure. The surfaces revealed a fractal structure at the nanometer scale. The fractal dimension, D, provided quantitative values that characterize the scale properties of surface geometry. Detailed characterization of the surface topography was obtained using statistical parameters, in accordance with ISO 25178-2: 2012. Results obtained by fractal analysis confirm the relationship between the value of the fractal dimension and the statistical surface roughness parameters. The surface structure of Bowman's membrane of the human cornea is complex. The analyzed AFM images confirm a fractal nature of the surface, which is not taken into account by classical surface statistical parameters. Surface fractal dimension could be useful in ophthalmology to quantify corneal architectural changes associated with different disease states to further our understanding of disease evolution.

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AFM Study for Morphological Characteristics and Biomechanical Properties of Human Cataract Anterior Lens Capsules

Cited by 20 publications

References 51 publications

Analysis of Femtosecond Laser Assisted Capsulotomy Cutting Edges and Manual Capsulorhexis Using Environmental Scanning Electron Microscopy

Analysis of Femtosecond Laser Assisted Capsulotomy Cutting Edges and Manual Capsulorhexis Using Environmental Scanning Electron Microscopy

The effects of UV irradiation on collagen D-band revealed by atomic force microscopy

Fractal Analysis of AFM Images of the Surface of Bowman’s Membrane of the Human Cornea

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