-
摘要: 本文提出了一种新的角膜面形分析方法，不仅消除了角膜本体厚度对塑形后角膜面形分析的影响，同时也能体现塑形后角膜的不对称性。在角膜前表面高度数据分析中引入基准参考面，以消除角膜本体厚度的影响，进而将塑形后的角膜前表面划分为光学区、转换区和边缘区。分析表明，角膜塑形后的光学区口径为（1.9±0.27） mm，曲率半径为（8.32±0.38） mm；转换区口径为（6.56±0.38） mm，曲率半径为（7.48±0.55） mm；边缘区的曲率半径为（10.49±1.83） mm。角膜塑形后的转换区水平方向屈光能力小于竖直方向的屈光能力，鼻侧屈光能力大于颞侧屈光能力，上侧屈光能力大于下侧屈光能力。利用所得参数建立半定制化的眼模型，对眼模型进行分析，结果表明：角膜塑形后周边呈近视性离焦，各方向的离焦呈非对称性分布，符合临床表现。Abstract: A new method of corneal shape analysis method is proposed. It not only eliminates the influence of corneal thickness on the shape of cornea after orthokeratology, but also reflects the asymmetry of a cornea. A reference surface is introduced into the analysis of the height data of the anterior surface of the cornea to eliminate the influence of corneal thickness. On the basis of above, anterior surface of the cornea is divided into the optical zone, transition zone and peripheral zone. The results show that the optical zone diameter is (1.9±0.27) mm, and the curvature radius is (8.32±0.38) mm; the transition zone diameter is (6.56±0.38) mm, and the curvature radius is (7.48±0.55) mm; the curvature radius of the peripheral zone is (10.49±1.83) mm. After orthokeratology, the horizontal refraction of the transition zone is lower than its vertical refraction. The refraction of the nasal side is greater than that of the temporal side and the refraction of the upper side is greater than that of the lower side. A semi-customized eye model is established based on the obtained parameters and the results show that its peripheral defocus is myopic after orthokeratology and its defocus is asymmetrical in each direction, which is consistent with clinical observations.
-
Key words:
- orthokeratology lens /
- division of cornea /
- peripheral defocus /
- partition algorithm /
- eye model
-
图 1 颞侧方向上不同距离下的相对高度图
Figure 1. Relative height at different distances in the temporal direction
图 3 不同视场下的周边相对离焦。图中下侧水平轴表示水平视场，上侧水平轴表示竖直视场。N代表鼻侧，T代表颞侧，U代表上侧，D代表下侧。垂直的短线代表该点的标准差。
Figure 3. Peripheral relative refractions at different visual field angles. The lower and upper horizontal axes represent horizontal and vertical visual field of view respectively. N, T, U, D represents nasal, temporal, superior and inferior visual field of view respectively. The vertical bar represents the standard deviation at that point.
表 1 Navarro眼模型结构参数
Table 1. Parameters of the Navarro eye model
人眼 位置/mm 半径/mm 折射率 非球面系数 角膜 0 7.72 1.367 −0.26 0.55 6.5 1.337 4 0 晶状体 3.6 10.2 1.42 −3.131 6 7.6 −6 1.336 −1 视网膜 24 −12.5 − − 
下载: 导出CSV
表 2 光学区,转换区和边缘区的平均分区口径、各区曲面曲率半径及分区平均圆心坐标
Table 2. The average zone diameter, radius of curvature and average center coordinates of the optical zone, the transition zone and the peripheral zone (mm)
光学区 转换区 边缘区 分区口径 1.90±0.27 6.56±0.38 >6.56 曲率半径 8.32±0.38 7.48±0.55 10.49±1.83 圆心坐标 Xo 0.01±0.05 0.14±0.14 −0.80±11.14 Yo 8.38±0.50 7.61±0.46 9.39±2.06
下载: 导出CSV
表 3 水平和竖直方向上的光学区、转换区及边缘区平均分区口径及各区曲面的曲率半径
Table 3. Zone diameter and curvature radius of the optical zone, the transition zone and the peripheral zone in the horizontal and vertical directions (mm)
光学区 转换区 边缘区 水平方向 分区口径 0.95±0.14 3.40±0.42 >3.40 曲率半径 8.47±0.30 7.67±0.33 10.67±1.25 竖直方向 分区口径 0.92±0.13 3.41±0.39 >3.41 曲率半径 8.15±0.28 7.56±0.73 11.00±1.58
下载: 导出CSV
表 4 鼻侧、颞侧、上侧和下侧角膜光学区、转换区及边缘的分区口径及曲率半径
Table 4. Zone diameter and curvature radius of the optical zone, the transition zone and the peripheral zone of the nasal,temporal,lower and upper cornea areas (mm)
光学区 转换区 边缘区 鼻侧 分区口径 0.94±0.14 3.41±0.42 >3.41 曲率半径 8.51±0.31 7.17±0.34 10.24±1.41 颞侧 分区口径 0.95±0.15 3.39±0.41 >3.39 曲率半径 8.42±0.27 7.62±0.33 11.11±1.14 上侧 分区口径 0.93±0.14 3.40±0.40 >3.40 曲率半径 8.13±0.48 7.72±0.76 10.59±1.27 下侧 分区口径 0.92±0.13 3.42±0.38 >3.42 曲率半径 8.18±0.16 7.40±0.70 11.01±1.85
下载: 导出CSV
-
[1] SWARBRICK H A. Orthokeratology review and update[J]. Clinical and Experimental Optometry, 2006, 89(3): 124-143. doi: 10.1111/j.1444-0938.2006.00044.x [2] KOFFLER B H, SEARS J J. Myopia control in children through refractive therapy gas permeable contact lenses: is it for real?[J]. American Journal of Ophthalmology, 2013, 156(6): 1076-1081. doi: 10.1016/j.ajo.2013.04.039 [3] CHO P, CHEUNG S W and EDWARDS M. The longitudinal orthokeratology research in children (LORIC) in Hong Kong: a pilot study on refractive changes and myopic control[J]. Current Eye Research, 2005, 30(1): 71-80. [4] WALLINE J J, JONES L A, SINNOTT L T. Corneal reshaping and myopia progression[J]. British Journal of Ophthalmology, 2009, 93(9): 1181-1185. doi:
留言板
尊敬的读者、作者、审稿人, 关于本刊的投稿、审稿、编辑和出版的任何问题, 您可以本页添加留言。我们将尽快给您答复。谢谢您的支持!
| 姓名 | |
|---|---|
| 邮箱 | |
| 手机号码 | |
| 标题 | |
| |
下载:
