Crystalline lens transmittance spectra and pupil sizes as factors affecting light‐induced melatonin suppression in children and adults

2021 ◽  
Author(s):  
Taisuke Eto ◽  
Michihiro Ohashi ◽  
Kotaro Nagata ◽  
Nakyeong Shin ◽  
Yuki Motomura ◽  
...  
Keyword(s):  
Crystalline Lens ◽  
Factors Affecting ◽  
Transmittance Spectra ◽  
Melatonin Suppression ◽  
Lens Transmittance

​Short-term changes in and preoperative factors affecting vaulting after posterior chamber phakic Implantable Collamer Lens implantation

2020 ◽  
Author(s):  
Qiujian Zhu ◽  
Wen-Jing Chen ◽  
Wei-Jian Zhu ◽  
Hai-Xiang Xiao ◽  
Man-Hui Zhu ◽  
...  
Keyword(s):  
Multiple Regression ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Crystalline Lens ◽  
Stepwise Multiple Regression ◽  
Multiple Regression Equation ◽  
Posterior Chamber ◽  
Key Factors ◽  
Implantable Collamer Lens ◽  
Factors Affecting

Abstract Background: To describe the very early changes in vault in the first month after Implantable Collamer Lens (ICL) implantation and to evaluate the effect of preoperative biometric factors on vault.Methods: A total of 83 eyes from 83 subjects with complete data who met follow-up requirements were recruited in this retrospective study between May 2019 and March 2020. We quantitatively assessed postoperative vault at 2 hours, 1 day, 1 week, and 1 month following implantation. Associations between postoperative vault and age, ICL size, spherical equivalent (SE), axial length (AL), central corneal thickness (CCT), flat K, steep K, mean K, anterior chamber depth (ACD), crystalline lens thickness (LT), white-to-white (WTW) diameter obtained by three devices, horizontal and vertical sulcus-to-sulcus (STS) diameter, bright and dark pupil sizes (BPS and DPS) and DPS-BPS were investigated using Spearman’s correlation analysis and stepwise multiple regression analysis.Results: The mean vault values at 2 hours, 1 day, 1 week, and 1 month after ICL implantation were 672.05 ± 30.72, 389.15 ± 28.33, 517.23 ± 30.76 and 530.12 ± 30.22 μm, respectively. There were significant differences in vault values between 2 hours, 1 day and 1 week after the operation. ICL size (β = 0.942; p < 0.001), followed by horizontal STS (β = -0.517; p < 0.001), crystalline LT (β = -0.376; p < 0.001) and vertical STS (β = -0.257; p = 0.017), significantly influenced vault at 1 month after the operation. The multiple regression equation was expressed as follows: central vault (μm) = -1369.05+ 657.121 × ICL size- 287.408 × horizontal STS - 432.497 × crystalline LT - 137.33 × vertical STS (adjusted R2 = 0.643).Conclusions: After ICL implantation, vault decreased and then increased, but it did not return to the vault value at 2 hours after surgery. ICL size, horizontal and vertical STS and crystalline LT were key factors for predicting postoperative vaulting.

scholarly journals A Purkinje image-based system for an assessment of the density and transmittance spectra of the human crystalline lens in vivo

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Taisuke Eto ◽  
Petteri Teikari ◽  
Raymond P. Najjar ◽  
Yuki Nishimura ◽  
Yuki Motomura ◽  
...  
Keyword(s):  
Optical Density ◽  
Objective Assessment ◽  
Wavelength Region ◽  
Crystalline Lens ◽  
Older Individuals ◽  
Short Wavelength Region ◽  
Density Spectrum ◽  
Lens Density ◽  
Lens Transmittance

Abstract A method for rapid and objective assessment of ocular lens density and transmittance is needed for research and clinical practice. The aim of this study was to determine whether the Purkinje image-based technique can be used for objective and accurate quantification of spectral density and transmittance of ocular media (the mainly crystalline lens) in visible light. Twenty-six individuals (10 young, 9 middle-aged and 7 older individuals) participated in this study. Spectral lens density was evaluated by detecting the intensity of the IVth Purkinje image for different wavelengths. Subsequently, optical density index (ODI), the area under the curve in the lens density spectrum, was calculated and ODIs were compared with clinical lens opacification scales assessed subjectively using a slit lamp. Spectral lens transmittance was estimated from the lens density spectrum. Lens densities were higher in the short wavelength region of the visible spectrum across all age groups. ODI was highly correlated with the clinical opacification scale, while lens transmittance decreased with aging. Our results showed that spectral transmittance of the human crystalline lens can be easily estimated from optical density spectra evaluated objectively and rapidly using the Purkinje image-based technique. Our results provide clinicians and scientists with an accurate, rapid and objective technique for quantification of lens transmittance.

scholarly journals Investigating the Factors Affecting Myopia in Retinopathy of Prematurity after Laser Treatment

2021 ◽  
Author(s):  
Shotaro Asano ◽  
Tatsuya Inoue ◽  
Kana Kure ◽  
Marie Kitano ◽  
Asahi Fujita ◽  
...  
Keyword(s):  
Retinopathy Of Prematurity ◽  
Matched Control ◽  
Structural Parameters ◽  
Crystalline Lens ◽  
Control Group ◽  
Spherical Equivalent ◽  
Factors Affecting ◽  
Similar Tendency ◽  
The Difference ◽  
Lens Power

Abstract To elucidate the mechanism of myopia development in laser-treated retinopathy of prematurity (ROP) eyes, we investigated the effect of the number of laser shots applied on the myopic variables. A total of 33 eyes of 17 infants with laser-treated ROP were included. Cycloplegic retinoscopic refraction testing was carried out and the spherical equivalent (SE) was calculated. Relationships between SE and various variables (including the number of laser shots applied) were examined. In addition, an age- and axial length (AL)-matched control group without ROP was prepared to compare ocular structural parameters. Although there was no statistical difference in AL between two groups (p = 0.88), SE was significantly more myopic in the ROP group (p < 0.001). SE was associated with AL, corneal refraction (CR), and crystalline lens power (CLP) in the ROP group. Of these three factors (AL, CR, and CLP), only CLP was significantly correlated with the number of laser shots applied (p = 0.003); no correlations were observed between the number of laser shots and AL or CR (p = 0.15 and 0.10, respectively). Very similar tendency was observed in the analysis of the difference between right and left eyes in each child.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

Factors affecting dentist participation in a state Medicaid program

1990 ◽  
Vol 54 (11) ◽  
pp. 638-643 ◽  
Author(s):  
PC Damiano ◽  
ER Brown ◽  
JD Johnson ◽  
JP Scheetz
Keyword(s):  
Medicaid Program ◽  
Factors Affecting

Speech Therapy Services in a Large School System: A Six-Year Overview

1976 ◽  
Vol 7 (4) ◽  
pp. 207-219 ◽  
Author(s):  
Constance P. DesRoches
Keyword(s):  
School System ◽  
Speech Therapy ◽  
Factors Affecting ◽  
Case Load ◽  
Number Of Children ◽  
School Population ◽  
System A ◽  
Therapy Services ◽  
And Shifts ◽  
Selection Factors

A statistical review provides analysis of four years of speech therapy services of a suburban school system which can be used for comparison with other school system programs. Included are data on the percentages of the school population enrolled in therapy, the categories of disabilities and the number of children in each category, the sex and grade-level distribution of those in therapy, and shifts in case-load selection. Factors affecting changes in case-load profiles are identified and discussed.

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