Institute of Experimental Ophthalmology, Saarland University, Homburg, Saarland, Germany.
PLoS One. 2018 Jun 14;13(6):e0198824. doi: 10.1371/journal.pone.0198824. eCollection 2018.
To discuss the impact of intraocular lens-(IOL)-power, IOL-thickness, IOL-shape, corneal power and effective lens position (ELP) on the distance between the anterior IOL vertex (ALP) of a thick IOL and the ELP of its thin lens equivalent.
We calculated the ALP of a thick IOL in a model eye, which results in the same focal plane as a thin IOL placed at the ELP using paraxial approximation. The model eye included IOL-power (P), ELP, IOL-thickness (Th), IOL-shape-factor (X), and corneal power (DC). The initial values were P = 10 D (diopter: 1 D = 1 m-1), 20 D, 30 D, Th = 0.9 mm, ELP = 5 mm, X = 0, DC = 43 D. The difference between ALP and the ELP was illustrated as a function of each of the model parameters.
The ALP of a thick lens has to be placed in front of the ELP for P>0 IOLs to achieve the same optical effect as the thin lens equivalent. The difference ALP-ELP for the initial values is -0.57 mm. Minus power IOLs (ALP-ELP = -0.07 mm, for IOL-power = -5 D) and convex-concave IOLs (ALP-ELP = -0.16 mm, for X = 1) have to be placed further posterior. The corneal power and ELP have less influence, but corneal power cannot be neglected.
The distance between ELP and ALP primarily depends on IOL-power, IOL-thickness, and shape-factor.
讨论人工晶状体（IOL）-屈光力、IOL 厚度、IOL 形状、角膜屈光力和有效晶状体位置（ELP）对厚 IOL 前晶状体顶点（ALP）与薄 IOL 等效 ELP 之间距离的影响。
我们使用傍轴近似法计算了模型眼中厚 IOL 的 ALP，该 IOL 产生与放置在 ELP 处的薄 IOL 相同的焦平面。模型眼包括 IOL 屈光力（P）、ELP、IOL 厚度（Th）、IOL 形状因子（X）和角膜屈光力（DC）。初始值为 P = 10 D（屈光度：1 D = 1 m-1）、20 D、30 D、Th = 0.9 mm、ELP = 5 mm、X = 0、DC = 43 D。以各模型参数为函数，展示了 ALP 与 ELP 之间的差值。
对于 P>0 IOL，为了达到与薄透镜等效的相同光学效果，必须将厚透镜的 ALP 放置在 ELP 之前。初始值的 ALP-ELP 差值为-0.57 mm。负屈光力 IOL（ALP-ELP = -0.07 mm，IOL 屈光力=-5 D）和凹凸形 IOL（ALP-ELP = -0.16 mm，X = 1）必须放置在更靠后的位置。角膜屈光力和 ELP 的影响较小，但不能忽略角膜屈光力。
ELP 和 ALP 之间的距离主要取决于 IOL 屈光力、IOL 厚度和形状因子。
