7 August 2015 Intraocular lens power estimation by accurate ray tracing for eyes underwent previous refractive surgeries
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For normal eyes without history of any ocular surgery, traditional equations for calculating intraocular lens (IOL) power, such as SRK-T, Holladay, Higis, SRK-II, et al., all were relativley accurate. However, for eyes underwent refractive surgeries, such as LASIK, or eyes diagnosed as keratoconus, these equations may cause significant postoperative refractive error, which may cause poor satisfaction after cataract surgery. Although some methods have been carried out to solve this problem, such as Hagis-L equation[1], or using preoperative data (data before LASIK) to estimate K value[2], no precise equations were available for these eyes. Here, we introduced a novel intraocular lens power estimation method by accurate ray tracing with optical design software ZEMAX. Instead of using traditional regression formula, we adopted the exact measured corneal elevation distribution, central corneal thickness, anterior chamber depth, axial length, and estimated effective lens plane as the input parameters. The calculation of intraocular lens power for a patient with keratoconus and another LASIK postoperative patient met very well with their visual capacity after cataract surgery.
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Que Yang, Que Yang, Shanshan Wang, Shanshan Wang, Kai Wang, Kai Wang, Chunyu Zhang, Chunyu Zhang, Lu Zhang, Lu Zhang, Qingyu Meng, Qingyu Meng, Qiudong Zhu, Qiudong Zhu, } "Intraocular lens power estimation by accurate ray tracing for eyes underwent previous refractive surgeries", Proc. SPIE 9623, 2015 International Conference on Optical Instruments and Technology: Optoelectronic Measurement Technology and Systems, 962311 (7 August 2015); doi: 10.1117/12.2193057; https://doi.org/10.1117/12.2193057

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