Calvo-Sanz Jorge A, Ruiz-Alcocer Javier, Sánchez-Tena Miguel A
1 Department of Optometry, Instituto de Ciencias Visuales (INCIVI), Madrid, Spain.
2 Universidad Europea de Madrid, Madrid, Spain.
Eur J Ophthalmol. 2018 Sep;28(5):559-565. doi: 10.1177/1120672117754170. Epub 2018 Mar 23.
To compare and analyze the accuracy of the refractive outcomes obtained in intraocular lens power calculation using the classical calculation method with mean keratometry (K) and the calculation method with both K meridians presented in this article.
A total of 62 eyes of 62 subjects who were undergoing cataract surgery were included in this study. Optical biometry was performed using mean K and Haigis formula for classical intraocular lens calculation methods to achieve intraocular lens power; 4 weeks after surgery, prior to medical discharge, subjective refraction was made. Alternatively, intraocular lens power was calculated with bicylindric method using both keratometry readings, obtaining spherocylindrical refractive expected outcomes. Finally, results obtained with intraocular lens calculation methods, bicylindric method, and Haigis formula were compared.
Spherical equivalent calculated by classical intraocular lens calculation methods using Haigis formula (H-SE) was -0.027 ± 0.115 D and using bicylindric method (B-SE) was -0.080 ± 0.222 D. Achieved spherical equivalent obtained 4 weeks after surgery (A-SE) was -0.144 ± 0.268 D. Difference between H-SE and A-SE was -0.117 D (p = 0.002). Difference between B-SE and A-SE was not significant (-0.054 D, p = 0.109). Analysis in refraction groups showed a positive correlation between A-SE confronted to B-SE and H-SE (r = 0.313; p = 0.013 and r = 0.562; p < 0.001, respectively). This indicated a reliability in ametropic group prediction of 0.767 in H-SE and 0.843 in B-SE.
Intraocular lens calculation with bicylindric method could be more accurate and had more reliability than classical intraocular lens calculation method. Bicylindric method adds astigmatism control and provides a reliable expected spherocylindrical refraction.
比较并分析使用平均角膜曲率（K）的经典计算方法与本文介绍的双子午线K计算方法在人工晶状体屈光力计算中获得的屈光结果的准确性。
本研究纳入了62例接受白内障手术患者的62只眼。使用平均K和Haigis公式进行光学生物测量，采用经典的人工晶状体计算方法来确定人工晶状体屈光力；术后4周，出院前进行主观验光。另外，使用双圆柱法根据两个角膜曲率读数计算人工晶状体屈光力，得出球柱面屈光预期结果。最后，比较人工晶状体计算方法、双圆柱法和Haigis公式获得的结果。
使用Haigis公式的经典人工晶状体计算方法计算的等效球镜度（H-SE）为-0.027±0.115D，使用双圆柱法（B-SE）计算的等效球镜度为-0.080±0.222D。术后4周获得的等效球镜度（A-SE）为-0.144±0.268D。H-SE与A-SE之间的差异为-0.117D（p=0.002）。B-SE与A-SE之间的差异无统计学意义（-0.054D，p=0.109）。屈光组分析显示，A-SE与B-SE和H-SE之间呈正相关（r分别为0.313；p=0.013和r=0.562；p<0.001）。这表明在屈光不正组中，H-SE的预测可靠性为0.767，B-SE的预测可靠性为0.843。
与经典的人工晶状体计算方法相比，双圆柱法进行人工晶状体计算可能更准确且可靠性更高。双圆柱法增加了散光控制，并提供了可靠的预期球柱面屈光。
