不同材料及设计的人工晶状体球面像差特性研究

Experimental study of spherical aberrations of intraocular lenses with different materials and designs

目的探讨传统人工晶状体（IOL）材料及设计等因素对其球面像差特性的影响。方法实验室搭建IOL波阵面相差测量光路系统，运用Hartmann-Shack检测仪实施像差测量。将8种不同类型IOL分为2组：不同材料组（SA60AT、AR40e、S140NB、PC330UV）和不同设计组（821T、PCI55、PS53ANB、UV2265N），在3、4、5、6、7mm通光孔径（模拟瞳孔变化）下对每组内每种IOL分别进行连续像差测量，处理并分析其测量结果。结果随通光孔径不断扩大，两组IOL球面像差均线性增大，通光孔径大小与IOL球面像差呈正相关关系（r=0．6465，0．7872；P〈0.01）；在3～7mm通光孔径下，8种IOL中分别有8、5、3、2、2种总像差符合Rayleigh判断。随通光孔径增大，符合量递减。不同材料组中，高折射率丙烯酸酯型IOL球面像差最大（P〈0．01），低折射率的丙烯酸酯型IOL球面像差最小（P〈0．01），硅凝胶型及PMMA型IOL的球面像差介于以上两类IOL之间；不同设计组中，双凸（后〉前）型IOL球面像差最大（P〈0．01），凸平型IOL球面像差最小（P〈0．01），双凸（前〉后）型IOL及双凸（前=后）型IOL球面像差介于以上两种IOL之间。结论不同材料和设计以及不同通光孔径下，IOL的像差特性均发生很大变化，这为IOL的不断改进提供了参考依据。诸因素影响IOL像差的确切机制尚待进一步研究。

Objective To study the characteristics of spherical aberrations （SA） of the traditional intraocular lenses （IOLs） produced by different materials and designs. Methods A special optical metrical system was established in the laboratory to measure the SA of IOLs by using the Hartmann-Shack aberrometer. Eight different types of IOLs were divided into two Groups. Group 1 consisted of 4 types of IOLs made by different materials, Group 2 consisted of 4 types of IOLs made by different designs. SA of these IOLs was measured at 3, 4, 5, 6 and 7 mm apertures separately. All data was analyzed statistically. Results With the size of aperture increased, SA in these two groups was both increased. There were positive correlations between the size of aperture and the SA （ r = 0. 6465,0. 7872 ; P 〈 0. 01 ）. The numbers of IOLs fitted with Rayleigh criterion at apertures of 3, 4, 5, 6, and 7 mm were 8, 5, 3, 2 and 2, respectively. In Group 1, the acrylic IOL （SA60AT） with high refractive index showed the greatest SA, and the acrylic IOL （ AR40e ） with low refractive index showed the smallest SA. The difference of SA between these two IOLs was statistically significant （P 〈0. 01 ）. SA of the silicon IOL （SI40NB） and PMMA IOL （PC330UV） lied between these two extremities. In Group 2, the convexo-convex IOL with the posterior surface more curved than the anterior surface had the greatest SA. The convex-piano IOL had the smallest spherical aberration. The difference of SA between these two IOLs was statistically significant （P 〈 0. 01 ）. SA of convexo-convex IOL with the anterior surface more curved and the epuiconvex IOL was lied between these two extremities. Conclusions IOLs made by different materials and designs under different apertures show significant difference of SA, which is useful for the improvement of optic quality of IOLs. Further studies on the exact mechanism of these differences are required.