散乱理論と幾何光学的モンテカルロ法を用いた白内障眼の網膜における放射照度シミュレーション  [in Japanese] Optical simulation in the human retina for cataract eye using scattering theory and geometric optics Monte Carlo method  [in Japanese]

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Abstract

<p>幾何光学的なモンテカルロ法により,白内障眼水晶体の波長特性を含む光散乱の評価を行った。Gullstrandの眼球光学モデルの水晶体核に相当する部分に白内障粒子を設定し,複数の入射波長に対する網膜上の放射照度分布を計算した。先行研究で報告されている白内障粒子のパラメータを使用し,粒子の屈折率は1.5,粒子径は1.0 μmと2.0 μm,粒子密度は500,4,000,100,000 /mm<sup>3</sup>,入射波長は400,600,800,1000 nmとした。粒子密度・粒子径が大きくなると,網膜上の点像の最大強度は低下するが,点像の広がりは粒子が無い場合と変わらない結果となった。散乱光は点像に比べて大きく広がるため,点像の広がりへの寄与は小さいことがわかった。また,長波長のほうが最大強度の低下は小さく,また,粒子密度・粒子径が大きくなると,その波長依存が強くなった。</p>

<p>We evaluated the light scattering from crystalline lenses of cataract using geometric optics Monte Carlo method. We used Gullstrand model eye that includes cataract particles in the nucleus of the lenses and calculate irradiance distribution in the retina for multiple incident wavelengths. Diameter, refractive index, and particle density reported in previous studies are used as those of the cataract particles. For the calculation, refractive index of the particles is 1.5; particle diameters are 1.0 μm and 2.0 μm; the particle density are 500, 4,000, 100,000 /mm<sup>3</sup>; the incident wavelengths are 400, 600, 800, 1000 nm. As the particle density and diameter becomes larger, the maximum intensity of the point image on the retina decreases, but the spread of the point image on the retina is the almost same as the case where the lens includes no particle. The simulated result indicates that the scattered light spreads wider than the point image and does not affect the spread of the point image. The maximum intensity decreases slightly for long wavelength. The wavelength dependence becomes significant for large diameter and high density of the particles.</p>

Journal

  • Japanese Journal of Visual Science

    Japanese Journal of Visual Science 39(3), 56-63, 2018

    The Japanese Society of Ophthalmological Optics

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