Top > Search of International Patents > Method of measuring the elasticity of crystalline lens, a method of determining whether crystalline lens is presbyopic, an apparatus for measuring the elasticity of crystalline lens and an apparatus for determining whether crystalline lens is presbyopic

Method of measuring the elasticity of crystalline lens, a method of determining whether crystalline lens is presbyopic, an apparatus for measuring the elasticity of crystalline lens and an apparatus for determining whether crystalline lens is presbyopic UPDATE_EN

Foreign code F190009917
File No. 08168-US
Posted date Aug 26, 2019
Country United States of America
Application number 201414203595
Gazette No. 20150022781
Gazette No. 9254082
Date of filing Mar 11, 2014
Gazette Date Jan 22, 2015
Gazette Date Feb 9, 2016
Priority data
  • P2013-147897 (Jul 16, 2013) JP
Title Method of measuring the elasticity of crystalline lens, a method of determining whether crystalline lens is presbyopic, an apparatus for measuring the elasticity of crystalline lens and an apparatus for determining whether crystalline lens is presbyopic UPDATE_EN
Abstract The present invention provides a method of measuring the elasticity of crystalline lens and an apparatus for measuring the elasticity of the crystalline lens for measuring stiffness of the crystalline lens 1, wherein the crystalline lens 1 is irradiated with pulse laser light to generate photoelastic waves from the crystalline lens 1, and the photoelastic waves from the crystalline lens 1 are measured.
Outline of related art and contending technology BACKGROUND
About half of a total population in Japan, eyes become presbyopia at 40 years old or higher, and most of eye disorders are associated with advancing age.
Under such circumstances, presbyopia is diagnosed by subjective inspection, and quantitative evaluation has not been conducted. Further, since it is difficult to grasp specific progress of presbyopia, presbyopia has not appropriately been medical treated.
For these reasons, quantitative evaluation of presbyopia is desired.
A cause of presbyopia is stiffening denaturation of protein in crystalline lens and following reduction of accommodation capability caused by the stiffened crystalline lens by advancing age.
Therefore, if it is possible to measure elasticity of a crystalline lens, quantitative diagnosis becomes possible.
As methods for measuring characteristics of eyes, research on methods using Raman scattering or stimulated Brillouin scattering is conducted.
According to the method using Raman scattering, stiffness of a crystalline lens and a state of progress of cataract are obtained from an amount of moisture in a crystalline lens.
According to the method using stimulated Brillouin scattering, an elasticity state of a corneae and a crystalline lens by a confocal optical system are obtained.
There is proposed an optical inspection apparatus for irradiating a front portion of an eye ball of a test subject with laser light, and measuring a state of an eye of the test subject from conditions of generated scattering light (Japanese Patent Application Laid-open No. S58-206718 and Japanese Patent Application Laid-open No. H6-217939).
Japanese Patent Application Laid-open No. S58-206718 proposes an eye ball opacity diagnostic apparatus for collecting emitted laser light at one point in an eye ball, receiving generated laser scattering light by a photoelectric conversion element to obtain a time correlation function, and calculating a diameter of protein.
Japanese Patent Application Laid-open No. H6-217939 proposes an ophthalmology measuring apparatus for irradiating an anterior segment of an eye ball with laser light, receiving scattering light from protein molecule or cell existing in aqueous humor in anterior chamber, receiving scattering light from corneae, and quantitatively obtaining protein concentration or cell density in aqueous humor in anterior chamber, and a degree of corneal opacity.
Scope of claims [claim1]
1. A method of measuring the elasticity of crystalline lens for measuring stiffness of the crystalline lens,
wherein the crystalline lens is irradiated with pulse laser light to generate photoelastic waves from the crystalline lens, and the photoelastic waves from the crystalline lens are measured whereby a damping factor of the crystalline lens is calculated,
the crystalline lens is irradiated with interference laser light to generate interference fringe by the photoelastic waves, and elastic modulus of the crystalline lens is calculated based on variation in the interference fringe, and
a wavelength of the pulse laser light is set such that light transmission in the crystalline lens becomes 20% or lower.

[claim2]
2. The method according to claim 1, wherein a wavelength of the pulse laser light is set in a range of 1,400 nm to 2,600 nm.

[claim3]
3. A method of determining whether crystalline lens is presbyopic, wherein elastic modulus of the crystalline lens is calculated by the method according to claim 1, and presbyopia caused by advancing age of the crystalline lens is determined from the calculated elastic modulus.

[claim4]
4. An apparatus for measuring the elasticity of crystalline lens for measuring stiffness of the crystalline lens, comprising:
a pumping laser for irradiating the crystalline lens with pulse laser light,
an interference laser for irradiating the crystalline lens with interference laser light,
a detector for measuring photoelastic waves from the crystalline lens,
a calculating unit for calculating elastic modulus of the crystalline lens, and
a display unit for displaying the elastic modulus calculated by the calculating unit,
wherein the photoelastic waves from the crystalline lens are measured whereby a damping factor of the crystalline lens is calculated.

[claim5]
5. An apparatus for determining whether crystalline lens is presbyopic for determining presbyopia caused by advancing age of the crystalline lens, comprising
a pumping laser for irradiating the crystalline lens with pulse laser light,
an interference laser for irradiating the crystalline lens with interference laser light,
a detector for measuring photoelastic waves from the crystalline lens,
a calculating unit for calculating elastic modulus of the crystalline lens,
a presbyopia determining unit for determining the presbyopia caused by advancing age of the crystalline lens from the elastic modulus calculated by the calculating unit, and
a display unit for displaying the elastic modulus calculated by the calculating unit and determination of presbyopia made by the presbyopia determining unit.
  • Inventor, and Inventor/Applicant
  • WADA Satoshi
  • TSUBOTA Kazuo
  • SHINJO Atsushi
  • RIKEN
IPC(International Patent Classification)

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