Estimating the astigmatic power of the crystalline lens and eye from ocular biometry.

IF 2.8 3区医学 Q1 OPHTHALMOLOGY Ophthalmic and Physiological Optics Pub Date : 2024-09-09 DOI:10.1111/opo.13387

Tanya Evans, Jos J Rozema

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Abstract

Purpose: To estimate the astigmatic power of the crystalline lens and the whole eye without phakometry using a set of linear equations and to provide estimates for the astigmatic powers of the crystalline lens surfaces.

Methods: Linear optics expresses astigmatic powers in the form of matrices and uses paraxial optics and a 4 × 4 ray transfer matrix to generalise Bennett's method comprehensively to include astigmatic elements. Once this is established, the method is expanded to estimate the contributions of the front and back lens surfaces. The method is illustrated using two examples. The first example is of an astigmatic model eye and compares the calculated results to the original powers. In the second example, the method is applied to the biometry of a real eye with large lenticular astigmatism.

Results: When the calculated powers for the astigmatic model eye were compared to the actual powers, the difference in the power of the eye was ${(0.03 0.13 0.04)}^{T} D$ (where T represents the matrix transpose) and for the crystalline lens, the difference was ${(0.08 0.29 0.08)}^{T} D$ (power vector format). A second example applies the method to a real eye, obtaining lenticular astigmatism of -5.84 × 175.

Conclusions: The method provides an easy-to-code way of estimating the astigmatic powers of the crystalline lens and the eye.

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通过眼部生物测量估算晶状体和眼球的散光功率。

目的：使用一组线性方程估算晶状体和整个眼球的散光功率，而无需进行相差测量，并提供晶状体表面散光功率的估算值：方法：线性光学以矩阵的形式表达散光功率，并使用准轴向光学和 4 × 4 射线传输矩阵对贝内特方法进行全面推广，以包含散光元素。一旦确定了这一点，该方法就可以扩展到估算前后透镜表面的贡献。下面用两个例子来说明该方法。第一个例子是散光模型眼，将计算结果与原始功率进行比较。在第二个例子中，该方法被应用于具有较大透镜散光的真眼的生物测量：当散光模型眼的计算功率与实际功率进行比较时，眼睛功率的差异为 0.03 0.13 0.04 T D $$ {left(0.03\kern0.5em 0.13\kern0.5em 0.04\right)}^{mathrm{T}}\ \mathrm{D}}$$（其中 T 代表矩阵转置），而对于晶状体来说，差值为 0.08 0.29 0.08 T D$ {\left(0.08\kern0.5em 0.29\kern0.5em 0.08\right)}^{mathrm{T}}\ \mathrm{D}}$$（功率矢量格式）。第二个示例将该方法应用于一只真实的眼睛，得到-5.84 × 175.结论的透镜散光：该方法提供了一种易于编码的方法来估算晶状体和眼球的散光功率。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Ophthalmic and Physiological Optics 医学-眼科学

CiteScore

5.10

自引率

13.80%

发文量

135

审稿时长

6-12 weeks

期刊介绍： Ophthalmic & Physiological Optics, first published in 1925, is a leading international interdisciplinary journal that addresses basic and applied questions pertinent to contemporary research in vision science and optometry. OPO publishes original research papers, technical notes, reviews and letters and will interest researchers, educators and clinicians concerned with the development, use and restoration of vision.