scholarly journals Assessment of the changes in corneal biomechanical properties after collagen cross-linking in patients with keratoconus

2019 ◽  
Vol 31 (3) ◽  
pp. 262-267 ◽  
Author(s):  
Ramin Salouti ◽  
Mohammad Reza Khalili ◽  
Mohammad Zamani ◽  
Maryam Ghoreyshi ◽  
M. Hossein Nowroozzadeh
Keyword(s):  
Biomechanical Properties ◽  
Cross Linking ◽  
Corneal Biomechanical Properties ◽  
Collagen Cross Linking

Impact of oral contraceptive use and menstrual phases on patellar tendon morphology, biochemical composition, and biomechanical properties in female athletes

2013 ◽  
Vol 114 (8) ◽  
pp. 998-1008 ◽  
Author(s):  
Mette Hansen ◽  
Christian Couppe ◽  
Christina S. E. Hansen ◽  
Dorthe Skovgaard ◽  
Vuokko Kovanen ◽  
...  
Keyword(s):  
Patellar Tendon ◽  
Female Athletes ◽  
Maximum Voluntary Contraction ◽  
Biomechanical Properties ◽  
Cross Sectional Area ◽  
Cross Linking ◽  
Sectional Area ◽  
Cross Sectional ◽  
Collagen Cross Linking

Sex differences exist with regards to ligament and tendon injuries. Lower collagen synthesis has been observed in exercising women vs. men, and in users of oral contraceptives (OC) vs. nonusers, but it is unknown if OC will influence tendon biomechanics of women undergoing regular training. Thirty female athletes (handball players, 18–30 yr) were recruited: 15 long-term users of OC (7.0 ± 0.6 yr) and 15 nonusers (>5 yr). Synchronized values of patellar tendon elongation (obtained by ultrasonography) and tendon force were sampled during ramped isometric knee extensor maximum voluntary contraction to estimate mechanical tendon properties. Furthermore, tendon cross-sectional area and length were measured from MRI images, and tendon biopsies were obtained for analysis of tendon fibril characteristics and collagen cross-linking. Overall, no difference in tendon biomechanical properties, tendon fibril characteristics, or collagen cross-linking was observed between the OC users and nonusers, or between the different phases of the menstrual cycle. In athletes, tendon cross-sectional area in the preferred jumping leg tended to be larger than that in the contralateral leg ( P = 0.09), and a greater absolute ( P = 0.01) and normalized tendon stiffness ( P = 0.02), as well as a lower strain ( P = 0.04), were observed in the jumping leg compared with the contralateral leg. The results indicate that long-term OC use or menstrual phases does not influence structure or mechanical properties of the patellar tendon in female team handball athletes.

scholarly journals Spatial characterization of corneal biomechanical properties with optical coherence elastography after UV cross-linking

2014 ◽  
Vol 5 (5) ◽  
pp. 1419 ◽  
Author(s):  
Michael D. Twa ◽  
Jiasong Li ◽  
Srilatha Vantipalli ◽  
Manmohan Singh ◽  
Salavat Aglyamov ◽  
...  
Keyword(s):  
Biomechanical Properties ◽  
Cross Linking ◽  
Optical Coherence ◽  
Spatial Characterization ◽  
Corneal Biomechanical Properties

Prospective one year study of corneal biomechanical changes following high intensity, accelerated cornea cross-linking in patients with keratoconus using a non-contact tonometer

2021 ◽  
pp. 112067212110697
Author(s):  
Mohammed Ziaei ◽  
Jinny J Yoon ◽  
Hans R Vellara ◽  
Akilesh Gokul ◽  
Jay J Meyer ◽  
...  
Keyword(s):  
High Intensity ◽  
High Speed ◽  
Biomechanical Properties ◽  
High Irradiance ◽  
Cross Linking ◽  
Continuous Exposure ◽  
Tertiary Referral Center ◽  
Significant Difference ◽  
Prospective Longitudinal ◽  
Corneal Biomechanical Properties

Purpose To characterize corneal biomechanical properties utilizing a dynamic ultra-high-speed Scheimpflug camera equipped with a non-contact tonometer (CorVis ST, CST) in keratoconic corneas following continuous high intensity, high irradiance corneal cross-linking. Design Prospective longitudinal single-centre study at a tertiary referral center. Methods Corneal biomechanical properties were measured in patients with progressive keratoconus undergoing high intensity (30 mW/cm2), high irradiance (5.4 J/cm2), accelerated corneal cross-linking with continuous exposure to ultraviolet-A for 4 min. CST was used to assess corneal biomechanical properties pre-operatively and at 1, 3, 6 and 12 months post-operatively. CST output videos were further analyzed using several previously reported algorithms. Results A total of 25 eyes of 25 participants were examined. The mean age of participants was 20.9 ± 5.3 years; 56% were male and 80% were of Māori or Pacific Island origin. Energy absorbed area (mN mm), was the only significantly changed parameter compared to baseline at all time points measuring 3.61 ± 1.19 preoperatively, 2.81 ± 1.15 at 1 month ( p = 0.037), 2.79 ± 0.81 ( p = 0.033) at 3 months, 2.76 ± 0.95 ( p = 0.028) at 6 months and 2.71 ± 1.18 ( p = 0.016) at 12 months. Conclusions The significant difference between the pre and post-operative energy absorbed area appears to reflect changes in corneal viscous properties that occur following corneal cross-linking.

scholarly journals Corneal Biomechanical Properties at Different Corneal Cross-Linking (CXL) Irradiances

2014 ◽  
Vol 55 (5) ◽  
pp. 2881 ◽  
Author(s):  
Arthur Hammer ◽  
Olivier Richoz ◽  
Samuel Arba Mosquera ◽  
David Tabibian ◽  
Florence Hoogewoud ◽  
...  
Keyword(s):  
Biomechanical Properties ◽  
Cross Linking ◽  
Corneal Biomechanical Properties

scholarly journals Technology of the Local Cross-linking (Part 1): Keratotensotopography and Vacuum-compression Topographic Test—New Diagnostic Possibilities for Studying the Local Biomechanical Properties of Cornea

2017 ◽  
Vol 6 (1) ◽  
pp. 14-16 ◽  
Author(s):  
SY Anisimova ◽  
AS Mistryukov ◽  
NS Anisimova ◽  
SI Anisimov
Keyword(s):  
Intraocular Pressure ◽  
Clinical Significance ◽  
Uv Irradiation ◽  
Compression Test ◽  
Biomechanical Properties ◽  
Cross Linking ◽  
Peripheral Part ◽  
Special Software ◽  
Collagen Cross Linking ◽  
Corneal Collagen

ABSTRACT Aim The aim of this study is the development and evaluation of clinical significance methodology for determining mech­anical stress (MS) and elasticity of the cornea comparable to its topographic settings. Materials and methods Combining the data of optical pachymeter, keratotopography, and pneumotonometry through our special software allows us to get Lokolink MS distribution in the cornea in the form of maps, which we propose to call keratotensotopogram (KTT). Results Normal KTT has the form of concentric, uniform, and symmetrical zones. In keratoconus (KC), the corneal center is more tense than peripheral part of cornea. The focus zone of KC may coincide with the region of maximum MS or may be out of this area. In the process of vacuum-compression test, the reaction of profile of the cornea was markedly different in patients with healthy corneas and in patients with KC. In all cases of healthy cornea, the curvature increased in the center. In KC, the cornea became more flat in the center under high intraocular pressure (in 100% of cases). Conclusion The KTT ineyes with the cornea without pathology differs from KTT in the different cases of KC. The KTT can be used for the diagnosis and prediction of cornea's state to perform the plan of UV irradiation areas for corneal collagen cross-linking. How to cite this article Anisimov SI, Anisimova SY, Mistryukov AS, Anisimova NS. Technology of the Local Cross-linking (Part 1): Keratotensotopography and Vacuum-compression Topographic Test—New Diagnostic Possibilities for Studying the Local Biomechanical Properties of Cornea. Int J Kerat Ect Cor Dis 2017;6(1):14-16.

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