Tilt and decentration of intraocular lenses in vivo from Purkinje and Scheimpflug imaging - Validation study
Tilt and decentration of intraocular lenses in vivo from Purkinje and Scheimpflug imaging - Validation study
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DOI：
10.1016/j.jcrs.2006.10.054
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发表时间：
2007-03-01
影响因子：
2.8
通讯作者：
Marcos, Susana
中科院分区：
文献类型：
--
作者：
de Castro, Alberto;Rosales, Patricia;Marcos, Susana
目得：在已知倾斜和偏心量的物理模型眼和患者中，使用Scheimpflug和Purkinje成像系统测量人工晶状体（IOL）的倾斜和偏心。使用商业Scheimpflug系统测量IOL倾斜和偏心（Pentacam，Oculus）、定制算法和定制的浦肯野成像装置。25 Scheimpflug图像的眼前段的眼睛，获得了不同的子午线。使用定制算法处理图像（几何失真校正、边缘检测和曲线拟合）。通过将正弦函数拟合到每张图像中的瞳孔轴和IOL轴的投影来估计眼内透镜倾斜和偏心。浦肯野成像系统捕获瞳孔图像，其示出来自角膜前表面以及透镜前表面和后表面的光的反射。使用定制算法检测浦肯野图像位置，并基于线性系统方程和具有个体生物统计学的计算机眼睛模型估计IOL倾斜和偏心。这两种方法均使用物理模型眼进行了验证，其中IOL倾斜和偏心可以标称设置。结果：物理模型眼的测量显示，倾斜度的标称值与测量值之间的绝对差异为0.279度（Purkinje）和0.243度（Scheimpflug），偏心度为0.094 mm（Purkinje）和0.228 mm（Scheimpflug）。在患者中，平均倾斜度小于2.6度，平均偏心小于0.4 mm。这两种技术都显示了右眼和左眼之间的镜像对称的垂直轴周围的倾斜和偏心在水平axies.CONCLUSIONS：这两个系统表现出较高的再现性。验证实验的物理模型的眼睛显示出较高的精度与浦肯野方法比Scheimpflug成像方法。两种技术患者的水平测量高度相关。大多数患者的IOL倾向于向鼻侧倾斜和偏心。
PURPOSE: To measure tilt and decentration of intraocular lenses (IOLs) with Scheimpflug and Purkinje imaging systems in physical model eyes with known amounts of tilt and decentration and patients.SETTING: Instituto de Optica Daza de Valdes, Consejo Superior de Investigaciones Cientificas, Madrid, Spain.METHODS: Measurements of IOL tilt and decentration were obtained using a commercial Scheimpflug system (Pentacam, Oculus), custom algorithms, and a custom-built Purkinje imaging apparatus. Twenty-five Scheimpflug images of the anterior segment of the eye were obtained at different meridians. Custom algorithms were used to process the images (correction of geometrical distortion, edge detection, and curve fittings). Intraocular lens tilt and decentration were estimated by fitting sinusoidal functions to the projections of the pupillary axis and IOL axis in each image. The Purkinje imaging system captures pupil images showing reflections of light from the anterior corneal surface and anterior and posterior lens surfaces. Custom algorithms were used to detect the Purkinje image locations and estimate IOL tilt and decentration based on a linear system equation and computer eye models with individual biometry. Both methods were validated with a physical model eye in which IOL tilt and decentration can be set nominally. Twenty-one eyes of 12 patients with IOLs were measured with both systems.RESULTS: Measurements of the physical model eye showed an absolute discrepancy between nominal and measured values of 0.279 degree (Purkinje) and 0.243 degree (Scheimpflug) for tilt and 0.094 mm (Purkinje) and 0.228 mm (Scheimpflug) for decentration. In patients, the mean tilt was less than 2.6 degrees and the mean decentration less than 0.4 mm. Both techniques showed mirror symmetry between right eyes and left eyes for tilt around the vertical axis and for decentration in the horizontal axis.CONCLUSIONS: Both systems showed high reproducibility. Validation experiments on physical model eyes showed slightly higher accuracy with the Purkinje method than the Scheimpflug imaging method. Horizontal measurements of patients with both techniques were highly correlated. The IOLs tended to be tilted and decentered nasally in most patients.