scholarly journals Assessing the biomechanical properties of the porcine crystalline lens as a function of intraocular pressure with optical coherence elastography

2018 ◽  
Vol 9 (12) ◽  
pp. 6455 ◽  
Author(s):  
Chen Wu ◽  
Salavat R. Aglyamov ◽  
Zhaolong Han ◽  
Manmohan Singh ◽  
Chih-Hao Liu ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Crystalline Lens ◽  
Biomechanical Properties ◽  
Optical Coherence

Characterization of biomechanical properties of crystalline lens using Brillouin microscopy and optical coherence elastography

2020 ◽  
Author(s):  
Yogeshwari Ambekar ◽  
Manmohan Singh ◽  
Jitao Zhang ◽  
Achuth Nair ◽  
Salavat R. Aglyamov ◽  
...  
Keyword(s):  
Crystalline Lens ◽  
Biomechanical Properties ◽  
Optical Coherence

scholarly journals Probing biomechanical properties of the cornea with air-puff-based techniques – an overview

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Patryk Mlyniuk ◽  
Ewa Maczynska-Walkowiak ◽  
Jagoda Rzeszewska-Zamiara ◽  
Ireneusz Grulkowski ◽  
Bartlomiej J. Kaluzny
Keyword(s):  
Intraocular Pressure ◽  
Mechanical Load ◽  
Accurate Determination ◽  
Anterior Segment ◽  
External Environment ◽  
Standard Technique ◽  
Biomechanical Properties ◽  
Corneal Biomechanics ◽  
Optical Methods ◽  
Optical Coherence

Abstract The cornea is a part of the anterior segment of the eye that plays an essential optical role in refracting the light rays on the retina. Cornea also preserves the shape of an eyeball and constitutes a mechanical barrier, protecting the eye against the factors of the external environment. The structure of the cornea influences its biomechanical properties and ensures appropriate mechanical load transfer (that depends on the external environment and the intraocular pressure) while maintaining its shape (to a certain extent) and its transparency. The assessment of the corneal biomechanics is important in clinical ophthalmology, e.g. in the diagnosis of ectatic corneal diseases, for precise planning of the refractive surgery, and in accurate determination of the intraocular pressure. A standard technique to determine corneal biomechanics requires the application of well-defined mechanical stimulus (e.g. air puff) and performing simultaneous imaging of the response of the tissue to the stimulus. A number of methods to assess the biomechanical properties of the cornea have been developed, including ultrasound, magnetic resonance imaging, and optical methods as visualization modalities. Commercially available methods include the ocular response analyzer (ORA) and corneal visualization scheimpflug technology (Corvis ST). Currently advanced research is conducted using optical coherence tomography (OCT). The extension of OCT called optical coherence elastography (OCE) possesses high clinical potential due to the imaging speed, noncontact character, and high resolution of images.

scholarly journals Correlation between vaulting intraoperative and postoperative of EVO implantable Collamer lens: a retrospective study of real-time observations of vaulting using the RESCAN 700 system

2020 ◽  
Author(s):  
Nian Guan ◽  
Xiao-Nong Zhang ◽  
Wan-Jun Zhang
Keyword(s):  
Optical Coherence Tomography ◽  
Intraocular Pressure ◽  
Retrospective Study ◽  
Multivariable Analysis ◽  
Anterior Chamber Depth ◽  
Crystalline Lens ◽  
Optical Coherence ◽  
Implantable Collamer Lens ◽  
Corrected Visual Acuity ◽  
Intraoperative Optical Coherence Tomography

Abstract Background: The prediction of implantable Collamer lens (ICL) vaulting is one of the most important parameters for ICL implantation for safety, aqueous humor circulation, and lens transparency.Methods: This was a retrospective study. A RESCAN 700 was used for intraoperative observation of vaulting. Spectral-domain optical coherence tomography was used for imaging. Results: Finally, 51 patients (102 eyes) were included in the study. Compared with the eyes with normal vaulting, those with high vaulting had higher preoperative diopter values (P=0.039), lower preoperative corrected visual acuity (P=0.006), lower preoperative intraocular pressure (P=0.029), higher preoperative anterior chamber depth (P=0.004), lower preoperative crystalline lens rise (P=0.046), higher ICL spherical equivalent (P=0.030), higher intraoperative vaulting (P<0.001), and lower intraocular pressure at 1 month (P=0.045). The multivariable analysis showed that the only factors independently associated with high vaulting at 1 month after surgery was the intraoperative vaulting value (odds ratio=1.005, 95% confidence interval: 1.002-1.007, P<0.001). The intraoperative and 1-month postoperative vaulting values were correlated (R2=0.562).Conclusions: The RESCAN700 system can be used to perform intraoperative optical coherence tomography to predict the vaulting value at 1 month.

scholarly journals Elasticity Changes in the Crystalline Lens during Oxidative Damage and the Antioxidant Effect of Alpha-Lipoic Acid Measured by Optical Coherence Elastography

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 207
Author(s):  
Hongqiu Zhang ◽  
Manmohan Singh ◽  
Achuth Nair ◽  
Kirill V. Larin ◽  
Salavat R. Aglyamov
Keyword(s):  
Oxidative Damage ◽  
Young’S Modulus ◽  
Lipoic Acid ◽  
Ex Vivo ◽  
Young's Modulus ◽  
Crystalline Lens ◽  
Biomechanical Properties ◽  
Optical Coherence ◽  
Age Related ◽  
Significant Difference

Age-related cataracts are one of the most prevalent causes of visual impairment around the world. Understanding the mechanisms of cataract development and progression is essential to enable early clinical diagnosis and treatment to preserve visual acuity. Reductive chemicals are potential medicines effective on cataract treatment. In this work, we investigated the cataract-induced oxidative damage in the crystalline lens and a kind of reductant, α-lipoic acid (ALA), ability to reduce the damage. We created oxidative environment to investigate the relationship between the progression of oxidative cataract and lenticular biomechanical properties measured by dynamic optical coherence elastography in porcine crystalline lenses ex vivo. The efficacy of ALA to minimize the stiffening of the lens was also quantified. The results showed a significant increase in Young’s modulus of the lens due to the formation of the oxidative cataract. We found a statistically significant difference between Young’s modulus of the lenses stored in phosphate-buffered saline and ALA solution after incubation in H2O2 solution for 3 h (43.0 ± 9.0 kPa versus 20.7 ± 3.5 kPa, respectively). These results show that the lens stiffness increases during oxidative cataract formation, and ALA has the potential to reverse stiffening of the lens caused by oxidative damage.

scholarly journals The Use of Anterior-Segment Optical-Coherence Tomography for the Assessment of the Iridocorneal Angle and Its Alterations: Update and Current Evidence

2021 ◽  
Vol 10 (2) ◽  
pp. 231
Author(s):  
Giacinto Triolo ◽  
Piero Barboni ◽  
Giacomo Savini ◽  
Francesco De Gaetano ◽  
Gaspare Monaco ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Intraocular Pressure ◽  
Clinical Relevance ◽  
Anterior Segment ◽  
Angle Closure ◽  
Current Evidence ◽  
Optical Coherence ◽  
Iridocorneal Angle ◽  
Wide Range

The introduction of anterior-segment optical-coherence tomography (AS-OCT) has led to improved assessments of the anatomy of the iridocorneal-angle and diagnoses of several mechanisms of angle closure which often result in raised intraocular pressure (IOP). Continuous advancements in AS-OCT technology and software, along with an extensive research in the field, have resulted in a wide range of possible parameters that may be used to diagnose and follow up on patients with this spectrum of diseases. However, the clinical relevance of such variables needs to be explored thoroughly. The aim of the present review is to summarize the current evidence supporting the use of AS-OCT for the diagnosis and follow-up of several iridocorneal-angle and anterior-chamber alterations, focusing on the advantages and downsides of this technology.

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