School of Biomedical Engineering, Capital Medical University, Beijing, China.
Comput Math Methods Med. 2013;2013:572530. doi: 10.1155/2013/572530. Epub 2013 Jul 14.
The tilt and decentration of intraocular lens (IOL) result in defocussing, astigmatism, and wavefront aberration after operation. The objective is to give a method to estimate the tilt and decentration of IOL more accurately. Based on AS-OCT images of twelve eyes from eight cases with subluxation lens after operation, we fitted spherical equation to the data obtained from the images of the anterior and posterior surfaces of the IOL. By the established relationship between IOL tilt (decentration) and the scanned angle, at which a piece of AS-OCT image was taken by the instrument, the IOL tilt and decentration were calculated. IOL tilt angle and decentration of each subject were given. Moreover, the horizontal and vertical tilt was also obtained. Accordingly, the possible errors of IOL tilt and decentration existed in the method employed by AS-OCT instrument. Based on 6-12 pieces of AS-OCT images at different directions, the tilt angle and decentration values were shown, respectively. The method of the surface fitting to the IOL surface can accurately analyze the IOL's location, and six pieces of AS-OCT images at three pairs symmetrical directions are enough to get tilt angle and decentration value of IOL more precisely.
人工晶状体（IOL）的倾斜和偏心会导致术后聚焦不良、散光和波前像差。目的是提供一种更准确估计 IOL 倾斜和偏心的方法。基于手术后十二只眼睛的八例脱位晶状体的 AS-OCT 图像，我们对 IOL 前表面和后表面图像进行拟合得到的数据拟合了球面方程。通过建立 IOL 倾斜（偏心）与仪器采集 AS-OCT 图像的扫描角度之间的关系，计算出 IOL 的倾斜和偏心。给出了每个受试者的 IOL 倾斜角度和偏心值。此外，还得到了水平和垂直倾斜。因此，AS-OCT 仪器所采用的方法可能存在 IOL 倾斜和偏心的误差。基于不同方向的 6-12 张 AS-OCT 图像，分别显示了倾斜角度和偏心值。对 IOL 表面进行曲面拟合的方法可以准确分析 IOL 的位置，并且在三个对称方向上采集六张 AS-OCT 图像就足以更精确地获得 IOL 的倾斜角度和偏心值。
