scholarly journals Analysis of Accommodation Gain of Presbyopia Eye After Laser Ablation (or Shrinkage) of Sclera Via Lens Reshaping and Lens Anterior Shift

2021 ◽  
pp. 13-22
Author(s):  
Jui-Teng Lin
Keyword(s):  
Laser Ablation ◽  
Ciliary Body ◽  
Measured Data ◽  
Thermal Shrinkage ◽  
Accommodative Response ◽  
Eye Model ◽  
Average Value ◽  
Component Theory ◽  
Taipei City ◽  
Rate Functions

Purpose: To derive and provide analytic formulas for an accommodative gain of presbyopia eyes. via sclera ablation and/or thermal shrinkage such that the lens is reshaped and/or its position is shifted. New mechanisms are also proposed. Study Design: To increase the accommodation of presbyopia. Place and Duration of Study: New Taipei City, Taiwan, between June 2021 and July 2021. Methodology: Accommodation gain is calculated by a 4-component theory, in which the rate functions are derived by an effective eye model for the change of anterior curvature of the lens and its anterior shift. The measured data of accommodative response of the lens versus the lens curvature change and anterior shift are analyzed. The measured net change of the posterior vitreal zonules (PVZ) length and the space between the ciliary body and lens (CLS) during the accommodation are also analyzed. Results: The accommodative gain (AG) is mainly due to the change of lens anterior curvature and its anterior shift. The AG per diopter change of the reshaped lens is 0.62 to 0.68 by our formulas, comparing to the measured average value M'=0.69.The efficacy of LASA (or AG) is proportional to the amount of scleral tissue removed (or shrinkaged), such that more space is produced for the change of PVZ and CLS from a UCS to AS for accommodation. Conclusion: The AG is proportional to the amount of scleral tissue removed (or shrinkaged), such that more space is produced for the change of PVZ and CLS from a UCS to AS for accommodation.

scholarly journals Analysis of Accommodation Gain of Presbyopia Eye after Laser Ablation (or Shrinkage) of Sclera via Lens Reshaping and Anterior Shift

2021 ◽  
Author(s):  
Jui-Teng Lin
Keyword(s):  
Laser Ablation ◽  
Ciliary Body ◽  
Measured Data ◽  
Thermal Shrinkage ◽  
Accommodative Response ◽  
Eye Model ◽  
Average Value ◽  
Component Theory ◽  
Taipei City ◽  
Rate Functions

Purpose: To derive and provide analytic formulas for accommodative gain of presbyopia eyes. via sclera ablation and/or thermal shrinkage such that lens is reshaped an/or its positon is shifted. New mechanisms are also proposed. Study Design: To increased accommodation of presbyopia. Place and Duration of Study: New Taipei City, Taiwan, between June, 2021 and July, 2021. Methodology: Accommodation gain is calculated by a 4-component theory, in which the rate functions are derived by an effective eye model for the change of anterior curvature of the lens and its anterior shift. The measured data of accommodative response of the lens versus the lens curvature change and anterior shift are analyzed. The measured net change of the posterior vitreal zonules (PVZ) length and the space between the ciliary body and lens (CLS) during the accommodation are also analyzed. Results: The accommodative gain (AG) is mainly due the change of lens anterior curvature and its anterior shift. The AG per diopter change of the reshaped lens is 0.62 to 0.68 by our formulas, comparing to the measured average value M'=0.69. The efficacy of LASA (or AG) is proportional to the amount of scleral tissue removed (or shrinkaged), such that more space is produced for the change of PVZ and CLS from a UCS to AS for accommodation. Conclusion: The AG is proportional to the amount of scleral tissue removed (or shrinkaged), such that more space is produced for the change of PVZ and CLS from a UCS to AS for accommodation.

scholarly journals Corneal changes induced by laser ablation: study of the visual-quality evolution by a customized eye model

2006 ◽  
Vol 53 (11) ◽  
pp. 1605-1618
Author(s):  
D. Ortiz ◽  
R. G. Anera ◽  
J. M. Saiz ◽  
J. R. Jiménez ◽  
F. Moreno ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Visual Quality ◽  
Eye Model ◽  
Ablation Study

scholarly journals Improvement of Automatic Measurement Evaluation System for Subway Structures by Adjacent Excavation

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7492
Author(s):  
Jung-Youl Choi ◽  
Sun-Hee Kim ◽  
Ho-Hyun Lee ◽  
Jee-Seung Chung
Keyword(s):  
Statistical Analysis ◽  
Evaluation System ◽  
Automatic Measurement ◽  
Measured Data ◽  
Automated Measurement ◽  
Method Evaluation ◽  
Average Value ◽  
Measurement Evaluation ◽  
Measurement Methodology ◽  
Track Deformation

This study evaluated the structural stability of subway structures based on adjacent excavations by comparing automatically measured and numerically analyzed data. The reliability of the automated measurement methodology was evaluated by first applying probability statistical analysis to the measured results and then comparing these results with the numerically analyzed results. An improvement in the calculation method evaluation system, including the method of processing and analysis of the automatically measured data of subway structures through the average value of probability density, was proposed. As a result of the field measurement and numerical analysis, the measured results of tunnel displacement and track deformation exhibited some differences. However, it was determined that the construction stage and location where the maximum values of the tunnel displacement and track deformation occurred had similarities.

scholarly journals Principles of Accommodation and Technology Update of Presbyopia Corrections using IR and UV Lasers

2021 ◽  
pp. 17-28
Author(s):  
Jui-Teng Lin
Keyword(s):  
Clinical Outcomes ◽  
Thermal Shrinkage ◽  
Key Factors ◽  
Improved Outcomes ◽  
New Directions ◽  
Taipei City ◽  
Key Issues ◽  
Property Changes ◽  
Uv Lasers ◽  
Index Size

Purpose: To update and review the technology and principles of laser presbyopia reversal (LAPR) via sclera ablation and thermal shrinkage using infrared and UV lasers. Recent clinical data and new methods are also summarized. Study Design: LAPR using laser sclera ablation for increased accommodation of presbyopic eyes. Place and Duration of Study: New Taipei City, Taiwan, between June, 2021 and July, 2021. Methodology: Accommodation gain was obtained by laser scleral ablation of an eye using Er:YAG laser (at 2.94 um) using either line-pattern or dots-pattern outside the limbus in the oblique quadrants of an eye. The principles of accommodation and the key factors influencing the outcomes are discussed. The accommodation gain (AG) after the surgery is mainly due the change in anterior curvature and anterior shift of the lens. The effectiveness of ciliary body contraction for lens relaxation (or accommodation) may be influenced by the combined aging factors, including lens property changes (index, size, thickness and curvature), tissue elastic changes (in sclera and ciliary) and the zonular tension change. Classical theories of accommodation include Helmholtz and Schachar hypothesis. The key issues and new directions to overcome the drawbacks of the existing LAPR procedure (based on scleral ablation) are proposed. Clinical outcomes from two major groups, SurgiLight and Ace Vision, with two years follow are summarized. Results: Clinical outcomes during 2000 to 2020 are summarized showing an average Accommodation gain about 2.0 D, and postoperative egression about 0.25 D (after two years). Conclusion: Laser presbyopia reversal (LAPR) via sclera ablation using infrared laser is safe and effective, but suffers drawbacks of being invasive and procedures are too slow. New directions are required for improved outcomes.

scholarly journals EVALUATION OF IRIDOCILIARY AND LENTICULAR ELASTICITY USING SHEAR-WAVE ELASTOGRAPHY IN RABBIT EYES

2014 ◽  
Vol 57 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Efstathios T. Detorakis ◽  
Eleni E. Drakonaki ◽  
Harilaos Ginis ◽  
Nikolaos Karyotakis ◽  
Ioannis G. Pallikaris
Keyword(s):  
Shear Wave ◽  
Ciliary Body ◽  
Ex Vivo ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Shear Wave Elastography ◽  
Ultrasound Elastography ◽  
Eye Model ◽  
Rabbit Eye

Introduction: A previous study has employed shear-wave ultrasound elastographic imaging to assess corneal rigidity in an ex-vivo porcine eye model. This study employs the same modality in vivo in a rabbit eye model in order to assess lens, ciliary body and total ocular rigidity changes following the instillation of atropine and pilocarpine. Methods: Ten non-pigmented female rabbits were examined. Measurements of the lens, ciliary body and total ocular rigidity as well as lens thickness and anterior chamber depth were taken with the Aixplorer system (SuperSonic Imagine, Aix-en-Provence, France) with the SuperLinear™ SL 15-4 transducer in both eyes at baseline as well as after pilocarpine and atropine instillation. The IOP was also measured with the TonoPen tonometer. Results: Changes in rigidity in the examined areas following atropine instillation were statistically not significant. Ciliary body rigidity was significantly increased whereas lens and total ocular rigidity were significantly reduced following pilocarpine instillation. The decrease in lens rigidity following pilocarpine was significantly associated with the respective increase in ciliary body rigidity. Conclusions: Shear-wave ultrasound elastography can detect in vivo rigidity changes in the anterior segment of the rabbit eye model and may potentially be applied in human eyes, providing useful clinical information on conditions in which rigidity changes play an important role, such as glaucoma, pseudoexfoliation syndrome or presbyopia.

Fabrication and characterization of mixed thin-/thick-film thermoelectric microgenerator based on constantan/chromium and silver arms

2020 ◽  
Vol 37 (2) ◽  
pp. 109-114
Author(s):  
Mirosław Gracjan Gierczak ◽  
Eugeniusz Prociów ◽  
Andrzej Dziedzic
Keyword(s):  
Laser Ablation ◽  
Seebeck Coefficient ◽  
Thick Film ◽  
Content Type ◽  
Average Value ◽  
Laser Ablation Process ◽  
Fabrication And Characterization ◽  
Copper Nickel Alloy ◽  
Screen Printing Technology

Purpose This paper aims to focus on the fabrication and characterization of mixed thin-/thick-film thermoelectric microgenerators, based on magnetron sputtered constantan (copper–nickel alloy) and screen-printed silver. To improve the adhesion of the constantan layer to the applied substrates, the additional chromium sublayer was used. The aim of the study was to investigate the influence of chromium sublayer on the electrical and thermoelectric properties of such hybrid microgenerators. Design/methodology/approach Fabrication of such structures consisted of several steps – magnetron sputtering of the chromium and then constantan layer, exposing the first arms of thermocouples, applying the second arms by screen-printing technology and firing the prepared structures in a belt furnace. The structures were made both on Al2O3 (alumina) and low temperature co-fired ceramics (LTCC) substrates. Findings To the best of the authors’ knowledge, for the first time, laser ablation process was applied to fabricate the first arms of thermocouples from a layer of constantan only or constantan with a chromium sublayer. Geometric measurements have shown that the mapping of mask pattern by laser ablation technique is very accurate. Originality/value The determined Seebeck coefficient of the realized structures was about 40.4 µV/K. After firing the exemplary structures at 850°C peak temperature, Seebeck coefficient is increased to an average value of 51 µV/K.

Observations on the growth of YBa2Cu3O7-δ thin films on MgO by pulsed-laser ablation

1991 ◽  
Vol 49 ◽  
pp. 1068-1069
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Laser Ablation ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Laser Ablation Process ◽  
Deposition Parameters

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.

153: Successful Gold Nanoshell Assisted Laser Ablation of Prostate Carcinoma in Vitro

2007 ◽  
Vol 177 (4S) ◽  
pp. 52-52
Author(s):  
Joshua M. Stem ◽  
Jer-Tsang Hsieh ◽  
Sangtae Park ◽  
Yair Lotan ◽  
Jeffrey A. Cadeddu
Keyword(s):  
Laser Ablation ◽  
Prostate Carcinoma ◽  
Gold Nanoshell
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